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为了改善聚对苯二甲酸乙二醇酯(PET)的流变性能,提高其发泡性能,以均苯四甲酸二酐(PMDA)对PET进行了熔融扩链改性,采用动态旋转流变仪表征扩链改性PET的流变性能。并利用间歇发泡装置,对扩链改性PET进行超临界流体发泡实验。研究了不同含量扩链剂的扩链效果,以及不同的发泡温度对PET扩链体系泡沫结构的影响。结果表明:PMDA的加入能够有效改善PET的弹性模量和复数黏度,PMDA质量分数为0.75%时,扩链效果最佳,PMDA质量分数为1%时发泡倍率更大。PMDA的添加能够有效拓宽发泡温区,随着发泡温度的升高,PET泡沫发泡倍率先增大后减小。在264℃时,实验制得发泡倍率为21倍、泡孔直径为46~50μm、泡孔密度为2.64×108~2.83×108个/cm3的低密度PET泡沫。
In order to improve the rheological properties of polyethylene terephthalate (PET) and improve its foaming properties, PET was modified by pyromellitic dianhydride (PMDA) Instrumentation characterization of rheological properties of chain extended modified PET. And the use of intermittent foam device, extended chain modified PET for supercritical fluid foam experiments. The effect of chain extenders with different content of chain extender and the influence of different foaming temperature on the foam structure of PET chain-extended system were studied. The results show that the addition of PMDA can effectively improve the elastic modulus and complex viscosity of PET. When the mass fraction of PMDA is 0.75%, the chain extension is the best and the expansion ratio is larger when the mass fraction of PMDA is 1%. The addition of PMDA can effectively broaden the foaming temperature zone. As the foaming temperature increases, the foaming ratio of PET foam first increases and then decreases. At 264 ℃, the experiment made a low density PET foam with an expansion ratio of 21 times, a cell diameter of 46 ~ 50μm and a cell density of 2.64 × 108 ~ 2.83 × 108 / cm3.