Premium
PP‐based WPCs—Influence of the molar mass of matrix and coupling agent
Author(s) -
Sobczak L.,
Steiner M.,
Schausberger A.,
Haider A.
Publication year - 2013
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.22392
Subject(s) - materials science , composite material , molar mass , polypropylene , mass fraction , maleic anhydride , polymer , rheometry , rheology , absorption of water , izod impact strength test , flexural strength , matrix (chemical analysis) , coupling (piping) , copolymer , ultimate tensile strength
Abstract Six commercial polypropylene (PP) homopolymer grades, ranging from 2 to 125 g/10 min in MFR (230°C/2.16 kg), and from 530 to 180 kDa in terms of molar mass (mass average; M w ), have been tested as matrix polymers in wood polymer composites (WPCs) with a wood content of 40%. To check for possible molecular weight controlled interactions between matrix and additives, five different maleic anhydride grafted PP (MA‐PPs) coupling agents (CAs) have been included in the screening as well. Flexural properties, impact strength, and water absorption of the resulting composites served as responses. In addition, crystallinities, surface contact angles (on solid specimens), and rheological properties of the melt were measured for several compounds. The most important outcome of the study is that matrix polymer properties, as influenced by molar mass, are largely reflected in the resulting WPCs. Surprisingly, water absorption of the composites increases with matrix MFR, a phenomenon as yet not published for PP‐based compounds. Furthermore, dynamic rheometry results indicate that the interaction of wood particles with PP melts is dependent on polymer and coupling agent M w . © 2013 Society of Plastics Engineers