Multifunctional cellulose ester containing hindered phenol groups with

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Applications of Polymer, Composite, and Coating Materials

Multifunctional cellulose ester containing hindered phenol groups with free-radical scavenging and UV-resistant activities Tiantian Yang, Peng Xiao, JinMing Zhang, Ruonan Jia, Haq Nawaz, Zhangyan Chen, and Jun Zhang ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b15642 • Publication Date (Web): 09 Nov 2018 Downloaded from http://pubs.acs.org on November 10, 2018

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ACS Applied Materials & Interfaces

Multifunctional Cellulose Ester Containing Hindered Phenol Groups with Free-radical Scavenging and UV-resistant Activities Tiantian Yang1,2, Peng Xiao1, Jinming Zhang1,*, Ruonan Jia1,2, Haq Nawaz1, Zhangyan Chen1,2, Jun Zhang1,2,* 1CAS

Key Laboratory of Engineering Plastics, CAS Research/Education Center for Excellence in Molecular

Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China 2University

of Chinese Academy of Sciences, Beijing 100049, China

Abstract Excessive radicals and UV irradiation can trigger oxidative and physiological stresses, which cause tissue aging, human disease, food spoilage, and material degradation. In this study, a multifunctional cellulose ester containing hindered phenol groups, cellulose 3,5-di-tert-butyl-4hydroxybenzoate (CBH), with free-radical scavenging and UV-resistant activities was synthesized and used as functional material. The obtained CBHs can effectively scavenge reactive nitrogen freeradicals and hydroxyl free-radicals in both solid and solution states. Moreover, CBHs have no cytotoxicity, and on the contrary, they promote the proliferation of human epidermal keratinocytes (HEK). Benefiting from excellent solubility, processsability and formability, CBHs have been readily processed into flexible films, transparent coatings, and nanoribbons membranes. The highly transparent and flexible CBH film completely absorbs the light of 200-300 nm range and partially absorbs the light of 300-400 nm range, indicating a UV-shielding capability. After CBHs were loaded on an ordinary facial mask by electrospinning or added into a hand-cream, the resultant facial-mask and hand-cream exhibited outstanding free-radical scavenging properties. In addition, CBHs can also be used to fabricate functional sprays with antioxidative and UV-shielding activities. Accordingly, the obtained CBHs have a huge potential in cosmetics, personal care products, biopharmaceuticals, papermaking, and art protection because of their excellent antioxidation, nontoxic, UV-resistance, formability, and odorless properties. Keywords: Antioxidation; Macromolecular antioxidant; Cellulose ester; Hindered phenol; UVresistance; Cosmetics



Corresponding authors.

E-mail address: [email protected] (J.M. Zhang); [email protected] (J. Zhang). Mailing address: Zhongguancun North First Street 2,100190 Beijing, PR China

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Introduction Radicals are ubiquitous and indispensable in nature and relate to many processes, such as photosynthesis, respiration, metabolism, energy transfer, sterilization and disinfection, combustion, and chemical industry.1-6 However, excessive free radicals cause oxidative stress, resulting in material aging,7 food spoilage,8 aging and damage of the human body.9 For instance, plastics, rubbers, and papers degrade faster when they are used outside, due to the generation of more radicals induced by ultraviolet rays, oxygen and moisture.10 In the human body, excess free radicals disrupt cellular ingredients, including protein, DNA, and lipids, resulting in irreversible damage of tissue and organs, and giving rise to diseases such as metabolic disorders, diverse inflammatory diseases, neural diseases, cancer and skin aging.11-15 Hence, various antioxidants with free radical scavenging capabilities have been developed to reduce or prevent oxidative stress in order to extend the lifetime of materials, cure inflammation and diseases, and delay the aging process.12,16,17 The currently available antioxidants include natural extracts and synthetic compounds. Many natural edible and medicinal plants have antioxidative properties, such as fresh fruits, vegetables, tea, cocoa, sage, rosemary, thyme, pepper, and cinnamon. In these plants, the essential components are tea polyphenols, resveratrol, rosemary extract, lycopene, carotene, tannin, flavone, curcumin, ascorbic acid (VC) and α-tocopherol (VE), which are usually extracted and used as natural antioxidants.18-24 Synthetic compounds, such as 2,6-butylated hydroxytoluene (BHT),25 tertbutylhydroquinone (TBHQ),26,27 butylated hydroxyanisole (BHA)28 and propyl gallate29, have excellent antioxidative properties, and can also inhibit excess oxidation. The above natural and synthetic antioxidants are already used in food, cosmetic, pharmaceutical and material fields. However, because most of these available antioxidants are low-molecular-weight compounds, several disadvantages originating from the inherent qualities of micromolecules, such as inevitable migration and leaching, short lifetime and poor stability, have yet to be overcome.17,30 In addition, the amount of natural antioxidants in plants is limited. Their extraction and purification processes are commonly time-consuming and labor-intensive.22 More importantly, natural antioxidants are mostly lipid soluble, meanwhile some of them, e.g., carotene, easily deactivate when they encounters light, heat or oxygen. Thus, before the practical application of natural antioxidants, a large amount of emulsifier and stabilizer need to be added to improve their dispersion in water and enhance their stability.31,32 Synthetic micromolecular antioxidants are relatively cheaper than natural antioxidants, but their


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potential biosecurity limits their applications in food, cosmetic and pharmaceutical fields.29,33 In contrast to micromolecular antioxidants, macromolecular antioxidants are stable and non-migratable because of the chemical anchoring effect of the macromolecular chain.34 Furthermore, owing to their high molecular weight, macromolecular antioxidants are more difficult to be ingested and absorbed by the human body, meaning that they are safer.34,35 Macromolecular antioxidants are nonvolatile, and thus are odorless, which is essential to the allergic population. Additionally, macromolecular antioxidants possess numerous antioxidative groups in a single chain, and thus usually exhibit superior antioxidant activities.34 It is worth noting that macromolecular antioxidants have good processability and formability, so various free-standing material forms can be easily fabricated to adapt to different application fields.36,37 Therefore, macromolecular antioxidants have received considerable attention. As the most abundant biopolymer produced by plant photosynthesis, cellulose has many attractive properties such as biodegradability, biocompatibility and inexhaustible renewability.38-40 More interestingly, cellulose has a substantial number of hydroxyl groups along its chain, which provide plenty of reactive sites for chemical modification.41-45 Furthermore, there are two kinds of hydroxyl groups in the repeat unit of cellulose, namely, one primary hydroxyl at the 6-position and two secondary hydroxyls at the 2- and 3-positions. By controlling the topological structure of the resultant cellulose derivatives, a series of cellulose-based functional materials with adjustable properties can be fabricated.45 Therefore, cellulose is an ideal platform polymer for fabricating macromolecular antioxidants. In this work, antioxidative cellulose 3,5-di-tert-butyl-4-hydroxybenzoate (CBH) was synthesized by chemically conjugating 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHA) onto a cellulose chain in ionic liquids, as shown in Figure 1a. The obtained CBHs exhibited superior freeradical scavenging properties, UV-resistance, non-toxicity, odorless and excellent formability, so were employed to prepare functional facial-masks, hand-creams and sprays.



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Figure 1. Synthesis route and structural characterization of CBH. (a) Synthesis route of CBH in AmimCl; (b) 1H-NMR spectrum of CBH with DS = 0.83 (CBH 13C-NMR spectrum of CBH with DS = 0.93 0.83); (c) (CBH0.93); (d) FTIR spectra of cellulose, CBH and BHA; (e) WXRD curves of cellulose, CBH and BHA.

Results and Discussion Homogeneous Synthesis and Characterization of CBH in AmimCl A series of CBH samples with different degree of substitution (DS) were homogeneously synthesized in 1-allyl-3-methylimidazolium chloride (AmimCl), as shown in Figure 1 and Table 1. By adjusting the reaction conditions, including feed molar ratio, reaction temperature, and reaction time, the DS values of CBH samples in the range of 0.19 to 1.52 were precisely controlled. When the


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molar ratio of 3,5-di-tert-butyl-4-hydroxybenzoyl chloride (BHC)/anhydroglucose unit (AGU) is below 3:1, there is a linear relationship between the feed molar ratio and DS values (Figure S1), because the whole process is completed under homogeneous conditions. In addition, an increase in the reaction temperature accelerates the reaction. For instance, the DS of CBH increases from 0.55 to 0.81 (sample 4 and 10), when the reaction temperature increases from 50 ºC to 80 ºC, at the feed molar ratio of 1:1 and reaction time of 2 h. However, high temperature will cause a degradation of cellulose. On the other hand, at a low temperature, the cellulose/ionic liquid (IL) solution has a high viscosity, which is unfavorable for the homogeneous reaction. Ultimately, 50 ºC is the optimum temperature for this reaction. The DS increases gradually as the reaction time prolongs. The DS of CBH increases from 0.56 to 1.38 (samples 11-15), when the reaction time is extended from 0.5 h to 5 h, at a reaction temperature of 50 ºC and a feed molar ratio of 3:1 (Figure S2). The degree of polymerization (DP) of cellulose has a slight effect on the DS. When cotton pulp with DP = 650 (sample 16) and microcrystalline cellulose (MCC) with DP = 220 (sample 7) are used as the raw materials, CBH samples with similar DS values were obtained. According to the above reaction rules, the CBH with a controllable DS value can be easily synthesized by the homogeneous esterification in ionic liquid AmimCl. Table 1. Conditions and results of homogeneous reaction of cellulose and 3,5-di-tert-butyl-4hydroxybenzoyl chloride (BHC) in AmimCl.

Cellulose Type

DP

Molar ratio of BHC/AGU

1

MCC

220

0.5:1

50

2.0

0.19

CBH0.19

2

MCC

220

0.75:1

50

2.0

0.33

CBH0.33

3

MCC

220

0.85:1

50

2.0

0.42

CBH0.42

4

MCC

220

1:1

50

2.0

0.55

CBH0.55

5

MCC

220

1.5:1

50

2.0

0.70

CBH0.70

6

MCC

220

2:1

50

2.0

0.93

CBH0.93

7

MCC

220

3:1

50

2.0

1.11

CBH1.11

8

MCC

220

6:1

50

2.0

1.06

CBH1.06

No.

T/°C

t/h

DS

Samples



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9

MCC

220

10:1

50

4.0

1.52

CBH1.52

10

MCC

220

1:1

80

2.0

0.81

CBH0.81

11

MCC

220

3:1

50

0.5

0.56

CBH0.56

12

MCC

220

3:1

50

1.0

0.83

CBH0.83

13

MCC

220

3:1

50

2.0

1.13

CBH1.13

14

MCC

220

3:1

50

3.0

1.22

CBH1.22

15

MCC

220

3:1

50

5.0

1.38

CBH1.38

16

Cotton pulp

650

3:1

50

2.0

1.04

CBH1.04

In the 1H-NMR spectrum of CBH (Figure 1b), the peaks at 2.8-5.5 ppm are ascribed to the protons of the cellulose backbone. The peaks at 0.8-1.8 ppm and 7.2-8.0 ppm are assigned to the protons of tert-butyl groups and phenyl rings, respectively, confirming that the acyl groups have been successfully incorporated into the cellulose. In the 13C-NMR spectrum (Figure 1c), cellulose backbone carbons are at 58-103 ppm, in which the appearance of new C1 and C6 peaks indicates that a part of the hydroxyl groups at 2- and 6-positions have been substituted. The carbons of phenyl rings and carbonyl groups appear at 120-163 ppm and 165 ppm, respectively. In the FTIR spectra of CBH (Figure 1d), there is clear evidence of successfully anchoring 3,5-di-tert-butyl-4-hydroxybenzoate group onto the cellulose chain by the new peaks of 1708 cm-1 for C=O stretching vibration, 1400-1600 cm-1 for aromatic C=C stretching and 700-980 cm-1 for aromatic C-H out-of-plane bending. In comparison with the FTIR spectrum of cellulose, the intensity of the O-H stretching vibration in CBH obviously decreases, and the O-H peak shows a strong blueshift from 3316 cm-1 to 3461 cm-1, because the hydroxyls are modified and the hydrogen bonding network is broken. In WXRD curves of CBH (Figure 1e), there is only one broad peak, indicating that the CBH samples are amorphous and the crystal structure of cellulose is disrupted. These date confirm that 3,5-di-tert-butyl-4-hydroxybenzoate groups are successfully incorporated into the cellulose chain. Antioxidation of CBH The antioxidation property of CBH was characterized by evaluating its free radical scavenging ability. As a typical nitrogen free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) is usually employed to evaluate the antioxidative properties of samples.46 The DPPH/alcohol solution is dark purple with


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a maximum absorption peak at 517 nm (Figure 2). When DPPH radicals are reduced to diphenyl dihydrazine by antioxidants, the DPPH/alcohol solution turns pale yellow, meanwhile the intensity of the absorption peak at 517 nm decreases.

Figure 2. (a) Time-dependent absorbance at 517 nm for the reaction of DPPH (150 μM) and CBH1.22 (40 mM) in ethanol. The insert is the absorbance of DPPH and CBH1.22 at 450-650 nm in ethanol as the increase of the reaction time. (b) Radical scavenging at the different concentration of CBH0.83 with the reaction time of 30 min. The insert is the digital picture of DPPH (75 μM), DPPH (150 μM) reacted with CBH0.83 (20 mM), and DPPH (150 μM) reacted with CBH0.83 (40 mM). (c) DPPH radical scavenging activity of CBH with the different DS values, and the reaction time of 30 min. The insert is the digital picture of DPPH (150 μM) reacted



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with CBH0.42 (40 mM), DPPH (150 μM) reacted with CBH0.83 (40 mM), and DPPH (150 μM) reacted with CBH1.52 (40 mM). (d) Digital pictures of DPPH (75 μM), DPPH reacted with CBH0.42 powder (eq. 40 mM), DPPH reacted with CBH0.70 film (eq. 40 mM), and DPPH reacted with CBH1.52 solution (40 mM), and the reaction time is 30 min. (e) EPR spectra of DPPH (250 μM) in the absence vs presence of CBH1.52 (50 mM). (f) EPR spectra of DMPO-OH in the absence vs presence of CBH1.52 (50 mM). The concentration of FeSO4∙7H2O, DMPO and H2O2 is 10 mM, 0.25 M and 10 mM, respectively.

After the addition of CBH, the DPPH solution changes from purple to yellow, and the intensity of the peak at 517 nm decreases gradually (Figure 2), proving that CBH can effectively scavenge nitrogen free radicals. At the beginning of 20 min, the intensity of DPPH peak decreases rapidly, then the decrease rate becomes slow (Figure 2a). After 30 min, the intensity of DPPH peak decreases to a plateau. Therefore, it needs approximately 20-30 minutes for CBH to effectively scavenge the nitrogen free radicals, indicating that the free radical scavenging process of CBH is gentle and safer for the human body. As the CBH concentration increases from 2 to 20 mM, the DPPH free radical scavenging activity dramatically increases and reaches a plateau at CBH concentrations above 20 mM (Figure 2b). DS of CBH also has an important influence on the free radical scavenging activity. As the DS increases, the DPPH free radical scavenging activity initially increases, reaches a maximum at DS of 0.83, then decreases when the DS is above 0.83 (Figure 2c). For all CBHs, the DPPH free radical scavenging activity is higher than 50%. The CBH with a DS of 0.83 exhibited the highest radical scavenging activity, 88%, which is similar with that of 3,5-di-tert-butyl-4hydroxybenzoic acid (BHA) (Figure S3). Selecting the suitable DS and concentration of CBH can precisely control the retained content of free radicals according to the demand, which is essential for the health of living organisms. In addition, both in the solid-state (like powder and film) and the solution state, CBH can effectively scavenge DPPH free radicals (Figure 2d), because the content of phenol groups at the surface of film is nearly the same as that in the bulk CBH (Figure S4 and Table S1). Thus, CBH can be prepared into a variety of material forms for antioxidation applications. The electron paramagnetic resonance (EPR) spectra also confirmed that CBH can effectively scavenge DPPH free radicals by the obvious decrease of the signal intensity of DPPH following the addition of CBH (Figure 2e). Hydroxyl free radicals, one kind of essential reactive oxygen species (ROS), are related to inflammatory, senility and some diseases. Here, hydroxyl radicals are produced by the Fenton reaction system, and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the trapping agent is added to make hydroxyl free radicals stable by forming a spin adduct DMPO-OH. When CBH is


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added into the Fenton reaction system, the signal intensity of the DMPO-OH decreases markedly, indicating that hydroxyl free radicals are scavenged by CBH (Figure 2f). Cytotoxicity Assay of CBH The cytotoxicity of CBH was evaluated on human epidermal keratinocytes (HEK-adult) by 3[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. CBH has no cytotoxicity within the test concentration (10-120 μM), as shown in Figure 3. More interestingly, at a high concentration (40-120 μM), CBH can promote HEK-adult cell viability, because the excellent radical scavenging ability make CBH to protect the cells from oxidative stress caused by radicals47. This nontoxic and safe antioxidant CBH is expected to be applied in cosmetics, medicine and food fields.

Figure 3．Cell viability of HEK-adult incubated with CBH0.70.

Solubility and Formability of CBH Cellulose is insoluble in conventional solvents because of the strong hydrogen bonding network. After partial modification of hydroxyls in cellulose, the original hydrogen-bonding network is broken, and the resultant cellulose derivatives, such as CBH, become soluble in some polar organic solvents, such as dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), pyridine, tetrahydrofuran (THF) and chloroform. Moreover, the number, nature and position of substituents on cellulose derivatives have significant effects on their solubility, which reflects the polarity and hydrophobicity of the whole polymer chain.



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All CBH samples are soluble in DMSO and DMF, and insoluble in water, as shown in Table 2. As the DS increases, the solubility of CBH improves. When the DS value is above 1.22, CBH become soluble in most of conventional polar organic solvents, including pyridine, chloroform, THF and ethyl acetate. CBH with an appropriate DS are soluble in alcohols, which are usually used as a precipitant for common cellulose derivatives. When the DS is above 0.56, the corresponding CBH can be dissolved in methanol; when the DS increases to 0.83, the CBH become soluble in both methanol and ethanol; when the DS further increases to 1.22, the CBH is soluble even in isopropanol. The good solubility of CBH in alcohols is related to the appropriate content of phenolic hydroxyls in cellulose chain. In contrast to other organic solvents, alcohols, especially ethanol, have low toxicity; and in contrast to water, alcohols are readily volatile; therefore, the alcohol solubility of CBH provides an environmentally friendly, convenient and opportunity for rapidly processing CBH into various material forms.

Table 2. Solubility of CBH with different DS in common organic solvents and water.

Samples

DMSO

DMF

CBH0.19

+

+

±

-

-

CBH0.56

+

+

+

+

CBH0.83

+

+

+

CBH1.06

+

+

CBH1.22

+

+

Pyridine Methanol Ethanol THF

Ethyl

Isopropanol

Chloroform

-

-

-

-

-

±

±

-

-

-

-

+

+

±

-

-

-

-

+

+

+

+

±

±

±

-

+

+

+

+

+

+

+

-

acetate

H2O

+, soluble; -, insoluble; ±, swollen.

Benefiting from the excellent solubility of CBH, a highly transparent and flexible film was easily obtained using ethanol as solvent. In the visible light region, the transmittance of CBH film was approximately 90%, which is higher than neat cellulose film (Figure 4a). Using a solution casting method, the transparent coatings form on glass, wood chip, iron sheet, and the surface of silica (Figures 4b, 4c and S5). In addition, nanoribbon films are readily fabricated by electrospinning the 25 wt% CBH1.52/ethanol solution (Figure 4d). More interestingly, the highly transparent CBH film has a strong absorption in ultraviolet light region because of numerous benzene rings in the CBH chain. It completely absorbs the light of 200-300 nm range and partially absorbs the light in the 300-


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400 nm range, indicating a UV-shielding capability. Therefore, CBH has great potential to be used as a highly transparent and UV-resistant film and coating.

Figure 4. (a) UV-Vis spectra of cellulose and CBH0.83 films. The insert is the digital picture of CBH0.83 film. (b) CBH0.70 coatings on glass slide, wood chip and iron sheet, respectively. (c) SEM image of SiO2 microsphere coated with CBH1.52 ([email protected]), and TGA curves of SiO2 microsphere, [email protected] and CBH1.52. The insert is the digital picture of [email protected]. (d) SEM image of CBH1.52 nano-ribbons by electro-spinning from 25 wt % CBH1.52/ethanol solution, and the width distribution of the CBH1.52 nano-ribbons. The insert is



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the CBH1.52 electro-spinning film.

Functional Facial Mask, Hand Cream and Spray Fabricated by CBH CBH can effectively scavenge nitrogen free-radicals and hydroxyl free-radicals, and the scavenging activity is tunable. In addition, CBH has good biocompatibility, no cytotoxicity and odorless as a bio-based macromolecular antioxidant. Moreover, CBH has a good solution processability, thus it can be prepared into various materials such as films, electrospinning nanofiber membranes, and coatings. Hence, CBH has a huge potential in cosmetics, personal care products, biopharmaceuticals, papermaking and art protection (Figure 5a). CBH nanoribbons were coated on the surface of an ordinary nonwoven facial mask to fabricate a functional facial mask by the electrospinning method. There was a negligible change on the appearance of the facial mask. When the facial mask was added into the DPPH solution, the DPPH solution became faintly yellow (Figure 5b), indicating that the antioxidative facial mask was fabricated successfully. In addition, [email protected] microspheres were directly added into Vaseline® hand cream to fabricate antioxidative hand cream (Figure 5b), because SiO2 microspheres are the most commonly used and safe additive in food, cosmetics and personal care products. The resultant hand cream containing 1 wt% [email protected] microspheres effectively scavenged free radicals, indicating that a functional hand cream was obtained. Furthermore, based on the water insolubility, excellent alcohol solubility and good formability, two kinds of functional CBH sprays with antioxidative and UV-shielding activities were obtained successfully (Figure 5c). The antioxidative activities of CBH facial-mask, hand-cream and spray are comparable to the commercial antioxidative cosmetics (Figure S6).


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Figure 5. (a) Schematic of functional facial-mask, hand-cream and spray with anti-oxidative and UV-shielding activities. (b) The functional facial mask and hand-cream scavenge DPPH free-radicals. The functional facial mask is the common facial mask coated with CBH1.52 nano-ribbons. The functional hand-cream is the Vaseline mixed with 1 wt% [email protected]. (c) (i) CBH1.52/ethanol spray; (ii) CBH0.70/water spray; (iii) CBH0.70 coating on glass slide fabricated by CBH0.70/water spray, and its anti-oxidative behavior for scavenging DPPH freeradicals; (iv) CBH1.52 coating fabricated by CBH1.52/ethanol spray, and its UV-Vis spectrum. The insert is the digital picture of CBH1.52 coating.

Conclusions A novel multifunctional cellulose ester, cellulose 3,5-di-tert-butyl-4-hydroxybenzoate (CBH), was homogeneously synthesized by conjugating 3,5-di-tert-butyl-4-hydroxybenzoic acid to the cellulose chain. The DS value of CBHs was easily controlled by adjusting the reaction conditions.



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The CBH samples with various DS values exhibit excellent and manageable solubility in most polar organic solvents, even alcohols, which enables CBHs to be processed into different material forms. CBHs exhibits a strong capability to scavenge nitrogen free radicals and hydroxyl free radicals in both the solid-state (like powder and film) and solution state. By regulating the DS and concentration of CBH, the retained content of free radicals can be precisely controlled according to the demand. The highest DPPH free radical scavenging activity is 88 %. CBH has no cytotoxicity, and even promotes the proliferation of HEK-adult cell. In addition, the transparent film and coating of CBH has a UV-shielding capability, because of complete absorption of light in the 200-300 nm range. After CBH was loaded onto the surface of an ordinary facial-mask by electrospinning or CBH was coated on silica microspheres which were then added into the hand-cream, the resultant facialmask and hand-cream exhibit outstanding free-radical scavenging properties. Furthermore, based on the excellent alcohol solubility and formability, functional sprays of CBH with antioxidative and UVshielding activities were obtained successfully. To sum up, the CBHs exhibit excellent antioxidative and nontoxic properties, in addition to UV-resistance and formability, thus they have a huge potential in cosmetics, personal care products, biopharmaceuticals, papermaking, and art protection. Supporting Information Materials, synthesis process, measurement and characterization, DS values of CBH samples versus different molar ratio and reaction time, XPS spectra of CBH samples, UV spectrum, SEM images. Acknowledgement This work was supported by the National Natural Science Foundation of China (Nos. 51425307, 51573196 and 51773210), the Innovative Research Team Program of Beijing Academy of Science and Technology (No. IG2016 05 N/C1), and the Youth Innovation Promotion Association CAS (No. 2018040). References [1] Yang, L.; Liu, G.; Zheng, M.; Jin, R.; Zhu, Q.; Zhao, Y.; Wu, X.; Xu, Y. Highly Elevated Levels and Particle-Size Distributions of Environmentally Persistent Free Radicals in Haze-Associated Atmosphere. Environmental Science & Technology, 2017, 51(14): 7936-7944. [2] Lubitz, W.; Lendzian, F.; Bittl, R. Radicals, Radical Pairs and Triplet States in Photosynthesis. Accounts of Chemical Research, 2002, 35(5): 313-320. [3] Humphries, K. M.; Yoo, Y.; Szweda, L. I. Inhibition of NADH-Linked Mitochondrial Respiration by 4-Hydroxy-2-


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nonenal. Biochemistry, 1998, 37: 552-557. [4] Millar, H. C.; Izgorodina, E. I.; Kowollik, C. B.; Coote, M. L. Radical Addition to Thioketones: Computer-Aided Design of Spin Traps for Controlling Free-Radical Polymerization. Journal of Chemical Theory and Computation, 2006, 2(6): 1632-1645. [5] Khamsen, N.; Onwimol, D.; Teerakawanich, N.; Dechanupaprittha, S.; Kanokbannakorn, W.; Hongesombut, K.; Srisonphan, S. Rice (Oryza sativa L.) Seed Sterilization and Germination Enhancement via Atmospheric Hybrid Nonthermal Discharge Plasma. ACS Applied Materials & Interfaces, 2016, 8(30): 19268-19275. [6] Qi, G.; Mi, Y.; Fan, R.; Zhao, B.; Ren, B.; Liu, X. Tea Polyphenols Ameliorates Neural Redox Imbalance and Mitochondrial Dysfunction via Mechanisms Linking the Key Circadian Regular Bmal1. Food and Chemical Toxicology, 2017, 110: 189-199. [7] Harding, L. B.; Klippenstein, S. J. Roaming Radical Pathways for the Decomposition of Alkanes. The Journal of Physical Chemistry Letters, 2010, 1(20): 3016-3020. [8] Wang, C. Y.; Wang, S. Y.; Yin, J.; Parry, J.; Yu, L. L. Enhancing Antioxidant, Antiproliferation, and Free Radical Scavenging Activities in Strawberries with Essential Oils. Journal of Agricultural and Food Chemistry, 2007, 55(16): 6527-6532. [9] Valko, M.; Leibfritz, D.; Moncol, J.; Cronin, M. T. D.; Mazur, M.; Telser, J. Free Radicals and Antioxidants in Normal Physiological Functions and Human Disease. The International Journal of Biochemistry & Cell Biology, 2007, 39(1): 44-84. [10] Sun, M.; Qiao, M.; Wang, J.; Zhai, L. Free-Radical Induced Chain Degradation of High-Molecular-Weight Polyacrylamide in a Heterogeneous Electro-Fenton System. ACS Sustainable Chemistry & Engineering. 2017, 5(9): 7832-7839. [11] Dugasani, S.; Pichika, M. R.; Nadarajah, V. D.; Balijepalli, M. K.; Tandra, S.; Korlakunta, J. N. Comparative Antioxidant and Anti-inflammatory Effects of [6]-Gingerol, [8]-Gingerol, [10]-Gingerol and [6]-Shogaol. Journal of Ethnopharmacology, 2010, 127(2): 515-520. [12] Liu, Y.; Ai, K.; Ji, X.; Askhatova, D.; Du, R.; Lu, L.; Shi, J. Comprehensive Insights into the Multi-Antioxidative Mechanisms of Melanin Nanoparticles and Their Application To Protect Brain from Injury in Ischemic Stroke. Journal of the American Chemical Society, 2017, 139(2): 856-862. [13] Hamasaki, T.; Kashiwagi, T.; Imada, T.; Nakamichi, N.; Aramaki, S.; Toh, K.; Morisawa, S.; Shimakoshi, H.; Hisaeda, Y.; Shirahata, S. Kinetic Analysis of Superoxide Anion Radical-Scavenging and Hydroxyl RadicalScavenging Activities of Platinum Nanoparticles. Langmuir, 2008, 24(14): 7354-7364. [14] Barreiro, S. L.; Díaz, C. B. Free Radicals and Polyphenols: The Redox Chemistry of Neurodegenerative Diseases. European Journal of Medicinal Chemistry, 2017, 133: 379-402. [15] Cuzzocrea, S.; Riley, D. P.; Caputi, A. P.; Salvemini, D. Antioxidant Therapy: A New Pharmacological Approach in Shock, Inflammation, and Ischemia/Reperfusion Injury. Pharmacological Review, 2001, 53(1): 135-159. [16] Zhao, L.; Cao, Z.; Fang, Z.; Guo, Z. Influence of Fullerene on the Kinetics of Thermal and Thermo-oxidative Degradation of High-density Polyethylene by Capturing Free Radicals. Journal of Thermal Analysis and Calorimetry, 2013, 114(3): 1287-1294. [17] Jeong, H.; Samdani, K. J.; Yoo, D. H.; Lee, D. W.; Kim, N. H.; Yoo, I. S.; Lee, J. H. Resveratrol Cross-linked Chitosan Loaded with Phospholipid for Controlled Release and Antioxidant Activity. International Journal of Biological Macromolecules, 2016, 93: 757-766. [18] Kähkönen, M. P.; Hopia, A. I.; Vuorela, H. J.; Rauha, J. P.; Pihlaja, K.; Kujala, T. S.; Heinonen, M. Antioxidant Activity of Plant Extracts Containing Phenolic Compounds. Journal of Agricultural and Food Chemistry, 1999, 47(10): 3954-3962. [19] Matthäus, B. Antioxidant Activity of Extracts Obtained from Residues of Different Oilseeds. Journal of Agricultural and Food Chemistry, 2002, 50(12): 3444-3452.



Page 16 of 18

[20] Škerget, M.; Kotnik, P.; Hadolin, M.; Hraš, A. R.; Simonič, M.; Knez, Ž. Phenols, Proanthocyanidins, Flavones and Flavonols in Some Plant Materials and their Antioxidant Activities. Food Chemistry, 2005, 89(2): 191-198. [21] Banerjee, S.; Chakravarty, A. R. Metal Complexes of Curcumin for Cellular Imaging, Targeting, and Photoinduced Anticancer Activity. Accounts of Chemical Research, 2015, 48(7): 2075-2083. [22] Balasundram, N.; Sundram, K.; Samman, S. Phenolic Compounds in Plants and Agri-industrial By-products: Antioxidant Activity, Occurrence, and Potential Uses. Food Chemistry, 2006, 99(1): 191-203. [23] Prameela, K.; Venkatesh, K.; Immandi, S. B.; Kasturi, A. P. K.; Krishna, C. R.; Mohan, C. M. Next Generation Nutraceutical from Shrimp Waste: The Convergence of Applications with Extraction Methods. Food Chemistry, 2017, 237: 121-132. [24] Singh, B.; Singh, J. P.; Kaur, A.; Singh, N. Phenolic Composition and Antioxidant Potential of Grain Legume Seeds: A Review. Food Research International, 2017, 101: 1-16. [25] Salam, D. A.; Suidan, M. T.; Venosa, A. D. Effect of Butylated Hydroxytoluene (BHT) on the Aerobic Biodegradation of a Model Vegetable Oil in Aquatic Media. Environmental Science & Technology, 2012, 46(12): 6798-6805. [26] Li, J.; Bi, Y.; Liu, W.; Sun, S. Simultaneous Analysis of Tertiary Butylhydroquinone and 2-tert-Butyl-1,4benzoquinone in Edible Oils by Normal-Phase High-Performance Liquid Chromatography. Journal of Agricultural and Food Chemistry, 2015, 63(38): 8584-8591. [27] Li, J.; Bi, Y.; Yang, H.; Wang, D. Antioxidative Properties and Interconversion of tert-Butylhydroquinone and tertButylquinone in Soybean Oils. Journal of Agricultural and Food Chemistry, 2017, 65(48): 10598-10603. [28] Johansson, H.; Shanks, D.; Engman, L.; Amorati, R.; Pedulli, G. F.; Valgimigli, L. Long-Lasting Antioxidant Protection: A Regenerable BHA Analogue. The Journal of Organic Chemistry, 2010, 75(22): 7535-7541. [29] Dolatabadi, J. E. N.; Kashanian, S. A Review on DNA Interaction with Synthetic Phenolic Food Additives. Food Research International, 2010, 43(5): 1223-1230. [30] García, M. S.; García, D.; Vilariñó, J. M. L.; Rodríguez, M. V. G. Antioxidant Content of and Migration from Commercial Polyethylene, Polypropylene, and Polyvinyl Chloride Packages. Journal of Agricultural and Food Chemistry, 2007, 55: 3225-3231. [31] Ge, W.; Li, D.; Chen, M.; Wang, X.; Liu, S.; Sun, R. Characterization and Antioxidant Activity of β-Carotene Loaded Chitosan-graft-poly(Lactide) Nanomicelles. Carbohydrate Polymers, 2015, 117: 169-176. [32] Wen, P.; Zong, M. H.; Linhardt, R. J.; Feng, K.; Wu, H. Electrospinning: A Novel Nano-encapsulation Approach for Bioactive Compounds. Trends in Food Science & Technology, 2017, 70: 56-68. [33] Eskandani, M.; Hamishehkar, H.; Dolatabadi, J. E.N. Cytotoxicity and DNA Damage Properties of tertButylhydroquinone (TBHQ) Food Additive. Food Chemistry, 2014, 153: 315-320. [34] Hagerman, A. E.; Riedl, K.M.; Jones, G. A.; Sovik, K. N.; Ritchard, N. T.; Hartzfeld, P. W.; Riechel, T. L. High Molecular Weight Plant Polyphenolics (Tannins) as Biological Antioxidants. Journal of Agricultural and Food Chemistry, 1998, 46(5): 1887-1892. [35] Gahruie, H. H.; Niakousari, M. Antioxidant, Antimicrobial, Cell Viability and Enzymatic Inhibitory of Antioxidant Polymers as Biological Macromolecules. International Journal of Biological Macromolecules, 2017, 104:606-617. [36] Trombino, S.; Cassano, R.; Bloise, E.; Muzzalupo, R.; Leta, S.; Puoci, F.; Picci, N. Design and Synthesis of Cellulose Derivatives with Antioxidant Activity. Macromolecular Bioscience, 2008, 8(1): 86-95. [37] Trombino, S.; Cassano, R.; Bloise, E.; Muzzalupo, R.; Tavano, L.; Picci, N. Synthesis and Antioxidant Activity Evaluation of a Novel Cellulose Hydrogel Containing trans-Ferulic Acid. Carbohydrate Polymers, 2009, 75(1): 184-188. [38] Kresse, K. M.; Xu, M.; Pazzi, J.; Ojeda, M. G.; Subramaniam, A. B. Novel Application of Cellulose Paper As a Platform for the Macromolecular Self-Assembly of Biomimetic Giant Liposomes. ACS Applied Materials & Interfaces, 2016, 8(47): 32102-32107.


Page 17 of 18 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


[39] Wu, S.; Lu, A.; Zhang, L. N. Recent Advances in Regenerated Cellulose Materials. Progress in Polymer Science, 2016, 53: 169-206. [40] Zhang, J. M.; Wu, J.; Yu, J.; Zhang, X. C.; He, J. S.; Zhang, J. Application of Ionic Liquids for Dissolving Cellulose and Fabricating Cellulose-based Materials: State of the Art and Future Trends. Mater. Chem. Front., 2017, 1: 12731290. [41] Heinze, T.; Liebert, T. Unconventional Methods in Cellulose Functionalization. Progress in Polymer Science, 2001, 26(9): 1689-1762. [42] Zhang, J. M.; Chen, W. W.; Feng, Y.; Wu, J.; Yu, J.; He, J. S.; Zhang, J. Homogeneous Esterification of Cellulose in Room Temperature Ionic Liquids. Polymer International, 2015, 64(8):963-970. [43] Lv, Y. X.; Zhang, J. M.; Wang, F. J.; Shao, Z. Q.; Zhang, J. Comparative Study on Structure and Properties of Cellulose Acetate Synthesized by Homogeneous and Heterogeneous Acetylation. Acta Polymerica Sinica, 2016, 3: 324-329. [44] Zhang, J. M.; Wu, J.; Yu, J.; Zhang, X. C.; Mi, Q. Y.; Zhang, J. Processing and Functionalization of Cellulose with Ionic Liquids. Acta Polymerica Sinica, 2017, 7: 1058-1072. [45] Fox, S. C.; Li, B.; Xu, D.; Edgar, K. J. Regioselective Esterification and Etherification of Cellulose: A Review. Biomacromolecules, 2011, 12(6): 1956-1972. [46] Xie, J.; Schaich, K. M. Re-evaluation of the 2,2-Diphenyl-1-picrylhydrazyl Free Radical (DPPH) Assay for Antioxidant Activity. Journal of Agricultural and Food Chemistry, 2014, 62(19):4251-4260. [47] Zhou, Y.; Li, J.; Ma, H. J.; Zhen, M. M.; Guo, J.; Wang, L. P.; Jiang, L.; Shu, C. Y.; Wang, C. R. ACS Applied

Materials & Interfaces, 2017, 9, 35539-35547.



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Multifunctional cellulose ester containing hindered phenol groups with

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