Abstract
A study was conducted on the effects of cooling conditions on flexural properties of aramid fiber knitted fabric (AFKF) and glass fiber knitted fabric (GFKF) reinforced thermoplastic polypropylene composites. To study these effects, composite laminates were fabricated under a molding pressure of 3MPa for 20min, then consolidated from the melt at different cooling conditions: rapid cooling i.e., quasi-quenching and gradual cooling. Flexural tests were carried out on specimens in two directions: wale and course. Evaluation on thermal properties and morphology was studied using a differential scanning calorimetry (DSC). Flexural properties were little sensitive to the cooling rates; however, gradually cooled specimens showed higher level of crystallinity than rapidly cooled specimens. Furthermore, flexural strengths displayed higher in the wale than in the course directions. SEM micrographs of fracture surfaces revealed poor adhesion between the fiber and polypropylene matrix.
