不同纺丝速度对涤纶混纤预取向丝结构及性能的影响

研究了在相同高速纺丝混纤异收缩一步法工艺和第二拉伸辊温度恒定的条件下,不同卷绕速度对用于制备涤纶混纤预取向丝的取向态结构、沸水收缩率以及力学性能的影响。实验结果表明,当卷绕速度由3 300 m/min提高到3 800 m/min时,涤纶预取向丝的取向因子和断裂强度随之增加,而断裂伸长率和沸水收缩率却随之减小。     

降低锦纶-6长丝沸水收缩率的实践体会

<正> 在以已内酰胺为原料生产锦纶6长丝中,经切片纺丝制得的卷绕丝其单体含量约为2～4％左右。单体的存在对丝的强度、色泽、染色均匀性等有一定影响。又因未定型丝中大分子各个链段的内应力是不均匀的,具有不稳定结构,使纤维的形状稳定性差,沸水收缩率高达10～15％。压洗定型的目的即为除去纤维中大部分单体和降低沸水收缩率。     

关于聚酰胺纤维在纺丝过程中的取向

1.纺丝速度与卷绕丝性质的关系 为了研究锦纶6在熔纺过程中的取向问题,在纺丝速度从500米/分到4400米/分的范围内,测定了卷绕丝的双折射、X光衍射、密度,沸水收缩率,纵向溶胀度等物理性质。 1.1 实验方法     

PET和PTT及PET/PTT复合纤维结构研究进展

概述了聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丙二醇酯(PTT)的结构异同点,以及高速纺丝工艺条件下纤维的超分子结构。PET和PTT纤维都只存在三斜晶系晶型,均属可高速纺拉伸诱导取向结晶类纤维。随着纺丝速度的增加,在纺丝速度为4000m/min左右时,PET和PTT纤维均出现取向诱导结晶现象,且晶体尺寸增大;双折射值则先增大后减小,但在相同的纺丝速度下,PTT初生纤维的双折射值要小于PET初生纤维的双折射值。综述了PET/PTT并列复合纤维的结构研究进展。单组分纤维和双组分纤维存在结构差异。指出应进一步研究PET/PTT并列复合纤维的结构和性能。     

涤纶预取向丝的结构和性质

<正> 一 序言 通常涤纶在常规纺丝速度(1000米/分以下),初生丝是无定形的,其取向度极低。随着纺丝速度的提高,可生成较高取向的和结晶的结构。 本文研究纺丝速度为1000～6000米/分的卷绕丝结构和性质随纺丝速度而改变的定性和定量关系,从而求得预取向丝向全取向丝(FOY)过渡的必要条件,进而从改变工艺着手来提高分子取向和结晶的方法,为研究制备FOY探索条件。     

涤纶高收缩全拉伸丝的应用及探讨

介绍了运用热辊纺丝拉伸一步法纺制高收缩全拉伸丝的工艺,同时论述了各项关键技术参数对纤维收缩率的影响。生产中纺丝温度在280￣288℃、纺丝速度在3900￣4500m/min、侧吹风速度在0.3￣0.5m/s、卷绕超喂率控制在0.7%￣1.4%,并根据需要控制拉伸温度和定型温度,可生产出优质的高收缩纤维。     

一步法制备高收缩涤纶FDY

以常规聚酯切片为原料 ,选择纺丝 -拉伸 -热处理一步法的工艺路线 ,主要通过调节热辊的温度和速度制备沸水收缩率大于 5 0 %的 F DY涤纶长丝 ,详细讨论了纤维的热收缩机理及影响热收缩的工艺条件。对纤维超分子结构的测试表明 :所制备的高收缩 FDY涤纶长丝具有低结晶、高取向的特点     

可熔融加工的PAN树脂纺丝工艺及卷绕丝的结构与性能研究

研究了可熔融加工的聚丙烯腈 (MPPAN)树脂的非增塑熔融纺丝工艺 ,并应用 X光衍射、声速、应力 -应变等方法对卷绕丝的结晶和取向结构、力学性能和沸水收缩性进行了表征 ,结果表明 ,两种MPPAN样品均可进行熔融纺丝 ,其纺丝压力比常规聚酯纤维、聚酰胺纤维高 ;MPPAN卷绕丝的结晶及晶粒尺寸较低 ,具有一定的机械强度 ,热水收缩较大。     

PTT的纺丝稳定性和聚集态结构

利用毛细管流变仪研究PTT熔体挤出时的破裂现象,讨论PTT纺丝稳定性和初生纤维聚集态结构。结屎表明,PTT熔体是一种拉伸变稀型流体。自由挤出时,即使剪切速率达到1.5×105 s-1时,挤出熔体也没有出现明显的熔体破裂;而在纺丝过程中,在卷绕速度达到3.8 km／min(剪切速率2.1×103 s-1)时,就出现明显的熔体断裂现象。在高速纺丝中,控制PTT初生纤维取向结构的关键是喷丝头拉伸比,决定结晶结构的关键是卷绕速度。增加喷丝头拉伸比可以提高初生纤维的取向度;提高卷绕速度可以提高纤维结晶度。     

抗菌PTT POY的结构与性能研究

采用银系抗菌母粒与聚对苯二甲酸丙二醇酯(PTT)切片共混熔融纺丝,在一定纺丝速度下,通过改变泵供量,制备了不同线密度的抗菌PTT预取向丝(POY);研究了纤维的结晶、取向、物理性能和抗菌性能。结果表明:与未加抗菌母粒的PTT POY相比,对于相同规格的PTT POY,随抗菌母粒的加入,其初生纤维的结晶度降低,取向度略有上升,断裂强度和断裂伸长率有所下降,沸水收缩率变化不大;加入5%抗菌母粒的PTT POY对大肠杆菌和金黄色葡萄球菌具有良好的抑菌效果;随着喷丝头拉伸比的增加,抗菌PTT POY的取向度和结晶度相应增加,断裂伸长率降低,断裂强度增加,沸水收缩率有所下降。     

熔融纺丝成形条件对PET初生丝超分子结构及其力学性能的影响——第1报 不同纺速下PET初生丝超分子结构及其力学性能的研究

本文借助于沸水收缩率、自然拉伸比以及用X射线衍射法测定的结晶度,表观晶粒尺寸和晶区取向因子等指标来描述熔融纺丝时不同纺速下PET初生丝的超分子结构。纺丝速度在1500～4800m/min范围内变化。测得的数据表明在较低的纺速下卷取的PET初生丝是不结晶的,而在较高纺速下纺制的PET初生丝结晶度要高得多。在实验的纺速范围内,PET初生丝的结晶度在纺速增加的过程中有突变现象,这主要是分子取向诱导所致,也即存在一个诱导结晶的临界取向度。最后,就不同纺速下PET初生丝的力学性能特征值进行了讨论。     

Melt spinning and drawing of 2‐methyl‐1,3‐propanediol‐substituted poly(ethylene terephthalate)

The structure and properties of fibers prepared from copolymers of poly(ethylene terephthalate) (PET) in which 2‐methyl‐1,3‐propanediol (MPDiol® Glycol is a registered trademark of Lyondell Chemical Company) at 4, 7, 10, and 25 mol% was substituted for ethylene glycol were studied and compared with those of PET homopolymer. Filaments were melt spun over a range of spinning conditions, and some filaments that were spun at relatively low spinning speeds were subjected to hot drawing. The filaments were characterized by measurements of birefringence, differential scanning calorimetry (DSC) crystallinity, melting point, glass transition temperature, wide‐angle X‐ray diffraction patterns, boiling water shrinkage, tenacity, and elongation to break. Filaments containing 25 mol% MPDiol did not crystallize in the spinline at any spinning speed investigated, whereas the other resins did crystallize in the spinline at high spinning speeds. However, compared with PET homopolymer, increasing substitution of MPDiol reduced the rate at which the crystallinity of the melt spun filaments increased with spinning speed and reduced the ultimate crystallinity that could be achieved by high‐speed spinning. The rate of development of molecular orientation, as measured by birefringence, also decreased somewhat with increasing MPDiol content. Shrinkage in boiling water decreased at high spinning speeds as the amount of crystallinity increased; however, the shrinkage decreased more slowly with increase in spinning speed as MPDiol content increased. Tenacity also decreased slightly at any given spinning speed as MPDiol content increased, but there was no significant effect on elongation to break. The addition of MPDiol in amounts up to 7 mol% increased the maximum take‐up velocity that could be achieved at a given mass throughput. This result indicates that the use of higher spinning speeds could potentially increase the productivity of melt spun yarns. Copolymer filaments spun at low speeds were readily drawn to produce highly oriented fibers with slightly less birefringence, crystallinity, and tenacity than similarly processed PET homopolymer. Preliminary dyeing experiments showed that the incorporation of MPDiol improved the dyeability of the filaments. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2598–2606, 2003     

WINGS系统纺预取向丝的结构与性能稳定性分析

以WINGS(Winding Integrated Gadet Solution)纺丝系统和传统ACW(Advanced Craft Winde)r纺丝系统为研究对象,比较同一纺丝位不同丝饼间预取向丝(POY)在相同纺丝条件下的结晶度、双折射率、力学性能、沸水收缩率等的变化规律。研究发现,WINGS纺丝系统同一纺丝位不同丝饼间POY的双折射率、结晶度、断裂强度、断裂伸长率、初始模量及沸水收缩率各值的变化率(CV值)均低于传统ACW工艺生产的POY的值,表明WINGS纺丝系统制得的POY有更稳定的结构和性能。     

熔融纺丝成形条件对PET初生丝超分子结构及其力学性能的影响——第2报 单丝线密度、喷丝头拉伸比及侧吹风速对PET初生丝结晶作用及力学强度的影响

本文考察了单丝线密度、侧吹风速度以及喷丝头拉伸比对PET初生丝结晶作用及力学强度的影响。表明PET初生丝的结晶作用对单丝线密度的变化极为敏感。当单丝纤度减少时,初生丝的结晶度、侧向晶粒尺寸均大幅度增加,且最大结晶度出现的位置移向低纺速区。增大喷丝头拉伸比的作用有点类似于减少单丝线密度。但当喷丝头拉伸比超过一定值之后,结晶度虽仍在增加,而侧向晶粒尺寸却似乎已达饱和值。强化冷却条件,即加大侧吹风速,虽然也能使PET初生丝的结晶度和侧向晶粒尺寸增加,但其作用却并不象我们所预期的那么大。此外,实验还表明,除单丝线密度变化时,PET初生丝的断裂强度出现反常现象外,一般说来断裂强度总是随取向度和结晶度的增加而增大,延伸度则相应减小。     

拉伸方式对聚醚醚酮纤维结构和性能的影响

采用进口聚醚醚酮(PEEK)树脂为原料,熔融纺丝制备了PEEK初生纤维,研究了一次拉伸和二次拉伸对PEEK纤维结构和力学性能的影响。结果表明:在150～270℃内,随着拉伸温度的提高,PEEK初生纤维的最大拉伸倍数增大,纤维的取向因子和力学性能提高;一次拉伸和二次拉伸时纤维的最大拉伸倍数相同,纤维的取向度、结晶度和力学性能基本相当,但二次拉伸纤维干热收缩率较低。二次拉伸时,总拉伸倍数相同,随着一段拉伸倍数的增大,纤维取向因子增大,力学性能提高;随着二段拉伸温度的提高,纤维结晶度增大,干热收缩率减小,取向因子基本相同,力学性能更优。     

Process–structure–property relationship of melt spun poly(lactic acid) fibers produced in the spunbond process

We report on the process–structure–property relationships for Poly(lactic acid) (PLA) filaments produced through the spunbond process. The influence of spinning speed, polymer throughput, and draw ratio on crystallinity and birefringence of fibers were evaluated. We established that increasing spinning speed increases crystallinity and birefringence of fibers. We also investigate the role of fiber structures on fiber tensile properties—breaking tensile strength, strain at break, initial modulus, and natural draw ratio. An increase in spinning speed leads to a higher breaking tensile strength, higher initial modulus and lower strain at break. We have shown an almost linear relationship between breaking tensile strength of PLA fibers and birefringence. This indicates that improved tensile properties at high spinning speeds can be attributed to enhanced molecular orientation. The dependency of fiber breaking tensile strength and strain at break on spun orientation were explained with natural draw ratio, as a measure of spun orientation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44225.     

聚丙烯高速纺丝工艺的研究——卷绕丝超分子结构与后加工性能的工艺控制

利用X射线衍射、DSC、双折射、密度梯度等方法探讨了在3km/min高纺速下,纺丝温度对丙纶POY的超分子结构与后加工性能的影响,对冷却条件的影响也进行了讨论。指出在280℃以下范围提高纺丝温度可以降低聚丙烯高速纺程上的流变张力,使卷绕丝的结晶度降低,结晶成分中次晶含量增加,非晶区取向度提高。采用缓慢冷却有和于提高POY的非晶区预取向。采用MI=35的聚丙烯树脂,在纺丝温度270℃和缓冷条件下可得具有优良后加工性能的丙纶POY,在414m/min速度下经加弹所得DTY的强度为41.1cN/t(?)x,伸长为34.1%,卷曲率为20%,卷曲稳定性为92%。     

Effect of jet stretch on polyacrylonitrile as‐spun fiber formation

In this article, the effect of jet stretch ratio on the extrudate die‐swell effect of polyacrylonitrile spinning solution and the structure and properties of as‐spun fibers was systematically analyzed by means of X‐ray diffraction (XRD), electron microprobe analysis, and the measurement of die‐swell ratio, boiling‐water shrinkage, porosity, mechanical properties analysis, etc. It revealed the formation mechanism of the die‐swell effect and spin orientation and its influences on the structure and properties of as‐spun fibers. It showed that with the increase of the jet stretch ratio the die‐swell ratio became smaller, both the degree of spin orientation and the crystallinity increased, the microstructure of as‐spun fibers became compact and homogeneous, and the cross section tended to be circular. As a result, the breaking tenacity of as‐spun fibers and resultant precursors all increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3348–3352, 2007     

The influence of isotacticity,ethylene comonomer content,and nucleating agent additions on the structure and properties of melt-spun isotactic polypropylene filaments

The influence of isotacticity, ethylene comonomer content, and nucleating agent additions on the structure and properties of melt-spun polypropylene filaments was studied for a series of polypropylenes having similar resin melt flow rates (MFR ≌ 35), average molecular weights, and polydispersities. In general, increasing the degree of isotacticity increases crystallinity and tensile modulus of the spun filaments, while increasing the copolymer content has the opposite effect. Nucleating agent additions also lead to greater crystallinity, but, under certain conditions, the addition of a nucleating agent can lead to lower tensile modulus in spite of higher crystallinity. For given spinning conditions, the tensile strength increased slightly with increased copolymer content but was little affected by tacticity in the range studied. Nucleating agent additions lowered the tensile strength of spun filaments. The effects of nucleating agents on the filament modulus and tensile strength were traced to their ability to raise the crystallization temperature and reduce the level of molecular orientation generated in the filaments. The reasons for the observed behavior are discussed. © 1996 John Wiley & Sons, Inc.     

芳香族聚噁二唑纤维结构对染色性能的影响

采用一步法合成不同分子结构的芳香族聚噁二唑(POD),用湿法纺丝法制备不同聚集态结构的POD纤维。通过使用分散染料对不同结构的POD纤维进行高温高压染色,研究其结构与染色性能的关系。结果表明:POD含有噁二唑环和少量的酰肼基团,对染料的吸附性好;噁二唑环化度影响上染率,环化度升高,纤维上染率降低;加入极性的第三功能单体可以提高环化度和纤维的上染率;染色主要发生在非晶区,凝固浴及后处理方法影响纤维的聚集态结构,提高纤维的结晶度及取向度,将降低上染率。