Comparative Analysis of the Effects of Time of Heat Setting and Wet Processing on Tensile Properties of Treated and Untreated Knitted PLA Fabric

Abstract

Poly (lactic acid) (PLA) is an aliphatic polyester and ecofriendly material of a natural origin with biodegradable properties. The monomer for PLA is lactic acid obtained from the fermentation of sugar and vegetables like corn and cassava. This study investigated the effect of heatsetting and wet processes on the tensile properties of treated and untreated Ingeo™ Poly (Lactic acid) PLA knitted fabrics. PLA samples of dimension 200mm x 200mm were subjected to heatsetting at a temperature of 130oC and increasing times of 15s, 30s, 45s, 60s, 90s, 120s and 240s respectively using the Werner Mathis infra-red heatsetting equipment and subsequently treated to wet processes including scouring, alkaline reduction clearing, dyeing and softening. Four tensile parameters were determined in warp and weft direction using the KES-FB system of fabric evaluation. These tensile parameters were tensile extension EM [%], linearity of load extension LT [-], tensile energy WT [g.cm/cm2] and tensile resilience RT [%]. The results showed (i) a consistent increase in tensile extension of treated PLA (unlike untreated PLA knitted fabric) with increasing time of heatsetting and wet finishing applications suggesting that treated PLA may tend to exhibit enhanced fabric hand or softness and increased formability (ii) Treated PLA to exhibit lower LT with increasing time of heatsetting and wet treatments implying a better formability and in-plane compressibility of treated PLA when compared to untreated PLA (iii) Treated PLA to display a greater tensile energy than untreated PLA, implying that treated PLA has greater flexibility, softness, gentleness and smoothness than the untreated PLA (iv) both PLAs exhibited low RT suggesting the general softness of PLA.