环氧基低聚物改性聚对苯二甲酸乙二醇酯的流变性能和发泡性能

Rheological behavior and foaming properties of polyethylene terephthalate modified with epoxy-based oligomers

为了提高聚对苯二甲酸乙二醇酯(PET)的流变性能和发泡性能,采用环氧基扩链剂(ADR)对PET进行反应挤出改性,并利用动态旋转流变仪和单轴拉伸黏度仪对PET的流变性能进行系统表征,同时通过快速降压法研究了改性PET的发泡性能。流变测试结果表明:与未改性PET相比,ADR改性PET具有更高的复数黏度和低频区储能模量、更低的损耗角正切,呈现出明显的应变硬化现象;当ADR质量分数超过0.5%时,改性PET表现出凝胶结构的流变特性。采用间歇发泡工艺得到了发泡倍率为30倍、泡孔均匀细密的PET发泡材料,说明改性PET具有优异的可发泡性能。

An epoxy-based chain extender（ ADR） has been used to improve the rheological behavior and foaming properties of polyethylene terephthalate（ PET） obtained by a reactive extrusion process. The rheological behavior of PETs was characterized by using a dynamic rheometer and a uniaxial stretching viscometer. In addition,a rapid depressurization method was used to investigate the foaming properties of the modified PETs. Rheological results showed that PETs modified with ADR had higher complex viscosity and storage modulus,and lower loss tangent than the neat PETs. Furthermore,the modified PETs exhibited obvious strain hardening. When the ADR content exceeded 0. 5 wt%,a gel structure appeared in the modified PETs. The modified PETs exhibited obvious strain hardening during tensile rheological tests. PET foam,with an expansion ratio of 30 and a fine cell structure,was obtained by using a batch foaming process,indicating the excellent foaming performance of the modified PETs.