Injection-molded parts of fully bio-based polyamide 1010 strengthened with waste derived slate fibers pretreated with glycidyl- and amino-silane coupling agents

Abstract Fully bio-based polyamide 1010 (PA1010) was melt-compounded with 15 wt% of slate fibers (SFs), which were obtained from wastes of the tile industry, and the resultant composites were shaped into parts by injection molding. The as-received fibers were first thermally treated and afterwards subjected to surface modification with glycidyl- and amino-silane coupling agents to improve the interfacial adhesion of the composites. The incorporation of both the glycidyl-silane slate fiber (G-SF) and amino-silane slate fiber (A-SF) remarkably improved the mechanical strength of PA1010, inducing a 3-fold increase in tensile modulus. The composite parts prepared with the silanized SFs also presented higher thermal stability and improved thermomechanical resistance. Water uptake was reduced below 1 wt%, encouragingly suggesting that the mechanical performance of the PA1010/SF composites would be scarcely affected by atmospheric humidity. G-SF was the most effective in strengthening PA1010. This improvement was ascribed to the higher reactivity of the cyclic anhydride in the coupled silane with the terminal hydroxyl groups of the biopolymer.