【摘要】 为解决现有聚酰胺6基弹性纤维强度不高、弹性不足、难以满足弹性纺织品应用要求的问题，从本征弹性(嵌段共聚改性)与形态弹性(并列复合纺丝)结合的角度制备了PA6基并列纤维f(PA6/TPAEE6)。首先开发高强度的聚醚酯酰胺6热塑性弹性体(TPAEE6),借助核磁共振氢谱(~1H NMR)、傅里叶红外光谱(FT-IR)、凝胶渗透色谱(GPC)、相对黏度、动态热力学分析(DMA)、广角X射线衍射(WAXD)、小角X射线散射(SAXS)、热失重(TGA)、差示扫描量热法(DSC)和拉伸测试分析了TPAEE6的分子结构、相态结构和热力学性能。结果表明：TPAEE6的软、硬链段通过酯键成功相连；TPAEE6具有较高的分子量；双重玻璃化转变和散射峰的变化展示出TPAEE6优异的微相分离结构；TPAEE6的断裂强度为23～47 MPa,断裂伸长率为373%～758%。将其与PA6并列熔融纺丝，得到的并列弹性纤维f(PA6/TPAEE6)断裂强度可达3.12 cN/dtex,高于现有研究的PA6基并列弹性纤维与商业弹力丝T400(2.44 cN/dtex),在定伸长5%～20%下弹性回复率与弹性持久性均优于T400,为弹性纤维市场提供了更多选择。更多还原

【Abstract】 Objective This study aimed to address the inherent elasticity limitations of polyamide 6(PA6) fibers by combining intrinsic elasticity through block copolymerization and morphological elasticity through side-by-side spinning. The research is focused on developing high-strength polyether-ester-amide 6 thermoplastic elastomers(TPAEE6) and fabricating f(PA6/TPAEE6) side-by-side elastic fibers, so as to overcome the challenges of low strength and declining elasticity in existing PA6-based elastic fibers.Method A novel TPAEE6 elastomer was synthesized using a three-step melt copolymerization process involving non-crystalline polyether-ester diols and PA6. Characterization techniques, including proton nuclear magnetic resonance spectroscopy(~1H NMR), Fourier-transform infrared spectroscopy(FT-IR), wide-angle X-ray diffraction(WAXD), small-angle X-ray scattering(SAXS), thermogravimetric analysis(TGA), differential scanning calorimetry(DSC), dynamic mechanical analysis(DMA), and tensile testing, were employed to verify the synthesis and evaluate the structural and thermodynamic properties of TPAEE6s. Side-by-side elastic fibers were prepared by blending PA6 with TPAEE6 elastomers at specific ratios and varying draw ratios.Results ~1H NMR and FT-IR results confirmed that TPAEE6 is composed of soft and hard segments connected by ester bonds. GPC analysis revealed that the molecular weight of the elastomer ranged from 36.5 to 45.7 kg/mol, while viscosity testing indicated a relative viscosity between 1.21 and 1.68, suggesting a high molecular weight for the elastomer. DMA exhibited dual glass transition temperatures, and structural changes in the crystalline regions observed in WAXD and SAXS demonstrated the excellent microphase-separated morphology of TPAEE6. Additionally, SAXS calculations indicated that the addition of polyether-ester segments did not alter the interplanar distance of the pure PA6 crystalline phase, confirming that the incorporation of soft segments did not disrupt the crystalline structure of pure PA6. Tensile testing results showed that the elastomer exhibited a tensile strength of 23-47 MPa and an elongation at break of 373%-758%. Cyclic tensile testing revealed a significant improvement in elastic recovery with increasing soft segment content. Beyond the first cycle, the subsequent tensile cycles showed minimal loss in elasticity. The f(PA6/TPAEE6) elastic fibers, prepared by side-by-side spinning of PA6 and TPAEE6-30 at a composite ratio of 4∶1, achieved a tensile strength of 3.12 cN/dtex, significantly outperforming previously reported PA6/TPAE composite fibers(2.14 cN/dtex), PA6/TPA6510 fibers(1.4 cN/dtex), PA6/PBTE fibers(2.4 cN/dtex), and commercial elastic fibers like T400(2.44 cN/dtex). Under fixed elongations of 5%-20%, the elastic recovery rate and durability of the PA6/TPAEE6 fibers were significantly superior to those of T400, with recovery rates exceeding 90% in low-strain cycles and significantly reduced hysteresis losses.The microphase-separated structure of TPAEE6 balances flexibility and strength, imparting exceptional elasticity and mechanical performance to the fibers.Conclusion The developed TPAEE6 thermoplastic elastomer exhibits excellent thermodynamic properties and a well-defined microphase-separated structure, offering new approaches and choices for the elastomer market. The PA6/TPAEE6 elastic fibers developed significantly outperform existing PA6-based and commercial elastic fibers in terms of strength and elasticity, showcasing broad application potential. This research integrates intrinsic and morphological elasticity, providing a new pathway for developing high-performance elastic fibers with the potential to enhance production and manufacturing efficiency.更多还原