| Natural rubber (NR) is a renewable resources, which are applied in tire products, latex products and other areas, so the consumption of NR is more. At present, the production process of natural rubber is the first solidified into blocks and then prillinged, which increases manufacturing costs and undermines the molecular weight of the natural rubber itself, and then affects the performance of the latter of the natural rubber. Therefore, it is necessary to study a new processing technology of natural rubber.In this study, rubber particles and purple black filled natural rubber composite particles were fabricated by adding xanthan gum as auxiliary agent, which was analyzed via RPA, SEM, TG and other means for structure and properties of rubber particles and compared with SCR5.The aim was to explore the influence of coagulant dosage for shape and performance of rubber particles. The results revealed that xanthan gum as adjuvant prepared rubber particles was feasible. Molding effect was related to adjuvant dosage. When the phr was small, which can't form good hydration layer and physical crosslinking to granulate. With the increase of its amount, high viscosity liquid latex system was not conducive to processing. So the dosage of xanthan gum was controlled between0.2%and0.6%. With the increase of the amount of xanthan gum, impurities, P0and PRI of rubber particles was little change. But six indicators were still in line with the relevant national standards.T10and T90of rubber particles were shorter than SCR5, but MH and (MH-ML) were higher than SCR5, which suggested that vulcanization rate and vulcanization strength of the rubber particles were high. Mechanical properties showed that300%of constant stress, strength of extension, Er hardness and elongation at break of rubber particles were higher than SCR5, when the dosage of xanthan gum was0.6%. RPA analysis of mixing rubber showed that rubber particle loss factor was higher, modulus of elasticity was smaller and processing performance was better. But rubber particle was more sensitive to temperature, and crosslinking temperature was lower than SCR5. Strain sweep vulcanizates found that loss factor (Tan?) and elastic modulus (G') changed little at low strain, and loss factor increased, but the elastic modulus decreased after strain increased to a certain value. SCR5vulcanizates changed more, which indicated that pimpled rubber crosslinking network stabilizer than SCR5. TGA showed that SCR5maximum degradation temperature was384.7?, and the degradation rate (Cp) was30.78%. The degradation temperature of pimpled rubber was380.4?and decomposition rate was the fastest, which was33.36%. The ultima degradation rate of SCR5and the rubber particles were89.44%and89.32%, that was little difference in the degradation rate. Thermal stability of rubber particles was poorer than SCR5.The performance of the pimpled rubber was investigated at different curing time, which xanthan gum was0.6%. When curing time was0.5-12h, T90was prolonged and mechanical properties was worse with the extension of curing time, but the curing time was16h, mechanical performance will be improved. When the curing time was0.5h, T90was shortest, overall performance was better. RPA analysis of the vulcanizates viewed that the crosslinking structure of vulcanizates became poorer, loss factor increased and elasticity decreased, when the aging time was12h.The drying temperature of pimpled rubber effected performance of the particle. Studies had shown that the moisture content of colloidal particles was about80%, the surface of pimpled rubber shrinked and more holes on particle surface after drying. Vulcanization time of rubber particle was longer, cross-linking density was first higher then decreased with increasing of temperature. When the drying temperature was80?, the crosslinking density of the rubber particle was higher, and comprehensive performance was better. |
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