Research On Compatibilization Of Silicone Rubber/thermoplastic Polyurethane Blends

Silicone thermoplastic vulcanizate(TPSiV)is a silicone elastomer with a special "sea-island" structure,a small amount of thermoplastic and a large amount of rubber are dynamically vulcanized,after the "reverse" occurs,the cross-linked rubber particles are dispersed in the thermoplastic matrix.TPSiV combines the outstanding aging resistance,excellent thermal stability of silicone rubber(SiR),good performance in high and low temperature environments,and high strength,high elasticity,oil and abrasion resistance of thermoplastic polyurethane(TPU),the advantage of its use performance far exceeds ordinary thermoplastic vulcanizate(TPV),it is used in sports and leisure products,food packaging,electronic equipment,automobile production and other industries.widely used.Fine microscopic phase is the prerequisite for TPV to have excellent performance,and the better the compatibility of the simple blend of SiR/TPU,the finer the TPV phase obtained after dynamic vulcanization.SiR and TPU are difficult to be compatible due to the large difference in polarity,so it is necessary to compatibilize the SiR/TPU blend system.This project takes SiR/TPU simple blend as the compatibilization research object,aims to improve the compatibility of the two,and provides theoretical guidance for the preparation of high-performance SiR/TPU TPV with fine phase state.The compatibility of SiR/TPU blends is improved by adding ethylene-methyl acrylate copolymer(EMA),polar silicone copolymer,and block copolymer silane-modified polyurethane(TPSiU).The current research results are as follows:(1)EMA with 30%grafted content of methyl acrylate(MA)is preferred as the reactive compatibilizer,and the compatibilization effect of EMA addition on the simple blend of SiR/TPU is studied,in the blend of SiR/TPU,after adding EMA,the dispersion of SiR in TPU tends to be uniform,the average particle size is reduced,and the mechanical properties are significantly enhanced.When the addition amount is 5 phr,the average particle size of the dispersed phase is reduced from 2.29μm,which is not compatibilized,to 1.51μm,and the tensile strength is increased from 7.5MPa to 18.5MPa.(2)The compatibilization effect of polar silicone copolymer(90%silicone copolymer content and 10%polar group content)on SiR/TPU blends was studied,when used as part of the rubber phase,the addition of more The particle size of the dispersed phase of the blend is reduced to a certain extent when a small amount is used,only when the content of the polar silicone copolymer is high or completely replaces SiR,the particle size of the dispersed phase of the blend is significantly reduced and can be reduced to 680nm.(3)Three kinds of silane-modified polyurethane TPSiU(V-165,V-175,V-185)block copolymers with different siloxane segment content and different hardness grades are selected to compatibilize SiR/TPU blends,it is found that when the three kinds of TPSiU are added in a small amount(5-10 parts),they all have obvious compatibilization effect on the simple blend of SiR/TPU,among them,the compatibilizer with higher siloxane segment content is the best,the average particle size of the dispersed phase of the blend system is greatly reduced,and the thickness of the two-phase interface is greatly increased from 2.29μm to 720nm when it is not compatibilized,and the mechanical properties of the blend are significantly improved when it is not compatibilized from 40nm to 110nm;Three types of compatibilizers were further used for the compatibilization of SiR/TPU TPV,and it was found that the compatibilization effect was better.Three types of TP Vs with different hardness levels and excellent comprehensive performance were successfully prepared.