PET结晶形态对其微孔发泡材料泡孔结构的影响

The Effect of PET Crystal Morphology on Cell Structure

以CO2为发泡剂,针对三种具有不同初始结晶形态的聚对苯二甲酸乙二醇酯(PET)原料进行间歇固态发泡的研究。结果表明,CO2的溶胀作用会导致PET晶片的显著增厚,而显著增厚的晶片会使微孔发泡材料的泡孔分布不均匀,但是对孔径和孔密度影响不大。调控PET的发泡条件制备泡孔结构好的PET微孔发泡材料方法之一是缩短溶胀时间,在PET晶片显著增厚以前快速卸压发泡,从而得到孔密度大、孔径小、泡孔分布均匀的微孔材料。

Microcellular foaming behavior of polyethylene terephthalate（PET） was investigated in a batch foaming process using CO2 as the foaming agent.PET with different crystalline morphology was used in this work,i.e.,amorphous PET,semicrystalline PET with the melting point of 258.0 ℃ and 263.5 ℃.It was observed that thickened crystals which was formed during the CO2 saturation would have great influence on foam morphology and generate unevenly distributed cells in the bulk.However,cell diameter and cell density were not affected by the formation of thickened crystals.As a result,it is possible to control the foaming conditions to obtain PET foams with evenly distributed cells.One effective method is reduction of the saturation time,then depressurized before the formation of thickened crystals.In this way,good cell morphology,small cell diameter and high cell density PET foams can be generated by depressurization.