Admicellar polymerization of polycaprolactone-polylactide on natural rubber latex particles and its nanocomposites with nanoclay

Abstract

Natural rubber was modified its surface by core-shell particle formation via admicellar polymerization by using polycaprolactone-polylactide copolymer as shell layer. Effect of particle factor, monomers ratio and initiator to monomers ratio, were observed for morphology, size, chemical function and thermal stability of admicelled particles. Then, it was incorporated with organoclay to become nanocomposite and using for PLA toughness modification. Effects of the particles factors and clay content were observed for mechanical and thermal properties of blends. Optical and transmission electron microscope revealed that core-shell structure of admicelled particles. That mean core-shell particles of natural rubber can be prepared via admicellar polymerization. IR spectra of shell layer showed characteristic peaks of PCL and PLA and also showed pattern of copolymer. TGA thermogram showed that the shell polymer did not sufficiently improve thermal stability of rubber core because there is only single decomposition which amazingly reveals good miscibility of the three components. DMA result showed that glass transition temperature (Tg) of the two components shifted close together, that means two components were more compatible. Impact testing showed that the particles with a high initiator to monomers ratio cause increasing of PLA's Impact force. Organoclay addition into admicelled rubber improved miscibility and storage modulus of blends in DMA, but impact force decreased severely.