Foamability of Natural rubber (NR)/Poly(butylenes adipate-co-terephthalate) (PBAT) Thermoplastic Vulcanizate with OBSH as a blowing agent

Abstract

Natural rubber, NR, is bio-based material that is generally used for foam preparation as it results in good softness and high resilience. Among many applications, NR foam/sponge is often used for shoe sole either insole or outsole. Likewise, rubber sponge is very important for healing Plantar Fasciitis as rubber sponge is soft, elastic and capable in impact absorption. NR is in fact non-biodegradable resulting in increasing of waste which is a hot issue at present. Huge interest has paid attention in using biodegradable polymer in various products and applications. Polybutylene adipate-co-terephthalate, PBAT, is one of many bioplastics that possesses biodegradability characteristic. It also shows excellent flexibility similar to elastomer. Many attempts have been focus on blending this polymer to improve toughness in brittle plastic. Our research is aimed to incorporate PBAT into NR and producing thermoplastic vulcanizate. NR/PBAT TPV foam is then produced using 4,4-’Oxybis-benzenesulfonyl hydrazide (OBSH) as a blowing agent. The ratios of NR/PBAT are varied as follow: 70/30 65/35 60/40 55/45 50/50 45/55. The polymer blends were mixed on a two-roll mill with the formulation of ZnO 3 phr, luperox 101 1 phr and OBSH 10 phr. Compression molding was used in order to prepare rubber sponge at 160 °C, 1500 psi. Cell size, cell size distribution, density and compression set of NR/PBAT foam were investigated.