Improvement of Thermal and Mechanical Properties of Vietnam Deproteinized Natural Rubber via Graft Copolymerization with Methyl Methacrylate

• Published in: International Journal of Polymer Science Vol. 2020; no. 2020; pp. 1 - 11
• Main Authors: Thuy, T. T., Huy, Tung Nguyen, Van, Nam Nguyen, Nguyen, Thu Ha, Thi, Thuong Nghiem, Dung, T. A., Duy, Hieu Nguyen, Nhan, N. T., Quang, Tung Tran
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 2020; Hindawi; Hindawi Limited; Wiley
• Subjects: Batch processing; Butyl hydroperoxide; Chemicals; Copolymerization; Copolymers; Efficiency; Emulsion polymerization; Fourier transforms; Free radicals; Graft copolymers; Heat resistance; Initiators; Latex; Mechanical properties; Methyl methacrylate; Molecular weight; Natural rubber; NMR; Nuclear magnetic resonance; Packaging industry; Polymer crosslinking; Polymers; Polymethyl methacrylate; Proteins; Rubber; Storage modulus; Sulfur; Sulfur compounds; Tear strength; Tensile strength; Thermal properties; Thermodynamic properties; Vulcanization; Zinc oxides; United States; Vietnam; Japan
• ISSN: 1687-9422; 1687-9430
• DOI: 10.1155/2020/9037827

In this study, we investigated the improvement of the thermal and mechanical properties of Vietnam deproteinized natural rubber (DPNR) via graft copolymerization of methyl methacrylate (MMA). The graft copolymerization was achieved successfully in latex stage using tert-butyl hydroperoxide (TBHPO) and tetra-ethylenepentamine (TEPA) as radical initiators at 30°C. By grafting with various MMA feeds and initiator concentration of 6.6×10−5 mol/g-rubber, the highest grafting efficiency and conversion were achieved at MMA of 15 wt.% per kg of rubber, 68% and 90%, respectively. The structure of grafted copolymers was characterized by 1H NMR, FTIR-ATR, and GPC, and thermal properties were investigated through DSC and TGA measurements. These showed that graft copolymers were more stable and rigid than DPNR. Storage modulus (G′) of graft copolymer was found to double that of DPNR, which contributed to the formation of graft copolymer. After sulfur vulcanization, the mechanical properties of DPNR-graft-PMMA, such as tensile strength, tear strength, and hardness, were improved significantly. Curing behaviors of the graft copolymers were found to be remarkably better than virgin DPNR.