Idumah C. I.^1,, Nwachukwu A. N.², Akubue B. N.³

This paper comparatively studied the effects of time of heatsetting and wet processes on shearing rigidity (G_{1 .}G₂ ) gf/cm. degree, shear hysteresis at 5%, shear angle (2HG₁, 2HG₂) and shear angle at 5% (2HG5₁ and 2HG5₂) of knitted Ingeo™ Poly (lactic) acid and Polyethyleneterepthalate fabrics in warp [G₁] and weft [G₂] directions using the KES-FS system of fabric evaluation. PLA samples of dimension 200 mm x 200 mm were subjected to heatsetting at temperatures of 130°C respectively and increasing times of 15 s, 30 s, 45 s, 60 s, 90 s, 120 s and 240 s using the Werner Mathis infra-red heatsetting equipment and subsequently treated to wet processes including scouring, alkaline reduction clearing, dyeing and softening. The KES Shear tester was used in determining the ease with which knitted PLA and PET fibers slided against each other to ascertain properties such as softness, pliability to stiffness/rigidity and inter yarn stability to mechanical distortion. They samples were measured to a maximum shear angle of ± 8°. Results showed that after subjecting the samples to various wet processes, PET exhibited higher shear rigidity G in both warp (G₁) and weft (G₂) directions with increasing times of heatsetting. Measurements of shear hysteresis at 0.5° shear angle (2HG) and 5° angle (2HG5) in gf/cm showed PLA exhibiting a higher shear hysteresis than PET with increasing times of heatsetting.

Ingeo™ Poly (lactic acid), KES-FB system, shearing rigidity (gf/cm), shearing hysteresis (gf/cm)