Effects of different types of functionalized polypropylenes on the tensile strength of short carbon fiber-reinforced polypropylene composites

• Published in: Polymer journal 2024-03, Vol.56 (3), p.205-214
• Main Authors: Yamaguchi, Ayaka, Uematsu, Hideyuki, Sakaguchi, Toshikazu, Hashimoto, Tamotsu
• Format: Article
• Language: English
• Subjects: 140/133; 639/638/298/303; 639/638/455/958; Adhesion; Biomaterials; Bioorganic Chemistry; Carbon fiber reinforced plastics; Carbon fibers; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Fiber composites; Fiber reinforced polymers; Filaments; Functional groups; Injection molding; Molecular chains; Original Article; Polymer Sciences; Polypropylene; Reinforced plastics; Shear flow; Surfaces and Interfaces; Tensile strength; Thin Films
• ISSN: 0032-3896; 1349-0540
• DOI: 10.1038/s41428-023-00856-8

In this study, the effects of various functionalized polypropylenes (PPs) with different types and contents of functional groups and crystallinities on the tensile strength of short carbon fiber (SCF)-reinforced plastics (SCFRPs) prepared by injection molding were evaluated. The tensile strengths of SCFRPs were significantly influenced by interfacial adhesion. The types and contents of functional groups introduced into functionalized PP were the dominant factors impacting the development of interfacial adhesion. In particular, near the surface where SCF and PP were highly oriented in parallel, functionalized PP with more functional groups added to side chains exhibited higher interfacial adhesion than that with fewer functional groups. These results suggested that PP molecular chain orientations resulting from the shear flow of injection molding were among the key factors affecting the interfacial adhesion of the PP matrix. The tensile strength of short carbon fiber (SCF)-reinforced plastics (SCFRPs) prepared by injection molding with various functionalized polypropylenes (PPs) using different types and contents of functional groups and crystallinity, depended on interfacial adhesion. Functionalized PP with more functional groups added to the side chains (PP-g- MA1) exhibited higher interfacial adhesion near the SCFRP surface where the SCF filaments and PP chains were highly oriented in parallel than that with fewer functional groups (PP-t-MA).