官能化超高相对分子质量聚乙烯的制备和表征

Preparation and Characterization of Functionalized Ultrahigh Molecular Weight Polyethylene

用60Coγ射线辐照方法,将丙烯酸(AA)单体接枝到超高相对分子质量聚乙烯(PEUHMW)分子链上。提出了接枝反应的机理。研究了单体浓度、辐照剂量及辐照时间对接枝率的影响。应用FTIR和DSC对接枝共聚物的结构及热性能进行了表征,用化学滴定法测定了接枝共聚物的接枝率。结果表明:接枝物在1716cm-1处有明显的羰基峰,说明AA分子确实接枝到PEUHMW分子链上,接枝率随单体浓度、预辐照剂量及辐照时间的增加而上升。

Grafting-copolymer of ultrahigh molecular weight polyethylene (PE-UHMW) with acrylic acid (AA) was prepared via γ ray co-radiation. FTIR spectra exhibited a new peak at 1 716 cm-1, which was attributed to the carbonyl of AA. This indicated that AA has been grafted onto PE-UHMW chains. Degree of grafting of functionalized PE-UHMW was measured by the chemical titration. Grafting mechanism was tentatively proposed. The effects of monomer concentration, radiation dose and radiation time on degree of grafting was studied systematically. The results showed that functionalized PE-UHMW with high degree of grafting and without any gelation. Thermal properties of ultrahigh molecular weight polyethylene grafted with acrylic acid (PE-UHMW-g-AA) and PE-UHMW were studied by using differential scanning calorimetry (DSC).The melting enthalpy of PE-UHMW-g-AA was lower than that of the neat PE-UHMW. Because PE-UHMW was grafted with polar AA molecular, functionalized PE-UHMW molecular chains would decrease the perfection of crystals of PE-UHMW.