【作者】 陈熙婷；

【导师】 俞建勇； 王妮；

【作者基本信息】 东华大学 ， 纺织材料与纺织品设计， 2010， 硕士

【摘要】 新型聚烯烃弹性纤维是乙烯与另一种或几种烯烃共聚成的带有部分交联网络的高分子材料。它具有良好的弹性及其回复性和优异的耐化学、耐热性,正逐步应用在纺织品中以提高织物的舒适性和功能性。本课题以新型聚烯烃弹性纤维及其包芯纱结构和弹性行为为主要研究对象,系统分析了纤维的结构、弹性行为、新型聚烯烃弹性纤维/棉包芯纱工艺和影响因素以及物理、化学处理对纤维和包芯纱弹性的影响。得到如下结论:1、纤维的截面为圆矩型,无皮芯或其他复合结构,表面光滑;纤维分子结构中不存在双键或其他非烃类物质,化学结构稳定;结晶度较低,包括两种晶态结构;纤维熔点低,常温下为高弹态,玻璃化温度为-32.3℃。2、纤维的断裂强度不及氨纶,断裂伸长率和初始模量较高,中弹区域的延展性比氨纶好;中低拉伸区域弹性回复性较好,弹性回复率随循环拉伸次数和伸长率的增加均减小;测试回弹性推荐使用回复停顿时间60s,以便其弹性充分回复。3、捻度、芯丝牵伸倍数和芯丝含量对包芯纱拉伸和弹性回复性有显著影响。随着捻度的增加,新型聚烯烃弹性纤维/棉包芯纱的断裂强力先增大后减小,弹性回复性得到改善;随着芯丝的预牵伸倍数增加,包芯纱的断裂强力先增大后减小,断裂伸长率减小,弹性回复率显著增大;芯丝含量增加使包芯纱的断裂强力和断裂伸长率减小;用Hearle短纤纱理论结合纱线结构,推导拉伸应力应变的关系式。4、新型聚烯烃弹性纤维/棉包芯纱和氨纶包芯纱的拉伸曲线相似,新型聚烯烃弹性纤维包芯纱的断裂伸长率更大,低应变时的应力较小;新型聚烯烃弹性纤维/棉包芯纱的弹性回复率随着伸长的增加而减小,定负荷弹性回复率随着负荷的增加呈下降趋势,幅度比氨纶包芯纱大;新型聚烯烃弹性纤维包芯纱的蠕变伸长率比氨纶包芯纱小,说明尺寸稳定性好;利用四元件模型成功模拟纱线的蠕变曲线。5、松弛热处理的新型聚烯烃弹性纤维,弹性回复率随着处理温度的增加先增大后减小,塑性变形率先减小后逐渐增加至与未处理前的值相近,拉伸强力持续减小;定长热处理的聚烯烃弹性纤维,弹性回复性有所改善,当处理温度高于熔融温度时,纤维的弹性回复性锐减;包芯纱经90℃热处理后,弹性回复率下降幅度较大,塑性变形率略有增加,拉伸强力显著提高;当处理温度升高至170℃时,纱线的弹性回复率有所改善,塑性变形率和拉伸强力均较小,说明新型聚烯烃弹性纤维的热处理温度范围较大。6、硫酸溶液、碱处理和氧化剂处理对纤维的弹性行为影响不大,在中高拉伸区域弹性回复率有所改善,说明新型聚烯烃弹性纤维经纺织常用化学试剂处理后的弹性损失很小,有利于纤维的进一步应用。7、包芯纱经碱处理后的断裂强力下降,断裂伸长增加,拉伸模量变小,弹性回复率和拉伸强力大幅减小;过氧化氢溶液处理包芯纱的断裂强力变小,断裂伸长率和拉伸模量无明显变化;硫酸溶液和次氯酸钠溶液处理后,纱线的弹性回复率和拉伸强力变小,其中次氯酸钠溶液处理后纱线的弹性回复率下降幅度较大。因此纺织加工过程中需注意化学处理后纱线的强力损失和弹性回复率的减小。更多还原

【Abstract】 Polyolefin based elastic fiber is polymeric material with partly cross-linking,copolymerized by ethylene and one or more olefins.It has excellent chemical resistance,soft handle and comfortable stretch compared to spandex fiber.The structure and elastic behavior of polyolefin based elastic fiber and core-spun yarns had been taken as main objects in this paper.Then the structure and elastic behavior of the fiber,the process of polyolefin based elastic fiber/cotton core-spun yarn and influencing factors,and the physical and chemical treatment on the impact of the fiber and yarns were studied in details.The following conclusions had been obtained.1.Polyolefin based elastic fiber had a round rectangular cross-section with no skin-core or other composite structures and the surface was smooth.Unsaturated C=C band and non-hydrocarbons were not presented in its molecular structure.The material had pseudo hexagonal and orthorhombic crystal structures and low crystallinity.This fiber was in high-elastic state at ambient temperature and the melting point is low,and glass transition temperature was -32.3℃.2.Polyolefin based elastic fiber with high elongation at break and initial modulus,had less tensile strength than that of spandex fibers.The elastic recovery decreased with the increase of both cycle number and elongation.The elastic recovery at medium and low elongation was better. Pause time had been recommended as 60s for better reposition.3.Twist,draw multiples of core wire and the content of the core wire had significant influences on the tension and elastic recovery of polyolefin based elastic fiber/cotton core-spun yarn.With the increase of twist,the strength at break of the yarn increased at first and then decreased.Meanwhile the elastic recovery had been improved dramaticlly.With draw multiples of core wire increasing,the strength at break of the yarn increased at first and then decreased; elongation at break was dropped,but the elastic recovery was highly improved.The rising content of core yarns lessened the breaking strength and elongation at break of the yarn.Applying Hearle staple yarn theory,the stretching stress-strain relationship based on the structure of polyolefin based elastic fiber/cotton core-spun yarn was derived.4.The tensile curve of polyolefin based elastic fiber/cotton core-spun yarn was similar to that of spandex core-spun yarn.The strength at break under low strain was slightly low,and breaking elongation of polyolefin based elastic fiber core-spun yarn was higher.The elastic recovery rate decreased with increasing elongation or load,which was lower than spandex core-spun yarn.The elongation rate at creep of polyolefin based elastic fiber core-spun yarn was smaller than that of spandex,indicating good dimensional stability.Four-component-model was used to simulate the elongation curve of yarn under fixed load.5.The rate of both elastic recovery and plastic deformation of polyolefin based elastic fiber under relaxation heat treatment increased at first and then decreased as the processing temperature was rising.And tensile strength was dropped continuously.Under the heat-setting process,the elastic recovery had been improved but had an obviously drop when the temperature was above the melting point.For the core-spun yarns,the elastic recovery rate had decreased largely, meanwhile,the rate of plastic deformation and the stretch force enhanced when the processing temperature was up to 90℃.Dealing with temperature up to 170℃,the elastic recovery rate had been improved and others kept low.6.There was little effect on the elasticity of polyolefin based elastic fiber under sulfuric acid solution,alkali and oxidant treatment.This indicated that the chemical resistance of this fiber was beneficial to further applications in textile industry.7.The tensile strength and modulus of the core-spun yarns decreased and elongation at break increased when they were treated by alkali solutions.Further drop in elastic recovery rate and the stretch force of the yarns were discovered under alkali treatment.The tensile strength came down under hydrogen peroxide solution treatment.After the effects of sulfuric acid solution and sodium hypochlorite,the elastic recovery rate and the stretch force of the yarns became smaller.Besides, the yarn treated by sodium hypochlorite solution had more remarkable decrease in elastic recovery rate.Therefore,more attention should be paid to the loss of the strength and elastic recovery rate after chemical treatment.更多还原