The Preparation And Characterization Of High Elasticity And High Hydrophlic Nylon-6 Fiber

Polyamide(PA)commonly referred to nylon,which is synthesized by polycondensation of diacid and diamine or amino acid,is the generic term for the resin containing iterative acid amide radical.PA was firstly exploited by American DuPont Co.PA has good mechanical properties, heat resistance,anti-corrosive properties,good lubricity and low friction coefficient,and also is easy to process.Therefore in many countries,PA is used for engineering plastics at the largest amount.However,PA6 (polyamide 6) fiber is not a good candidate for clothings,because of its poor comfortbility,and can only be used as stockings.It is well known that the clothing comfort degree is depended on hydrophilic and elasticity of fiber or textile.For example,cotton has best hydrophilic property among the fibers ever known,however poor at elasticity;polyurethane elastic fiber is the best in elasticity,while its hydrophilic property is not good.To improve PA6 fiber’s comfort degree,both hydrophilic and elasticity should be integrated.Polyether amide modified PA6 copolymer was prepared by block polymerization.The molecular weight was measured by viscosimetry, and the structure of the copolymer was analyzed by FUR and DSC.The FUR test results indicated that the C-OC of polyether amide was successfully embed into PA6 chains.With the increase of polyether amide amount,the polymer melting temperature increased within the range of 219.6℃and 221.3℃while the crystallization temperature decreased from 177.5℃to 174.3℃.The capillary rheometer was used to study rheology behavior and spinnability.Pure PA6 and modified PA-6 fiber were prepared by melt spinning.Fiber mechanical properties,elasticity and rebound resilience were tested and it was found that with the increase of the content of polyether amide,elongation at break of the fiber increased,Young’ modulus decreased.It is indicated that the hydrophilic property and the elasticity of the fibers were greatly improved by modification.The moisture regain,shrinking percentage of the fibers in boiling water and heat shrinkage were tested in order to reveal the inner mechanism between structure and property.The dye-staining analysis, color fastness analysis and anomeric analysis were used to expounde the relationship among them.WAXD analysis was used to analyze the crystal structure and the crystal form transformation.A model,called soft-hard model,was suggested to explain why the fiber’s elasticity aggrandized.At last,an orthogonal experiment was taken to discuss the changes of the remain elasticity recovery after the strained thermosetting at different temperatures and different times.The results showed that the strength of modified PA6 fiber is similar with pure PA6 fiber,the hydrophilic property and the elasticity of the fibers,dye-staining performance and color fastness were greatly improved by modification. The conclusion is that the new fiber could meet the requirements for high comfortable clothings.