Graft copolymerization of methyl methacrylate and vinyltriethoxysilane binary monomers onto natural rubber

• Published in: Journal of polymer research 2021-07, Vol.28 (7), Article 246
• Main Authors: Nghiem Thi, Thuong, Cao Hong, Ha, Nurul Hayati, Yusof, Kawahara, Seiichi
• Format: Article
• Language: English
• Subjects: Acrylics; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Conversion; Copolymerization; Graft copolymers; Industrial Chemistry/Chemical Engineering; Latex; Monomers; Morphology; Natural rubber; NMR spectroscopy; Original Paper; Polymer Sciences; Polymethyl methacrylate; Silicon dioxide; Storage modulus; Structural analysis; Tensile strength
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-021-02606-x

This work presents two different paths of graft-copolymerization of methyl methacrylate (MMA) and vinyltriethoxysilane (VTES) binary monomers onto natural rubber (NR) to prepare NR/PMMA/silica hybrid materials and investigates their properties. The first path was performed by adding VTES during graft copolymerization of MMA onto NR initiated by TBHP/TEPA initiators. The second path was carried out with two consecutive graft copolymerizations of MMA and VTES, in which VTES was grafted onto the gross NR- graft -PMMA latex. The products prepared by these two paths were denoted as NR- graft -PMMA-PVTES, NR- graft -PMMA- graft -PVTES, respectively. The formation of PMMA and silica particles were confirmed through structural characterization by NMR spectroscopy. The NR- graft -PMMA- graft -PVTES has lower MMA conversion, higher MMA grafting efficiency, and higher VTES conversion than NR- graft -PMMA-PVTES. And it has higher tensile strength, higher hardness but lower storage modulus than NR-graft-PMMA-PVTES. However, the frequency dependence of loss tangent for NR- graft -PMMA- graft -PVTES did not follow the ordinary rubber elasticity as NR and NR- graft -PMMA-PVTES did. These were due to the different morphology of PMMA and silica in the graft copolymers.