Studies on PA6–PP–wollastonite composite compatibilised by PP– graft –maleic anhydride prepared via pan milling

Abstract

A composite of PA6–PP–wollastonite compatibilised by PP-g-maleic anhydride has been prepared using pan type milling equipment, and its structure and properties investigated by IR, DSC, melt index measurements, SEM, and mechanical testing. The experimental results show that during pan milling, PP, PA6, and wollastonite are effectively pulverised, reaching better mixing owing to the very strong shear forces and pressure exerted by the pan type milling equipment. In particular, some PA6 polymer chains are grafted onto the wollastonite surface and the pan milling affects the crystallinity of PA6 and PP to some degree. The compatibiliser prepared via solid phase grafting of maleic anhydride onto PP via pan milling shows a reasonably good compatibilising effect on the composite, improving the morphology and therefore the mechanical properties of the composite. If combined with suitable coupling agent, the PA6–PP–wollastonite compatibilised by PP-g-maleic anhydride prepared via pan milling (wollastonite content 30 wt-%) possesses much better mechanical properties, its tensile strength increases from 54·6 to 58·6 MPa, and its notched Izod impact strength increases from 29·4 to 48·7 J m^-1, compared with the uncompatibilised system. Pan milling is a novel way to achieve desired structure and hence improved properties of polymer based materials via the polymer processing procedure.