摘要
用X-射线衍射、动态力学测定等手段研究了不同拉伸倍数的超高分子量聚丙烯薄膜的力学性能的变化.以X-射线衍射法并基于串联力学模型的假设得到的各样品的表观晶区模量E_c^(app)约为34-38GPa.样品模量E_b随拉伸倍数增加而逐渐增大,其变化趋势与非晶区取向因子的变化相类似,说明非晶区取向是左右样品模量的重要因素.室温下,69倍拉伸样品的模量为27GPa,约为表观结晶模量的3/4,且其值在-150-160℃的温度范围内没有急剧变化,说明超拉伸明显改善了材料的力学性能及热稳定性.在各拉伸样品中,考虑伸直链结晶生成的可能性,利用并串联力学模型对伸直链结晶的体积分数做了估算,并对X-射线衍射法所得表观结晶模量进行了修正,认为室温下聚丙烯的真正晶区模量约为47GPa.
The mechanical properties of ultrahigh molecular weight polypropylene films with various draw ratios have been studied by WAXD and dynamic mechanical measurements. The 'apparent' crystalline modulus (Ecapp) evaluated by the X-ray diffraction method are about 34-38 GPa for the various samples. The Young's modulus of the samples is found to become larger gradually and to correlate with the increase in the noncrystalline orientation. For the sample with draw ratio of 69, the Young's modulus at room temperature is about 27 GPa, which corresponds to about three fourths of the apparent crystalline modulus, and the temperature dependence of the modulus is very small in the temperature region of -150 to 160℃ These results indicate that the mechanical property and the thermal stability of su-perdrawn films are remarkably improved. Based on the parallel-series mechanical model, the fully straight crystalline fraction and the 'true' crystalline modulus Ectrme are evaluated and the estimated Ectrme is about 47 GPa.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
1992年第3期265-272,共8页
Acta Polymerica Sinica
基金
北京化纤学院科研基金
关键词
薄膜
性能
结构
聚丙烯
超拉伸膜
Superdrawn polypropylene films, Mechanical property,Morphology, Parallel-series model, Crystalline modulus
