Wen Zhou

Effect of nucleating agent on the structure and properties of polypropylene/poly(ethylene–octene) blends

Abstract The effect of the sorbital nucleating agent on properties of the ethylene–octene copolymer (POE) toughened polypropylene (PP) was studied. The results show that the addition of POE increases notched Izod and Charpy impact strength significantly but impair the tensile strength and flexural modulus. As a nucleating agent (1,3,2,4-di(p-methylbenzylidene) sorbitol, DM) was added, the toughness and stiffness of toughed PP increased simultaneously at the same content of POE. This result shows that the toughness and stiffness of toughed PP are in balance. Polarized light microscopy analysis shows that with the addition of POE and nucleating agent, only a low level of PP spherulites were observed.

Effects of Trans-Esterification Stabilizers on Mechanical Properties and Structure of Poly(butylene terephthalate)/Polycarbonate Blends

The effects of triphenyl phosphite (TPPi) and disodium diphosphate (DSDP) on the trans-esterification between poly(butylene terephthalate) (PBT) and polycarbonate (PC) in melt mixing and the mechanical properties of PBT/PC blends were studied. The experimental results showed that the Vicat temperature of the blends increased because of the addition of TPPi or DSDP. DSDP had little effect on the mechanical properties of the toughened PBT/PC blends containing poly(ethylene–butylacrylate-glycidyl methacrylate) (PTW) as toughener, and TPPi led to a decrease in the notched Izod impact strength of the toughened PBT/PC blends. DSDP was confirmed to be an effective stabilizer for the trans-esterification of PBT and PC, using the methods of Fourier Transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and solvent extraction.

Toughening modification of poly(butylene terephthalate)/ polycarbonate blends by poly(ethylene-co-octene)

New toughened poly(butylene terephthalate) (PBT)/bisphenol A polycarbonate (PC) blends were obtained by melt blending with commercial poly(ethylene-co-octene) copolymer (POE), varying the POE content up to 10 wt%, in a twin screw extruder, followed by injection moulding. The influence of POE on the properties of the PBT/PC blends was investigated in terms of mechanical testing, dynamic mechanical thermal (DMTA) analysis, differential scanning calorimetry (DSC), and scanning electronic microscopy (SEM). The results showed that addition of POE led to remarkable increases in the impact strength, elongation at break and Vicat temperature, and a reduction in the tensile strength and flexural properties of PBT/PC blends. The morphology of the blends was observed using SEM and the average diameter of the dispersed phase was determined by image analysis. The critical inter-particle distance for PBT/PC was determined.