Epoxy Group-Functionalized

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Preparation and performance of silica/epoxy groupfunctionalized bio-based elastomer nanocomposite He Qiao, Wenji Xu, Mingyuan Chao, Jun Liu, Weiwei Lei, Xinxin Zhou, Runguo Wang, and Liqun Zhang Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.6b03517 • Publication Date (Web): 06 Jan 2017 Downloaded from http://pubs.acs.org on January 10, 2017

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Preparation and performance of silica/epoxy group-functionalized bio-based elastomer nanocomposite

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He Qiao,a,b Wenji Xu,a,b Mingyuan Chao,b Jun Liu,a,b Weiwei Lei,a,b Xinxin Zhou,a,b

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Runguo Wang, b * Liqun Zhang a, b*

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a

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Technology, Beijing 100029, China

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b

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Materials, Beijing 100029, China

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State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical

Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer

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KEYWORDS: bio-based elastomer; silica; interfacial interaction

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ABSTRACT:

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itaconate-ter-isoprene-ter-glycidyl methacrylate) (PDBIIG) was synthesized via redox

23

emulsion

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group-included monomer. The silica/PDBIIG nanocomposite was prepared without

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adding silane coupling agents. Ring-opening reaction, which occurred between the

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hydroxyl groups on the silica surfaces and the epoxy groups of the PDBIIG chains during

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mixing and vulcanization, was confirmed via bound rubber tests and Fourier transform

28

infrared spectroscopy. This reaction was facilitated through heat treatment at 150 °C

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effectively. The introduction of covalent bonds significantly improved the interfacial

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interaction and dispersion of silica, which was indicated by transmission electron

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microscopy and rubber process analyzer (RPA) results. With the same silica loading and

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compounding procedure, the inclusion of 3.7 wt.% GMA increased the modulus at 100%

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strain by 150.0% and the modulus at 300% strain by 152.3%. For the dynamic

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mechanical properties, the nanocomposite with GMA exhibited higher wet skid resistance

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and lower rolling resistance than the nanocomposite without GMA.

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1. Introduction

Epoxy

group-functionalized

polymerization

using

glycidyl

bio-based

methacrylate

elastomer

(GMA)

poly

as

the

(dibutyl

epoxy

37

Elastomers have excellent elasticity and play a significant role in national defense,

38

industries, and daily living. With the dwindling fossil resources, soaring energy demand, 2

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and growing environmental concerns, bio-based elastomers derived from renewable

40

resources have attracted increasing attention1-3. Natural rubber is a typical bio-based

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elastomer, which is directly acquired from the natural rubber tree Hevea brasiliensis.

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However, natural rubber faces several serious problems, such as the harsh growth

43

conditions of rubber trees, fungal disease threat to rubber trees, and increasing allergic

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reactions to the proteins in natural rubber 4; thus, the development of bio-based

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synthesized elastomers, particularly those for engineering applications, is highly

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important and urgent 5. Several types of bio-based synthesized elastomers, including polyester elastomers 6-10,

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11-17

itaconic acid-based elastomers

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rubber 22, have been developed in recent years. The present study is related to an itaconic

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acid-based elastomer poly (dibutyl itaconate-co-isoprene) (PDBII) and its relevant

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nanocomposites. Itaconic acid is a bio-based building block chemical with multiple

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functional groups; this acid is produced industrially through the fermentation of sugars23,

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24

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are promising bio-based monomers for bio-based elastomers 11-15. Comonomer isoprene is

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used to increase the flexibility of macromolecular chains and to provide crosslink points

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for elastomers. Bio-isoprene from renewable resources is expected to become available in

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the market in the near future because of numerous efforts devotedly working on it 22, 25.

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, polyurethane elastomers

18-21

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, and the bio-isoprene

. Itaconate esters made through the esterification of itaconic acid and bio-based alcohols

The addition of a filler is necessary to improve elastomer properties 3

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. Silica is a

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non-petroleum-based filler and is widely used in the rubber industry because it can

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provide excellent mechanical properties, low rolling resistance, and high wet skid

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resistance

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polar silica is prone to agglomerating because of its abundant surface hydroxyl groups,

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thereby leading to the poor dispersion of silica and the weak interfacial interaction

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between silica and elastomers 30, 31. The most common method to solve these problems is

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to use silane coupling agents, such as bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si69) and

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3-(mercaptopropyl trimethoxysilane (KH590), which can modify the silica surface and

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link silica with elastomer macromolecules

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(VOCs), such as methanol and ethanol, are released during high-temperature silanization

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at approximately 150 °C 32, 35, 36; these compounds are harmful to the environment and to

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operators. The functionalization of the elastomer matrix can also improve the dispersion

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of silica and the interfacial interaction between silica and elastomer. The hydroxyl groups

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on the silica surface are numerous; hence, if we endow the bio-based PDBII with

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functional groups that can react directly with the hydroxyl groups, then interfacial

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interaction improves by forming covalent bonds at the interfaces. The dispersion of silica

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can also be improved. The ring-opening reaction between the epoxides and hydroxyl

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groups of silica occurs with the help of a mechanical force and increased temperature 37-41.

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Thus, we intend to functionalize PDBII with epoxy groups. The addition of epoxy

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group-included comonomer in the polymerization can realize this idea easily. Glycidyl

28, 29

. The present study used silica to reinforce bio-based PDBII. However,

31-34

. However, volatile organic compounds

4

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methacrylate (GMA) is a bifunctional chemical with a double bond and an epoxy group.

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It was chosen as the appropriate third comonomer for PDBII in this study. The terpolymer

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poly (dibutyl itaconate-ter-isoprene-ter-glycidyl methacrylate) (PDBIIG) was designed as

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the matrix of the silica-filled nanocomposite. The designed schematic is shown in Figure

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1.

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In the present work, epoxy group-functionalized bio-based elastomer PDBIIG was

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synthesized via mild free-radical redox emulsion polymerization, and silica/PDBIIG

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nanocomposite was prepared via simple mechanical blending. Silica was covalently

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linked with PDBIIG because of the ring-opening reaction between silica and PDBIIG.

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The direct matrix–filler linkage avoids the addition of any silane coupling agent and

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inhibits the release of VOCs during processing. The ring-opening reaction between silica

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and PDBIIG during mixing and vulcanization was discussed and affirmed. The effects of

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the covalent bonding interfaces on the interfacial interaction between silica and elastomer,

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the dispersion of silica, the dynamic mechanical properties, and the static mechanical

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properties of the nanocomposite were investigated. Our research on elastomer

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functionalization through polymerization to improve interfacial interaction between the

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filler and the matrix provides a new idea for preparing nanocomposite with desired

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properties.

97

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Figure 1. Designed schematic of the nanocomposite with covalent linkage between silica and the elastomer.

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2. Experimental section

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2.1. Materials

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Dibutyl itaconate (96%) was bought from Sigma-Aldrich. Isoprene (99%) was

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bought from Alfa Aesar and distilled before use. GMA (97%) was bought from

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Sigma-Aldrich and passed through a neutral alumina column before use. Sodium dodecyl

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benzene sulfonate (SDBS, 95%) was purchased from Aladdin. Ferric ethylene diamine

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tetraacetic acid salt (Fe-EDTA), sodium hydroxymethanesulfinate (SHS), tert-butyl

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hydroperoxide (TBH), and hydroxylamine (HA) were bought from Sigma-Aldrich and

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used as received. The precipitated silica (Ultrasil VN3) with a BET specific surface of

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175 m2/g and a particle size of 20–30 nm was bought from Degussa Chemical. Other

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materials used were of analytical grade and commercially available.

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2.2. Synthesis of PDBII and PDBIIG

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Figure 2. Polymerization reaction of PDBIIG.

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Bio-based PDBIIG was synthesized via free-radical emulsion polymerization under

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20 °C based on the formula shown in Table S1. The polymerization reaction is shown in

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Figure 2. In a three-neck glass flask, deionized water, SDBS solution, Fe-EDTA solution,

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SHS solution, and a mixture of the monomers (dibutyl itaconate, isoprene, and GMA)

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were added under nitrogen atmosphere, and the emulsion system was stirred at 400 rpm

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for 1 h. The initiator TBH was then added, and the stirring rate was reduced to 250 rpm.

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After 12 h, the polymerization reaction was terminated with HA, and the PDBIIG latex

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was obtained. The PDBIIG latex was then flocculated with ethanol to acquire the wet

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PDBIIG elastomer, which was dried in a vacuum oven for 24 h at 60 °C. The PDBII

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elastomer was also synthesized in the same way except for the addition of GMA to

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compare with the PDBIIG elastomer.

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2.3. Preparation of nanocomposites

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The compounding formulation for silica/PDBII and silica/PDBIIG is shown in Table

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S2. First, silica was mixed with the elastomer in a Haake internal mixer at 30 °C for 10

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min. The silica/PDBII (silica/PDBIIG) mixture was taken out and cooled down to room

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temperature. Second, the other additives were mixed with the silica/PDBII 7

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(silica/PDBIIG) mixture at 30 °C to obtain the silica/PDBII (silica/PDBIIG) compound.

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Finally, the compound was vulcanized at 150 °C under 15 MPa to obtain the silica/PDBII

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(silica/PDBIIG) nanocomposite. The optimum curing time of the compound was

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determined using a disc vulkameter. A silica/PDBIIG-150 nanocomposite was also

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prepared to investigate the reaction between PDBIIG and silica. The silica/PDBIIG

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mixture obtained at the first step was added to the Haake internal mixer at 150 °C and

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treated for 5 min to facilitate further reaction between PDBIIG and silica. The obtained

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silica/PDBIIG-150 mixture was then taken out and cooled down to room temperature.

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The subsequent steps were the same as those for silica/PDBIIG. The neat PDBII and

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PDBIIG elastomers were also compounded and vulcanized in the same manner as the

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silica/PDBII (silica/PDBIIG) nanocomposite except for the addition of silica.

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2.4. Measurements and characterization

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1

H nuclear magnetic resonance (1H NMR) measurements were obtained using a

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Bruker AV400 spectrometer with CDCl3 as the solvent. Fourier transform infrared (FTIR)

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spectra were collected on a Bruker Tensor 27 spectrometer. Differential scanning

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calorimetry (DSC) was conducted with a Mettler-Toledo DSC instrument under nitrogen.

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The sample was heated to 100 °C and kept isothermal for 3 min to remove the previous

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history. Then, it was cooled to −100 °C and reheated to 100 °C. The heating (cooling)

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rate was 10 °C/min. Gel permeation chromatography was performed with a Waters

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Breeze instrument equipped with three columns (Styragel HT3_HT5_HT6E) and a 8

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refractive index detector. Tetrahydrofuran was used as the eluent with a flowing rate of

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1.0 mL/min, and polystyrene standards were used for calibration. The morphologies of

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the nanocomposites were observed using a Tecnai G2 20 S-TWIN transmission electron

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microscope (TEM) at an acceleration voltage of 200 KV, and the ultrathin sections were

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cut with an EM UC7/FC7 microtome at −100 °C. The strain sweep measurements of the

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compounds and the nanocomposites were analyzed with an RPA 2000 at 60 °C, and the

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test frequency was 1 Hz. The dynamic mechanical thermal properties were implemented

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on a 01dB-Metravib VA 3000 dynamic mechanical thermal analyzer at 10 Hz under the

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strain amplitude of 0.1% in a tension mode. The temperature was scanned from −80 °C to

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80 °C with a heating rate of 3 °C/min. The mechanical properties were implemented

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using a SANS CMT 4104 electrical tensile instrument at 25 °C with a tensile rate of 500

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mm/min according to ASTM D412. The bound rubber tests were measured based on the

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previously reported methods 42.

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3. Results and discussion

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3.1. Structure and characterization of PDBIIG

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Table 1 Yields, compositions, and molecular weights of PDBII and PDBIIG. Sample

Yield (%)

GMA content in feed (wt.%)

Actual GMA content in PDBIIG (wt.%)

Mn (g/mol)

PDI

PDBII

89

0

0

475000

2.5

PDBIIG

92

5

3.7

397000

2.2

The bio-based elastomer PDBIIG was successfully synthesized via a mild redox 9

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free-radical emulsion polymerization. After polymerization for 12 h, the yields of PDBII

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and PDBIIG reached 89% and 92%, respectively. Table 1 shows that the number-average

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molecular weight (Mn) of PDBII is 475000 g/mol with a polydispersity index (PDI) of 2.5,

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whereas the Mn of PDBIIG is 397000 g/mol with a PDI of 2.2. The actual GMA content

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of PDBIIG was estimated by NMR. The result shows that the GMA content in the

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elastomer is lower than that in the feed.

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Figure 3. FTIR spectra of PDBII and PDBIIG.

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The chemical structure of PDBIIG was determined by FTIR and 1H NMR. Figure 3

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shows the FTIR spectra of PDBII and PDBIIG. The two spectra present similar

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absorption peaks. The peaks at 1173 cm−1 and 1728 cm−1 belong to the C-O-C and C=O

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stretching vibrations of dibutyl itaconate, respectively. The peak at 1663 cm−1 is

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attributed to the C=C stretching vibration of isoprene. The peaks at 844 cm−1 and 1350

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cm−1 are assigned to the C-H out-of-plane and in-plane deformation vibrations of the 10

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double bonds of isoprene, respectively. The peaks at 739 cm−1 and 967 cm−1 correspond

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to the C-H deformation vibration of the cis-1,4 structures and trans-1,4 structures of

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isoprene, respectively. The small difference of the two spectra lies on the weak peak at

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908 cm−1, which corresponds to the ring vibration of the epoxy group. The structure of

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PDBIIG was further confirmed by 1H-NMR. The spectra and the detailed assignments of

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each peak to the molecular structure are shown in Figure 4. The small peaks at 2.82, 3.20,

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and 3.82 ppm originate from the protons of an epoxy group and its adjacent methylene.

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The results of the FTIR and 1H-NMR verify that GMA has been successfully introduced

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into the PDBII chains.

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Figure 4. 1H-NMR spectra of PDBII and PDBIIG.

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The glass transition temperature (Tg) of PDBII and PDBIIG was obtained using DSC

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thermograms (Figure 5). The introduction of GMA increases the Tg of the elastomer.

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Moreover, neither of the two curves shows any crystallization peak, which indicates that

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the elastomers are amorphous. 11

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Figure 5. DSC curves of PDBII and PDBIIG. 3.2. Characterization of nanocomposites

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Figure 6. Bound rubber contents of silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150 compounds.

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Bound rubber is the rubber absorbed on the filler surfaces. The interaction between

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the filler and the rubber leads to the formation of bound rubber; bound rubber

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significantly affects filler reinforcement

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silica/PDBIIG, and silica/PDBIIG-150 compounds were measured. Figure 6 shows that

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the introduction of GMA considerably increases bound rubber content, and the additional

43

. The bound rubber contents of silica/PDBII,

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heat treatment at 150 °C further increases bound rubber content. Bound rubber

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measurements were conducted on unvulcanized compounds; hence, we can speculate a

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ring-opening reaction between PDBIIG and silica during the mixing process, and the heat

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treatment further facilitates the reaction. The results of the bound rubber content indicate

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that the interfacial interaction in silica/PDBIIG is stronger than that in silica/PDBII

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because of the introduction of covalent bonds between silica and the matrix. Moreover,

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the shear force during mixing with a high temperature facilitates the ring-opening

218

reaction between silica and PDBIIG.

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Figure 7. FTIR spectra of (a) PDBIIG, (b) silica/PDBIIG compound, (c) silica/PDBIIG nanocomposite, (d) silica/PDBIIG-150 compound, (e) silica/PDBIIG-150 nanocomposite, and (f) silica/PDBII compound. (All the test samples were prepared using an identical procedure, as described in Section 2.3, but without the addition of any rubber ingredient to avoid interference peaks.) The

FTIR

spectra the

of

the

silica/PDBIIG

silica/PDBIIG-150

compound,

compound,

and

silica/PDBIIG

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nanocomposite,

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nanocomposite were obtained to further investigate the reaction between silica and 13

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the

silica/PDBIIG-150

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PDBIIG during the preparation of the nanocomposites. The corresponding spectra are

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shown in Figure 7. All the spectra were normalized with the peak of the C=O stretching

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vibration at 1728 cm−1. The intensity variation of the peak of the epoxy group ring

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vibration at 908 cm−1 was used to characterize the ring-opening reaction between the

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epoxy groups of PDBIIG and the hydroxyl groups of silica. The intensity of the peak at

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908 cm−1 for the silica/PDBIIG compound (b) is slightly lower than that for the neat

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PDBIIG (a), thereby indicating the ring-opening reaction between PDBIIG and silica

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during the mixing process. After vulcanization, the intensity of the peak at 908 cm−1 of

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silica/PDBIIG (c) continuously decreases, which indicates that the ring-opening reaction

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proceeds during the hot-press process at 150 °C. The comparison between (b) and (d)

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shows that the intensity of the peak at 908 cm−1 of the silica/PDBIIG-150 compound is

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lower than that of the silica/PDBIIG compound, thereby indicating that the additional hot

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treatment with shear force and temperature effectively facilitates ring-opening reaction,

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which is consistent with the result of the bound rubber content mentioned earlier. The

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subsequent vulcanization further promotes the reaction, and the peak at 908 cm−1 of the

244

silica/PDBIIG-150 nanocomposite (e) nearly disappears similar to that of the

245

silica/PDBII compound (f), which indicates that the ring-opening reaction between silica

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and PDBIIG is nearly complete. The FTIR results of all the compounds and the

247

nanocomposites manifest that the reaction between silica and PDBIIG occurs in the

248

mixing and vulcanization processes. The hot treatment at 150 °C will make the reaction 14

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The dispersion of the filler in the matrix is an important factor for a composite to

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achieve high performance. The TEM micrographs shown in Figure 8 exhibit the

252

dispersion of silica in PDBIIG and PDBII. The dark spots in the micrographs are silica

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particles. Figure 8(a) shows that the dispersion of silica in PDBII is poor with a few

254

aggregates and voids. The introduction of GMA significantly improves the dispersion of

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silica. Figures 8(b) and 8(c) show that silica disperses uniformly in PDBIIG without any

256

evident aggregates and voids. The significant improvement of dispersion is attributed to

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the formation of covalent bonds between silica and PDBIIG in the silica-filled PDBIIG

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nanocomposites.

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Figure 8. TEM micrographs of (a) silica/PDBII, (b) silica/PDBIIG, and (c) silica/PDBIIG-150 nanocomposites.

Figure 9. Strain amplitude dependence of (a) G′ of unvulcanized PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150; and (b) tan δ of vulcanized PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150. RPA was used to investigate the effect of covalent bonding interfaces on the filler 16

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network, which consists of the filler–filler network and the filler–rubber network, and the

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interfacial interaction between silica and PDBIIG. Figure 9 shows the strain amplitude

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dependence of the G′ of the unvulcanized compounds and the tan δ of the vulcanized

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PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150. Little difference

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exists between PDBII and PDBIIG in the RPA results. In the filled elastomers, the

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structure of the filler–filler networks can be reflected by the Payne effect

274

referred to as the strain dependence of G′. G′ decreases sharply when the filler–filler

275

networks are broken after the strain reaches a critical value.

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initial G′ of the silica/PDBII compound is the highest, and the Payne effect is evident,

277

which indicates that the filler–filler networks are strong in silica/PDBII because of the

278

poor dispersion of silica. The introduction of GMA effectively reduces the Payne effect,

279

and silica/PDBIIG and silica/PDBIIG-150 are less strain-dependent than silica/PDBII,

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thereby indicating the improved dispersion of silica. Although the shapes of the curves of

281

silica/PDBIIG and silica/PDBIIG-150 are similar with long plateau regions of G′, the G′

282

of silica/PDBIIG-150 is higher than that of silica/PDBIG. This finding can be attributed

283

to the presence of more covalent bonds between silica and PDBIIG in silica/PDBIIG-150;

284

hence, the interfacial interaction between silica and PDBIIG in silica/PDBIIG-150 is

285

stronger than that in silica/PDBIIG. The strong interfacial interaction strengthens the

286

filler–rubber networks and restrains the mobility of the macromolecular chains, which

287

leads to an increase in G′. The tan δ of the vulcanized nanocomposites is presented in 17

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, which is

Figure 9(a) shows that the

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Figure 9(b). The minimal difference is between the tan δ of silica/PDBII and

289

silica/PDBIIG at a low strain value (less than 1%). With increasing strain, the tan δ of

290

silica/PDBII increases sharply, whereas the tan δ of silica/PDBIIG increases gradually.

291

The different tendencies of tan δ with increasing strain between silica/PDBII and

292

silica/PDBIIG is attributed to the different filler network structures. The poor dispersion

293

of silica in silica/PDBII leads to strong filler–filler networks, which are easily destroyed

294

with increasing strain. The destruction of strong filler–filler networks increases filler–

295

filler friction, and the weak interfacial interaction increases filler–rubber friction

296

which leads to the high tan δ at high strain. The improved interfacial interaction and

297

dispersion of silica in silica/PDBIIG contribute to the strong filler–rubber networks and

298

few filler–filler networks. Thus, the tan δ of silica/PDBIIG is lower than that of

299

silica/PDBII at high strain. The interfacial interaction between silica and PDBIIG is

300

stronger in silica/PDBIIG-150 than in silica/PDBIIG. Hence, the filler–rubber friction in

301

silica/PDBIIG-150 is further decreased, and the value of tan δ is lower.

302

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303 304 305 306

Figure 10. Vulcanization curves of the PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150 nanocomposites.

307

Figure 10 shows the vulcanization curves of the PDBII, PDBIIG, silica/PDBII,

308

silica/PDBIIG, and silica/PDBIIG-150 nanocomposites. The corresponding vulcanization

309

characteristics are summarized in Table S3. The minimum torque (ML) and the maximum

310

torque (MH) of the neat PDBIIG are nearly the same as those of the neat PDBII. However,

311

the curing time of PDBIIG is longer than that of PDBII. All the rubber additives and

312

operations are the same; therefore, the increase in curing time is attributed to the presence

313

of the epoxy groups, which may react with the rubber accelerators

314

their accelerating effect on vulcanization. The addition of silica evidently extends the

315

curing time. Delayed vulcanization results from the adsorption of the accelerators on the

316

silica surfaces. The curing time of silica/PDBIIG is longer than that of silica/PDBII

317

because of the probable reaction between the epoxy groups and the accelerators. The

318

curing time of silica/PDBIIG-150 is shorter than that of silica/PDBIIG. The decrease in

319

the curing time of silica/PDBIIG-150 is attributed to the additional mixing at 150 °C, 19

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, and thus, reduce

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during which more epoxy groups in PDBIIG react with silica, such that fewer epoxy

321

groups react with the accelerators during the vulcanization process. The torque of

322

silica/PDBIIG is significantly lower than that of silica/PDBII because filler–filler

323

networks are less in silica/PDBIIG. The interfacial interaction in silica/PDBIIG-150 is

324

stronger; hence, its torque values are higher than those of silica/PDBIIG. The torque

325

difference (MH−ML) of the vulcanization curve is closely related to crosslink density. The

326

two neat elastomers exhibit similar crosslink densities. In the silica-filled nanocomposites,

327

crosslink densities increase with the increase in interfacial interaction.

328

3.3. Performance of the nanocomposites

329 330 331 332 333 334

Figure 11. Temperature dependence of (a) E′ of the PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, silica/PDBIIG-150, and silica/PDBII-Si69 nanocomposites; and (b) tan δ of the PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, silica/PDBIIG-150, and silica/PDBII-Si69 nanocomposites.

335

The dynamic mechanical thermal properties of the PDBII, PDBIIG, silica/PDBII,

336

silica/PDBIIG, and silica/PDBIIG-150 nanocomposites are shown in Figure 11. With the

337

exception of the slightly higher Tg and lower tan δ at Tg, minimal difference is observed 20

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between the two neat elastomers in the temperature dependence of E′ and tan δ. The

339

curves change significantly after silica is added. Figure 11(a) represents the temperature

340

dependence of E′ of the PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, and

341

silica/PDBIIG-150 nanocomposites. The high E′ of silica/PDBII at the rubbery region is

342

attributed to the strong filler–filler networks that result from the poor dispersion of silica.

343

The E′ of silica/PDBIIG-150 is higher than that of silica/PDBIIG because of the

344

improved interfacial interaction between silica and PDBIIG. This finding is consistent

345

with the RPA results. The temperature dependence of the tan δ of the PDBII, PDBIIG,

346

silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150 nanocomposites is shown in Figure

347

11(b) and summarized in Table 2. The Tg and the highest tan δ at Tg increase significantly

348

after the introduction of GMA into PDBII. The increase in Tg is attributed to the

349

strengthened filler–rubber networks resulting from the improved dispersion of silica and

350

interfacial interaction, which confines the mobility of the polymer chains. The confined

351

mobility of the polymer chains also decreases the highest tan δ at Tg. However, the

352

improved dispersion of silica increases the rubber fraction that participates in chain

353

segment relaxation by decreasing the amount of macromolecular chains trapped in the

354

filler–filler networks 45, 48, thereby increasing the highest tan δ at Tg. In silica/PDBIIG, the

355

second factor is dominant, and the highest tan δ at Tg of silica/PDBIIG is higher than that

356

of silica/PDBII. The Tg of silica/PDBIIG-150 is nearly the same as that of silica/PDBIIG,

357

whereas the highest tan δ at Tg of silica/PDBIIG-150 is lower because of the improved 21

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interfacial interaction between silica and PDBIIG in silica/PDBIIG-150. It is widely

359

accepted in tire industry that the high tan δ at 0 °C indicates good wet skid resistance, and

360

the low tan δ at 60 °C indicates low rolling resistance

361

silica/PDBIIG nanocomposite exhibits significantly better wet skid resistance and lower

362

rolling resistance than silica/PDBII. The wet skid resistance of silica/PDBIIG-150 is

363

slightly lower than that of silica/PDBIIG given the lower tan δ at Tg. Moreover, the

364

silica-filled PDBII nanocomposite which contains 5 phr of Si69 (silica/PDBII-Si69) is

365

also prepared. The Tg and tan δ values of silica/PDBII-Si69 are presented in Table 2. The

366

comparison shows that silica/PDBIIG performs better than silica/PDBII-Si69 in terms of

367

wet skid resistance and rolling resistance. It is worth mentioning that the silica/PDBIIG

368

nanocomposite exhibits excellent wet skid resistance property compared with other

369

silica-filled traditional rubber composites 42, 51-55.

370 371

49, 50

. Table 2 shows that the

Table 2 Tg and tan δ values of the silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150 nanocomposites. Sample

Tg (°C) Tan δ at 0 °C Tan δ at 60 °C

Silica/PDBII

−16.5

0.553

0.155

Silica/PDBIIG

−5.3

1.035

0.123

Silica/PDBIIG-150

−5.4

0.954

0.122

Silica/PDBII-Si69

−12.4

0.546

0.152

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372 373 374 375

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Figure 12. Stress–strain curves of the PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, silica/PDBIIG-150, and silica/PDBII-Si69 nanocomposites.

376

The stress–strain curves of PDBII, PDBIIG, silica/PDBII, silica/PDBIIG,

377

silica/PDBIIG-150, and silica/PDBII-Si69 are displayed in Figure 12 and summarized in

378

Table S4. The mechanical properties of the neat PDBII and PDBIIG are similar and poor,

379

and the addition of silica significantly improves the mechanical properties of PDBII and

380

PDBIIG. Moreover, silica/PDBIIG exhibits better mechanical properties than

381

silica/PDBII because of the strong interfacial interaction and the good dispersion of silica.

382

With the same silica loading and procedure, the inclusion of 3.7 wt.% GMA increases the

383

modulus at 100% strain by 150% and the modulus at 300% strain by 152.3%. The low

384

elongation at break of silica/PDBIIG results from the strong interfacial interaction

385

because the slippage of the polymer chains is restricted. The interfacial interaction of

386

silica/PDBIIG-150 is stronger than that of silica/PDBIIG. Thus, the elongation at break of

387

silica/PDBIIG-150 is lower and the modulus of silica/PDBIIG-150 is higher. The 23

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388

mechanical properties of silica/PDBII-Si69 were also measured. Silica/PDBIIG performs

389

better than silica/PDBII-Si69 in modulus at 100% strain. However, the tensile strength of

390

silica/PDBIIG is slightly lower compared with other traditional rubber composites 31, 42, 48,

391

51-55

.

392 393

4. Conclusions

394

Epoxy group-functionalized bio-based elastomer PDBIIG was synthesized via

395

free-radical redox emulsion polymerization, and silica/PDBIIG nanocomposite was

396

prepared without the addition of silane coupling agents. The dispersion of silica in the

397

elastomer matrix and the interfacial interaction between silica and the elastomer was

398

improved significantly after the introduction of epoxy groups into PDBII. The

399

improvements were attributed to the ring-opening reaction between the hydroxyl groups

400

of silica and the epoxy groups of PDBIIG. Heat treatment at 150 °C facilitated the

401

ring-opening reaction, which further improved the interfacial interaction between silica

402

and PDBIIG. Silica/PDBIIG demonstrated better wet skid resistance, lower rolling

403

resistance, and better mechanical properties than silica/PDBII because of the strong

404

covalent bonding interfacial interaction and the uniform dispersion of silica. Moreover,

405

silica/PDBIIG performed better than silica/PDBII-Si69 in dynamic and static mechanical

406

properties. Silica/PDBIIG nanocomposite may have great potential in tire application

407

after our effort to further improve its comprehensive properties in the future. 24

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ASSOCIATED CONTENT

409

Supporting Information

410

The Supporting Information is available free of charge on the ACS Publications website

411

at DOI:

412

Formulation for the emulsion polymerization of PDBII and PDBIIG. Formulation for the

413

silica/PDBII and silica/PDBIIG nanocomposites. Vulcanization characteristics of the

414

PDBII, PDBIIG, silica/PDBII, silica/PDBIIG, and silica/PDBIIG-150 nanocomposites.

415

Mechanical

416

silica/PDBIIG-150, and silica/PDBII-Si69 nanocomposites (PDF)

417

AUTHOR INFORMATION

418

Corresponding Author

419

*

420

Wang)

421

Author Contributions

422

The manuscript was written through contributions of all authors. All authors have given

423

approval to the final version of the manuscript.

424

Funding Sources

425

This work was supported by the National Natural Science Foundation of China

426

(50933001 and 51221002), the Key Program of Beijing Municipal Science and

properties

of

the

PDBII,

PDBIIG,

silica/PDBII,

silica/PDBIIG,

E-mail: [email protected] (Liqun Zhang), [email protected] (Runguo

25

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Technology Commission (D14110300230000), and the Joint Development Project of

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Beijing Municipal Education Commission (JWGJ201602).

429

References

430

(1) Ragauskas, A. J.; Williams, C. K.; Davison, B. H.; Britovsek, G.; Cairney, J.; Eckert,

431

C. A.; Frederick, W. J.; Hallett, J. P.; Leak, D. J.; Liotta, C. L. The path forward for

432

biofuels and biomaterials. Science 2006, 311, 484-489.

433

(2) Hermann, B.; Blok, K.; Patel, M. K. Producing bio-based bulk chemicals using

434

industrial biotechnology saves energy and combats climate change. Environ. Sci. Technol.

435

2007, 41, 7915-7921.

436

(3) Gandini, A. Polymers from renewable resources: a challenge for the future of

437

macromolecular materials. Macromolecules 2008, 41, 9491-9504.

438

(4) Van Beilen, J. B.; Poirier, Y. Establishment of new crops for the production of natural

439

rubber. Trends Biotechnol. 2007, 25, 522-529.

440

(5) Wang, R.; Zhang, J.; Kang, H.; Zhang, L. Design, preparation and properties of

441

bio-based elastomer composites aiming at engineering applications. Compos. Sci. Technol.

442

2016, 133, 136-156.

443

(6) Wu,

444

poly(glycerol-sebacate-citrate)

445

adjustable degradability, and better biocompatibility. J. Appl. Polym. Sci. 2012, 123,

446

1612-1620.

Y.;

Shi,

R.;

Chen,

D.;

Zhang,

elastomers

with

L.;

Tian,

improved

26

ACS Paragon Plus Environment

W.

Nanosilica

mechanical

filled

properties,

Page 27 of 34

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

447

(7) Wei, T.; Lei, L.; Kang, H.; Qiao, B.; Wang, Z.; Zhang, L.; Coates, P.; Hua, K.-C.;

448

Kulig, J. Tough Bio-Based Elastomer Nanocomposites with High Performance for

449

Engineering Applications. Adv. Eng. Mater. 2012, 14, 112-118.

450

(8) Lei, L.; Li, L.; Zhang, L.; Chen, D.; Tian, W. Structure and performance of

451

nano-hydroxyapatite

452

elastomers. Polym. Degrad. Stab. 2009, 94, 1494-1502.

453

(9) Kang, H.; Li, X.; Xue, J.; Zhang, L.; Liu, L.; Xu, R.; Guo, B. Preparation and

454

characterization of high strength and noncytotoxic bioelastomers containing isosorbide.

455

RSC Adv. 2014, 4, 19462-19471.

456

(10) Hu, X.; Kang, H.; Li, Y.; Li, M.; Wang, R.; Xu, R.; Qiao, H.; Zhang, L. Direct

457

copolycondensation of biobased elastomers based on lactic acid with tunable and

458

versatile properties. Polym. Chem. 2015, 6, 8112-8123.

459

(11) Wang, R. G.; Ma, J.; Zhou, X. X.; Wang, Z.; Kang, H. L.; Zhang, L. Q.; Hua, K. C.;

460

Kulig, J. Design and Preparation of a Novel Cross-Linkable, High Molecular Weight, and

461

Bio-Based Elastomer by Emulsion Polymerization. Macromolecules 2012, 45,

462

6830-6839.

463

(12) Qiao, H.; Wang, R.; Yao, H.; Wu, X.; Lei, W.; Zhou, X.; Hu, X.; Zhang, L. Design

464

and preparation of natural layered silicate/bio-based elastomer nanocomposites with

465

improved dispersion and interfacial interaction. Polymer 2015, 79, 1-11.

466

(13) Zhou, X.; Wang, R.; Lei, W.; Qiao, H.; Ji, H.; Zhang, L.; Hua, K.-C.; Kulig, J.

filled

biodegradable

poly((1,2-propanediol-sebacate)-citrate)

27

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

467

Design and synthesis by redox polymerization of a bio-based carboxylic elastomer for

468

green tire. Sci. China: Chem. 2015, 58, 1561-1569.

469

(14) Qiao, H.; Wang, R.; Yao, H.; Zhou, X.; Lei, W.; Hu, X.; Zhang, L. Preparation of

470

graphene oxide/bio-based elastomer nanocomposites through polymer design and

471

interface tailoring. Polym. Chem. 2015, 6, 6140-6151.

472

(15) Lei, W.; Zhou, X.; Russell, T. P.; Hua, K.-c.; Yang, X.; Qiao, H.; Wang, W.; Li, F.;

473

Wang, R.; Zhang, L. High performance bio-based elastomers: energy efficient and

474

sustainable materials for tires. J. Mater. Chem. A 2016, 4, 13058-13062.

475

(16) Lei, W.; Wang, R.; Yang, D.; Hou, G.; Zhou, X.; Qiao, H.; Wang, W.; Tian, M.;

476

Zhang, L. Design and preparation of bio-based dielectric elastomer with polar and

477

plasticized side chains. RSC Adv. 2015, 5, 47429-47438.

478

(17) Satoh, K.; Lee, D. H.; Nagai, K.; Kamigaito, M. Precision Synthesis of Bio‐Based

479

Acrylic Thermoplastic Elastomer by RAFT Polymerization of Itaconic Acid Derivatives.

480

Macromol. Rapid Commun. 2014, 35, 161-167.

481

(18) Wang, W.; Ping, P.; Yu, H.; Chen, X.; Jing, X. Synthesis and characterization of a

482

novel biodegradable, thermoplastic polyurethane elastomer. J. Polym. Sci., Part A:

483

Polym. Chem. 2006, 44, 5505-5512.

484

(19) Skarja, G. A.; Woodhouse, K. A. Structure-property relationships of degradable

485

polyurethane elastomers containing an amino acid-based chain extender. J. Appl. Polym.

486

Sci. 2000, 75, 1522-1534. 28

ACS Paragon Plus Environment

Page 28 of 34

Page 29 of 34

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

487

(20) Petrović, Z. S. Polyurethanes from Vegetable Oils. Polym. Rev. 2008, 48, 109-155.

488

(21) Hojabri, L.; Kong, X.; Narine, S. S. Novel long chain unsaturated diisocyanate from

489

fatty acid: Synthesis, characterization, and application in bio-based polyurethane. J.

490

Polym. Sci., Part A: Polym. Chem. 2010, 48, 3302-3310.

491

(22) Whited, G. M.; Feher, F. J.; Benko, D. A.; Cervin, M. A.; Chotani, G. K.; McAuliffe,

492

J. C.; LaDuca, R. J.; Ben-Shoshan, E. A.; Sanford, K. J. Technology update:

493

Development of a gas-phase bioprocess for isoprene-monomer production using

494

metabolic pathway engineering. Ind. Biotechnol. 2010, 6, 152-163.

495

(23) Willke, T.; Vorlop, K. D. Biotechnological production of itaconic acid. Appl.

496

Microbiol. Biotechnol. 2001, 56, 289-295.

497

(24) Okabe, M.; Lies, D.; Kanamasa, S.; Park, E. Y. Biotechnological production of

498

itaconic acid and its biosynthesis in Aspergillus terreus. Appl. Microbiol. Biotechnol.

499

2009, 84, 597-606.

500

(25) Morais, A. R.; Dworakowska, S.; Reis, A.; Gouveia, L.; Matos, C. T.; Bogdał, D.;

501

Bogel-Łukasik, R. Chemical and biological-based isoprene production: Green metrics.

502

Catal. Today 2015, 239, 38-43.

503

(26) Bokobza, L. The reinforcement of elastomeric networks by fillers. Macromol. Mater.

504

Eng. 2004, 289, 607-621.

505

(27) Wang, Z.; Liu, J.; Wu, S.; Wang, W.; Zhang, L. Novel percolation phenomena and

506

mechanism of strengthening elastomers by nanofillers. Phys. Chem. Chem. Phys. 2010, 29

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

507

12, 3014-3030.

508

(28) Mouri, H.; Akutagawa, K. Improved tire wet traction through the use of mineral

509

fillers. Rubber Chem. Technol. 1999, 72, 960-968.

510

(29) Job, K. Trends in green tire manufacturing. Rubber World 2014, 249, 32-38.

511

(30) Yatsuyanagi, F.; Suzuki, N.; Ito, M.; Kaidou, H. Effects of secondary structure of

512

fillers on the mechanical properties of silica filled rubber systems. Polymer 2001, 42,

513

9523-9529.

514

(31) Gui, Y.; Zheng, J.; Ye, X.; Han, D.; Xi, M.; Zhang, L. Preparation and performance

515

of silica/SBR masterbatches with high silica loading by latex compounding method.

516

Composites Part B 2016, 85, 130-139.

517

(32) Reuvekamp, L.; Ten Brinke, J.; Van Swaaij, P.; Noordermeer, J. Effects of time and

518

temperature on the reaction of TESPT silane coupling agent during mixing with silica

519

filler and tire rubber. Rubber Chem. Technol. 2002, 75, 187-198.

520

(33) Ten Brinke, J.; Debnath, S.; Reuvekamp, L.; Noordermeer, J. Mechanistic aspects of

521

the role of coupling agents in silica–rubber composites. Compos. Sci. Technol. 2003, 63,

522

1165-1174.

523

(34) Park, S.-J.; Cho, K.-S. Filler–elastomer interactions: influence of silane coupling

524

agent on crosslink density and thermal stability of silica/rubber composites. J. Colloid

525

Interface Sci. 2003, 267, 86-91.

526

(35) Goerl, U.; Hunsche, A.; Mueller, A.; Koban, H. Investigations into the silica/silane 30

ACS Paragon Plus Environment

Page 30 of 34

Page 31 of 34

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

527

reaction system. Rubber Chem. Technol. 1997, 70, 608-623.

528

(36) Cataldo, F. Preparation of silica‐based rubber compounds without the use of a silane

529

coupling agent through the use of epoxidized natural rubber. Macromol. Mater. Eng. 2002,

530

287, 348-352.

531

(37) Xu, T.; Jia, Z.; Luo, Y.; Jia, D.; Peng, Z. Interfacial interaction between the

532

epoxidized natural rubber and silica in natural rubber/silica composites. Appl. Surf. Sci.

533

2015, 328, 306-313.

534

(38) Kaewsakul, W.; Sahakaro, K.; Dierkes, W.; Noordermeer, J. Verification of

535

Interactions between Silica and Epoxidized Squalene as a Model for Epoxidized Natural

536

Rubber. J. Rubber Res. 2014, 17, 129-142.

537

(39) Varughese, S.; Tripathy, D. K. Chemical interaction between epoxidized natural

538

rubber and silica: Studies on cure characteristics and low-temperature dynamic

539

mechanical properties. J. Appl. Polym. Sci. 1992, 44, 1847-1852.

540

(40) Sengloyluan, K.; Sahakaro, K.; Dierkes, W. K.; Noordermeer, J. W. M.

541

Silica-reinforced tire tread compounds compatibilized by using epoxidized natural rubber.

542

Eur. Polym. J. 2014, 51, 69-79.

543

(41) Ragosta, G.; Abbate, M.; Musto, P.; Scarinzi, G.; Mascia, L. Epoxy-silica particulate

544

nanocomposites: Chemical interactions, reinforcement and fracture toughness. Polymer

545

2005, 46, 10506-10516.

546

(42) Qu, L.; Yu, G.; Xie, X.; Wang, L.; Li, J.; Zhao, Q. Effect of silane coupling agent on 31

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

547

filler and rubber interaction of silica reinforced solution styrene butadiene rubber. Polym.

548

Compos. 2013, 34, 1575-1582.

549

(43) Choi, S.-S. Influence of storage time and temperature and silane coupling agent on

550

bound rubber formation in filled styrene–butadiene rubber compounds. Polym. Test. 2002,

551

21, 201-208.

552

(44) Payne, A. R. The dynamic properties of carbon black‐loaded natural rubber

553

vulcanizates. Part I. J. Appl. Polym. Sci. 1962, 6, 57-63.

554

(45) Wu, Y. P.; Zhao, Q. S.; Zhao, S. H.; Zhang, L. Q. The influence of in situ

555

modification of silica on filler network and dynamic mechanical properties of silica‐

556

filled solution styrene–butadiene rubber. J. Appl. Polym. Sci. 2008, 108, 112-118.

557

(46) Martin, P. J.; Brown, P.; Chapman, A. V.; Cook, S. Silica-reinforced epoxidized

558

natural rubber tire treads-performance and durability. Rubber Chem. Technol. 2015, 88,

559

390-411.

560

(47) Gelling, I. R.; Morrison, N. J. Sulfur Vulcanization and Oxidative Aging of

561

Epoxidized Natural Rubber. Rubber Chem. Technol. 1985, 58, 243-257.

562

(48) Li, Y.; Han, B.; Wen, S.; Lu, Y.; Yang, H.; Zhang, L.; Liu, L. Effect of the

563

temperature on surface modification of silica and properties of modified silica filled

564

rubber composites. Composites. Part A 2014, 62, 52-59.

565

(49) Wang, M.-J. Effect of polymer-filler and filler-filler interactions on dynamic

566

properties of filled vulcanizates. Rubber Chem. Technol. 1998, 71, 520-589. 32

ACS Paragon Plus Environment

Page 32 of 34

Page 33 of 34

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Industrial & Engineering Chemistry Research

567

(50) Takino, H.; Nakayama, R.; Yamada, Y.; Kohjiya, S.; Matsuo, T. Viscoelastic

568

properties of elastomers and tire wet skid resistance. Rubber Chem. Technol. 1997, 70,

569

584-594.

570

(51) Yan, H.; Tian, G.; Sun, K.; Zhang, Y.; Zhang, Y. Effect of silane coupling agent on

571

the polymer-filler interaction and mechanical properties of silica-filled NR. J. Polym. Sci.

572

Part B: Polym. Phys. 2005, 43, 573-584.

573

(52) Kim, K.; Lee, J.-Y.; Choi, B.-J.; Seo, B.; Kwag, G.-H.; Paik, H.-J.; Kim, W.

574

Styrene-butadiene-glycidyl methacrylate terpolymer/silica composites: dispersion of

575

silica particles and dynamic mechanical properties. Compos. Interfaces 2014, 21,

576

685-702.

577

(53) Kaewsakul, W.; Sahakaro, K.; Dierkes, W. K.; Noordermeer, J. W. M. Optimization

578

of mixing conditions for silica-reinforced natural rubber tire tread compounds. Rubber

579

Chem. Technol. 2012, 85, 277-294.

580

(54) Feng, W.; Tang, Z.; Weng, P.; Guo, B. Correlation of filler networking with

581

reinforcement and dynamic properties of ssbr/carbon black/silica composites. Rubber

582

Chem. Technol. 2015, 88, 676-689.

583

(55) Choi, S.-S.; Nah, C.; Jo, B.-W. Properties of natural rubber composites reinforced

584

with silica or carbon black: influence of cure accelerator content and filler dispersion.

585

Polym. Int. 2003, 52, 1382-1389.

586 587 33

ACS Paragon Plus Environment

Industrial & Engineering Chemistry Research

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

588

Table of content

589 590

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