Polypropylene–phenol formaldehyde‐based compatibilizers. I. Preparation and characterization

This work deals with the synthesis of a new type of compatibilizer suitable for blends or alloys of polypropylene and engineering polymers having aromatic residues or functionality complimentary to hydroxyl. Polypropylene–phenol formaldehyde graft copolymers from thermoplastic phenol formaldehyde (PF) resins and functionalized polypropylene (f‐PP) were synthesized by reactive extrusion. The content of PF in the graft copolymer was determined by reaction variables like type and density of functionality on PP, molecular weight of PF, and viscosity ratio of f‐PP and PF. The results showed that the viscosity ratio is of primary importance for such reactive processing. Also, type and concentration of the functional groups were important variables. The glycidyl methacrylate functionality resulted in higher conversions than did PP‐g‐maleic anhydride within the available reaction times. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 347–354, 2000