通过反应挤出提高聚丙烯的熔体强度

Increasing melt strength of polypropylene via reactive extrusion

利用反应挤出技术研究了不同反应物对聚丙烯(PP)熔体强度的影响。考察了不同用量的低密度聚乙烯(LDPE)、乙烯-乙酸乙烯酯共聚物(EVA)、季戊四醇三丙烯酸酯(PETA)、二乙烯基苯(DVB)以及上述物质的混合物在过氧化二异丙苯的引发下对PP熔体强度、熔体流动速率、熔垂的影响。结果表明,LDPE、EVA的加入对产物熔体强度的影响有限,PFTA也只能使其提高1倍左右;而DVB的加入可使产物的熔体强度显著提高,仅加入1％就可使熔体强度提高20倍,熔垂实验也证明了这一点;几种反应物混合使用效果不如单独使用好。

The effect of diverse reactants on melt strength of polypropylene （PP） was studied with reactive extrusion process. The dosages of low density polyethylene （LDPE）, ethylene-vinyl acetate copolymer （EVA）, pentaerythritol triacrylate （PETA）, divinyl benzene （DVB） and their mixture, as the modifier, influenced the melt strength, melt flow rate and melt sag of PP at the initiation of dicumyl peroxide. The addition of LDPE or EVA exerted a limited effect on the melt strength though PETA could make the value double. The contribution of DVB to the melt strength was so great that even mere 1% DVB could bring about an increment of 20 folds of the value, as confirmed by the melt drop experiment. However, the mixture of the reactants compared unfavorably with each individual reactant in improving the melt strength because of the mutual interference among them.