Hard coal modified with silanes as polyamide filler

Purpose: This paper shows the influence of coupling agents, especially silanes, on mechanical properties of polyamide 6 filled with hard coal dust. Design/methodology/approach: Before preparing compositions, pulverised filler surface was modified with coupling agents. Then, it was compounded using a twin-screw extruder composite consisting of modified hard coal and polyamide 6. A blend was granulated later and test samples were subjected to injection moulding. Afterwards, mechanical properties were evaluated. These properties have essential meaning for applications of new composites as structural materials. Findings: Tests demonstrated that modification of powdered hard coal surface with coupling agents had not significant effect on mechanical properties of polyamide/hard coal composites. Research limitations/implications: Applied compounding procedure did not allow to achieve good compositions homogenisation. A new method to be applied is planned in future research. Simultaneously, it is necessary to investigate composites with other coupling agents which will improve filler’s adhesion to a polymer. Long-term test are also planned. Practical implications: Hard coal, cheap and widely available filler, used to modify thermoplastic polymers, enable to obtain new materials with attractive properties and many applications. Originality/value: Paper represents innovative polymer filler and methods to modify it.