改性聚苯醚国内外进展

聚苯醚 (ＰＰＯ)树脂属五大通用工程塑料。ＰＰＯ具有优良的物理机械性能、耐热性和电气绝缘性 ,其吸湿性低 ,强度高 ,尺寸稳定性好 ,高温下耐蠕变性是所有热塑性工程塑料中最优的。但是纯ＰＰＯ树脂玻璃化温度高 ,熔融流动性差 ,需要在30 0℃高温下加工。为此 ,ＧＥ公司采用掺混ＰＳ或ＨＩＰＳ“合金化”方法对ＰＰＯ树脂改性 ,并于 1966年实现改性聚苯醚 (ＭＰＰＯ)的工业化生产 ,商品名为Ｎｏｒｙ1。这种改性的ＰＰＯ玻璃化温度较低 ,较易加工 ,无降解。虽然耐热性有所降低 ,但保留了ＰＰＯ树脂的大部分有用性能。ＭＰＰＯ的世界产量与Ｐ…     

增韧聚苯硫醚的力学性能和破坏形态

研究了高性能热塑性树脂双酚Ａ聚砜（ＰＳＦ）、酚酞型聚醚酮（ＰＥＫ－Ｃ）增韧聚苯硫醚（ＰＰＳ）的破坏韧性、破坏形态以及抗溶剂性能。ＰＳＦ和ＰＥＫ－Ｃ能提高ＰＰＳ的冲击强度和破坏韧性。不同共混方法由于形成不同形态的分散相粒子对增韧效果和抗溶剂性能有不同的影响。增韧体系的抗溶剂性能随热塑性树脂加入及其含量增加而降低。     

特种工程塑料聚醚醚酮

聚醚醚酮 (ＰＥＥＫ)是由英国ＩＣＩ公司于 1978年首先开发出来的一种具有超高性能的特种工程塑料。其后 ,美国Ｄｕｐｏｎｔ公司、德国ＢＡＳＦ公司等也先后研究开发具有自己知识产权的类似产品 ,但一直未能推出商品化的产品。目前Ｖｉｃｔｒｅｘｐｌｃ .公司是ＰＥＥＫＴＭ 的唯一制造商。ＰＥＥＫ的结构式为　　Ｏ Ｏ ＣＯ 　　 ｎ该产品至今被认为是热塑性聚合物中性能最好的材料。其主要的物理性能如下 :　高温性能ＰＥＥＫＴＭ 聚合物的玻璃化温度为 143℃ ,熔化温度为 343℃。其热变形温度 (ＩＳＯＲ75,加玻璃纤维 )高达 315℃ ,…     

高性能热塑性树脂增韧聚苯硫醚的韧性

研究了高性能热塑性树脂双酚Ａ型聚砜（ＰＳＦ）、酚酞型聚醚酮（ＰＥＫ－Ｃ）增韧聚苯硫（ＰＰＳ）的破坏韧性和破坏形态。实验表明：ＰＳＦ与ＰＥＫ－Ｃ两种材料的加入都能改善ＰＰＳ的冲击强度和破坏韧性。不同共混（加入）方法对ＰＳＦ／ＰＰＳ与ＰＥＫ／－Ｃ／ＰＰＳ两体系的增韧效果有效果。     

日本五大工程塑料开发动向

日本五大工程塑料开发动向１９９４年日本塑料产量突破１３００万吨，其中五大工程塑料（聚酰胺ＰＡ，聚甲醛ＰＯＭ，聚酯ＰＢＴ，改性聚苯醚ＰＰＥ（或ＰＰＯ），聚碳酸酯（ＰＣ）的产量也超过６０余万吨。五大工程塑料是以代替金属材料为其开发目标的。近年来由于聚烯烃...     

嵌段共聚物对PPO／PP共混物的增容作用

研究表明苯乙烯－乙烯／丙烯嵌段共聚物及其混合顺序对聚／聚丙烯共混物形态和性能有一定影响。ＰＰＯ／ＰＰ共混物加入增容剂后，分散相颗粒变得精细均匀，缺口冲击强度大大提高。文中计算了ＳＥＰ／ＰＰＯ及ＳＥＰ／ＰＰ共混物的相互作用能密度Ｂ，计算表明，ＥＰ体积分数高的ＳＥＰ和ＰＰＯ的亲和力比ＳＥＰ与ＰＰ的亲和力小，因此当ＳＥＰ先与ＰＰＯ预混合，然后与ＰＰ混合，ＳＥＰ易于迁移到两相界面，降低了界面张力，减小了分     

三嵌段共聚物合成SiO2中孔材料的制备化学

采用溶胶－凝胶法,以正硅酸乙酯（ＴＥＯＳ）为前驱体,添加聚氧乙烯醚（ＰＥＯ）－聚氧丙烯醚（ＰＰＯ）－聚氧乙烯醚（ＰＥＯ）共聚物为模板剂制备结构可控的ＳｉＯ２中孔材料,通过ＢＥＴ、ＴＧ／ＤＴＡ、ＦＴ－ＩＲ、＾２９ＳｉＮＭＲ等分析手段,     

短纤维增强塑料中纤维定向及微观断裂形态分析

本文研究了四种注射模塑碳纤维增强热塑性复合材料的空间纤维分布和断裂形态（ＰＰＳ，ＰＥＩ，ＰＥＥＫ，ＰＡ）。运用了电子扫描电镜，对注塑试件断裂表面进行观察，发现除了芯部外，一般说来大多数纤维排列在注塑方向。在芯部的纤维倾向于和注塑方向垂直，但是，确切的纤维分布图与注胶口的设计以及基体的熔体粘度有关。检查材料的断裂表面发现ＰＥＥＫ和ＰＡ与纤维之间的界面结合最好，其次是ＰＥＩ。而且在芯部区断裂表面一般有定向纤维存在。尽管ＰＰＳ复合材料的界面键较弱，但与基体树脂相比在静态拉伸强度方面有较大改善。ＰＥＩ复合材料性能改进最少，而且在基体断裂时伴随着纤维的断裂。但是，最终最强的基体得到最强的复合材料，最弱的基体仍得到最弱的复合材料。     

大型电容薄膜卷绕真空镀膜机的研制

本文通过对大型电容薄膜卷绕真空镀膜机（ＣＲＣ－６５０／ＭＰ）的研制介绍，着重叙述该机结构特点，蒸发系统的设计，说明该设备可广泛运用于ＯＰＰ、ＰＥＴ、ＰＣ、ＢＯＰＰ等带材上蒸镀电容膜，是国内目前具有先进性能的电容器用多功能卷绕真空镀膜机。     

兼具PET高性能和PBT易加工性的PTT

兼具ＰＥＴ高性能和ＰＢＴ易加工性的ＰＴＴ在热塑性聚酯市场上又出现一个新面孔，这就是性能介于ＰＥＴ和ＰＢＴ之间的ＰＴＴ树脂———聚对苯二甲酸丙二醇酯。这种新的热塑性聚酯树脂的商品名为Ｃｏｒｔｅｒｒａ。它同时具有ＰＥＴ的高性能和ＰＢＴ的优良成型加工性，而...     

Processing of a High Temperature Imide Copolymer into Hollow Fibers

Hollow fibers spun from synuietic fiber forming polymers have been of interest, especially for producing high-bulk, low-density fabrics. Such fibers produced from a high temperature resistant polymer provide a number of advantages in certain applications. Ultem, a polyetherimide resin marketed by General Electric company, is a copolymer with ether molecules between imide groups and is thermoplastic. Being an amorphous thermoplastic polyimide, the Ultem resin combines the high performance associated with exotic specialty polymers and the good processability of typical engineering plastics. Equipment was built at the Air Force Research Laboratory of Edwards AFB, CA to spin hollow fibers. The spinneret designed has a hollow tube supported in the center of the orifice, and an inert gas is injected through the needle to maintain the tubular shape until the solidification of the fiber. Using that set-up, fibers were spun from Ultem under several different conditions. Effect of some of the processing conditions on the evolution of structure and properties during hollow fiber formation is discussed.     

Mechanical property evaluation of natural fiber coir composite

The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural. Past studies show that only artificial fibers such as glass, carbon etc., have been used in fiber-reinforced plastics. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. In this connection, an investigation has been carried out to make use of coir, a natural fiber abundantly available in India. Natural fibers are not only strong and lightweight but also relatively very cheap. In the present work, coir composites are developed and their mechanical properties are evaluated. Scanning electron micrographs obtained from fractured surfaces were used for a qualitative evaluation of the interfacial properties of coir/epoxy and compared with glass fiber/epoxy. These results indicate that coir can be used as a potential reinforcing material for making low load bearing thermoplastic composites.     

原位复合材料同纤维增强复合材料的性能比较

本文将新型聚合物合金原位复合材料同纤维增强塑料进行了比较。结果表明 ,这类材料在加工性、制品表面性能 ,及可循环加工性等方面均优于纤维增强塑料 ,少数力学性能指标与纤维增强塑料相当 ,多数力学性能指标不如纤维增强塑料。     

低成本PVA纤维对超高韧性水泥基复合材料力学性能的影响

超高韧性纤维增强水泥基复合材料（ECC）因其出色的高韧性及多缝开裂特性备受关注,然而一直以来因配比中进口PVA纤维的使用导致高昂的价格限制了其在工程中的大规模应用。为了进一步降低成本及实现原材料的本土化,研究低成本国产PVA纤维对ECC力学性能的影响十分必要。通过单轴拉伸、压缩、三点抗弯及单裂缝拉伸等宏观、细观试验研究两种国产低成本PVA-ECC的力学性能,并借助纤维分散性试验及SEM,探讨纤维的分散等微观特征。结果表明,低成本国产纤维在基体中具有良好的分散性,尽管其纤维桥接余能、最大桥接应力及PSH指数低于进口纤维,但均能满足能量与强度准则,即便相对较差的纤维A试件的3 d、7 d及28 d的极限拉伸应变也可达到2.52%、3.34%及3.08%,可实现良好的应力硬化行为及饱和多缝开裂特性,满足ECC的使用要求。     

Die Faserverstärkung von Aluminium

Fiber-Reinforced Aluminium . Light-weight construction requires materials of very high tensile strength and Young's modulus. For this reason, the principles of fiber reinforcement is also applied to light metals, preferably aluminium as in the case of reinforced plastics, which have already found a wide variety of applications. Unidirectional fiber reinforcement of aluminium can be achieved either by filaments or by short fibers. For these two types of fibers, different technologies have been developed. The mechanical, properties so far achieved by filament reinforcement enable high-performance composites for special applications to be developed. Composites reinforced with low-cost short fibers, on the other hand, should be developed in particular for the production of mass products.     

Elektrisch leitfähige kohlenstofffaserverstärkte Kunststoffe (CFK) mit freiliegender Funktionsschicht

Efficient lightweight requires intelligent materials that meet versatile functions. One approach is to extend the range of properties of carbon‐fiber‐reinforced plastics (CFRP) by plating the fiber component. Functions such as thermal and electrical conductivity, contactability, solderability, and adhesion promoting are integrated on this road. When processing the metallized carbon fibers to carbon‐fiber‐reinforced plastics the functional layer is covered by the matrix polymer. Thus, it is no longer accessible for further proceeding. In this work, different strategies for the production of carbon‐fiber‐reinforced plastics with accessible functional layers are analyzed. Thereby, selective uncovering of the functional layer as well as proceeding the carbon‐fiber‐reinforced plastics and metal‐layers without damages are important criteria. An evaluation of the processes was carried out using microstructural investigations and adhesive tensile testing. Correlations between electrical conductivity measurements, wetting and joining experiments, surface machining and solderability can be derived.     

Dynamisch-mechanische Analyse naturfaserverstärkter Kunststoffe

Dynamic-mechanical analysis of natural fiber reinforced plastics Recently natural fibers are increasingly used as reinforcement in plastics. These materials are distinguished by their high tensile strength and stiffness as well as their low density at the same time. For technical applications the material behaviour in addiction of temperature is very interesting. Useing the example of flax fiber reinforced polypropylen it is shown, that the dynamic-mechanical analysis can be a meaningful test to describe the behaviour of natural fiber composites by different temperatures.     

碳纤维对工程结构加固的试验研究

碳纤维及其复合材料是伴随着军工事业的发展而成长起来的新型材料,碳纤维布由于其高强、轻质、耐腐蚀等优点而广泛用于结构加固中,与其它加固方法相比,碳纤维布加固具有易于施工、工效高、造价低且耐腐蚀等优点.本文在总结前人工作基础上,研制了用于碳纤维布加固的GF结构胶,并测试了其物理力学性能;通过试验研究了碳纤维布加固梁在荷载作用下的挠度、强度、裂缝展开情况及破坏模式.试验结果表明,经过碳纤维布加固的梁,其承载能力和刚度均较未加固梁有较大幅度的增加,采用碳纤维布加固对裂缝的开展有明显的约束效果.     

Influence of fiber length on the mechanical properties of wood-fiber/polypropylene prepreg sheets

Natural fiber based composites have the potential to improve the mechanical properties of plastics while reducing the cost and weight. This study shows a practical method of blending natural-fiber with polypropylene to form a mat and then consolidated into a sheet by hot pressing. The natural fibers assessed were Pinus radiata and Eucalyptus regnan high temperature thermomechanical pulps and sisal (Agave sisalana) fibers. The tensile strength was shown to decrease with an increase in fiber content, while the tensile modulus was shown to increase. Tensile and flexural modulus were positively influenced by fiber length. The water performance tests of the sheets generally showed approximately 20% weight gain and approximately 3% thickness swell at 30% fiber content. The natural fiber surface chemical composition was determined by X-ray photoelectron spectroscopy and shown to be primarily covered with hydrophobic material such as lignin and extractives, while polypropylene was shown to be partially oxidized. Received: 18 September 2000 / Reviewed and accepted: 20 September 2000     

A Study on flexural properties of wildcane grass fiber-reinforced polyester composites

The main objective of this study is to introduce a new natural fiber as reinforcement in polymers for making composites. Wildcane grass stalk fibers were extracted from its stem using retting and chemical (NaOH) extraction processes. These fibers were treated with KMnO₄ solution to improve adhesion with matrix. The resulting fibers were intentionally reinforced in a polyester matrix unidirectionally, and the flexural properties of the composite were determined. The fibers extracted by retting process have a tensile strength of 159 MPa, modulus of 11.84 GPa, and an effective density of 0.844 g/cm³. The composites were formulated up to a maximum fiber volume fraction of 0.39, resulting in a flexural strength of 99.17 MPa and flexural modulus of 3.96 GPa for wildcane grass fibers extracted by retting. The flexural strength and the modulus of chemically extracted wildcane grass fiber composites have increased by approximately, 7 and 17%, respectively compared to those of composites made from fibers extracted by retting process. The flexural strength and the modulus of KMnO₄-treated fiber composites have increased by 12 and 76% over those of composites made from fibers extracted by retting process and decreased by 3 and 48% over those of composites made from fibers extracted by chemical process, respectively. The results of this study indicate that wildcane grass fibers have potential as reinforcing fillers in plastics in order to produce inexpensive materials with high toughness.