Elastomers and Composites

The Rubber Society of Korea (한국고무학회)
권호 표지
DOI QR코드

DOI QR Code

Characterization of Poly(ethylene-co-vinyl acetate) (EVA) Using Thermal Analytical Techniques

  • Received : 2019.02.23
  • Accepted : 2019.03.13
  • Published : 2019.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

Poly(ethylene-co-vinyl acetate) (EVA) is a copolymer of ethylene and vinyl acetate (VA). It is important to determine the VA content of EVA, since the properties of EVA depend highly on the VA content. EVA copolymers have been used in a wide range of applications appropriate for the different VA contents. IR, NMR, and TGA are generally used for determination of the VA content of EVA copolymers. Of these, TGA is the most reliable method and can be applied to cured EVAs. Analytical methods for determination of the VA content and properties of EVA copolymers via TGA were herein reviewed. Thermal behaviors of EVA copolymers (glass transition temperature ($T_g$), melting point ($T_m$), and crystallization temperature ($T_c$)) determined by DSC were also reviewed. Analysis of the related literature revealed that the $T_g$, $T_m$, and $T_c$ decrease by about 0.46, 1.36, and $2.08^{\circ}C$, respectively, for every 1 wt% in VA content. A method for determining the degree of crosslinking of cured EVA copolymers was also reviewed, and the degree of crosslinking tends to increase with the decrease in the VA content.

Keywords

HKGMCJ_2019_v54n1_61_f0001.png 이미지

Figure 1. Typical TGA thermogram of EVA.

HKGMCJ_2019_v54n1_61_f0002.png 이미지

Scheme 1. Non-catalytic and catalytic deaceatylation process of EVA.

HKGMCJ_2019_v54n1_61_f0003.png 이미지

Figure 2. Typical TGA thermogram of silica-filled EVA compound.

HKGMCJ_2019_v54n1_61_f0004.png 이미지

Figure 3. Typical DSC thermogram of EVA.

HKGMCJ_2019_v54n1_61_f0005.png 이미지

Figure 4. Variations of (a) glass transition temperature (Tg), (b) crystallization temperature (Tc), and melting temperature (Tm) of EVA with the VA content.

HKGMCJ_2019_v54n1_61_f0006.png 이미지

Figure 5. Typical DSC thermogram of uncured EVA compound.

Table 1. Application Fields of EVAs According to the VA Contents.

HKGMCJ_2019_v54n1_61_t0001.png 이미지

Table 2. Improvement of EVA by Blending with the Other Polymers.

HKGMCJ_2019_v54n1_61_t0002.png 이미지

Table 3. Improvement of EVA by Reinforcing with Filler.

HKGMCJ_2019_v54n1_61_t0003.png 이미지

Table 4. Glass Transition Temperatures (Tgs), Crystallization Temperatures (Tcs) and Melting temperatures (Tms) of EVAs According to the VA contents.

HKGMCJ_2019_v54n1_61_t0004.png 이미지

References

  1. G. Meszlenyi and G. Kortvelyessy, "Direct determination of vinyl acetate content of ethylene vinyl acetate copolymers in thick films by infrared spectroscopy", Polym. Test., 18, 551 (1999). https://doi.org/10.1016/S0142-9418(98)00053-1
  2. I. A. Hussein, M. H. Iqbal, and H. I. Al-abdul-Wahhab, "Influence of $M_w$ of LDPE and vinyl acetate content of EVA on the rheology of polymer modified asphalt", Rheol. Acta., 45, 92 (2005). https://doi.org/10.1007/s00397-005-0455-2
  3. D. Briassoulis, M. Hiskakis, E. Babou, S. K. Antihos, and C. papadi, "Experimental investigation of the quality characteristics of agricultural plastic wastes regarding their recycling and energy recovery potential", Waste Manage., 32, 1075 (2012). https://doi.org/10.1016/j.wasman.2012.01.018
  4. P. Appendini and J. H. Hotchkiss, "Review of antimicrobial food packaging", Innov. Food Sci. Emerg. Technol., 3, 113 (2002). https://doi.org/10.1016/S1466-8564(02)00012-7
  5. A. C. Cameron, W. Boylan-Pett, and J. Lee, "Design of modified atmosphere packaging systems: modeling oxygen concentrations within sealed packages of tomato fruits", J. Food Sci., 54, 1413 (1989). https://doi.org/10.1111/j.1365-2621.1989.tb05123.x
  6. Le-Bail, N. Hamadami, and S. Bahuaud, "Effect of high-pressure processing on the mechanical and barrier properties of selected packagings", Packag. Technol. Sci., 19, 237 (2006). https://doi.org/10.1002/pts.727
  7. M. Shafiee and S. A. A. Ramazani, "Investigation of barrier properties of poly(ethylene vinyl acetate)/organoclay nanocomposite films prepared by phase inversion method", Macromol. Symp., 274, 1 (2008).
  8. A. Riva, G. Camino, L. Fomperie, and P. Amigouet, "Fire retardant mechanism in intumescent ethylene vinyl acetate compositions", Polym. Degrad. Stab., 82, 341 (2003). https://doi.org/10.1016/S0141-3910(03)00191-5
  9. F. Laoutid, L. Ferry, E. Leroy, and J. M. Lopez Cuesta, "Intumescent mineral fire retardant systems in ethylene-vinyl acetate copolymer: effect of silica particles on char cohesion", Polym. Degrad. Stab., 91, 2140 (2006). https://doi.org/10.1016/j.polymdegradstab.2006.01.010
  10. B. Li, H. Jia, L. Guan, B. Bing, and J. Dai, "A novel intumescent flame-retardant system for flame-retarded LLDPE/EVA composites", J. Appl. Polym. Sci., 114, 3626 (2009). https://doi.org/10.1002/app.31027
  11. I. O. Ucar, M. D. Doganci, C. E. Cansoy, H. Y. Erbil, I. Avramova, and S. Suzer, "Combined XPS and contact angle studies of ethylene vinyl acetate and polyvinyl acetate blends", Appl. Surf. Sci., 257, 9587 (2011). https://doi.org/10.1016/j.apsusc.2011.06.070
  12. A. W. Czanderna and F. J. Pern, "Encapsulation of PV modules using ethylene vinyl acetate copolymer as a pottant: A critical review", Sol. Energy Mater. Sol. Cells, 43, 101 (1996). https://doi.org/10.1016/0927-0248(95)00150-6
  13. C. Hirshl, M. Biebl-Rydlo, M. DeBiasio, W. Muhleisen, L. Neumaier, W. Scherf, G. oreski, G. Eder, B. Chernev, W. Schwab, and M. Kraft, "Determining the degree of crosslinking of ethylene vinyl acetate photovoltaic module encapsulants-A comparative study", Sol. Energy Mater. Sol. Cells, 116, 203 (2013). https://doi.org/10.1016/j.solmat.2013.04.022
  14. K. Agroui, G. Collins, and J. Farenc, "Measurement of glass transition temperature of crosslinked EVA encapsulant by thermal analysis for photovoltaic application", Renew. Energ., 43, 218 (2014). https://doi.org/10.1016/j.renene.2011.11.015
  15. M. D. Kempe, G. J. Jorgensen, K. M. Terwilliger, T. J. McMahon, C. E. Kennedy, and T. T. Borek, "Acetic acid production and glass transition concerns with ethylene-vinyl acetate used in photovoltaic devices", Sol. Energy Mater. Sol. Cells, 91, 315 (2007). https://doi.org/10.1016/j.solmat.2006.10.009
  16. A. M. Henderson, "Ethylene-vinyl acetate (EVA) copolymers: A general review", IEEE Electr. Insul. Mag., 9, 30 (1993). https://doi.org/10.1109/57.249923
  17. R. Langer, "Polymetric delivery system for controlled drug release", Chem. Eng. Commun., 6, 1 (1980). https://doi.org/10.1080/00986448008912519
  18. S. C. Vasudev, T. Chandy, and C. P. Sharma, "Development of chitosan/polyethylene vinyl acetate co-matrix: controlled release of aspirin-heparin for preventing cardiovascular thrombosis", Biomaterials, 18, 375 (1997). https://doi.org/10.1016/S0142-9612(96)00131-7
  19. R. Langer and J. Forkman, "Polymers for the sustained release of proteins and other macromolecules", Nature, 263, 797 (1976). https://doi.org/10.1038/263797a0
  20. J. Kost, J. Wolfrum, and R. Langer, "Magnetically enhanced insulin release in diabetic rats", J. Biomed. Mater. Res., 21, 1367 (1987). https://doi.org/10.1002/jbm.820211202
  21. H. Creque, R. Langer, and J. Folkman, "One month sustained release of insulin from a polymer implant," Diabetes, 29, 37 (1980). https://doi.org/10.2337/diab.29.1.37
  22. A. Marcilla, A. Gomez, and S. Menargues, "TG/FTIR study of the thermal pyrolysis of EVA copolymers", J. Anal. Appl. Pyrolysis, 74, 225 (2005).
  23. M. C. Costache, D. D. Jiang, and C. Wilkie, "Thermal degradation of ethylene-vinyl acetate copolymer nanocomposites", Polymer, 46, 6947 (2005). https://doi.org/10.1016/j.polymer.2005.05.084
  24. Z. Wenwei, Z. Xiaoguang, Y. Li, Z. Yuefang, and S. Jiazhen, "Determination of the vinyl acetate content in ethylene acetate copolymers by thermogravimedtric analysis", Polymer, 35, 3348 (1994). https://doi.org/10.1016/0032-3861(94)90148-1
  25. S-S. Choi and E. Kim, "Comparison of vinyl acetate content of poly(ethylene-co-vinyl acetate) analyzed by IR, NMR, TGA", Elast. Compos., 50, 18 (2015). https://doi.org/10.7473/EC.2015.50.1.018
  26. E. Ramirez-Vargas, D. Navarro-Rodriguez, A. I. Blanqueto-Menchaca, B. M. Huerta-Martine, and M. Palacios-Mezta, "Degradation effects on the rheological and mechanical properties of multi-extruded blends of impact-modified polypropylene and poly(ethylene-co-vinyl acetate) blends", J. Therm. Anal. Calorim., 63, 748 (2001).
  27. R. J. Koopmans, R. van der Linden, and E. F. Vansnat, "The characterisation of newly developed and promising hydrolyzed ethylene vinyl acetate copolymers", J. Adhesion, 11, 191 (1980). https://doi.org/10.1080/00218468008078916
  28. B. Rimez, H. Rahier, G. V. Assche, and T. Artoos, "The thermal degradation of poly(vinyl acetate) and poly(ethylene-covinyl acetate), Part 1: Experimental study of their degradation mechanism", Polym. Degrad. Stab., 93, 800 (2008). https://doi.org/10.1016/j.polymdegradstab.2008.01.010
  29. I. Poljansek, E. Fabjan, K. Burja, and D. Kukanja, "Emulsion copolymerization of vinyl acetate-ethylene in high pressure reactor-characterization by inline FTIR spectroscopy", Prog. Org. Coat., 76, 1798 (2013). https://doi.org/10.1016/j.porgcoat.2013.05.019
  30. Y. Chen, H. Zou, M. Liang, and Y. Cao. "Melting and crystallization behavior of partially miscible high density polyethylene/ethylene vinyl acetate copolymer (HDPE/EVA) blends", Thermochim. Acta, 586, 1 (2014). https://doi.org/10.1016/j.tca.2014.04.007
  31. K. Wattananawinrat, P. Threepopnatkul, and C. Kulsetthanchalee, "Morphological and thermal properties of LDPE/EVA blended films and development of antimicrobial activity in food packaging film", Energy Procedia, 56, 1 (2014). https://doi.org/10.1016/j.egypro.2014.07.125
  32. H. A. Khonakdar, "Dynamic mechanical analysis and thermal properties of LLDPE/EVA/modified silica nanocomposites", Compos. Part B-Eng, 76, 343 (2015). https://doi.org/10.1016/j.compositesb.2015.02.031
  33. M. Faker, M. K. R. Aghjeh, M. Ghaffari, and S. A. Seyyedi, "Rheology, morphology and mechanical properties of polyethylene/ethylene vinyl acetate copolymer (PE/EVA) blends", Eur. Polym. J., 44, 1834, (2008). https://doi.org/10.1016/j.eurpolymj.2008.04.002
  34. C. K. Radhakrishnan A. Sujith, and G. Unnikrishnan, "Thermal behavior of styrene butadiene rubber/poly(ethylene-covinyl acetate) blends TG and DSC analysis", J. Therm. Anal. Calorim., 90, 11 (2007).
  35. Y. Wang, S. Ge, M. Rafailovich, J. Sokolov, Y. Zou, H. Ade, L. Luning, A. Lustiger, and G. Maron, "Crystallization in the thin and ultrathin films of poly(ethylene-vinyl acetate) and linear low-density polyethylene", Macromolecules, 37, 3319 (2004). https://doi.org/10.1021/ma030456b
  36. Y. Cai, L. Song, Q. He, D. Yang, and Y. Hu, "Preparation, thermal and flammability properties of a novel form-stable phase change materials based on high density polyethylene/poly(ethylene-co-vinyl acetate)/organophilic montmorillonite nanocomposites/paraffin compounds", Energy Convers Manag., 49, 2055 (2008). https://doi.org/10.1016/j.enconman.2008.02.013
  37. H. A. Khonakdar, U. Wagenknecht, S. H. Jafari, R. Hassler, and H. Eslami, "Dynamic mechanical properties and morphology of polyethylene/ethylene vinyl acetate copolymer blends", Adv. Polym. Technol., 23, 307 (2004). https://doi.org/10.1002/adv.20019
  38. S. Hobeika, Y. Men, and G. Strobl, "Temperature and strain rate independence of critical strains in polyethylene and poly(ethylene-co-vinyl acetate)", Macromolecules, 33, 1827 (2000). https://doi.org/10.1021/ma9910484
  39. S. Dalai and C. Wenxiu, "Radiation effects on HDPE/EVA blends", J. Appl. Polym. Sci., 86, 553 (2002). https://doi.org/10.1002/app.10829
  40. A. Sasikala and A. Kala, "Thermal stability and mechanical strength analysis of EVA and blend of EVA with natural rubber", Mater. Today Proc., 5, 8862 (2018). https://doi.org/10.1016/j.matpr.2017.12.318
  41. A. T. Koshy, B. Kuriakose, S. Thomas, and S. Varghese, "Studies on the effect of blend ratio and crosslinking system on thermal, X-ray and dynamic mechanical properties of blends of natural rubber and ethylene-vinyl acetate copolymer", Polymer, 34, 3428 (1993). https://doi.org/10.1016/0032-3861(93)90472-M
  42. M. Kim, C. Park, S. R. Chowdhury, and G. Kim, "Physical properties of ethylene vinyl acetate copolymer (EVA)/natural rubber (NR) blend based foam", J. Appl. Polym. Sci., 94, 2212 (2004). https://doi.org/10.1002/app.21174
  43. J. Sharif, W. M. Z. W. Yunus, K. H. Dahlan, and M. H. Ahmad, "Natural rubber/poly(ethylene-co-vinyl acetate)-blend-based nanocomposites", J. Appl. Polym. Sci., 100, 353 (2006). https://doi.org/10.1002/app.23121
  44. A. K. Gupta, B. K. Ratnam, and K. R. Srinivasan, "Melt-rheological properties of PP/EVA blend", J. Appl. Polym. Sci., 46, 281 (1992). https://doi.org/10.1002/app.1992.070460209
  45. E. Ramirez-Vargas, D. Navarro-Rodriguez, A. I. Blanqueto-Menchaca, B. N. Huerta-Martinez, and M. Palacios-Mezta, "Degradation effects on the rheological and mechanical properties of multi-extruded blends of impact-modified polypropylene and poly(ethylene-co-vinyl acetate) blends", J. Therm. Anal. Calorim., 63, 748 (2001).
  46. C. K. Radhakrishnan, R. Alex, and G. Unnikrishnan, "Thermal, ozone and gamma ageing of styrene butadiene rubber and poly(ethylene-co-vinyl acetate) blends", Polym. Degrad. Stab., 91, 902 (2006). https://doi.org/10.1016/j.polymdegradstab.2005.06.013
  47. M. Copuroglu and M. Sen, "A comparative study of thermal ageing characteristics of poly(ethylene-co-vinyl acetate) and poly(ethylene-co-vinyl acetate)/carbon black mixture", Polym. Adv. Technol., 15, 393 (2004). https://doi.org/10.1002/pat.485
  48. Z. Zhang, W. Wang, C. Li, L. Wei, X. Chen, Y. Tong, K. Mai, and X. Lu, "Highly conductive ethylene-vinyl acetate copolymer/carbon nanotube paper for lightweight and flexible super capacitors", J. Power Sources, 248, 1248 (2014). https://doi.org/10.1016/j.jpowsour.2013.10.061
  49. Y. Chen, J. Zhan, P. Zhang, S. Nie, H. Lu, L. Song, and H. Yuan. "Preparation of intumescent flame retardant poly(butylene succinate) using fumed silica as synergistic agent", Ind. Eng. Chem. Res., 49, 8200 (2010). https://doi.org/10.1021/ie100989j
  50. M. Sabet, A. Hassan, and C. T. Ratnam, "Properties of ethylene-vinyl acetate filled with metal hydroxide", J. Elast. Plast. 47, 88 (2015). https://doi.org/10.1177/0095244313489907
  51. D. Q. Tham, V. M. Tuan, D. T. M. Thanh, N. T. Chinh, N. V. Giang, N. T. T Trang, T. T. X. Hang, H. T. Huong, N. T. K. Dung, and T. Hoang, "Preparation and properties of ethylene vinyl acetate copolymer/silica nanocomposites in presence of EVA-g-acrylic acid", J. Nanosci. Nanotechnol., 15, 2777 (2015). https://doi.org/10.1166/jnn.2015.9209
  52. J. N Asaad, N. N. Rozik, and S. H. Mansour, "Effect of surface modification of magnesium hydroxide on the flammability, mechanical and thermal properties of $EVA/Mg(OH)_2$ composites", Kgk-Kaut. Gummi Kunst., 66, 49 (2013).
  53. R. Sonnier, A. Viretto, L. Dumazert, M. Longerey, S. Buonomo, B. Gallard, C. Longuet, F. Cavodeau, R. Lamy, and A. Freitag, "Fire retardant benefits of combining aluminum hydroxide and silica in ethylene-vinyl acetate copolymer (EVA)", Polym. Degrad. Stab., 128, 228 (2016). https://doi.org/10.1016/j.polymdegradstab.2016.03.030
  54. M. Gelfer, C. Avila-orta, L. Liu, L. Yang, B. Chu, B. S. Hsiao, H. H. Song, M. Si, M. Rafailovich, and A. H. Tsou, "Manipulating the microstructure and rheology in polymer-organoclay composites", Polym. Eng. Sci., 42, 1841 (2002). https://doi.org/10.1002/pen.11077
  55. A. I. Fernandaz, L. Haurie, J. Formosa, J. M. Chimenos, M. Antunes, and J. I. Velasco, "Characterization of poly(ethylene-co-vinyl acetate) (EVA) filled with low grade magnesium hydroxide", Polym. Degrad. Stab., 94, 57 (2009). https://doi.org/10.1016/j.polymdegradstab.2008.10.008
  56. S. Elanthikkal, U. Gopalakrishnapanicker, S. Varghese, J. T. Guthrie, and T. Francis, "Effect of cellulose whisker content on the properties of poly(ethylene-co-vinyl acetate)/cellulose composites", Carbohydr. Polym., 95, 773 (2013). https://doi.org/10.1016/j.carbpol.2013.02.039
  57. E. K.Silviya, G. Unnikrishnan, S. Varghese, and J. T. Guthrie, "Thermal and mechanical characterization of EVA/banana fiber-derived cellulose composites", J. Appl. Polym. Sci., 125, 786 (2011). https://doi.org/10.1002/app.35140
  58. Y. Park, H. J. H. Kim, and Y. Lee, "Adhesion and rheological properties of EVA-based hot-meld adhesives", Int. J. Adhes. Adhes., 26, 571 (2006). https://doi.org/10.1016/j.ijadhadh.2005.09.004
  59. N. Okui and T. Kawai, "Crystallization and ethylene/vinylacetate random copolymers", Makromol. Chem., 154, 161 (1972). https://doi.org/10.1002/macp.1972.021540115
  60. M. A. Jacobs, M. F. Kemmere, and J. T. F. Keurentjes, "Foam processing of poly(ethylene-co-vinyl acetate) rubber using supercritical carbon dioxide", Polymer, 45, 7539 (2004). https://doi.org/10.1016/j.polymer.2004.08.061
  61. A. Arsac, C. Carrot, and J. Guillet, "Determination of primary relaxation temperature and melting point of ethylene vinyl acetate copolymers", J. Therm. Anal. Calorim., 61, 681 (2000). https://doi.org/10.1023/A:1010160105917
  62. X. Shi, J. Jin, S. Chen, and J. Zhang, "Multiple melting and partial miscibility of ethylene-vinyl acetate copolymer/low density polyethylene blends", J. Appl. Polym. Sci., 113, 2863 (2009). https://doi.org/10.1002/app.30271
  63. X. M. Shi, J. Zhang, J. Jin, and S. J. Chen, "Non-isothermal crystallization and melting of ethylene-vinyl acetate copolymers with different vinyl acetate contents", Express Polym. Lett., 2, 623 (2008). https://doi.org/10.3144/expresspolymlett.2008.75
  64. C. Motta, "The effect of copolymerization on transition temperature of polymeric materials", J. Therm. Anal., 49, 461 (1997). https://doi.org/10.1007/BF01987471
  65. M. Shinoyama, S. Hayano, K. Matsukawa, H. Inoue, T. Ninomiya, and Y. Ozaki, "Discrimination of ethylene/vinyl acetate copolymers with different composition and prediction of the content of vinyl acetate in the copolymers and their melting points by near-infrared spectroscopy and chemometrics", J. Polym. Sci. B. Polym. Phys., 36, 1529 (1998). https://doi.org/10.1002/(SICI)1099-0488(19980715)36:9<1529::AID-POLB10>3.0.CO;2-7
  66. I. G. Voigt-Martin, "A Quantitative Electron Microscopic Study of the Crystalline Structure of Ethylene Copolymers", J. Polym. Sci. B. Polym. Phys., 24, 1283 (1986). https://doi.org/10.1002/polb.1986.090240608
  67. R. Kuwahara, R. Tomita, N. Ogawa, K. Nakajima, T. Takeda, H. Uehara, and T. Yamanobe, "Crystallization and hardening of poly(ethylene-co-vinyl acetate) mouthguards during routine use", Sci. Rep., 7, 1 (2017). https://doi.org/10.1038/s41598-016-0028-x
  68. S. Park, C. Yim, B. H. Lee, and S. Choe, "Properties of the blends of ethylene-vinyl acetate and ethylene-${\alpha}$-olefines copolymers", Macromol. Res., 13, 243 (2005). https://doi.org/10.1007/BF03219059
  69. G. Xu and K. Min, "Nonisothermal crystallization and melting behavior of EVA/OMWNTs nanocomposites", Polym. Plast. Technol. Eng., 54, 390 (2014). https://doi.org/10.1080/03602559.2014.935402
  70. S. B. Yamaki, E. A. Prado, and T. D. Z. Atvars, "Phase transitions and relaxation processes in ethylene-vinyl acetate copolymers probed by fluorescence spectroscopy", Eur. Polym. J., 38, 1811 (2002). https://doi.org/10.1016/S0014-3057(02)00067-8
  71. M. A. Bahattab, J. Mosnacek, A. A. Basfar, and T. M Shukri, "Cross-linked poly(ethylene vinyl acetate) (EVA)/low density polyethylene (LDPE)/metal hydroxides composites for wire and cable applications", Polym. Bull., 64, 569 (2010). https://doi.org/10.1007/s00289-009-0194-0
  72. F. J. Pern, "Luminescence and absorption characterization of ethylene-vinyl acetate encapsulant for PV modules before and after weathering degradation", Polym. Degrad. Stab., 41, 125 (1993). https://doi.org/10.1016/0141-3910(93)90035-H
  73. C. Hirschl, M. Biebl-Rydlo, M. DeBiasio, W. Muhleisen, L. Neumaier, W. Scherf, G. Oreski, G. Eder, B. Chernev, W. Schwab, and M. Kraft, "Determining the degree of crosslinking of ethylene vinyl acetate photovoltaic module encapsulants-A comparative study", Sol. Energ. Mater. Sol. Cells, 116, 203 (2013). https://doi.org/10.1016/j.solmat.2013.04.022
  74. Z. Xia, D. Cunningham, and J. Wohlgemuth, "A new method for measuring crosslink density in ethylene vinyl acetate-based encapsulant", Photovoltaics Int., 5, 150 (2009).
  75. W. Stark and M. Jaunich, "Investigation of ethylene/vinyl acetate copolymer (EVA) by thermal analysis DSC and DMA", Polym. Test., 30, 236 (2011). https://doi.org/10.1016/j.polymertesting.2010.12.003