长碳链聚醚酰胺弹性纤维开发及其弹性机理

以长碳链聚酰胺弹性体为原料,通过熔融纺丝技术制备了高性能化新型长碳链聚醚酰胺(LPAE)弹性纤维.该弹性体是以基于生物来源单体的长碳链聚酰胺为硬段,以聚醚为软段,其弹性可通过调节软硬段比例有效调控.测试结果表明,与目前市场上应用广泛的氨纶莱卡(LYCRA)相比,软段含量较高的LPAE纤维具有高断裂伸长,低初始模量的特点;在200%伸长范围内,其弹性回复率与氨纶相当,耐热性优于氨纶.分析得知,LPAE纤维的高弹性源于硬段聚酰胺存在强氢键相互作用且结晶度高,同时硬段充当物理交联点;软段具有良好的柔性,可以发生大变形,这种软硬段交替的嵌段分子链结构形成三维网络.大应变下,LPAE纤维弹性回复率降低是由分子链滑移及软段拉伸诱导结晶共同造成的.

Research and Development of Long Chain Poly(amide-co-ether) Elastic Fibers and the Corresponding Elastic Mechanism

To develop elastic fibers with high performance,long chain poly(amide-co-ether) (LPAE) elastic fiber was prepared by melt spinning based on the long chain polyamide (LCPA) elastomer.The elastomer contained LCPA as hard segment,which was produced from bio-fermenting source and features by lower water absorption,better dimensional stability and excellent mechanical properties,and polyether as the soft segment with easy conformation change.The corresponding elasticity was effectively regulated by varying the ratio of hard/soft segments.The stretching tests results confirmed that these LPAE fibers with higher fraction of soft segment represented higher elongation and lower initial modulus,compared with the commercially used LYCRA.The cyclic tensile loading measurements revealed that the corresponding elastic recovery rate was almost equal to that of LYCRA when the strain was less than 200％.Moreover,LPAE fibers favored better thermo-stability than LYCRA,verified by higher onset degradation temperature.It also offered some advantages of LCPA,such as better wear resistance,oil or solvent resistance and absorbency to skin with the amide groups.The super elasticity of the LPAE fiber may be well originated from the dual effect that the polyamide hard segments served as the physical crosslinking point due to their strong hydrogen bonding interaction and high crystallinity,and that the polyether soft segments largely deformed due to their better flexibility.The three dimensional network was created this way by alternative hard and soft segments in the polymer chains.At large strain,the strain-induced crystallization definitely occurred,as indicated by enhanced melting enthalpy,which was especially pronounced in the soft segments.Therefore,both the slippage of the molecular chain and newly formed crystals from strain-induced crystallization predominately contributed to the reduced elastic recovery.Based on the current results,it is expected that spandex can be partially replaced with the LPAE fiber in practice.