化学交联PP／LDPE共混材料的熔体强度及发泡性能

Melt Strength and Foaming Behavior of Crosslinked PP/LDPE Blend

通过化学交联提高聚丙烯/低密度聚乙烯(PP/LDPE)共混物的熔体强度,并对交联PP/LDPE共混物的发泡性能进行了研究。结果表明:交联PP/LDPE共混物熔体在拉伸过程中出现明显的应变硬化现象,熔体强度明显提高;采用交联PP/LDPE共混物可制得泡孔均匀、性能良好的闭孔泡沫材料;随着LDPE含量的增加,交联PP/LDPE共混物的凝胶含量逐渐增加,熔体流动速率(MFR)减小;随着发泡剂用量的增加,交联PP/LDPE共混物泡沫的密度逐渐减小,泡孔孔径略有增大;随着泡沫密度的减小,泡沫材料的拉伸强度、压缩强度及压缩永久变形逐渐减小,拉伸断裂伸长率基本不变。

PP/LDPE blend was crosslinked through chemical initiation so as to im-prove its melt strength. The foaming behavior of crosslinked PP/LDPE blend was studied. The experimental results show that the crosslinked PP/LDPE melt has noticea-ble strain hardening behavior during elongational flow, and its melt strength increases clearly. The closed-cell foam with uniform cell and good performance is prepared with crosslinked PP/LDPE blend. With the increase of LDPE content, the gel content of crosslinked PP/LDPE blend increases, its MFR decreases. With the increase of blowing agent amount, the density of the crosslinked PP/LDPE foam decreases, and its average cell diameter increases slightly. With the decrease of foam density, the tensile strength, compression strength and compression set of crosslinked PP/LDPE foam decrease, its e-longation at break remains unchanged basically.