Study On Blends Of PC And PETG

Blending of two or more polymers is an important way to prepare novel polymermaterials. Polycarbonate (PC) is a kind of engineering plastic with excellent performance, butit has poor flowability and stress cracking. Polyethylene terephthalate glycol (PETG), whichhas high transparency and glossiness, is a novel transparent engineering plastic. Therefore, anovel polymer material could be obtained by the blending of PC and PETG. In thedissertation, the blends of PC/PETG were prepared in the twin-screw extruder by meltblending, and their density, hardness, transparency, mechanical properties,micromorphological structure, thermal properties,and compatibility were studied. The resultswere as followings:1. PC/PETG alloy’s density was close to the PC and below the PETG; the Rockwellhardness was slightly lower than the PC but higher than the PETG; PC/PETG alloy was atransparent systemwith the light transmittance as high as90%.PC/PETG alloy’s mechanical properties was similar to the PC which has good tensilestrength, flexile strength and flexile modulus. Compared with pure PC, PC/PETG alloy’selongation at break was significantly improved, and the notched izod impact strengthalsoincreased with a certain extent.2. With the increase of the PETG content, PC/PETG alloy’s vicat softening temperatureand heat distortion temperature were decreased. Thermogravimetric(TG) analysis resultsshowed that the decomposition temperature of the PC/PETG alloy was above400℃. Itsthermal stability was lower than the pure PC, but higher than the pure PETG.3. DSC analysis results showed that only one glass-transition temperature (TG) could beobserved in the PC/PTEG(85/15), which demonstrated that PC was completely compatiblewith PTEG. Moreover, FTIR analysis results showed that slip diffusion and ester interchangereaction between molecular chain took place during melting blend of PC/PTEG.4. Morphological structure of PC/PETG alloys were investigated by SEM. In the SEMphotographs, it could be seen that the two phases of PC/PETG alloys were distributeduniformly and the ruptured surfaces were coarse, which betrayed that the fracture of PC/PTEG blends belonged to ductile fracture. With the increasing of the PETG content,PC/PETG alloys’ molecular chain structures were more compact.5. The products stress cracking of PC/PETG alloys were studied by acetone immersiontest. The results showed that with the increasing of the PETG content, accumulation of innerstress in products was decreased. When the content of PTEG was more than45wt%, thephenomenon of stress cracking almost disappeared.In the real project development, the processing conditions, performance of PC/PTEG andits application were further studied, which showed that PC/PETG alloys could replace the PCand PETG to be used in various products, and have certain advantages in the processing andapplication.