Melt free-radical grafting of glycidyl methacrylate (GMA) onto EPDM backbone and effect of EPDM-g-GMA on the morphology and mechanical properties of PS/EPDM/PA6 ternary blends

Document Type : Original research


1 Polymer Engineering Department, Amirkabir University of Technology, P.O. Box 5875/4413, Tehran, Iran

2 Chemical, Polymeric and Petrochemical Technology Development Research Division, Research Institute of Petroleum Industry, Tehran, Iran


Melt free-radical grafting reactions between ethylene-propylene-dieneterpolymer (EPDM) and glycidyl methacrylate (GMA) were investigated in a batch mixer (170°C, 60rpm). Effect of dicumylperoxide (DCP) initiator and GMA functionalizing monomer concentrations was studied on the grafted EPDM characteristics. Titration results indicated an increase in the graft degree (GD) and gel content (GC) values with increasing DCP concentration as a result of increasing primary free radical concentration and strengthening cross-linking side reaction. FTIR spectrums confirmed that GMA functionalities have been grafted onto EPDM with appearing carbonyl (C=O) peak. After that, the resultant EPDM-g-GMA was used as compatibilizer in PS(polystyrene)/EPDM/PA6 (polyamide6) ternary blends. The effect of rubbery compatibilizer on the blend morphology and mechanical properties was studied. The ATR-FTIR spectra of ternary blends, etched to remove unreacted PA6, demonstrated that the compatibilizing reactions occurred during melt blending. By investigating the SEM micrographs it was revealed that the EPDM-g-GMA compatibilizer at the concentration range of 5 wt.% to 15 wt.% changed the size and type of the blend morphology from separated dispersed to multicore-shell morphology. The finest morphology was achieved by using 7.5 wt.% EPDM-g-GMA. Also, the presence of compatibilizer up to 7.5 wt.% could improve the tensile modulus, yield stress and impact strength, but a decreasing trend was observed at higher concentration of the compatibilizer.


Main Subjects

  1. Passaglia E, Coiai S, Augier S (2009) Control of macromolecular architecture during the reactive functionalization in the melt of olefin polymers. Prog Polym Sci 34: 911-947
  2. Belekian D, Beyou E, Chaumont P, Cassagnau P, Flat JJ, Quinebèche S, Guillaneuf Y, Gigmes D (2015) Effect of nitroxyl-based radicals on the melt radical grafting of maleic anhydride onto polyethylene in presence of a peroxide. Eur polym J 66: 342-351
  3. Liu W, Liu T, Liu T, Liu T, Xin J, Hiscox WC, Liu H, Liu L, Zhang J (2017) Improving grafting efficiency of dicarboxylic anhydride monomer on polylactic acid by manipulating monomer structure and using comonomer and reducing agent. Ind Eng Chem Res 56: 3920-3927
  4. Bansod ND, Kapgate BP, Maji PK, Bandyopadhyay A, Das C (2018) Functionalization of EPDM rubber toward better silica dispersion and reinforcement. Rubber Chem Techn 92: 219-236
  5. Cho KY, Eom J-Y, Kim C-H, Park J-K (2008) Grafting of glycidyl methacrylate onto highdensity polyethylene with reaction time in the batch mixer. J Appl Polym Sci 108: 1093-1099
  6. Doudin K, Ahmad A, Al-Malaika S (2009) Reactive processing of polymers: Structural characterisation of products by 1H and 13C NMR spectroscopy for glycidyl methacrylate grafting onto EPR in the absence and presence of a reactive comonomer. Polym Degrad Stabil 94: 1599-1614
  7. Saeb MR,Garmabi H (2009) Investigation of styrene-assisted free-radical grafting of glycidyl methacrylate onto high-density polyethylene using response surface method. J Appl Polym Sci 111: 1600-1605
  8.  Jazani OM, Rastin H, Formela K, Hejna A, Shahbazi M, Farkiani B, Saeb MR (2017) An investigation on the role of GMA grafting degree on the efficiency of PET/PP-g-GMA reactive blending: Morphology and mechanical properties. Polym Bull 74: 4483-4497
  9. Papke N, Karger-Kocsis J (1999) Determination methods of the grafting yield in glycidyl methacrylate-grafted ethylene/propylene/diene rubber (EPDM-g-GMA): Correlation between FTIR and 1H-NMR analysis. J Appl Polym Sci 74: 2616-2624
  10. Gross IP, Schneider FS, Caro MS, da Conceição TF, Caramori GF, Pires AT (2018) Polylactic acid, maleic anhydride and dicumyl peroxide: NMR study of the free-radical melt reaction product. Polym Degrad Stabil 155: 1-8
  11. Huang L-P, Zhou X-P, Cui W, Xie X-L, Tong S-Y (2009) Maleic anhydride-grafted linear lowdensity polyethylene with low gel content. Polym Eng Sci 49: 673-679
  12. Fang Z, Guo Z, Zha L (2004) Toughening of polystyrene with ethylene-propylene-diene terpolymer (EPDM) compatibilized by styrenebutadiene-styrene block copolymer (SBS). Macromol Mater Eng 289: 743-748
  13. Li J, Guo S, Slezák R, Hausnerová B (2005) In situ compatibilization of PS/EPDM blends during ultrasonic extrusion. Macromol Chem Phys 206: 2429-2439
  14. Scares BG, Sirqueira AS, Oliveira MG, Almeida MS (2002) Compatibilization of elastomer-based blends. Macromol Symp 189: 59-82
  15. Shokoohi S, Arefazar A, Naderi G (2012) Compatibilized PP/EPDM/PA6 ternary blends: extended morphological studies. Polym Adv Technol 23: 418-424
  16. Ravanbakhsh M, Khorasani SN, Khalili S (2015) Blending of NR/BR/ENR/EPDM-gGMA by reactive processing for tire sidewall applications: Effects of grafting and ENR on curing characteristics, mechanical properties, and dynamic ozone resistance. J Elastom Plast 48: 394-403
  17. Alidadi-Shamsabadi M, Arefazar A, Shokoohi S (2020) Response surface analysis of PS/EPDM/PA6 ternary blends: Effect of mixing sequence, composition, and viscosity ratio on the mechanical properties. J Vinyl Addit Technol 26: 282-290
  18. Sheshkali HRZ, Assempour H, Nazockdast H (2007) Parameters affecting the grafting reaction and side reactions involved in the free-radical melt grafting of maleic anhydride onto high-density polyethylene. J Appl Polym Sci 105: 1869-1881
  19. Wei Q, Chionna D, Galoppini E, Pracella M (2003) Functionalization of LDPE by melt grafting with glycidyl methacrylate and reactive bending with polyamide-6. Macromol Chem Phys 204: 1123- 1133
  20. 20.Al-Malaika S, Eddiyanto E (2010) Reactive processing of polymers: Effect of bifunctional and tri-functional comonomers on melt grafting of glycidyl methacrylate onto polypropylene. Polym Degrad Stabil 95: 353-362
  21. Brito GF, Xin J, Zhang P, Mélo TJ, Zhang J (2014) Enhanced melt free radical grafting efficiency of polyethylene using a novel redox initiation method. RSC Adv 4: 26425-26433
  22. Al-Malaika S, Kong W (2001) Reactive processing of polymers: Melt grafting of glycidyl methacrylate on ethylene propylene copolymer in the presence of a coagent. J Appl Polym Sci 79: 1401-1415
  23. Libio IC, Grassi VG, Dal Pizzol MF, Bohrz Nachtigall SM (2012) Toughened polystyrene with improved photoresistance: Effects of the compatibilizers. J Appl Polym Sci 126: 179-185
  24. Yang W, Dominici F, Fortunati E, Kenny JM, Puglia D (2015) Melt free radical grafting of glycidyl methacrylate (GMA) onto fully biodegradable poly (lactic) acid films: Effect of cellulose nanocrystals and a masterbatch process. RSC Adv 5: 32350-32357
  25. Hu G-H, Cartier H (1999) Styrene-assisted melt free radical grafting of glycidyl methacrylate onto an ethylene and propylene rubber. J Appl Polym Sci 71: 125-133
  26. Al-Malaika S, Kong W (2005) Reactive processing of polymers: Functionalisation of ethylene–propylene diene terpolymer (EPDM) in the presence and absence of a co-agent and effect of functionalised EPDM on compatibilization of poly(ethylene terephthalate)/EPDM blends. Polym Degrad Stabil 90: 197-210
  27. Heinen W, Rosenmöller C, Wenzel C, De Groot H, Lugtenburg J, Van Duin M (1996) 13C NMR study of the grafting of maleic anhydride onto polyethene, polypropene, and ethene− propene copolymers. Macromolecules 29: 1151-1157
  28. Jazani OM, Arefazar A, Peymanfar MR, Saeb MR, Talaei A, Bahadori B (2013) The Influence of NBR-g-GMA compatibilizer on the morphology and mechanical properties of poly (ethylene terephthalate)/polycarbonate/NBR ternary blends. Polym-Plast Technol 52: 1295-1302
  29. Jazani OM, Arefazar A, Jafari SH, Peymanfar MR, Saeb MR, Talaei A (2013) SEBS-g-MAH as a reactive compatibilizer precursor for PP/PTT/SEBS ternary blends: Morphology and mechanical properties. Polymer-Plastics Technol 52: 206-212
  30. Li H, Sui X, Xie X-M (2018) Correlation of morphology evolution with superior mechanical properties in PA6/PS/PP/SEBS blends compatibilized by multi-phase compatibilizers. Chinese J Polym Sci 36: 848-858
  31. Jazani OM, Arefazar A, Jafari S, Beheshty M, Ghaemi A (2011) A study on the effects of SEBSg-MAH on the phase morphology and mechanical properties of polypropylene/polycarbonate/SEBS ternary polymer blends. J Appl Polym Sci 121: 2680-2687