改性PET的微孔注塑成型

采用均苯四甲酸二酐(PMDA)扩链增粘改性后的聚对苯二甲酸乙二醇酯(PET)(M-PET)进行Mucell微孔注塑成型实验。扫描电镜(SEM)结果表明,M-PET具备了维持良好泡孔形态所需的熔体强度,其微孔注塑制品分为皮层、中间层与芯层三部分。通过正交实验和信噪比(S/N)分析法,考察了M-PET在微孔注塑成型过程中各重要操作参数对制品拉伸强度的影响。研究结果表明,高的熔胶量,适中的发泡剂含量和熔体温度,以及较低的射胶速率和模具温度有利于提高制品的拉伸强度,在各操作参数中,熔胶量对制品拉伸强度影响最大。获得了发泡样条力学性能与减质量之间的关系。

Microcellular Injection Molding of Modified Poly(Ethylene Terephthalate)

Microcellular injection molding was applied for both fiber-grade poly(ethylene terephthalate)(V-PET) and pyromellitic dianhydride(PMDA) modified poly(ethylene terephthalate)(M-PET).Scanning electron microscope(SEM) characterization indicates that M-PET is provided with high melt strength for keeping fine cell structure,and the foaming specimens include three parts: skin layer,intermediate layer and core layer.Through the designed orthogonal experiments and signal-to-noise(S/N) ratio analysis,the effects of molding conditions on tensile strength of molded specimens were investigated.It is shown that the large shot size,moderate supercritical fluid(SCF) content and melting temperature,low injection speed and mold temperature are favorable to produce tensile specimens with preferred mechanical properties.Among the operating parameters,shot size has the most significant effect on the tensile strength.The relation between mechanical properties and weight reduction of molded specimens was also obtained.