Synergistic effects of hyperbranched flow modifiers and toughening agents on the processability and interfacial properties of pultruded glass fiber/PA6 composites

Abstract This study addresses the critical challenges of high melt viscosity and matrix brittleness in pultruded continuous glass fiber reinforced polyamide 6 (GF/PA6) composites. A synergistic modification strategy combining a hyperbranched polymer (HBP) flow modifier and a reactive elastomer (POE-g-MAH) was developed to optimize the “process-structure-property” relationship. Results indicate that at a high fiber loading (36 bundles), the addition of 3 phr HBP significantly reduced porosity to 0.49 % and enhanced flexural strength to 928.4 MPa through a “ball-bearing” effect and heterogeneous nucleation. Furthermore, the incorporation of 4 phr POE-g-MAH achieved an optimal stiffness-toughness balance. In-situ interfacial reactions formed stable imide linkages, increasing notched impact strength by 18.6 % while maintaining a high flexural strength of 836.6 MPa. This multi-scale co-design strategy effectively overcomes the trade-off between impregnation quality and mechanical toughening, providing a theoretical framework for manufacturing high-performance thermoplastic pultruded profiles.