微波处理和溶胶凝胶法共同改性废胶粉及其与天然橡胶复合材料性能的研究

采用微波处理打断废胶粉(WRP)的三维网状结构用来提高WRP在有机溶剂中的溶胀性,然后采用溶胶凝胶法,将微波改性后的WRP浸入正硅酸乙酯中,通过水解反应和缩合反应,在WRP表面原位生成SiO2网络,从而制得改性废胶粉(MWRP).将制得MWRP与天然橡胶(NR)共混,制备了NR/MWRP复合材料,研究了NR/MWRP复合材料的性能.通过热重分析仪、差示扫描量热仪和力学分析表明微波处理最佳时间是20 s.由于微波处理提高了NR与WRP的相容性,原位生成的SiO2粒子起到了补强作用,所以所制备的NR/MWRP复合材料拥有较好的力学性能;随着Si69的加入,抑制了SiO2粒子聚集,提高了SiO2粒子的分散性,从而进一步提高复合材料的力学性能并降低复合材料的Payne效应;在进行频率扫描时,硫化胶的储存模量随频率的增大而增大;硫化胶的温度扫描结果表明,随着温度的升高,复合材料中SiO2粒子聚集程度加剧并且复合材料出现老化的现象.为了提高复合材料的耐老化性能,N,N-间苯撑双马来酰亚胺(BMI)作为一种防老剂加入复合材料中,BMI利用Diels-Aider反应补偿橡胶在老化过程中所损失的交联键并提高NR与WRP的界面相容性,从而提高复合材料的耐老化性能.

WASTE RUBBER POWDER MODIFIED BY BOTH MICROWAVE TREATMENT AND SOL-GEL METHOD AND THE PROPERTIES OF NATURAL RUBBER/MODIFIED WASTE RUBBER POWDER COMPOSITES

Microwave treatment was used to cut off the three-dimensional structure of waste rubber powder(WRP),which increased the swelling degree of WRP in organic solvent.Then WRP modified by microwave treatment was immersed in tetraethoxysilane.During hydrolysis and condensation reaction process,SiO2 network was in situ generated on the surface of WRP by sol-gel method,which prepared modified waste rubber powder(MWRP).Natural rubber(NR)/MWRP composites were prepared by NR blended with MWRP.The properties of NR/MWRP composites were investigated.Thermogravimetry,differential scanning calorimetry and mechanical properties analysis showed that the best microwave treatment time was 20 s.The NR/MWRP composite owned the good mechanical properties,due to the improvement of compatibility between NR and WRP after microwave treatment and the reinforcement effect of in situ generated SiO2 particles.Si69 which prevented SiO2 particles aggregation and improved the dispersion of SiO2 particles was added to the rubber matrix.With Si69 content increased,the mechanical properties of NR/MWRP composites further improved and the Payne effect decreased.The storage modulus increased with increasing frequency during frequency sweep.The result of temperature sweep showed that with temperature increased,the aggregation of SiO2 particles increased and NR/MWRP composites exhibited the aging phenomenon.To improve the aging resistance properties of NR/MWRP composites,N,N-m-phenylene bismaleimide(BMI) as an antioxidant was added.BMI compensated for the lost crosslinking bonds during rubber aging process and improved the interfacial compatibility between NR and WRP by Diels-Aider reaction,which increased the aging resistance properties of NR/MWRP composites.