| Summary: | 碩士 === 南臺科技大學 === 化學工程與材枓工程系 === 103 === In the past decade, scientists have shown great interest in nanoparticle-additives since their application dramatically improved material properties such as stiffness, tensile strength, fracture toughness, thermal stability. Compare with inorganic nanoparticle-additives, organic nanoparticle-additives have the advantage in terms of manufacturing, easy to preparation and dispertion in organic matrix. In addition, organic nanoparticle have low-density and low cost.
Polystyrene (PS) nanoparticles were synthesized via emulsion polymerization in the present paper. The variations of the 2-hydroxyl ethylene methacrylate(2-HEMA) content in 3, 5, 7, 10 wt.% (based on styrene monomer) were used as co-monomer which co-polymerized with styrene. This kinds of copolymer nanoparticles have hydroxyl group which can interact with carboxylic acid group within rubber, and the mechanical properties of rubber was thus improved. The average size of the poly(St-co-HEMA)s shows ca. 45 nm after zetasizer(DLS) measurement. The effect of poly(St-co-HEMA)s nanoparticles(1 w.t.% based on the solid contents of rubber) in rubber on tensile strength were investigated. From the results, when poly(St/HEMA)s nanoparticles carried out with St/HEMA molar ratio of 97:3, the best elongation at break that up to more than 3500%. On the other hand, highly rigid polymeric particle of poly(St-co-DVB-co-HEMA)s were carried out with constant St/HEMA molar ratio of 97:3 and the variations of the DVB content in 5, 7, 10 wt.% (based on styrene monomer) as a cross-linker during polymerization. From the SEM image of poly(St-co-DVB-co-HEMA)s nanoparticles, in which particles have a better defined individual shape and the average diameter ca. 44 nm after DLS measurement. The mechanical properties of the poly(St-co-DVB-co-HEMA)s/rubber nanocomposites, including the tensile strength, modulus and elongation, were increased with that of increasing of poly(St-co-DVB-co-HEMA)s adding. When the poly(St-co-DVB-co-HEMA)s nanoparticles carried out with constant St/HEMA molar ratio of 97:3 and the DVB content in 10 wt.%, the elongation at break that up to more than 3500% and the ultimate stress increased from 0.2 MPa to 0.6 MPa. Summary, the poly(St-co-DVB-co-HEMA)s nanoparticles prepared by emulsion polymerization could be successfully enhanced the mechanical properties of rubber latex. The poly(St-co-DVB-co-HEMA)s nanoparticles can also be applied on other latex blending system.
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