Ultrasonic induced grafting of maleic anhydride onto polypropylene in melt state

This paper presented a model study on maleic anhydride (MAH) grafted polypropylene (PP) performed in melt state through ultrasonic initiation without any chemical initiator and solvent. The structures of PP-g-MAH were characterized by FTIR and ¹³C NMR and the mechanism were discussed. The graft degree (G) was determined by titration using a solution of organic base tetra-butyl ammonium hydroxide (TBAOH) in ethanol, and the effects of ultrasonic intensity, MAH concentration and styrene (St) on G and graft efficiency (G _E ) of MAH were investigated. Results showed that MAH was successfully grafted onto the PP chain and the optimum conditions for grafting were at an ultrasonic intensity of 300 W with a MAH concentration of 25 wt.%, and the maximum G of MAH of 3.34 wt.% was obtained when the molar ratio of St to MAH was 1:1. DSC and XRD were also employed to determine the thermodynamic performance and crystalline structures of the products.