Polypropylene Having a High Maleic Anhydride Content

Title Polypropylene Having a High Maleic Anhydride Content 

A method of incorporating between 5% to 45% maleic anhydride into polypropylene without chain scission or viscosity increase is described. The method entails an initial thermally induced ene reaction followed by the free radical addition of the anhydride to the polymer backbone. 

A reactor was charged with polypropylene containing an ene terminus (250 g), and the temperature was increased and maintained at 185°C. This material was then treated with maleic anhydride (20 g) dissolved in 24 ml of acetone followed by the dropwise addition of di-t-butyl peroxide (6 g). The reaction was maintained at this temperamre for 3 hours and then gradually cooled over 60 minutes. The product was isolated having an 11.3% maleic anhydride content. 

TABLE 1. Selected polypropylene succinic anhydrides prepared using polypropylene containing an ene terminus and maleic anhydride. 

Entry Polypropylene-ene Copmponent Final Maleic Anhydride Content (wt%) 

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