Preparation of poly(methyl methacrylate-co-butyl methacrylate) nanoparticles and their reinforcing effect on natural rubber

Poly(methyl methacrylate- co -butyl methacrylate) [P(MMA- co -BMA)] nanoparticles were synthesized via emulsion polymerization, and incorporated into natural rubber (NR) by latex compounding. Monodispersed, core-shell P(MMA- co -BMA)/casein nanoparticles (abbreviated as PMBMA-CA) were produced with casein (CA) as surfactant. The chemical structure of P(MMA- co -BMA) copolymers were confirmed by 1 H-NMR and FTIR analyses. Transmission electron microscopy demonstrated the core–shell structure of PMBMA-CA, and PMBMA-CA homogenously distributed around NR particles, indicating the interaction between PMBMA-CA and NR. As a result, the tensile strength and modulus of NR/PMBMA-CA films were significantly enhanced. The tensile strength was increased by 100% with 10% copolymer addition, when the molar ratio of MMA:BMA was 8:2. In addition, scanning electron microscopy and atomic force microscopy results presented that the NR/PMBMA-CA films exhibited smooth surfaces with low roughness, and PMBMA-CA was compatible with NR. FTIR-ATR analyses also suggested fewer PMBMA-CA nanoparticles migrated out of NR. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43843.