采用钴源以剂量率为2.5kGy·h?1的γ射线对超高分子量聚乙烯(Ultra-high Molecular Weight Polyethylene,UHMWPE)片材在空气、水、甲醇和乙醇氛围中进行了辐照,吸收剂量范围为0–200kGy.通过机械性能、凝胶含量、差示扫描量热仪(Differential Scanning Calorimetry,DSC)、傅里叶变换红外光谱仪(Fourier Transform Infrared Spectrometer,FTIR)等对不同辐照氛围中辐照前后UHMWPE样品进行了测试和表征.机械性能测试结果表明,在空气中UHMWPE的断裂伸长率随吸收剂量呈幂指数下降,同时屈服强度略有下降,而在水、甲醇、乙醇为辐照体系中UHMWPE的断裂伸长率随吸收剂量也是呈下降趋势,但下降的程度依次减轻,同时屈服强度基本保持不变;DSC测试结果显示,在空气氛围中,随着吸收剂量的增加,UHMWPE样品的初始熔融温度、熔点、结晶温度和结晶度逐渐降低;而在空气、水、甲醇和乙醇氛围中,UHMWPE样品的初始熔融温度、熔点和结晶度依次上升;红外光谱测试结果显示在空气中辐照,UHMWPE样品表面随着吸收剂量的增加其氧化程度加重,而在水、甲醇和乙醇中辐照UHMWPE分子链生成了不饱和的分子双键.%Background:Ultra-high molecular weight polyethylene (UHMWPE) is a kind of widely used engineering plastics due to its excellent physical and chemical properties. But it has the poor creep resistance. Purpose:The aim is to improve its creep resistance, environmental stress cracking and shape stability.Methods:The UHMWPE sheets were irradiated in air, water, methanol and ethanol at the dose rate of 2.5kGy·h?1 in the range of 0–200kGy. And the UHMWPE samples were tested and characterized by mechanical properties, gel content, differential scanning calorimetry (DSC) and infrared spectra.Results and Conclusion: The mechanical property test results revealed that the elongation at break of UHMWPE samples decreased obviously with the increasing of radiation dose. In water, methanol and ethanol, the elongation at break of UHMWPE samples also decreased with the increasing radiation dose, but the decrease degree was reduced, while the yield strength remained unchanged. DSC test results showed that the initial melting temperature, melting point and crystallinity of the UHMWPE samples decreased with the increasing absorbed dose in the air atmosphere, while increased in the atmosphere of water,methanol and ethanol. Infrared spectrum test results showed that the oxidation on the surface of the UHMWPE samples increased with the absorbed dose irradiated in the atmosphere of air, and in water, methanol and ethanol, the molecular chains of UHMWPE molecules generated double bond under radiation.
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