Analysis of Nanodomain Composition in High-Impact Polypropylene

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Analysis of Nanodomain Composition in High-Impact Polypropylene by AFM-IR Fugang Tang, Peite Bao, and Zhaohui Su Anal. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.analchem.6b00798 • Publication Date (Web): 14 Apr 2016 Downloaded from http://pubs.acs.org on April 20, 2016

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Analytical Chemistry

Analysis of Nanodomain Composition in High-Impact Polypropylene by AFM-IR Fuguang Tang,ab Peite Bao,c and Zhaohui Sua*

a

State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China

b

University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100039, P. R. China c

ExxonMobil Asia Pacific R&D., Ltd., 1099 Zixing Road, Shanghai, 200241, P. R. China

*Corresponding author: Phone: +86-431-85262854; Fax: +86-431-85262126; E-mail: [email protected]

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ABSTRACT In this paper, compositions of nanodomains in a commercial high-impact polypropylene (HIPP) were investigated by AFM-IR technique. An AFM-IR quantitative analysis method was established for the first time, which was then employed to analyze the polyethylene content in the nanoscopic domains of the rubber particles dispersed in the polypropylene matrix. It was found that the polyethylene content in the matrix was close to zero, and was high in the rubbery intermediate layers, both as expected. However, the major component of the rigid cores of the rubber particles was found to be polypropylene rather than polyethylene, contrary to what previously believed. The finding provides new insight into the complicated structure of HIPPs, and the AFM-IR quantitative method reported here offers a useful tool for assessing compositions of nanoscopic domains in complex polymeric systems.

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INTRODUCTION Polypropylene (PP) is one of the most important and widely used commodity polymers due to its heat resistance, tensile strength, processability, and low cost. However, application of PP is often limited by its poor impact resistance, in particular at low temperatures. Over the past three decades various approaches have been developed to improve its toughness, such as addition of nucleating agent to reduce its crystallite size and blending with different elastomers, including copolymers of ethylene with propylene and other higher α-olefins.1-3 However, the properties of these blends are not satisfactory due to poor compatibility between the elastomer and the matrix. More recently, a new copolymerization process has been developed, which enables economic production in reactor of PP alloys with high impact resistance.4,5 These PP alloys, called impact polypropylene copolymer (IPC) or high-impact polypropylene (HIPP), have found extensive application in various fields. The excellent properties of these alloys have been attributed to their complicated composition and phase structure, which have attracted significant research interest in recent years. By using solvent/thermal fractionation in conjunction with spectroscopic techniques such as NMR and FTIR, it has been established that the alloys contain PP and possibly a small amount of polyethylene (PE) homopolymers, as well as ethylene-propylene random copolymer (or ethylene-propylene rubber, EPR) and ethylene-propylene block copolymers (EbP) with different sequence lengths, the content, molecular weight, and exact structure of each depending on polymerization conditions.6-8 These components form complex multi-level phase structures, typically consisting core-shell rubber particles with internal structures dispersed in a continuous PP matrix,9 as revealed mainly by transmission electron microscopy (TEM), selected area electron diffraction (SAED), atomic force microscopy (AFM), and scanning electron microscopy

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in conjunction with selective solvent etching. In general, it is well established that the soft intermediate layers and the rigid outer shells consist of amorphous EPR and semi-crystalline EbP, respectively.7,9-13 On the basis of TEM and SAED studies, it has been concluded that the major component of the rigid cores of the particles is PE, and models with a PE-rich core composing crystalline PE homopolymer9,13,14 or PE-riched EbP12 or both10 have been proposed.

Infrared spectroscopy is a powerful and readily available technique that can provide rich composition and structure information of polymer materials. However, its spatial resolution is limited by the incident wavelength, typically at several micrometers or greater.15 Thus traditional FTIR is not capable of directly assessing the composition of the particle cores in HIPP, which normally are in the order of several hundred nanometers. Recently, a new technique, AFM-IR, has emerged, which by taking advantage of the photothermal induced resonance (PTIR) effect, has increased the spatial resolution of IR spectroscopy to sub-100 nm scale.15-19 Figure 1 is a schematic illustration of the AFM-IR setup, which is built around an AFM and a tunable pulsed infrared laser. The sample is illuminated by the infrared pulses of a single wavelength, through total internal reflection mode in this case, and infrared absorption by the sample at this particular wavelength results in thermal expansion of the sample, which is detected by the AFM tip placed on the sample surface. The technique thus combines the spatial resolution of AFM with the chemical analysis capability of IR spectroscopy, making it a powerful tool for studying microscopic objects. In the present study, the compositions of the different phase domains in a commercial HIPP was determined quantitatively for the first time by using the AFM-IR technique. The results show that the cores of the particles in the HIPP are mainly composed of PP, rather than PE. 4


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Figure 1. Schematic illustration of the AFM-IR setup (a) used to analyze the composition of nanodomains in HIPP (b).

EXPERIMENTAL SECTION The HIPP as well as the PP homopolymer and the EPRs with known ethylene contents (used as standards) were all commercial grade products provided by ExxonMobil in the form of pellets, which were then injection molded into disks. TEM samples were prepared into thin sections by microtomy at -125 °C and then stained with RuO4 for overnight, and the images were collected on a FEI Tecnai F20 ST microscope. Tapping mode AFM images were collected on a Bruker Dimension Icon AFM, and the samples were cross sectioned by microtomy at -120 °C. FTIR spectra were collected on a Bruker Vertex-70 spectrometer equipped with a DTGS detector and an ATR accessory (ZnSe crystal, 45°) at 4 cm-1 resolution. Thin films of the polymers for the AFM-IR experiments, of ~400-700 nm thickness, were prepared using a Leica microtome. AFM-IR experiments were carried out on a nanoIR instrument (Anasys Instruments). The sample was placed on a ZnSe prism and an AFM image was acquired in contact mode using EX-C450 tips (Anasys Instruments) to identify the morphology, then the sample was illuminated from

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underneath by total internal reflection with a Ekspla optical parametric oscillator laser with a 900-2000 cm-1 tuning range and a spectral resolution of 4 cm-1. AFM-IR spectra were generated by measuring with the AFM tip the thermal expansion of the sample as a function of the IR laser wavelength normalized by the laser intensity averaged over 128 pulses. IR images were acquired by scanning the AFM tip across the sample surface while illuminating the sample at a fixed wavelength (1378 cm-1).

RESULTS AND DISCUSSION The HIPP used in this study was first analyzed by FTIR. Figure 2 presents the spectrum in the 650-1500 cm-1 region, which is dominated by the symmetric C-H bending of methyl group located at ~1378 cm-1, characteristic of PP, and the symmetric C-H bending band of methylene group observed at ~1456 cm-1 due to both PP and PE in the HIPP. The presence of the CH2 rocking band at ~720 cm-1 provides clear evidence of PE blocks and homopolymer in the alloy. Therefore, FTIR confirms the presence of both propylene and ethylene components in the HIPP. Furthermore, the ethylene content of the HIPP was determined to be 9.0 wt% from the 1456/1378 cm-1 peak ratio (discussed in later section), in excellent agreement with the number provided by the supplier determined by NMR (8.8 wt%). Next, morphology of the HIPP was examined by TEM and AFM. As seen in Figure 3, dispersed in the PP matrix are rubber particles with multilayered core-shell structure (Figure 3a), and the cores are rigid whereas the intermediate layers are soft (Figure 3b), consistent with that widely reported in the literature.7,9,12,13 The size of the rigid cores of the rubber particles, seen as the bright objects embedded in the dark rubber

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domains in Figure 3b, are mostly in the order of several hundred nanometers. These results indicate that this material is a typical HIPP.

Figure 2. FTIR spectrum of the HIPP.

Figure 3. TEM image (a) and AFM phase image (b) of the HIPP showing heterogeneous structure and distribution of rubber particles within the PP matrix. The scale bars in the images are 2 µm.

Infrared spectroscopy is often employed to study polymeric materials because it can provide rich composition and structure information. However, its spatial resolution is poor, typically at several micrometers or greater.15 It is therefore not suitable for studying the composition of the

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micro domains in our system. The recently emerged AFM-IR technique (Figure 1) has enabled IR analyses with a spatial resolution of 100 nm or higher,15-19 making it a powerful tool for exploring the structure and composition of the rubber particles in the HIPP. Figures 4a and 4c present an AFM image of a microtomed thin film of the HIPP, in which a core-shell particle is clearly seen, and corresponding AFM-IR spectra in the C-H bending region acquired at the color-coded locations in the core and the rubbery phase of the particle as well as in the matrix, respectively. The peak at ~1378 cm-1 is the symmetric C-H bending of methyl group, characteristic of PP, whereas both PP and PE in the HIPP contribute to the symmetric C-H bending band of methylene group, observed at ~1456 cm-1. From the relative intensity of the 1378 cm-1 band, it appears that all three phases contain significant amounts of PP. From the AFM-IR image acquired at 1378 cm-1 (Figure 4b) it can be seen that the domains correspond well with that in the AFM image (Figure 4a), however, the cores of the particle are quite bright, suggesting a high content of PP in the cores. This contradicts the models proposed in the literature, where the cores are believed to be PE-rich.9-14 Since the local AFM-IR signal is also proportional to sample thickness, which was not uniform throughout, the AFM-IR signal detected was compounded by both concentration and thickness factors. To further clarify the compositions of these phases, quantitative analysis by AFM-IR was attempted.

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Figure 4. (a) AFM height image and (b) AFM-IR map of the methyl symmetric C-H bending at 1378 cm-1. (c) AFM-IR spectra taken at the locations marked in (a) and (b), normalized to the 1378-cm-1 band, indicative of different ethylene contents as shown by the intensity of the 1456-cm-1 band.

It was demonstrated recently that AFM-IR signal is proportional to the energy absorbed, and hence proportional to sample concentration, and increases linearly with thickness for samples of up to 1 µm thickness.15 This has laid the foundation for quantitative chemical analysis by the technique. However, a calibration is required for this purpose, and yet composition standards homogeneous down to nanoscopic scale, needed for generating the calibration, are not readily 9



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available, especially for polymer blends or copolymers, which generally exhibit microphase separation. As in our case, the available EPR standards (with known global ethylene contents) exhibit large local composition variation (for example see Figure 3), and the sampling size of AFM-IR is too small for individual measurements to represent the global composition. As a result, a very large number of measurements must be taken for each standard to average out local composition variations so that the average value can be correlated to its global composition with confidence. For example, we carried out as many as 28 replicate measurements on one EPR standard by AFM-IR, and still observed a large relative standard deviation of ~14%, and a relative error of ~20% (Table S1, ESI). This indicates that it is unpractical to construct a calibration directly by the AFM-IR technique.

To circumvent this problem, an alternative approach was adopted. In fact, strong agreement between AFM-IR and conventional FTIR for both peak position and band shape has been demonstrated in the literature,16,20 and our own data (Figure 5a) also show excellent match between the spectra obtained by AFM-IR and conventional FTIR in the region of interest for both PE and PP in terms of peak position and relative intensity, each presumably being homogeneous throughout as a homopolymer. Based on the strong correlation between the two techniques, conventional FTIR was employed to generate a calibration from the standards with known global compositions, to correlate the ethylene content in the copolymers with the peak area ratio of the CH2 and CH3 bending bands at ~1456 and ~1378 cm-1, respectively,21,22 which would then be used to convert the peak ratio data obtained by AFM-IR into ethylene contents for the micro domains. Excellent linear correlation is observed for the calibration (Figure 5b). To validate this approach, PP homopolymer and three EPR standards, which appeared more homogeneous as 10


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examined by TEM and AFM with no significant phase separation observed (Figure S1, ESI) were analyzed by AFM-IR, and the average peak ratios (each from at least 15 replicates) are plotted in Figure 5b (the red squares), showing satisfactory agreement quantitatively between the two techniques.

Figure 5. (a) Comparison of FTIR and AFM-IR spectra of PE and PP homopolymers in the 1300-1600 cm-1 region. (b) Calibration generated by FTIR (black squares and the dash line) to be used in the quantitative composition analysis by AFM-IR. The red squares represent the 1456/1378 cm-1 peak ratios obtained by AFM-IR for four of the standards.

Next, the intermediate layers and cores of the rubber particles as well as the matrix in multiple microtomed films of the HIPP sample were analyzed by AFM-IR, and the composition of each location analyzed quantified using the calibration established. The numbers are listed in Table 1. It can be seen that the ethylene content in the matrix is close to zero, consistent with the fact that the matrix is essentially PP homopolymer. The intermediate layer has a high ethylene content of ~39 wt%, corresponding to the EPR phase. The cores, on the other hand, contain only ~17 wt% ethylene units, which confirms our above finding by AFM-IR mapping, that the cores in the

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rubber particles are rich in PP. A different commercial grade was also examined by AFM-IR, and it was found that the major component of the cores of the rubber particles was PP as well, although the ethylene content was different. It should be pointed out that the local composition numbers obtained exhibit rather broad distribution as indicated by the large standard deviations. This is not unexpected for a commercial material considering that the sample size analyzed by AFM-IR each time is nanoscopic. The local ethylene content for the intermediate layer varies much more than that for the other two, which can be attributed to broad distribution in structure and composition of the EPR chains. Nevertheless, even though the exact composition of each phase varies, it is clear that the cores in the rubber particles are mainly composed of PP.

So far morphological analysis of complex polymeric systems mainly rely on imaging techniques such as TEM and SEM, which can be very challenging for polyolefin systems where contrast between phases is lacking. In this case solvent etching or extraction is often implemented in order to differentiate the phases.21,23 The process is tedious and time-consuming, and provides only qualitative results at best. The AFM-IR method reported here offers a new and alternative approach, which can identify and assess quantitatively the composition of different micro domains in situ, making it a powerful technique in morphological study of complex polymeric systems.

Table 1. Composition of Different Domains in the HIPP.

domain

replicates analyzed

average PE content (wt%)

StdDev (wt%)

matrix

19

2.0

6.0

intermediate layer

21

38.8

10.1

core

37

17.2

6.9

12


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CONCLUSIONS

We have demonstrated for the first time that quantitative agreement between conventional FTIR and AFM-IR data can be established, and AFM-IR can be employed for quantitative analysis of composition of nanoscopic domains in polymer systems using a calibration generated by conventional FTIR. By using this approach, compositions of different phase domains in a commercial HIPP have been determined quantitatively, which shows that contrary to previously believed, the major component of the rigid cores in the rubber particles of the HIPP is PP, not PE. This finding may provide new insight into the structure-property relationship of impact propylene copolymer and help guide the design and production of this commercially important material. Furthermore, the method reported here affords a practical solution to application of AFM-IR as a quantitative analysis technique with nanoscale resolution.

AUTHOR INFORMATION

Corresponding Author *E-mail: [email protected].

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT

F.T. and Z.S. thank ExxonMobil for providing the samples and the financial support for this work. 13



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ASSOCIATED CONTENT

Supporting Information. Additional AFM and AFM-IR data. This material is available free of charge via the Internet at http://pubs.acs.org.

REFERENCES (1) Rungswang, W.; Saendee, P.; Thitisuk, B.; Pathaweeisariyakul, T.; Cheevasrirungruang, W. J.

Appl. Polym. Sci. 2013, 128, 3131-3140. (2) Gahleitner, M.; Tranninger, C.; Doshev, P. J. Appl. Polym. Sci. 2013, 130, 3028-3037. (3) Li, R.; Zhang, X.; Zhao, Y.; Hu, X.; Zhao, X.; Wang, D. Polymer 2009, 50, 5124-5133. (4) Galli, P.; Vecellio, G. Prog. Polym. Sci. 2001, 26, 1287-1336. (5) Cecchin, G. Macromol. Symp. 1994, 78, 213-228. (6) Xu, J. T.; Feng, L. X.; Yang, S. L.; Wu, Y. N.; Yang, Y. Q.; Kong, X. M. Polymer 1997, 38, 4381-4385. (7) Fernandez, A.; Exposito, M. T.; Pena, B.; Berger, R.; Shu, J.; Graf, R.; Spiess, H. W.; Garcia-Munoz, R. A. Polymer 2015, 61, 87-98. (8) Tan, H. S.; Li, L.; Chen, Z. N.; Song, Y. H.; Zheng, Q. Polymer 2005, 46, 3522-3527. (9) Chen, Y.; Chen, Y.; Chen, W.; Yang, D. J. Appl. Polym. Sci. 2008, 108, 2379-2385. (10) Tong, C. Y.; Lan, Y.; Chen, Y.; Chen, Y.; Yang, D. C.; Yang, X. N. J. Appl. Polym. Sci. 2012,

123, 1302-1309. (11) Shang-Guan, Y.; Chen, F.; Zheng, Q. Sci. China Chem. 2012, 55, 698-712. (12) Zhang, C.; Shangguan, Y.; Chen, R.; Wu, Y.; Chen, F.; Zheng, Q.; Hu, G. Polymer 2010, 51, 4969-4977. (13) Song, S. J.; Feng, J. C.; Wu, P. Y.; Yang, Y. L. Macromolecules 2009, 42, 7067-7078. (14) Ito, J.; Mitani, K.; Mizutani, Y. J. Appl. Polym. Sci. 1992, 46, 1221-1233. (15) Marcott, C.; Lo, M.; Kjoller, C. P. K.; Noda, I. Appl. Spectros. 2011, 65, 1145-1150. (16) Lahiri, B.; Holland, G.; Centrone, A. Small 2013, 9, 439-445. (17) Dazzi, A.; Glotin, F.; Carminati, R. J. Appl. Phys. 2010, 107, 124519.

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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


(18) Dazzi, A.; Prazeres, R.; Glotin, F.; Ortega, J. M.; Al-Sawaftah, M.; de Frutos, M.

Ultramicroscopy 2008, 108, 635-641. (19) Dazzi, A.; Prazeres, R.; Glotin, F.; Ortega, J. M. Ultramicroscopy 2007, 107, 1194-1200. (20) Dazzi, A.; Prater, C. B.; Hu, Q.; Chase, D. B.; Marcott, C. Appl. Spectros. 2012, 66, 1365-1384. (21) de Goede, E.; Mallon, P.; Pasch, H. Macromol. Mater. Eng. 2010, 295, 366-373. (22) Strate, G. V.; Cozewith, C.; West, R. K.; Davis, W. M.; Capone, G. A. Macromolecules 1999,

32, 3837-3850. (23) Cheruthazhekatt, S.; Pasch, H. Polymer 2014, 55, 5358-5369.

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Table of Contents Graphic

Analysis of Nanodomain Composition in High-Impact Polypropylene by AFM-IR Fuguang Tang, Peite Bao, and Zhaohui Su*

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Analysis of Nanodomain Composition in High-Impact Polypropylene

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