Studies On PC/PS Plastic Material

Polycarbonate(PC) has many excellent mechanical properties, such as excellent impact resistance, high tensile strength and bending strength, high compressive strength; small creep, size stability, good heat resistance and low temperature resistance. So PC can be used as LED encapsulant material and so on. However, PC surffers easy stress cracking, bad weather resistance and poor abrasion resistance. In order to take advantage of the high performance of PC in the area of LED encapsulant material, TiO2/SiO2/polycarbonate(PC)/polystyren-e(PS) was prepared. Meanwhile, SiO2-modified nano-TiO2 was prepared by Na2Si03 hydrolysis method. The equally transparent PS was added to PC to improve its toughness, at the same time SiO2-coated TiO2 was added to the PC/PS composite to improve the wear resistance and lightfastness, and at last polycarbonate plastic material was prepared. Compared with previous transparent materials, the PC composite was a plastic alloy rather than pure plastic, which had the advantages of two kinds of plastic, and made up for each other's limitation.And its molding process was simpler and more practical.TiO2/SiO2 nanoparticles were prepared by enveloping SiO2 layer on the surface through hydrolysis of Na2Si03 and were modified by silane coupling agent KH-550. PC, PC/PS, TiO2/SiO2/PC/PS, KH550-NanoTiO2/SiO2/PC/PS nanocomposites were prepared by melt injecting molding method. Infrared Spectroscopy(FT-IR), Scanning Electron Microscopy(SEM), XRD,EDS,UV-Vis Spectrophotometer were used to characterize TiO2/SiO2 and KH550-NanoTiO2/SiO2.The thermal stability, Total light Transmission and tensile properties of nano-composites samples were characterized by TG, UV-vis and tension gauge.The results show that:(1) The formation of Ti-O-Si bond in SiO2-coated TiO2 indicated the chemical bonding of SiO2 on the surface of TiO2;(2) The dispersivity of TiO2 was improved after SiO2 coating. The particle size became larger. The nano-TiO2/SiO2 have better dispersion after being surface modified by KH550;(3) The photocatalytic activity of TiO2/SiO2 was improved.The photocatalytic activity of KH550-NanoTiO2/SiO2 was lower than that of TiO2/SiO2;(4) Nano-TiO2/SiO2 particles play the role of cross-linking into PC/PS matrix. PC/PS composities with 1% nano-TiO2/SiO2 particles have the highest starting thermal decomposition temperature(450℃). And the residue of thermal decomposition is about 22%;(5) The transmittance of PC/PS composites with 0.5% nano-TiO2/SiO2 particles was 89%;(6) The mechanical properties of PC/PS composites with 0.5% nano-TiO2/SiO2 particles was excellent. PC/PS composites with 0.5% nano-TiO2/SiO2 particles dealed with KH-550 improved its mechanical properties;...