Polypropylene-graft-maleic anhydride (PP-g-MAH) ionically modified with zinc(II) (PP-g-MAHZn) in varying amounts of ionic associations were prepared via melt reaction. Absorption bands in FTIR-ATR and shifted binding energy in X-ray photoelectron spectroscopy showed the formation of zinc carboxylates in PP-g-MAHZn. Decreased crystallinity, gradually increased viscosities, and storage modulus with the increment of zinc carboxylates in the PP-g-MAHZn were investigated by thermal and rheological analysis, which were attributed to the restriction of chain mobility via ionic interactions between polymer chains and aggregations of ionic domains. Furthermore, PP-g-MAHZn was introduced to polypropylene as an additive to promote foamability, and the PP/PP-g-MAHZn blends displayed higher viscosities and storage modulus compared with pristine PP in rheological measurements. In addition, the PP/PP-g-MAHZn blends were foamed by supercritical CO₂ and cryogenically fractured surfaces were observed by scanning electron microscope. PP/PP-g-MAHZn foams presented high closed-cell content, uniformity of cells, and increasing cell density owing to the combined effects of rheological properties, while maintaining the cell structures and good dispersion of the PP-g-MAHZn as nucleating sites. These results reveal that PP-g-MAHZn is a suitable additive to produce high melt strength PP for foam production.

通过熔融反应制备了以不同离子缔合量的锌（II）（PP-g-MAHZn）离子改性的聚丙烯接枝马来酸酐（PP-g-MAH）。FTIR-ATR中的吸收带和X射线光电子能谱中的移动键能表明PP-g-MAHZn中形成了羧酸锌。通过热和流变分析研究了结晶度降低，粘度逐渐增加以及随着羧酸锌在PP-g-MAHZn中的增加而增加的储能模量，这归因于聚合物链之间的离子相互作用和离子的聚集对链迁移率的限制。域。此外，将PP-g-MAHZn作为添加剂引入聚丙烯中以提高发泡性，在流变学测量中，与原始PP相比，PP / PP-g-MAHZn共混物显示出更高的粘度和储能模量。此外，PP / PP-g-MAHZn共混物通过超临界CO发泡_{如图2所示}，通过扫描电子显微镜观察到低温断裂的表面。PP / PP-g-MAHZn泡沫由于流变性质的综合作用，具有较高的闭孔含量，泡孔均匀性和增加的泡孔密度，同时保持了泡孔结构和PP-g-MAHZn作为成核部位的良好分散性。这些结果表明PP-g-MAHZn是合适的添加剂，用于生产用于泡沫生产的高熔体强度PP。