聚丙烯与马来酸酐在超临界CO2中的接枝聚合

聚丙烯(PP)以其强度高、耐热性好、密度小、易加工和价廉等特点成为重要的通用塑料。但由于非极性的分子结构，其亲水性、染色性、抗静电性、粘接性和印刷性并不理想，难以与极性聚合物和填料共混、复合。PP通过接枝引入极性基团是最常用的化学改性方法。常用的接枝单体有马来

GRAFTING OF MAH AND POLYPROPYLENE IN SUPERCRITICAL CO2 MEDIUM

The grafting of maleic anhydride onto a granular polypropylene (PP) using supercritical CO-2 as a solvent and swelling agent was studied to prepare granular PP-g-MAH polymers.The factors affecting the graft degree of PP,such as the monomer content,initiator content,reaction temperature and reaction pressure were discussed.The maximum graft degree of PP with MAH in supercritical CO-2 medium was 5^23% under the optimal reaction conditions at 125℃ and 15 MPa for 5 h.By using the supercritical CO-2 technique the operation of grafting reaction and separation of products became simple and easy to deal with.The formation of PP-g-MAH grafting copolymer was evidenced by FTIR measurements.An absorption peak at 1720^6 cm -1 assigned to the stretching vibration of carbonyl groups was observed.DSC results indicated that the grafting gave almost no influence of T-g values,but may increase the crystallinity of PP.