Research On The Modification Of NR/CPVC Blended Thermoplastic Elastermer

The dynamically vulcanized NR(Natural Rubber)/CPVC(Chlorinated Polyvinyl Chloride) blended thermoplastic elastomer(TPV) has been prepared on the two-roll mill. The effect of NR-g-(GMA-co-St)/nano-SiO2as a compound compatibilizer and reinforcing agent upon TPV has been systematically studied by the means of static mechanical properties、dynamical mechanical properties and SEM. The results show that comprehensive properties of TPV have been significantly improved after adding NR-g-(GMA-co-St) as the compatibilizer into TPV. And The properties have been further enhanced when nano-SiO2as the reinforcing agent was added into NR/CPVC TPV compatibilized by NR-g-(GMA-co-St). The adding means of nano-SiO2has some influence upon the effect of modification. When the mass ratio of NR-g-(GMA-co-St) and nano-SiO2was7%and3%respectively, NR-g-(GMA-co-St)/nano-SiO2collaboratively compatibilized and reinforced NR/CPVC TPV has the best performance. Compared with unmodified TPV, tensile strength、tear strength、 elongation at break and spring rate of NR/CPVC TPV modified by NR-g-(GMA-co-St) and nano-SiO2,which has good resistance to mixed solvent and heat deformation, increased by230%、44%、300%and14.3%respectively. The analysis of the morphological structure showed that NR-g-(GMA-co-St)/nano-SiO2synergistic compatibilizer can significantly improve the uniformity of cross-linked NR as the dispersed phase in the CPVC matrix, decrease the particle size of cross-linked NR and incraese the contact area between NR and CPVC for the purpose of enhancing the interfacial strength between them.Based on the research above, the effect of the flame retardants JLS-PNP3D and JLS-PNP3D/Sb2O3upon NR/CPVC has been studied by the means of analyzing LOI、 vertical flammability rating、dripping and black-smoke when it was burning. The static mechanical properties have been measured and combustion mechanism of TPV has also been studied by the means of TG. The results show that the mass ratio of the flame retardant has great impact upon the flame-retardant properties and mechanical properties of TPV, and its adding means has some influence on the mechanical properties without affecting the flame-retardant properties. JLS-PNP3D/Sb2O3complex flame retardant shows good flame-retardant effect while not deteriorating the mechanical properties too much. When the mass ratio of JLS-PNP3D and Sb2O3was 40%and3%respectively, LOI of the flame retardant modified TPV reached26.9%and vertical flammability rating was UL94-V0. When the mass ratio of JLS-PNP3D and Sb2O3was40%and5%respectively, LOI of TPV reached28.1%. The flame-retardant mechanism of modified TPV is mainly condensed complementary charcoal flame-retardant mechanism. By the implementation of effective surface modification of JLS-PNP3D and Sb2O3, a key direction of our future research is improving the dispersity of the flame retardants in order to enhance the flame-retardant and mechanical properties of TPV.