High-performance thermoplastic composite materials based on polyamides for 3D printing and continuous fibres laminates

In this work tensile and flexural tests have been carried out on UD-tape laminate with PA6 matrix and glass fibre reinforcement arranged in 3 different directions:0°/90°/Cross-ply.The same approach has been conducted on PA6 organosheet reinforced with woven glass fibres.Impact tests have been performed on two different composite materials,the first addressed as“Experimental material”,the second as PA6 organosheet with woven glass fibres.Lastly,a 3D filament for FDM technology,made of,PA6/66 with 10% of short carbon fibre,has been tested in tension and flexion.The specimens to be tested have been printed in the 3 different printing directions XY,XZ and ZX with three Infill grades:20%,60%,100%.The moisture effect on the filament has also been studied.The tensile and flexural test on laminates has shown higher properties for the 0° oriented samples,followed by the Cross-ply,organo-sheet and 90°.Impact tests have given promising results regarding the “experimental material “.These types of laminates,at increasing impact energy,tend to absorb less energy compared to the organosheet,with consequential lower damages.Moreover,the“experimental material”is able to absorb up to 3 times the energy absorbed by the organosheet,after being impacted multiple times at 35J.Nevertheless,the impact resistance of this material could be further improved by increasing the thickness,in order to avoid instability phenomena like buckling,and by using a more efficient sizing treatment for the fibres to reduce the pull-out mechanism.Regarding the 3D printed specimens,the elastic modulus was higher for the XZ layout,with the ZX showing the lowest results.Tensile and flexural strength have shown a similar trend.The elastic modulus and the tensile and flexural strength for the same printing direction but different infill grade,increase by increasing the infill value.The moisture limit at which no issues are present is 0.40%,after which defects start appearing on the samples.