Study On Preparation And Properties Of Polycarbonate Nanocomposites

The application of polycarbonate have developed toward multifunction, customization and serialization.Therefore,the extending of modification methods of polycarbonate is required besides blending and copolymerization. With the development of nanocomposite technology,it will provid new route and idea for developing new methods ofpolycarbonate modification.In this paper,SiO₂/PC nanocomposites were prepared by sol-gel method, and the dispersivity of nanoparticles in matrix,thermal stability and transparency property were analysed.These rusults showed that SiO₂ nanopaticles,particle size about 20-60nm,were homogeneously dispersed in PC matrix without obvious agglomeration.The thermal decomposable temperature of 1%SiO₂/PC nanocomposite increased 60℃,that is the thermal stabilitiy of PC was improved,and its visible light transmittance at 800nm still keep up to 74%.However,the thermal decomposable retained content of 5%SiO₂/PC nanocomposite materials at 800℃was highest.ZnO/SiO₂ nanoparticles((w/w)=1/1)were prepared by enveloping SiO₂ layer on the surface through hydrolysis of TEOS and Na₂SiO₃ respectly and were modified by silane coupling agent KH-550.Meanwhile,ZnO/SiO₂ nanoparticles were charactered by IR,XRD,SEM,TEM and photocatalysis experiment.These results indicated that the SiO₂ prepared through hydrolysis of TEOS have better enveloping effect.ZnO/SiO₂ nanoparticles size were 50-70nm and the thickness of SiO₂ layer was about 20nm.Single ZnO/SiO₂ nanoparticle contained a ZnO particle or ZnO particles.In addition,results of photocatalytic degradation showed that the catalytic activity of ZnO nanoparticles enveloped with SiO₂ prepared by hydrolysis of TEOS was markedly decreased.PC,ZnO/PC,ZnO/SiO₂/PC nanocomposites were prepared by melt injecting molding method,and the mechanical properties,optical properties and ultraviolet light aging resistance of nanocomposites were analysed.These rusults indicated that ZnO/SiO₂ nanoparticles dispersed homogeneous without obvious agglomeration.Nano-ZnO accelerated the degradation of PC,and the ultraviolet aging resistance property of PC was greatly improved by addition of ZnO/SiO₂ nanoparticles.After UV light radiation for 600h,the color difference and Yellow Index of unmodified PC,ZnO/PC and ZnO/SiO₂/PC nanocomposites were 4.56 and 10.71,3.18 and 20.86,1.09 and 6.56, respectively,their notch impact strength decreased from 9.52 kJ/m²,9.58 kJ/m² and 9.58kJ/m² to 8.35kJ/m²,7.94kJ/m² and 8.53kJ/m²,respectively.The visible light transmittance at 800nm of 1%ZnO/SiO₂/PC nanocomposite was 52%, which was higher than 31%of 1%ZnO/PC nanocomposite.