喷丝速率对连续水浴静电纺纳米纤维包芯纱结构与性能的影响

Effect of spinneret rate on structure and properties of nanofiber core-spun yarns prepared by continuous water bath electrospinning

为实现工艺参数对纳米纤维包芯纱的结构调控,采用连续水浴静电纺丝的方法,以聚对苯二甲酸乙二醇酯(PET)纤维为芯纱,聚酰胺6(PA6)纳米纤维为包覆层,制备兼具纳米纤维特性和传统纱线力学性能的纳米纤维包芯纱。对PET/PA6纳米纤维包芯纱的形态、晶体结构和力学性能进行分析与表征。结果表明:纳米纤维包芯纱具有良好的皮芯结构;PA6包覆层的纳米纤维直径为66~80 nm,其孔隙率随喷丝速率的提高而下降,结晶度在19%~24.15%范围内,且随喷丝速率的提高而减小;PA6纳米纤维包覆层的断裂强度和断裂伸长率随喷丝速率的增大而降低,其断裂强度降为常规PA6纤维的1/5;纳米纤维包芯纱保持了芯纱的强力与断裂伸长率等力学性能。

Objective The spinneret rate as one of the electrostatic spinning parameters affects the performance of nanofiber core-spun yarns structure.This research aims to optimize the process parameters of electrospinning in order to meet the technical requirements for structure and properties of nanofiber core-spun yarns made from such made nanofibers.Method A homemade electrostatic spinning device was set up for continuous preparation of nanofiber core-spun yarns.Through continuous double needle bath electrostatic spinning method,a core yarn was created using polyester(PET)as the core yarn,polyamide 6(PA6)nanofibers as the coating layer,offering properties of the nanofibers and traditional yarn mechanical properties of nanofiber core-spun yarn.The morphology,crystal structure and mechanical properties of PET/PA6 nanofiber core-spun yarns were analyzed and characterized by scanning electron microscopy,differential scanning calorimetry and universal material testing machine.The influence of spinneret rate on the structure and properties of nanofiber core-spun yarns in double-needle water bath electrospinning was investigated.Results By changing the spinneret rate in electrospinning process,the influence of different spinneret rates on the structure and properties of nanofiber core-spun yarn was analyzed.The results show that nanofibers could be formed on the surface of core yarn in the range of 0.10-0.40 mL/h spinneret rate,but the collection state and diameter of nanofibers were different.When the spinneret rate was greater than 0.10 mL/h,the adhesion phenomenon occurred between nanofibers due to the larger jet solution from the surface of Taylor cone.With the increase of spinneret rate,the diameter of nanofibers increased to a certain extent,and the porosity of PA6 nanofiber coating decreased because of the adhesion between nanofibers.In the range of 0.10-0.40 mL/h of spinneret rate,the crystallinity of nanofibers decreased with the increase of spinneret rate.When the spinneret rate is 0.10 mL/h and 0.15 mL/h,the crystallinity of nanofibers was within the range of conventional PA6 fiber crystallinity.The crystallinity of nanofibers was slightly less than that of conventional PA6 fibers.The reason was that the shape of Taylor cone was broken with higher spinneret rate,and the increasing instability of jet flow leads to the decrease of crystallinity.In the range of 0.10-0.40 mL/h spinneret rate,with the increase of spinneret rate,leading to the increase of breaking force.But the strength and elongation at break show a decreasing trend,which is consistent with the changing trend of crystallinity.The highest breaking strength was(0.66±0.13)cN/dtex at 0.10 mL/h,which was about 1/5 of that of conventional PA6 fiber.The breaking strength and elongation at break of nanofiber core-spun yarns were slightly higher than those of core-spun yarn,while the breaking strength of nanofiber core-spun yarns decreases with the increase of its linear density.Therefore,the combination with conventional fiber yarn is beneficial to improve its mechanical properties,and can give yarn high specific surface area,and expand the use of yarn.Conclusion The prepared nanofiber cored yarn has a good cored structure according to the scanning electron microscope characterization of cross-section and surface morphology of nanofiber core-spun yarns.And the diameter of the coated nanofiber is 66-80 nm,and the porosity decreases with the increase of the spinneret rate.The crystallinity of nanofibers is in the range of 19%-24.15%,and decreases while spinneret rate increases.The strength and elongation at break of PA6 nanofiber coatings decrease with the increase of spinneret rate,and the strength of PA6 nanofiber coatings is about 1/5 of that of conventional polyamide 6 fibers.The nanofiber core-spun yarn maintains its mechanical properties such as strength and elongation at break.It is of great significance to study the influence of process parameters on the structure and performance of nanofiber core-spun yarns in the process of electrospinning,which can also bring thinking to researchers and provide reference for subsequent research and experiments.