Structure characterization of heat set and drawn polyamide 66 fibers by FTIR spectroscopy

Structural changes that occur during thermally induced and strain induced crystallization of polyamide 66 fibers were studied by infrared spectroscopy, density measurement and optical microscopy. Two bands at 924 and 1136 cm^–1 were shown to arise from the amorphous phase and assignment of the bands at 936 and 1200 cm^–1 to the crystalline phase were confirmed. We demonstrated that two different infrared spectroscopic methods could be used to determine the total crystallinity of polyamide 66 fibers. One is a calibration method in which the band ratio of 1200 and 1630 cm^–1 is plotted against the crystallinity measured by density measurements. The other one is an independent infrared method. Crystallinity obtained by the independent infrared spectroscopic method showed good agreement with crystallinity observed by density measurement. Infrared dichroism was used to obtain the crystalline orientation using the band at 936 cm^–1. The transition moment angle of 48° was found for the band at 936 cm^–1 with respect to chain axis. Amorphous orientation was obtained using Stein’s equation. Received: 18 September 2000 / Reviewed and accepted: 20 September 2000     

混杂纤维增强PA66复合材料扶正器的研究

采用注塑工艺制备了碳纤维(CF)/玻璃纤维(GF)混杂增强尼龙66(PA66)复合材料,并在模拟高含水及高腐蚀两种井况下分别进行摩擦磨损、线胀系数对比和冲击试验,最终筛选了15%CF/20%GF和20%CF/20%GF两种混杂纤维增强PA66,制成了新型油井用扶正器,利用扫描电子显微镜对材料的磨擦表面及冲击断口进行了观察与分析。结果表明,在高含水的稀油井中,适合使用15%CF/20%GF增强PA66扶正器;在高含水的稠油井中,由于井下温度较高,20%CF/20%GF增强PA66扶正器与15%CF/20%GF增强PA66扶正器相比,尺寸稳定性更好,耐磨性更高,因此适合该类油井。     

不同原始颗粒尺寸的PHE对PA66/PHE共混物力学性能影响

使用不同原始颗粒尺寸的聚酚氧(PHE)通过双螺杆挤出机分别与尼龙(PA)66共混制备PA66/PHE共混物.测试其力学性能,并用扫描电子显微镜(SEM)表征.研究发现,小颗粒尺寸的PHE制备的PA66/PHE共混物的分散相尺寸小、分散均匀且冲击强度得到提高,呈现协同效应,而拉伸强度基本与纯PA66保持一致;大颗粒尺寸的PHE制备的PA66/PHE共混物的分散相尺寸较大且容易发生团聚,其冲击强度降低,而拉伸强度有所增加.     

PA66/GF复合材料研制及应用

研究了不同单纤维直径的玻璃纤维(GF)增强尼龙(PA)66复合材料的力学性能,通过扫描电子显微镜研究了PA66/GF复合材料的微观形貌结构.结果表明,GF直径减小,其与PA66的界面结合程度变好,PA66/GF复合材料的力学性能逐渐提高,但增幅不尽相同,直径为11 μm的GF制得的PA66/GF复合材料的力学性能与GF直径为10 μm的力学性能相当、微观结构也相似.采用直径为11 μm的GF制得的PA66/GF复合材料具有更高的性价比,已广泛应用于汽车行业.     

浸润剂对短切玻纤增强尼龙66性能影响的研究

利用双螺杆挤出机制备短玻纤增强尼龙66（GF／PA66）复合材料,采用不同组成的浸润剂处理玻璃纤维,研究其对GF／PA66的微观结构及性能的影响。结果表明,在T435D中加入乙烯基树脂或三聚氰胺后,玻纤增强尼龙66复合材料的拉伸强度、弯曲强度、简支梁冲击强度均有不同程度的提高,并通过扫描电镜观察到PA66基体与玻纤相界面的微观结构在一定程度上得到了改善,但在T435D中加入三聚氰胺在三种浸润剂配方中效果最佳。     

Synergistic effect of melamine polyphosphate with macromolecular charring agent novolac in wollastonite filled PA66

In this article, macromolecular charring agent linear novolac (NA) was served as a synergist with nitrogen‐phosphorous flame retardant melamine polyphosphate (MPP) for the flame‐resistance of wollastonite (WT) filled polyamide 66 (PA66). The investigations showed that MPP/NA system possessed obvious synergistic effects by increasing the charring rate and amount, therefore, showing much higher flame retardancy than the filled PA66 flame retarded with MPP alone. The corresponding char layer structure of MPP/WT/PA66 and MPP/NA/WT/PA66 was investigated and their difference was analyzed. In addition, as a multifunctional additive, NA could act as a compatibilizer and lubricant in the system, and endowed the material with improved mechanical performance and processability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Toughened nylon66/nylon6 ternary nanocomposites by elastomers

The elastomer toughening of PA66/PA6 nanocomposites prepared from the organic modified montmorillonite (OMMT) was examined as a means of balancing stiffness/strength versus toughness/ductility. Several different formulations varying in OMMT content were made by mixing of PA6 and OMMT as a master‐batch and then blending it with PA66 and different elastomers in a twin screw extruder. In this sequence, the OMMT layers were well exfoliated in the nylon alloy matrix. The introduction of silicate layers with PA6 induced the appearance of the γ crystal phase in the nanocomposites, which is unstable and seldom appears in PA66 at room temperature and it further affected the morphology and dispersion of rubber phase resulting in much smaller rubber particles. The incorporation of POE‐g‐MA particles toughened the nanocomposites markedly, but the tensile modulus and strength were both reduced. Conversely, the use of OMMT increased the modulus but decreased the fracture toughness. The nanocomposites exhibited balanced stiffness and toughness. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Continuous amino-functionalized University of Oslo 66 membranes as efficacious polysulfide barriers for lithium−sulfur batteries

The shuttle effect of soluble polysulfides is a serious problem impeding the development of lithium−sulfur batteries. Herein, continuous amino-functionalized University of Oslo 66 membranes supported on carbon nanotube films are proposed as ion-permselective interlayers that overcome these issues and show outstanding suppression of the polysulfide shuttle effect. The proposed membrane material has appropriately sized pores, and can act as ionic sieves and serve as barriers to polysulfides transport while allowing the passage of lithium ions during electrochemical cycles, thereby validly preventing the shuttling of polysulfides. Moreover, a fast catalytic conversion of polysulfides is also achieved with the as-developed interlayer. Therefore, lithium−sulfur batteries with this interlayer show a desirable initial capacity of 999.21 mAh·g^–1 at 1 C and a durable cyclic stability with a decay rate of only 0.04% per cycle over 300 cycles. Moreover, a high area capacity of 4.82 mAh·cm^–2 is also obtained even under increased sulfur loading (5.12 mg·cm^–2) and a lean-electrolyte condition (E/S = 4.8 μL·mg^–1).     

锦纶6与锦纶66弹力丝织袜过程中性能的差别

本文通过织造、染色、定型三个过程的对比，对锦纶6与锦纶66弹力丝在织袜过程中的性能差别进行了分析。     

基于灰色理论的尼龙/碳钢摩擦副磨损量预测*

在传动系统中,尼龙66制零件会与碳钢零件配合传递运动和转矩,由于尼龙66硬度远远低于碳钢,所以尼龙66制零件表面极易产生磨损导致失效,因此在产品设计中必须考虑尼龙66的摩擦磨损。为有效评估尼龙66与碳钢配对运行的摩擦磨损性能,在不同载荷下进行尼龙66/45钢摩擦副的摩擦磨损试验,通过超景深显微镜观察磨损形貌及磨痕的深度,采用灰色系统理论建立磨损量预测的灰色GM（1,1）模型,建立考虑表面接触应力的磨损量预测模型。结果表明：采用灰色理论预测尼龙66/45钢的磨损量具有高精度和高可靠性,预测值和试验值的最大误差为9.26%,平均相对误差为3.60%。采用该预测模型进行尼龙零部件磨损寿命设计,无需开展大量重复性的磨损试验,能够快速为尼龙零部件的产品设计提供磨损量的参数指标。