摘要
针对新疆长绒棉在机采及加工过程中受到机械拉伸导致纤维断裂损伤的问题,首先,通过试验分析纤维直径、试样长度和拉伸速度对单根长绒棉纤维力学特性和形态变化的影响规律;其次,通过响应面法分析并建立3种因素交互作用的响应面回归模型,得到3种因素交互作用对单根长绒棉纤维力学特性的影响规律;最后,借助扫描电子显微镜对不同断裂方式的棉纤维断口形貌进行观察与分析。结果表明:当试样长度和拉伸速度一定时,随着单根长绒棉纤维直径的增大,断裂强力逐渐减小,纤维表面形态变化差异较大;当纤维直径一定时,单根长绒棉纤维断裂强力随着拉伸速度的增大而增大,随着试样长度的增加而减小;单根长绒棉纤维力学特性不仅受上述3种因素的单一影响,受其交互作用的影响也较为显著,影响顺序依次为纤维直径、拉伸速度、试样长度;在低载荷下,单根长绒棉纤维断裂伸长率与拉伸速度没有较大关系,但其随试样长度的增加而增加;新疆单根长绒棉纤维在拉伸过程中力学特性曲线表现为直接断裂和逐渐断裂2种类型,主要原因依赖于棉纤维初始形态和缺陷程度,其拉伸形态变化归纳为纵向微原纤分裂且在纤维内传播,断裂方式具有直接断裂、轴向撕裂、扭转断裂和纤维丝间滑移。
Objective The paper aims to reduce the mechanical damage of long staple cotton caused by during mechanical processing.Exploring the changes of physical properties and morphological transition under different mechanical process parameters.Method The tensile test of long-staple cotton fiber was conducted on tensile tester,and the mechanical properties and morphological changes of fiber samples during the tensile process were analyzed.The test temperature was(21±2)℃ and the relative humidity was(65±5)%.The influence of fiber diameter,specimen length and tensile speed on the mechanical properties and morphological changes was investigated using a single factor method.The response surface regression model of the interaction of three factors was analyzed and established by the response surface method.The morphology of cotton fiber fractures with different fracture methods was analyzed by scanning electron microscopy.Results The breaking strength decreased gradually with increasing diameter when the length and tensile speed of cotton fibers remain unchanged.It was found that the diameter and surface morphology are related to the maturity of the fibers,the breaking strength increased with the increasing tensile speed for the same diameter,and minor defects appeared along the tensile direction.As the load further increases,the cracks gradually growth due to a large number of defects accumulated and leading to fiber breakage.The tensile speed and length of fiber have a great influence on the fracture strength,the breaking strength of fiber increases with the increase of tensile speed while decreases with the increase of length.The breaking strength is 38.48 mN for the length of 1 mm and tensile speed of 2μm/s,and 52.63 mN for the speed of 6μm/s.The mechanical properties of fibers affected by the three factors mentioned above,and the interaction of them in the order of fiber diameter>tensile speed>sample length.When the load is small during the stretching process,the break elongation and tensile speed of fibers did not have much effect,but both of them increased as the sample length increasing.Furthermore,the two forms of breakage of cotton fibers during stretching often occur.One is that the fiber tension increases with stretching and suddenly breaks when it reaches the maximum bearing tension of cotton fiber.The second is that the tensile force increases firstly to the peak value,then suddenly drop to a certain tensile force and continue for a period of time and then drop to zero.The load-tension curves of fibers showed direct and gradual fracture during stretching,which was related to the initial morphology and the degree of defects of the cotton fibers.Conclusion The experimental results indicate that the tensile morphology changes of long-staple cotton fiber mainly presented as longitudinal microfibril splitting and propagation in the fiber,and the fracture mode included direct fracture,axial tear,torsional fracture and interfilament slip.The research results will helpful for reducing fiber damage during mechanical processing.
作者
马承诺
姜开翔
陈春晖
刘园玲
张有强
MA Chengnuo;JIANG Kaixiang;CHEN Chunhui;LIU Yuanling;ZHANG Youqiang(College of Mechanical and Electrical Engineering,Tarim University,Alar,Xinjiang 843300,China;Key Laboratory of Modern Agricultural Engineering of Colleges and Universities,Department of Education of Xinjiang Uygur Autonomous Region,Tarim University,Alar,Xinjiang 843300,China)
出处
《纺织学报》
EI
CAS
CSCD
北大核心
2024年第2期36-44,共9页
Journal of Textile Research
基金
国家自然科学基金项目(12262034)
兵团财政科技计划资助项目(2021CB036)
塔里木大学校长基金创新研究团队项目(TDZKCX202202)。
关键词
单根长绒棉纤维
力学特性
断裂机制
断口形貌
新疆棉
single long-staple cotton fiber
mechanical property
fracture mechanism
fracture morphology
Xinjiang cotton
