การปรับปรุงความเข้ากันได้ของเทอร์โมพลาสติกวัลคาไนซ์จากการเบลนด์ระหว่างยางธรรมชาติ ยางรีเคลม และโพรพิลีนเอทิลีนโคพอลิเมอร์

Abstract

Effect of modifying agents i.e. phenolic resin, maleic anhydride and glycidyl methacrylate on properties of natural rubber/reclaimed rubber (NR/RR) blend was studied. Results show that longer scorch time and cure time of the blend with modifying agent were achieved compared to those of the blend without modifying agent. The blend with phenolic resin gave the best overall properties. Therefore, it was then further used for promoting the phase compatibility in thermoplastic vulcanizates (TPVS) based on blending of NR/RR/ propylene ethylene copolymer (PEC). Different mixing methods, melt mixing and reactive blending, were designed to prepare TPVs with phenolic resin. It was found that the TPVs prepared via melt mixing method provided superior mechanical, rheological and dynamic mechanical properties as well as better phase morphology than the TPVS prepared via reactive blending. Furthermore, suitable quantity of phenolic resin was at 10 phr. Influence of blend proportion of NR/RR/PEC TPVs, 60/0/40, 45/15/40, 30/30/40, 15/45/40 and 0/60/40 parts by weight, was also investigated. Increasing of RR in the rubber component of TPVS clearly impacted on deterioration of mechanical property. This was due to the RR had low molecular weight, remained carbon black and could not be much re-vulcanized during blending. In addition, effect of PEC-g- Ph compatibilizer in combination with phenolic resin as modifying agent on properties of NR/RR/PEC TPVs was studied. The use of compatibilizer could promote a slight increasing of tensile strength, elongation at break, storage modulus and complex viscosity of the TPVs. Furthermore, synergistic effect of PEC-g-Ph compatibilizer and phenolic resin could be found from the highest tensile strength and hardness of the TPVs. Epoxidized natural rubber (ENR) was also applied to the TPVs in replacement of NR. It was found that the TPVs with NR still showed better mechanical, rheological and morphological properties than the TPVs with ENR. Overall properties of the TPVs were decreased with increasing epoxy contents in the ENR.