Ping Fan

Improving the Compatibility of Polycarbonate/UHMWPE Blends through Gamma-Ray Irradiation

Abstract Gamma-ray irradiation treatment in air has been used as an alternative to the common surface treatment of ultrahigh molecular weight polyethylene (UHMWPE) powders to induce some oxygen-containing groups onto the molecular chain of UHMWPE to enhance its compatibility with polycarbonate (PC). The effect of gamma-ray irradiation on the structure and properties of UHMWPE was studied by FTIR, gel content measurement, mechanical property testing, and melt flow rate measurement. The mechanical properties and compatibility of polycarbonate/gamma-ray irradiated UHMWPE (γ-UHMWPE) blend were also studied. The experimental results show that gamma-ray irradiation partly causes oxidative degradation of UHMWPE and the content of oxygen-containing groups increases with irradiation dose. The surface hydrophilicity of UHMWPE is improved due to the presence of oxygen-containing groups. SEM observation of the fractured surface of the PC/UHMWPE blends indicates the compatibility is improved through γ-ray irradiation. Meanwhile, improved fracture toughness and mechanical strength can also be achieved; both yield and notched impact strength of PC/γ-UHMWPE blends are greatly increased from 39.7 MPa and 9.9 kJ/m2 to 49.2 MPa and 24.9 kJ/m2, respectively, compared with the PC/UHMWPE (85/15) blend. Gamma-ray irradiation treatment is efficient for enhancing the compatibility of polycarbonate/UHMWPE blends.

Effect of Interfacial Interaction on Properties of Gamma Ray-Irradiated High Density Polyethylene Reinforced by Sericite-Tridymite-Cristobalite

A Gamma-ray irradiation was employed to modify high density polyethyelene (HDPE) in order to impart poor interfacial interaction between hydrophobic matrix and hydrophilic Sericite-Tridymite-Cristobalite (STC) filler. The STC filler was further treated with a silane coupling agent. The FTIR, SEM and rheological observations confirmed enhanced interactions between oxygen containing groups on the irradiated matrix (γ-HDPE) and NH2 groups of silane-treated filler (t-STC), resulting in improved mechanical properties of the composites (10 times in case of impact strength). The parameter of the theoretical model used characterizing interfacial interaction increased from 2.69 for HDPE/STC up to4 for irradiated and surface treated material.

Improving Polarity of UHMWPE Through γ-Ray Irradiation and Its Application

Gamma-ray irradiation treatment in air has been used to induce some oxygen-containing groups onto the molecular chains of ultra-high molecular weight polyethylene (UHMWPE) to improve its polarity. The effect of γ-ray irradiation on the structure and polarity of UHMWPE was studied by the Fourier transform infrared spectroscopy, gel content measurement, and static contact angle measurement. Gamma-ray-irradiated UHMWPE was then blended with two commonly used engineering plastics, polyamide (PA) and polycarbonate (PC), and their mechanical and frictional properties were studied. The experimental results show that the content of oxygen-containing groups increased with irradiation dose, improving the polarity of UHMWPE. Both the friction coefficient and the yield strength of the blends with PA and PC decreased with increasing UHMWPE content. However, compared with the nonirradiated blends of the same UHMWPE content, the yield strength and notched impact strength of the irradiated blends were improved, while the friction coefficient decreased.