The effect of impregnation technique on bending properties of glass fiber reinforced polyethylene terephthalate composites

An investigation was conducted to check the effect of impregnation techniques on bending properties of glass fiber reinforced polyethylene terephthalate (PET). The impregnation techniques used commingled yarn and parallel yarn methods. Holding time during fabrication varied between 1 and 20 min. The morphology and thermal properties of the composites were studied by using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results showed that commingled yarn can be fabricated at low pressure with good impregnation characteristics whilst parallel yarn requires a high pressure before a good impregnation of matrix resin into fiber can be achieved. Bending properties of commingled yarn composites were higher than those of parallel yarn composites. This was due to different impregnation techniques. The crystallinity of the matrix resin was not affected by different holding time during compression molding.