准动态连续扩张法制备双向拉伸自增强PEX管材方法的研究

发布时间：2018-05-22 10:53

本文选题：自增强 + 聚氯乙烯管材　；参考：《北京化工大学》2010年硕士论文

【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,以及使用要求不断提高,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%。
[Abstract]:With the increase of the demand for plastic pipe, the application field is widened, and the application requirement is improved, the performance of plastic pipe has been put forward higher requirements in many countries, how to save the material, It is an important direction to improve the properties of plastic pipes. The biaxial tensile self-reinforcing technique is a production method for the preparation of high performance plastic pipes. The mechanical properties of the pipes are self-reinforced by the axial and circumferential tensile orientation of the tubes. This self-reinforcing technique is suitable for both crystalline and amorphous materials. The crosslinking reaction of polyethylene initiated by chemical or physical method can lead to the crosslinking polyethylene. The material changed from linear structure to three-dimensional network structure, which obviously improved the properties of polyethylene. After crosslinking, the heat resistance, thermal strength, heat and oxygen aging resistance, environmental stress cracking resistance and oil resistance of polyethylene were greatly improved. In this paper, the mechanism of quasi-dynamic continuous expansion of PEX pipes is studied. The so-called quasi-dynamic expansion is to decompose the continuous expansion of the pipe into segmented static expansion and then control all static expansion to realize the static expansion. After each section is expanded, the length of the expansion section increases, and the tube blank is cooled and finalized when it is too late to retract in a circumferential direction. The optimum experimental parameters of PEX pipe are given in this paper, including heating temperature, heating time, expanding pressure, expanding time and so on. In this experiment, by controlling the process parameters of quasi-dynamic continuous expansion, the mechanical properties of the self-reinforced oriented PEX pipe samples were improved by different degrees of mechanical properties. By testing the circumferential tensile strength, the maximum tensile strength of biaxial self-reinforced PEX pipe can reach 32.29, the maximum elastic modulus can be increased 13.06, and the elongation at break decreases 5.88%.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TQ325.1

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