不同端基官能团PEG与聚丙烯接枝马来酸酐的接枝反应

Graft Reactions of Polyethylene Glycol Bearing Different End Functional Groups with Polypropylene Grafted Maleic Anhydride

利用羟基与对甲苯磺酰氯和邻苯二甲酰亚胺钾的分步反应或者与二异氰酸酯的反应,将聚乙二醇单甲醚(MPEG)的端羟基分别转化为端氨基和端异氰酸酯基。将带有端羟基、端胺基和端异氰酸酯基的MPEG分别与聚丙烯接枝马来酸酐(MPP)反应,制备聚丙烯/聚乙二醇接枝共聚物,并比较不同体系的动力学。MPEG端基官能团与MPP链上马来酸酐的反应活性顺序为:-NCO>-NH2>-OH。在端异氰酸酯基MPEG与MPP反应体系中,随n(NCO)/n(MAH)增大,PEG接枝率增大;随MPEG分子量增大,接枝到PP链上的PEG支链数目减少。

The end-hydroxy groups of poly（ethylene glycol） methyl ether（MPEG） were converted into end-amino and end-isocyanate groups,respectively,by step reactions of MPEG with para-toluenesulfonamide and phthalimide potassiumand,and/or by the reaction of MPEG with diisocyanate.The graft reactions between polypropylene grafted maleic anhydride（MPP） and MPEG with different end groups were conducted in xylene,in order to prepare graft copolymer of polypropylene and polyethylene glycol（PP-g-PEG）.FT-IR and 1H-NMR were used to characterize structure of the reaction products.It was found that the reactivity of the end-functional groups of MPEG in the reaction with MPP follows this order：-NCO〉-NH2〉-OH.For MPP/MPEG-NCO reaction system,reaction extent and PEG grafting ratio increase when the molar ratio of（NCO）/（anhydride） raises from 1∶1 to 5∶1.However,the reaction extent and the number of PEG chains grafted onto PP chains decrease when the molecular weight of MPEG increases from 1000 to 6000.