Processing of a Polyamide-12/carbon nanofibre composite by laser sintering

Additive layer techniques, such as laser sintering, are increasingly being considered for the production of fully functioning end-use parts due to the significant advantages they hold in the design and implementation of products. However, one of the main obstacles to widespread adoption of this technology is the limited range of materials that can currently be processed using additive techniques. This paper presents initial research into the reinforcement of laser sintered polyamides with carbon nanofibres (CNFs). The effects of CNF addition on the processing parameters and mechanical properties of laser sintered parts have been investigated. A 3wt % carbon nanofibre-polyamide 12 composite (CNF-PA12) powder was prepared using melt mixing and cryogenic milling. Following laser sintering, characterisation of the polymer nanocomposite parts by SEM and dynamic mechanical testing showed that the nanofibres were well dispersed within the polymer matrix and gave a 22% increase in the storage modulus compared to the base material. However, the cryogenic fracturing method used in this research did not produce powder with suitable morphology for laser sintering. If improved powder production can be achieved, the use of CNF reinforcements to improve mechanical properties in laser sintering holds promise.