Study on Preparation and Properties of Biodegradable Polylactic Acid Doubling and Twisting Filament Yarn

This paper prepares polylactic acid doubling and twisting filament yarn through doubling and twisting and heat setting with biodegradable polylactic acid filament as raw material,optimizes doubling and twisting process and heat setting process and tests and analyzes the structure and property of yarn.The result shows that the optimal degree of twist of doubling and twisting process is 300 twists/m;compared to protofilament,polylactic acid doubling and twisting filament yarn has a reduced breaking strength and increased elongation at break;with the increase of degree of twist,the breaking strength of yarn gradually decreases and the elongation at break increases;the optimal heat setting temperature of heat setting process is 80 ℃ and heat setting time is 1 h;polylactic acid doubling and twisting filament yarn has a bright,clear and glossy surface;the yarn has a compound yarn structure and its breaking strength reduces by 9.7% and elongation at break increases by 7.6% compared to protofilament tows.Polylactic acid doubling and twisting filament yarn improves the bundling and abrasive resistance of filament yarn and is conducive to future weaving process.