自增强高性能聚合物的成型工艺同力学性能间相关性研究——5.一种从实验上来测定取向聚乙烯纤维理论强度的新方法

A STUDY OF THE RELATIONSHIP BETWEEN THE MECHANICAL PROPERTIES AND PROCESSING FOR SELF-REINFORCED POLYMERS 5- A New Method for Determining the Theoretical strength of Oriented Polymers from Experiments

本文提出了一种从实验上来测定取向聚乙烯纤维理论强度的新方法。它基于自增强高聚物恒定应力下持久强度动力学模型理论,采用自增强高聚物非晶区(或微区)中伸直应力集中链系数作为自变量来建立微区中伸直应力集中链(TautTie Molecule和/或Trapped Entanglement Chain)的断链动力学方程,经积分和化简后,得到了自增强高聚物的抗张强度同其起始结构、成型工艺、测试条件和断裂时间等的一般关系式。当把牵伸时间t_D远远大于松弛时间τ_3和起始分子量趋近无穷大时,结合光子强度理论后就得到了超拉伸高取向高聚物的抗张强度同理论强度、微区中应力集中伸直链(TTM和/或TEC)的重量分数(X_(e3))和热涨落等间的定量关系,并提出了一种从实验上来测定高取向纤维理论强度的新方法。用该法测定了超高分子量聚乙烯(UHMWPE)纤维的理论强度,其结果同理论计算值很好符合。

A new method for determining the theoretical strength of oriented polymers was developed. It is based on the kinetic model theory of creep strength, in which a kinetic equation for bond rupture of overs-stressed Taut Tie Molecules(TTM)and/or Trapped Entanglement Chains(TEC) in the disordered domain is established by using the coefficient of overs-tressed TTM and/or TEC as a variable. After integration and simplifica-tion a general correlation among the tensile strength with the primary molecular weight, the processing condition and dursbility was obtained. When the drawn ratio of processing and primary molecular weight is extro-polated to infinity, a general relation of actual tensile strength to the theoretical strength, the fraction of TTM and/or TEC(X03) in the disord-ered domain and the thermal fluctuation was derived. Based upon this rela-tion a new method for determining the tteoreticel strength of oriented polymers from the measurement of the actuale strength and the fraction of TTM and/or TEC and of fiblillar materials was proposed. The theoretical strength of UHMWPE chain was yielded by this method.