解决PA66细旦丝质量问题实例

在PA66细旦丝的实际生产过程中,控制好最基本的纤度指标,是其质量生命的核心。文章从质量管理的第一线出发,将实际生产过程中的质量管理实例进行总结、升华,提炼出PA66细旦丝质量控制的应对策略。     

PA6/PA66共聚酰胺纤维的制备及结构性能研究

为提高聚己内酰胺(PA6)纤维的结强比和勾结韧性，采用PA6/聚己二酰己二胺(PA66)共聚酰胺切片进行熔融纺丝，制备PA66质量分数分别是10%和20%的PA6/PA66共聚酰胺纤维，测试并分析不同牵伸倍数的PA6及PA6/PA66共聚酰胺纤维的物理性能(包括结晶度、取向度、线密度和回潮率)和拉伸性能(包括直接拉伸法、单勾结法和双勾结法)。结果显示：PA66共聚单体的引入使得PA6/PA66分子链规整性降低，纤维的结晶度、取向度、断裂强度均有所下降，回潮率略有上升，结强比和断裂伸长率保持率较PA6纤维的大幅度提高。PA6/PA66共聚酰胺纤维非常适合用于勾结类织物。     

聚酰胺原液着色母粒的制备及其性能

针对聚酰胺66(PA66)原液着色过程中炭黑在PA66基体中分散性差的问题，首先，将炭黑加入到含有一定质量分数的分散剂的水溶液中，采用超声波分散协同喷雾干燥技术制备了自分散炭黑(SPCB);随后将SPCB再分散于含有一定质量分数PA66盐的水溶液中，制备了PA66盐基炭黑分散体，并通过原位聚合法制备了PA66原液着色母粒；最后，通过熔融共混法制备了PA66膜。探究了分散剂结构和质量分数、炭黑质量分数、超声波处理功率和时间对PA66盐基炭黑分散体粒径、粒径分布及稳定性的影响，分析了SPCB质量分数与PA66膜性能的关系。结果表明：聚乙烯吡咯烷酮相对炭黑质量分数为15%,炭黑相对体系的质量分数为10%,超声波处理功率为1 260 W,时间为80 min时，制备的PA66盐基炭黑分散体粒径最小为184.1 nm,离心稳定性和放置稳定性均在90%以上；SPCB与PA66的相容性良好，在PA66基体中分布均匀，粒径约为200 nm,当其质量分数为0.2%时，制备的PA66膜的熔融温度为259.2℃,L^*值为26.82。     

共聚酰胺6/66相对分子质量对其结晶和流变性能的影响

为探索共聚酰胺6/66(PA6/66)的熔体加工性能,研究PA6/66相对分子质量对其熔融行为、结晶行为和熔体流变行为的影响,借助差示扫描量热仪、熔体流动速率仪、毛细管流变仪等对系列不同相对分子质量PA6/66和PA6树脂的结晶行为和流变性能等进行表征。结果表明:PA6/66呈现单一的熔融峰,其熔点和玻璃化转变温度受相对分子质量影响较小,分别约为210 ℃和45 ℃;与PA6相比,PA6/66的熔点、熔融焓值和结晶焓值显著降低;随相对分子质量的增加,降温速率为20 ℃/min时,PA6/66的结晶焓值由45.16 J/g下降为43.67 J/g,明显低于同等相对分子质量下PA6的结晶焓值;不同相对分子质量的PA6/66共聚物均为假塑性流体,随着温度的升高,其非牛顿指数增大,对剪切速率的敏感程度降低;在高剪切速率下,PA6/66具有比PA6更高的黏流活化能。     

PET-PA66相容性及其复合沉析纤维的制备研究

采用沉析法制备了聚对苯二甲酸乙二醇酯(PET)-聚酰胺66(PA66)复合沉析纤维,探讨了PA66的用量对复合沉析纤维的表面形貌、尺寸、亲水性能及PET和PA66分子间相容性的影响,并研究了PET复合纸强度性能。结果表明,PET-PA66复合沉析纤维形态呈带状,表面有少量褶皱;随着PA66含量的增加,PET-PA66复合沉析纤维的尺寸减小,比表面积从7.38 m~2/g增加到10.12 m~2/g,接触角从107°降低到88°,DSC曲线上仅出现了一个熔融峰,表明PET和PA66间有良好的相容性。同时FT-IR谱图中1724.3 cm~(-1)处C=O的伸缩振动峰向低波数移动,说明PET和PA66在溶解过程中分子间产生氢键作用,增加了PET-PA66体系的相容性;随着PA66含量的增加,PET复合纸的抗张指数和撕裂指数分别提高了12.0%和47.8%。     

PA66抗热氧化技术在聚合工艺中的应用

介绍了聚酰胺6(6 PA66)树脂的热氧化情况,阐述了常见热稳定剂、抗氧化剂对PA66树脂的作用机理及应用,从原料配方和聚合设备操作两方面分析了PA66树脂固相聚合工业化技术中的抗热氧化技术。     

超细特锦纶66及其仿羊绒纱线的性能研究

基于对超细特PA66短纤维与山羊绒在强伸性能、吸湿与电学、热力学等物理性能的研究，分析了超细特PA66短纤维与山羊绒在性能上的相似之处；设计了4种超细特PA66仿羊绒纱线的工艺方案，研究了超细特PA66短纤仿山羊绒纱线的服用性能，为化纤仿真产品开发提供了借鉴。     

PA66/Kevlar29纤维复合材料的力学性能研究

以PA66为基体,加入不同质量分数的Kevlar29纤维,制成PA66/Kevlar29纤维复合材料,并研究复合材料的力学性能。结果表明,加入Kevlar29纤维能起到增强作用,复合材料的拉伸强度、弯曲强度都增加。但是Kevlar29纤维具有很高的结晶度且表面光滑,其与PA66复合时,界面的钩锚作用较弱,界面结合强度较低,造成复合材料的冲击强度低于纯PA66材料的冲击强度。     

聚酰胺66/氨基化多壁碳纳米管纤维制备及其性能

为提高聚酰胺66(PA66)纤维的力学性能,将羧基化碳纳米管(CMWNTs)与乙二胺(EA)进行功能化反应得到氨基化碳纳米管(AMWNTs),再将AMWNTs与PA66盐原位聚合制备AMWNTs掺杂PA66材料(PACNTs),并通过熔融纺丝制备成纤维。采用热重分析仪、差示扫描量热仪、X射线衍射仪及单纤维强力仪等对PA66和PACNTs纤维进行结构和性能表征。结果表明:PACNTs纤维的熔点随着AMWNTs的加入向低温方向移动,AMWNTs的加入使PA66分子质量下降,PACNTs纤维的结晶温度向高温方向移动,AMWNTs起到异相成核作用;随着AMWNTs的加入,PACNTs纤维的拉伸强度和弹性模量增加,当AMWNTs质量分数为0.5%时,PACNTs纤维的拉伸强度和弹性模量达到最大,比纯PA66纤维分别提高了约157%和455%。     

国产聚乙烯粗旦单丝纺牵联合机的探讨与分析

介绍国产聚乙烯粗旦单丝纺牵联合机的结构,着重分析了聚乙烯粗旦丝设备中的关键技术和推广应用成果。     

锦纶纤维酸性染料染色动力学对比研究

选用酸性蓝NHFS研究了3种锦纶纤维(生物基PA56、PA6和PA66)的染色动力学数据并进行了对比。通过测定上染速率曲线,计算出了扩散系数、染色速率常数及半染时间,探讨了锦纶56结构与染色性能的关系。结果表明:生物基锦纶56的扩散系数明显高于锦纶6和锦纶66,染色速率常数也明显高于锦纶6和锦纶66,半染时间最短;3种锦纶纤维在相同的染色温度下各自的半染时间染色后,锦纶56染色后的K/S值明显高于锦纶6、锦纶66。因此采用酸性蓝NHFS对锦纶56进行染色时,需要较短时间就可得到较深的颜色。     

尼龙66织物的磷氮复合阻燃整理

摘要:采用有机磷酸酯和含氮阻燃剂复配阻燃体系对尼龙66(PA66)织物进行阻燃整理。探讨了阻燃剂用量及配比、焙烘温度对织物燃烧性能的影响。优化的阻燃整理工艺条件为:含磷阻燃剂和含氮阻燃剂质量比1:3,阻燃剂30%,焙烘温度160℃。经阻燃整理的尼龙66织物具有良好的耐熔滴性,其极限氧指数可达35.0%,损毁长度降至4.2 cm,续燃时间仅为1.04 s,断裂强力仅下降3.6%。热重分析(TGA和DTA)表明,阻燃整理后的PA66织物在燃烧过程中分解温度提前,降解速率变小,残炭量增加;扫描电镜(SEM)发现,燃烧残余物表面有蜂窝状的孔洞。该阻燃体系通过气相阻燃、吸热阻燃及凝聚相成炭阻燃等多重阻燃机制,提高了PA66织物的阻燃性能。     

贻贝中微塑料检测的消解方法比较

目的 比较双壳贝类中微塑料检测常用的酸消解、碱消解、氧化消解和酶消解等方法,推荐适用于贝类中微塑料检测的通用型消解方式。方法 以常用的指示性双壳贝类贻贝作为研究对象,确定食品样品检测通用的消解条件。在这些条件下对聚苯乙烯（polystyrene,PS）、聚丙烯（polypropylene,PP）、聚碳酸酯（polycarbonate,PC）、聚乙烯（polyethylene,PE）、聚对苯二甲酸乙二醇酯（polyethylene terephthalate,PET）、聚酰胺6（polyamide,PA6）和聚酰胺66（polyamide,PA66）七种微塑料进行消解,考察不同条件下微塑料粒子消解前后重量、红外光谱、粒径分布和形貌特征的变化。结果 采用不同的消解方式对不同的微塑料影响不同,其中重量受影响较大的是PA6和PA66,在硝酸-高氯酸混合溶液和高氯酸-双氧水混合溶液中完全溶解损失,PC和PET在氢氧化钾溶液中损失严重。通过结构表征,PE、PA6和PC的粒径增加,PC的形貌结构发生彻底改变。结论 微塑料含量甚微的双壳贝类样品进行检测,推荐采用胃蛋白酶溶液和胰蛋白酶溶液进行消解;如需缩短消解时间,推荐采用双氧水在高温下消解。     

PA66黑芯切片的产生原因分析与控制

针对间歇法合成PA66树脂实际生产中出现的黑芯切片问题,从聚合过程和造粒系统两方面对PA66黑芯切片的产生原因进行分析,并给出控制和预防措施。     

Validation and application of an LC-MS/MS method for the determination of cyclic oligomers originating from polyamide 6 and polyamide 66 in food simulant

Polyamides (PAs) are used in the production of various food contact materials (FCMs) and articles such as kitchen utensils and packaging material. Cyclic oligomers have been identified as potential migrants from PA. This study describes the development, validation and application of a multi-oligomer analytical method based on LC-ESI-MS/MS for the identification and quantification of eight cyclic oligomers of PA 6 and four PA 66 migrating from FCMs into food simulant B (3% acetic acid) and beverages. It was proved that doubly charged precursor ions of the cyclic PA 6 and PA 66 oligomers above a mass of 500 Da are formed during the ionisation process of the electrospray technique used. Direct injection of a diluted food simulant into the LC-ESI-MS/MS system after migration makes the validated method a valuable tool for investigating migration of cyclic PA oligomers. The validation results demonstrate that the multi-oligomer method is applicable for the analysis of cyclic PA 6 and PA 66 oligomers in food simulant B. For all investigated cyclic PA oligomers, detection limits were in the range of 0.1–1.1 µg/l. Linearity (r² ≥ 0.99), trueness values between 91% and 122%, and intra-day (RSD_r < 10%) and inter-day precision (RSD_R < 19%) were determined and satisfied validation criteria set out by the European Reference Laboratory for FCMs. The method was extended to tap water and tea. Finally, the multi-oligomer method was successfully applied to determine cyclic PA oligomers in migration solutions originating from different PA FCMs. In all migration solutions, concentrations of cyclic PA oligomers were determined above the LOQ. A preliminary risk assessment based on in silico tools was performed. The results demonstrate the urgent need for toxicological data that would facilitate the evaluation of the health risk of cyclic PA oligomers.     

Altering palmitic acid and stearic acid ratios in the diet of early-lactation Holsteins under heat stress: Feed intake,digestibility, feeding behavior,milk yield and composition,and plasma metabolites

The objective of this study was to evaluate the effects of varying the ratio of dietary palmitic (C16:0; PA) and stearic (C18:0; SA) acids on nutrient digestibility, production, and blood metabolites of early-lactation Holsteins under mild-to-moderate heat stress. Eight multiparous Holsteins (body weight = 589 ± 45 kg; days in milk = 51 ± 8 d; milk production = 38.5 ± 2.4 kg/d; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design (21-d periods inclusive of 7-d data collection). The PA (88.9%)- and SA (88.5%)-enriched fat supplements, either individually or in combination, were added to diets at 2% of dry matter (DM) to formulate the following treatments: (1) 100PA:0SA (100% PA + 0% SA), (2) 66PA:34SA (66% PA + 34% SA), (3) 34PA:66SA (34% PA + 66% SA), and (4) 0PA:100SA (0% PA + 100% SA). Diets offered, in the form of total mixed rations, were formulated to be isonitrogenous (crude protein = 17.2% of DM) and isocaloric (net energy for lactation = 1.69 Mcal/kg DM), with a forage-to-concentrate ratio of 40:60. Ambient temperature-humidity index averaged 72.9 throughout the experiment, suggesting that cows were under mild-to-moderate heat stress. No differences in DM intake across treatments were detected (mean 23.5 ± 0.64 kg/d). Increasing the dietary proportion of SA resulted in a linear decrease in total-tract digestibility of total fatty acids, but organic matter, DM, neutral detergent fiber, and crude protein digestibilities were not different across treatments. Decreasing dietary PA-to-SA had no effect on the time spent eating (340 min/d), rumination (460 min/d), and chewing (808 min/d). As dietary PA-to-SA decreased, milk fat concentration and yield decreased linearly, resulting in a linear decrease of 3.5% fat-corrected milk production and milk fat-to-protein ratio. Feed efficiency expressed as kg 3.5% fat-corrected milk/kg DM intake decreased linearly with decreasing the proportion of PA-to-SA in the diet. Treatments had no effect on milk protein and lactose content. A linear increase in de novo and preformed fatty acids was identified as the ratio of PA to SA decreased, while PA and SA concentrations of milk fat decreased and increased linearly, respectively. A linear reduction in blood nonesterified fatty acids and glucose was detected as the ratio of PA to SA decreased. Insulin concentration increased linearly from 10.3 in 100PA:0SA to 13.1 µIU/mL in 0PA:100SA, whereas blood β-hydroxybutyric acid was not different across treatments. In conclusion, the heat-stressed Holsteins in early-lactation phase fed diets richer in PA versus SA produced greater fat-corrected milk and were more efficient in converting feed to fat-corrected milk.     

新型聚酰胺纺丝油剂

介绍了德国HTC公司研制的用于尼龙6和尼龙66纺丝和尼龙膨体纱的新型油剂.新油剂可以确保纤维的染色均匀性,延长加热器的清理周期,使各道工序顺利进行.