不同助剂对大豆蛋白质塑料挤出工艺的影响

本文主要从大豆蛋白质塑料的加工工艺角度考虑，通过添加大豆油、硬脂酸、十二烷基硫酸钠、壳聚糖、淀粉、聚乙烯醇，研究其对大豆蛋白质塑料挤出加工和力学性能的影响。     

聚四氟乙烯纤维的制备与性能表征

通过聚乙烯醇(PVA)作为载体,与聚四氟乙烯(PTFE)分散液配成混合溶液进行湿法纺丝制备PTFE/PVA初生纤维,成形后经烧结去除PVA。根据TG/DTG曲线选取烧结温度并判断烧结后样品的PVA去除程度,用扫描电镜观察了初生丝及烧结后纤维的形貌,同时通过强力测试得出烧结后试样的力学性能,结果表明,随着烧结时间的延长,烧结越充分,力学性能越优。     

膜裂切割法聚四氟乙烯纤维的制备及其力学性能

以不同聚四氟乙烯分散树脂为原料,通过混料、熟化、预成型、压延、双向拉伸及膜裂切割等工艺,制备了高性能聚四氟乙烯(PTFE)纤维.试验结果表明:树脂原料的优劣、热处理温度及拉伸工艺是影响PTFE纤维力学性能的主要因素,PTFE纤维的拉伸倍数应该控制在32～49之间,最佳的拉伸温度在240～320℃之间.     

载体法制备聚四氟乙烯纤维及烧结工艺研究

以载体法制备出聚四氟乙烯纤维(PTFE)/聚乙烯醇(PVA)初生丝,然后对初生丝进行不同时间的烧结,以除去PVA制得PTFE纤维,对PTFE纤维进行不同程度的拉伸,检测不同烧结时间和拉伸倍数对纤维力学性能的影响。     

挤出成型制备高强度氮化硅陶瓷

以羧甲基纤维素(CMC)为黏结剂，通过挤出成型的方式制备氮化硅陶瓷管材，并研究了黏结剂含量对陶瓷管材生坯性能的影响，烧结温度对氮化硅陶瓷相对密度、弯曲强度和微观形貌的影响，以及氮化硅陶瓷的高温强度性能。结果表明：黏结剂含量为7%(质量分数)时，可制得干燥收缩均匀、表面光滑、无微裂纹的陶瓷管材生坯；烧结温度在1 740℃时，氮化硅陶瓷的相对密度和弯曲强度达到最大值，分别为96%和(684±23) MPa,其1 200℃时的弯曲强度达(380±21) MPa,具有良好的高温强度性能。     

反应挤出制备尼龙6工艺研究

采用反应挤出方法制备了高性能尼龙6材料.考察了不同催化剂、加工工艺和原料配比对反应挤出尼龙6性能的影响.结果表明,选用Cat.A作为催化剂,配合适当的加工工艺,可显著提高尼龙6的相时分子质量和力学性能.     

膜裂法聚四氟乙烯纤维生产工艺研究

在研究聚四氟乙烯纤维加工参数与性能关系的基础上,通过对工艺开发与设备研制相结合,确定生产聚四氟乙烯长纤维和短纤维最佳生产工艺。研究表明,膜裂法工艺生产的聚四氟乙烯纤维的细度、均匀性、力学性能和热收缩率等性能均有大幅度的提高。     

短切纤维填充聚四氟乙烯的减摩耐磨性能研究

以聚四氟乙烯(TPFE)为基体,通过添加10%、15%、20%、25%、30%的短切纤维制备纤维填充复合材料,研究了其摩擦磨损等相关性能。结果表明:短切纤维的填充增强了材料的压缩强度和硬度,但拉伸强度减弱;随着短切纤维含量的增多,磨痕宽度越来越小,材料的耐磨性能不断提高,摩擦系数也随之下降;电镜结果显示TPFE复合材料摩擦表面短切纤维分布均匀且无明显带状磨痕,但存在少量短切纤维剥离现象,分析发现剥离主要发生于摩擦的磨合阶段,不影响材料稳定磨损阶段的性能。     

聚四氟乙烯纤维滤料及其制备方法

本发明提供一种聚四氟乙烯纤维滤料及其制备方法，它具有极强的高温化学稳定性、过滤精度高、耐磨损、使用寿命长、应用范围广等优点，尤其适用于工况环境恶劣的过滤需要。本发明的聚四氟乙烯纤维滤料是使用聚四氟乙烯纤维滤布经过浸渍处理，再进行覆膜或涂层处理；所述浸渍处理采用聚四氟乙烯溶液进行浸渍；所述聚四氟乙烯溶液包括：聚四氟乙烯和质量分数30％-40％；聚苯酯的质量分数20％-30％；粘合剂的质量分数1％-3％；水，余量。     

共挤出法生产碳纤维增强热塑性制品

日本东丽公司在法国的合资企业索菲卡(Soficar)公司,是生产热塑性树脂混杂碳纤维纱制品市场中的新的一员。该公司采用廉价的共挤出工艺过程的线状粒取代热塑性树脂粉末,生产的产品有窄带和织物;所用的纤维是东丽公司的碳纤维T700;基体树脂采用PA11和PA12。表2中列出含有T700碳纤维的Soficar带子的力学性能。     

反应性挤出制备PP-g-PEGA调温纤维的研究

以过氧化二异丙苯(DCP)为引发剂,通过反应性挤出的方法将相变材料丙烯酸聚乙二醇酯(PE-GA)接枝到聚丙烯(PP)基体上,利用熔融纺丝的方法制备PP-g-PEGA调温纤维。通过红外光谱法和溶剂萃取法表征了PEGA在PP上的接枝情况;通过差示扫描量热仪、纤维强力仪和扫描电镜分别表征了PP-g-PE-GA调温纤维的储热性能、力学性能和外观形态。结果表明:PEGA与PP发生了化学接枝,PP-g-PEGA纤维的接枝率达3.2%;当PEGA的质量分数为8.0%,引发剂DCP质量分数为0.6%时,相变焓达6.93 J/g;PP-g-PEGA调温纤维的断裂强度随着PEGA含量的增加呈先增大后减小的趋势;PP与PEGA相容性良好,纤维的外观光滑均匀。     

玻璃纤维增强聚四氟乙烯材料性能的研究

通过冷压成型和烧结固化工艺制备了不同配方下玻璃纤维增强聚四氟乙烯(GFRPTFE)试样，对其进行了机械性能、摩擦磨损性能的测试，用扫描电子显微镜进行了组织结构观察。实验结果表明：GFRPTFE材料随着短切玻璃纤维含量的增加，抗冲击性能有所下降，而耐磨损性能明显提高；偶联剂的加入明显地提高了复合材料的力学性能。     

Viscosity characterization and flow simulation and visualization of polytetrafluoroethylene paste extrusion using a green and biofriendly lubricant

Polytetrafluoroethylene (PTFE) and expanded PTFE (ePTFE) are ideal for various applications. Because PTFE does not flow, even when heated above its melting point, PTFE components are fabricated using a process called paste extrusion. This process entails blending PTFE powder particles with a lubricant to form PTFE paste, which is subsequently preformed, extruded, expanded (in the case of ePTFE), and sintered. In this study, ethanol was proposed as an alternative green lubricant for PTFE processing. Not only is ethanol benign and biofriendly, it provides excellent wettability and processing benefits. Using ethanol as a lubricant, the shear viscosity of PTFE paste and its flow behavior during paste extrusion were investigated. Frequency sweeps using a parallel-plate rheometer were performed on PTFE paste samples and various grits of sandpaper were used to reduce wall slip of PTFE paste. A viscosity model was generated and a multiphysics software was used to simulate PTFE paste extrusion. The simulated extrusion pressure was compared to experimental data of actual paste extrusion. Flow visualization experiments using colored PTFE layers were conducted to reveal the flow profile of the PTFE paste. The morphology of the expanded ePTFE tubes was examined using scanning electron microscopy and the effect of expansion ratio on ePTFE morphology was quantified.     

喷丝速度对PAN中空纤维成形的影响

研究了于湿法纺丝工艺中喷丝速度对聚丙烯腈(PAN)中空初生纤维成形与性能的影响.结果表明:喷丝速度对PAN纤维截面的规整性、表面形貌、异形度、声速取向和致密性等均会产生影响.在喷丝速度为0.20～0.45m/min时,PAN纤维中空度与声速取向随着喷丝速度的增加而快速增加,随后其增幅逐渐变小或基本不变.纤维内表面在较高的喷丝速度下会产生条纹、粗糙度增大,纤维外表面无明显变化.     

Preparation and properties of porous polytetrafluoroethylene hollow fiber membrane through mechanical operations

Porous polytetrafluoroethylene (PTFE) hollow fiber membranes were prepared from fine powder through a series of mechanical operations including paste extrusion, heat treatment, stretching and sintering. In contrast to conventional process, the heat treatment used in this study was performed at 200°C to 330°C (near the melting point) on the PTFE nascent hollow fiber (precursor of membrane). The results showed that the introduction of heat treatment step effectively improved the mechanical properties of precursors, the ultimate stress and strain increased observably with heat treatment temperature, which was beneficial to subsequently stretching precursors to make them porous. Furthermore, the morphological changes and improvement of membrane properties caused by stretching operation were investigated for porous PTFE hollow fiber membrane having finer pore size and higher porosity. The porous microstructure of nodes interconnected by fibrils varied depending on the stretching conditions, such as the stretching temperature, rate, and ratio. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42696.     

Additive manufacturing of high-strength polyamide 6 composites reinforced with continuous carbon fiber prepreg

The additive manufacturing of continuous fiber reinforced thermoplastics (CFRTPs) paves way for the high-strength, light-weight components for variety of load-bearing applications. In this work, the continuous carbon fiber reinforced PA6 (CCF-PA6) composites was successfully printed from the prepreg filament. The prepreg filament was prepared in-house by impregnating the heat-and-acid treated 1 K carbon fiber bundle with the molten PA6. The tensile strength of the prepreg filament, which contained with 40 vol% CF, reached 984 MPa. The unidirectional CCF-PA6 specimens were subsequently 3D-printed with the prepreg filament, and the mechanical strength of those 3D-printed specimens were tunable by adjusting a set of printing parameters, such as layer thickness, hatch spacing and printing temperatures. The highest tensile strength of the specimen reached 555 MPa. Those specimens also exhibited outstanding mechanical strength at elevated temperatures, still reaching 184 MPa at 150°C. The mechanical strength of those specimens was dependent on the content of the fiber. This study can hopefully provide new insights for feedstock design and spur novel ideas in tailoring the mechanical properties of the 3D-printed CFRTPs.     

双向拉伸法制备聚醚砜中空纤维

采用双向拉伸的方法制备了聚醚砜中空纤维,探讨了工艺条件对聚醚砜中空纤维取向度和水通量的影响。结果表明:随着纺丝速度的提高,纤维的取向度上升,水通量下降;在总拉伸倍数不变的前提下,随着凝固浴拉伸倍数的提高,纤维的取向度和水通量都减小;随着填充液压力的提高,纤维的取向度下降,水通量增加;随着凝固浴中二甲基亚砜含量的提高,纤维的取向度先增大后减小,出现了一个最大值,水通量先减少后增加,出现了一个最小值。     

New approach to fabricate densificated continuous fiber reinforced polytetrafluoroethylene composites with significantly improved interfacial bonding and mechanical properties

An unique two‐step technique to fabricate densified continuous fiber reinforced polytetrafluoroethylene (PTFE) composites with significantly improved interfacial bonding and mechanical properties have been successfully developed. The technique is conventional sintering followed by resin film infusion (RFI). The mechanical properties of the composites were studied, and results show that the composites have significantly improved interfacial bonding and mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3588–3591, 2007     

Mechanical characterization of parts produced by ceramic on‐demand extrusion process

Ceramic On‐Demand Extrusion (CODE) is an additive manufacturing process recently developed to produce dense three‐dimensional ceramic components. In this paper, the properties of parts produced using this freeform extrusion fabrication process are described. High solids loading (~60 vol%) alumina paste was prepared to fabricate parts and standard test methods were employed to examine their properties including the density, strength, Young's modulus, Weibull modulus, toughness, and hardness. Microstructural evaluation was also performed to measure the grain size and critical flaw size. The results indicate that the properties of parts surpass most other ceramic additive manufacturing processes and match conventional fabrication techniques.