双单体固相接枝制备高熔体强度聚丙烯

Preparation of high melt strength polypropylene by grafting of dual monomer in solid phase

采用一种有机溶胀剂作为聚丙烯(PP)基体的溶胀剂及接枝单体的溶剂,协助1,6-己二醇二丙烯酸酯(HDDA)及苯乙烯(St)固相接枝PP。考察了单体用量、引发剂用量、反应条件和溶胀条件对接枝反应的影响。用红外光谱和热重分析法对接枝产物的结构及性能进行分析。结果表明:接枝产物的接枝率、熔体强度相对于未溶胀时均有所提高。在优化反应条件下,即按照PP,HDDA,St与偶氮二异丁腈的质量比为100.00∶4.00∶1.82∶0.30投料,用6.6 g溶胀剂在40℃溶胀3 h,85℃反应2.0 h,接枝产物的熔体强度增加到2.51 kPa.s(为原料的4.48倍)。热稳定性与原料相比明显增强。

Polypropylene （PP） was grafted with 1,6-hexanediol diacrylate （HDDA） and styrene （St） in solid state, after being swollen with an organic solvent of the grafting monomers and initiator for some time. The influences of the monomer and initiator amount, reaction and swelling conditions on the graft reaction were investigated. The structure and properties of the graft products were analyzed by infrared spectroscopy （IR） and thermogravimetric （TG） analysis. The results show that the grafting ratio and melt strength of the graft product are increased compared to those of the non-swelled product. The melt strength of the graft PP increases to 2.51 kPa . s which is 4.48 times of that of the pure PP under the optimal conditions of being swollen in 6.6 g sweller at 40 ℃ for 3 hours, and reacting at 85 ℃ for 2 hours when the mass ratio of PP/HDDA/St/azobisisobutyronitrile is 100.00 ： 4.00 ： 1.82 ： 0.30. The thermal stability of the graft product is improved dramatically in comparison with that of the pure PP.