导　　师： 吴大鸣

学科专业： H0203

授予学位： 硕士

作　　者： ;

机构地区： 北京化工大学

摘　　要： 随着对塑料管材的需求量大幅度提高，应用领域不断拓宽，使用要求不断提高，各国对塑料管材的性能提出了更高的要求，如何既节省材料，又提高管材的各方面性能是塑料管材研究的一个重要方向。双向拉伸自增强技术是一种制备高性能塑料管材的生产方法，该方法通过对管材进行轴向和环向拉伸取向，使管材力学性能得到自增强。这种自增强技术，对结晶材料和无定形材料都适用。聚乙烯通过化学或物理方法引发交联反应可以得到交联聚乙烯，材料由线型结构转变为三维网状结构，明显的改善了聚乙烯的性能。聚乙烯交联后，耐热性及热强度、耐热氧老化性、耐环境应力开裂性、耐油性等都得到较大提高。本文研究了pex管材的准动态连续扩张机理。 所谓准动态扩张是将管材的连续扩张分解成分段的静态扩张，再将所有静态扩张起来，加以控制之后实现的静态扩张。每段管坯被扩张后，扩张段长度增加，在管坯来不及周向回缩时冷却定型。本文给出了pex管材的最佳实验参数，包括管材的加热温度、加热时间、扩张压力、扩张时间等。本实验中通过控制准动态连续扩张工艺参数，得到的自增强取向pex管材样品其力学性能得到程不同度的提高。通过测试环向拉伸强度，双向自增强pex管材的拉伸强度最高可达到32.29％，弹性模量最大可提高13.06％，断裂伸长率平均减小5.88％。关键词：自增强，聚氯乙烯管材，交联聚乙烯管材，取向度，力学性能 Along with the increasing of requirement of plastic pipes, the widening of the application field of plastic pipes and increasing of the request for using plastic pipes, most of counties wish the higher performance of plastic pipe. The research direction of plastic pipe is aim at how to enhance the performance of all aspects of the pipe as well as saving the material of pipe. The biaxial orientation enhancement technology of plastic pipe is a new production technology in the plastic pipe field, which means stretching the pipe in axial direction and expanding the pipe in hoop direction in production process so that the axial and hoop properties are self-reinforced. This self-reinforcement technology is applied to both of crystalline and amorphous material. After cross-linking, the cross-linked polyethylene gets the three-dimen-sional network structure which improves the performance of polyethylene. What's more, after cross-linking, the heat resistance, thermal strength, heat aging resistance, environmental stress cracking resistance, electrical insulation, barrier resistance, oil resistance of cross-linking polyethylene are all improved significantly. This paper studied on the quasi-dynamic expansion mechanism of PEX pipe. The so-called quasi-dynamic expansion is not the traditional dynamic expansion. The continuous expansion of the pipe is broken down to some repeat static expansion of pieces of pipe, then the all static expansion are combined and achieve the quasi-dynamic after controlling the expanding condition. After each piece is expanded, the shape is determined by cooling before it shrinking, then the length of the piece and the diameter is increased and the wall of the pipe gets thinner. In this paper, the optimal experimental parameters of the expansion of PEX pipe are provided, which include of the heating temperature, heating time, the expansion pressure, the expansion time and so on. After controlling the parameter in expanding process of quasi-dynamic continuous expansion equipment, the oriented PEX pipe with increased properties is gotten. The result reveals that the biaxial oriented PEX pipe can increase the tensile strength by 32.29/% at most, while the modulus of elasticity increasing 13.06/% and the elongation at break reducing 5.88/%.

关 键 词： 自增强 聚氯乙烯管材 交联聚乙烯管材 取向度 力学性能

分 类 号： [U66 TU8]

领　　域： [交通运输工程] [交通运输工程] [建筑科学]