The pulverizing of polypropylene (PP) and the solid phase grafting of hydroxylmethyl-acrylamide (HMA) onto PP during Pan-milling were studied by means of fractal geometry.The particle size distribution of milled PP was determined by particle size analyzer

and the obtained data were analyzed by fractal theory.The results showed that there was a non-scaling region in PP particle size distribution

a feature of linear fractal.Pan-milling affected the fractal behavior of PP particle size distribution quite a lot.The fractal dimension value of PP particles in creased with increase of milling cycles

and the size reduction of PP particles became more pronounced with the larger particles.Also the experimental results of the solid phase grafting of hydroxymethyl-acrylamide (HMA) onto PP revealed that the grafting rate increased with increase of milling cycles and was

therefore

related with the change of the fractal dimension value.Obviously

fractal geometry is useful for study of the quite complicated process of solid state mechanochemical reactions of polymers such as pulverization of PP particles and solid phase grafting of HMA onto PP during pan-milling.