Preparation and characterization of polypropylene grafted halloysite and their compatibility effect to polypropylene/halloysite composite

The method to increase the compatibility between polypropylene (PP) and halloysite by grafting PP chains onto the surface of halloysite through a two-step method was investigated. PP chains were chemically grafted onto the surface of halloysite and then the g-halloysite were compounded with PP to form composite. The halloysites was pretreated with silanes in which ethanol water solution was adjusted to pH value of 5 with acetic acid in a flask. The halloysites was precipitated from the mixture and extracted three times with xylene, and the modified halloysite (g-halloysite) were vacuum dried at 100°C for 5h to remove the solvent residue. A thermogravimetric analysis of pristine and g-halloysite was performed under nitrogen atmosphere to identify the presence of PP-g-MAH on the surface of g-halloysite. Results show that g-halloysite dispersed in PP matrix in the form of micro-scale clusters have strong interfacial adhesion with PP matrix.