MECHANICAL PROPERTIES OF CNTS INTEGRATED PP/GLASS FIBER REINFORCED BIAXIAL WEFT-KNITTED THERMOPLASTIC COMPOSITES WITH DIFFERENT KNITTING STRUCTURES

Abstract

In this study, four types of biaxial weft-knitted (BWK) fabrics (polypropylene (PP) resin yarn/glass fiber (GF) with different knitting structures such as plain (P), interlock (INT), tuck (T) and tuck&miss (TM) and multi-walled carbon nanotubes (MWCNTs) (0.4 wt%) were used as reinforcements to produce thermoplastic laminates with MWCNTs. In order to study the mechanical characteristics of the laminates, the flexural, short beam and Charpy impact tests on the samples were performed. In preliminary studies, the BWK fabrics with the plain knittings were used to produce the thermoplastic laminates with and without MWCNTs and positive effect of MWCNTs on the laminates were found out by performing the flexural tests on the specimens. The BWK laminates with the INT and TM knitting types with 0.4 wt% MWCNTs had almost same bending modulus and strength. 5% and 41% higher bending modulus and strength were gained with the BWK laminates with the interlock knitting type with 0.4-wt% MWCNTs compared to that was with the tuck type. 28.2% higher short beam strength and 57% higher Charpy impact energy were obtained with tuck&miss with 0.4-wt% MWCNTs (21.02 MPa and 6.34 Joule) compared to that was with the tuck knitting (16.39 MPa and 4.04 Joule).