A new method to prepare maleic anhydride grafted poly(propylene)

A new method to prepare maleic anhydride grafted poly(propylene) (MAPP) was developed successfully. The grafting reaction of maleic anhydride (MA) onto poly(propylene) (PP) was performed with the aid of ball-milling, and the grafting mechanism was proposed based on the experimental results. MAPP was prepared by ball-milling of PP powder, MA, and peroxide initiator in balls-containing jars with a planetary ball mill for a certain time. Factors were considered on reaction time, rotational speed of the mill, cyclic milling mode, kind and concentration of peroxide, and concentration of MA. Results show that MAPP obtained contains the main structures of end-grafting type (both single and oligomeric) and bridge-grafting type. Compared with the conventional melt-mixing method, MAPP obtained through the ball-milling method reveals alleviated degradation of PP or even increased molecular weight of resultant MAPP. This novel method has also the advantages of lower process temperature and solventless, energy efficient, low cost and simple running process. Furthermore, it is very easy to get purified products.