(A) study on the synthesis and properties of acrylonitrile-butadiene-styrene copolymer/layered silicate nanocomposites using reactive amphiphiles with vinyl group by emulsion polymerization

Abstract

Grafted Acrylonitrile-Butadiene-Styrene copolymer/layered silicate nanocomposites were prepared via in-situ emulsion polymerization. Acrylonitrile and styrene monomer and polybutadiene latex copolymerize with double bonds started by radical initiator. Reactive amphiphile with vinyl group and cation exchangeable group was used to examine its role on the silicate dispersion. Vinylbenzyldimethyldodecylammonium chloride (VDAC) was synthesized by direct reaction of vinylbenzylchloride with dimethyldodecylamine. The surfactant, DBS-Na, was used in this system. Prepared nanocomposites with 3 and 5 PHM of silicate loading were characterized by XRD, TGA and TEM. The exfoliated morphology of layered silicate was confirmed from the data. However, when we used DBS-Na as a surfactant, the emulsion showed very poor stability during polymerization. To obtain fine latex condition, another kind of surfactant, SDS, was employed and its suitable addition condition was investigated to make a stable emulsion. The synthesized ABS/layered silicate nanocomposite using VDAC as an amphiphile and SDS as a surfactant were characterized by XRD, TGA, DMTA and TEM. From XRD patterns, the silicates are exfoliated in ABS matrix, because VDAC widens silicate layers and accelerates the insertion of monomers. In a point of storage modulus, the nanocomposite using VDAC with 7 PHM of clay shows up to 15.08% increment to neat copolymer with VDAC. Also, there is 32.17% increment of sample with VDAC compare to nanocomposite with the same content of clay without VDAC in storage modulus respectively. From TEM image of stained sample of ABS nanocomposites, some silicate layers are attached on the rubber latex surface due to the reactivity of reactive amphiphile. The synthesis of ABS/layered silicate nanocomposite using 3-(dimethylamino) propyl acrylate (DMPA) as an amphiphile was also performed and it had an intercalated morphology investigated. This result could be explained that smaller s...