PBO纤维及其改性的研究进展

简述了聚对苯撑苯并双噁唑(PBO)纤维的结构与性能;详述了PBO纤维的改性研究进展。PBO纤维的改性主要是改善其抗压性能和表面粘结性能。提高微纤间相互作用或交联等方法可提高PBO纤维的压缩强度;通过酸处理、偶联剂处理、等离子体处理及电晕处理等方法可提高PBO纤维的表面粘结性能。指出表面改性仍将是PBO纤维改性研究的重点。     

PBO纤维的开发及应用

详细介绍了聚苯并双噁唑(PBO)的合成方法、PBO纤维的制备方法、PBO纤维的改性方法以及PBO纤维的主要应用领域,并对我国PBO纤维的研究开发及应用提出了建议。PBO的合成方法主要有对苯二甲酸法、对苯二甲酰氯法、三甲基硅烷基化法、对苯二甲酸盐法、对羟基苯甲酸酯法;PBO纤维的制备主要有液晶纺丝法和静电纺丝法;PBO纤维的改性方法主要有化学处理法、共聚处理法、偶联剂处理法、等离子体处理法及辐射处理法;PBO纤维主要应用于耐热性能材料及力学增强材料。我国PBO纤维的研究开发应注重产学研结合,从提高单体4,6-二氨基间苯二酚的纯度及PBO的特性黏数,优化单体合成、聚合及纺丝技术等环节着手,促进PBO纤维的产业化。     

PBO纤维表面改性的研究进展

简要介绍了PBO纤维的结构、性能以及制备方法,综述了PBO纤维的表面改性方法,包括酸处理、碱处理、酶处理、偶联剂处理、辐射处理和等离子体处理等。     

PBO纤维界面改性研究

介绍了聚对苯撑苯并双噁唑(PBO)单体的盐酸盐合成及其优缺点;阐述了PBO的对苯二甲酸法、对苯二甲酞氯法、三甲基硅烷基化法、五氧化二磷调节法及预聚合法的合成方法及其优缺点;简述了PBO的纺丝方法。分析了PBO纤维的物理化学性能,对其各项性能做了比较;论述了PBO纤维界面改性界面理论及改性处理方法。指出PBO纤维的综合性能优异,应加大PBO规模的生产方法和界面改性研究,实现PBO纤维的规模化生产。     

低温等离子体处理对PBO纤维润湿性的影响

为改善PBO纤维的润湿性,拓宽其应用领域,探究了空气低温等离子体处理对PBO纤维润湿性的影响。通过芯吸效应和接触角表征处理前后PBO纤维润湿性,并采用扫描电子显微镜SEM观察处理前后PBO纤维表面形貌,用X射线光电子能谱仪(XPS)对处理前后PBO纤维表面化学组成进行定性分析。实验结果表明,改性后PBO纤维芯吸高度大幅上升,接触角明显降低,并且在其表面产生明显刻痕,局部有剥离现象,改性后PBO纤维O、N元素含量均有所提高,PBO纤维润湿性明显增强。()     

PBO纤维表面改性及其与树脂基体界面性能研究

分别采用化学处理、等离子体处理、偶联剂处理、γ射线辐照等单一改性方法和“辐照+等离子体”、“辐照+等离子体+偶联剂”等综合改性方法对PBO纤维进行表面处理,之后对各种不同方法改性后的纤维进行了单丝拉伸强度、与树脂的接触角和单丝拔出性能测试.结果表明,经综合改性方法处理后的PBO纤维综合性能最优,单丝拉伸强度保持率为85.1％,与水的接触角达到74.15°;与未经表面处理的纤维相比,其与树脂基体间的粘结强度提高了48.6％.     

PBO 纤维表面改性研究进展

简要介绍了聚苯并双恶唑(PBO)纤维的结构与性能,综述了利用等离子体、γ射线、化学试剂、超临界流体以及生物载体等进行表面改性的方法,分析了各种方法的优劣并对 PBO 纤维的应用前景进行了展望。指出利用这些介质对 PBO 进行表面处理各有利弊,因此 PBO 纤维的表面处理由以前的单一、间歇性的化学改性方法逐步向连续的、在线的以及多种手段共用的复合处理方向发展。     

聚对苯撑苯并双噁唑纤维改性技术的研究进展

介绍了近年来聚对苯撑苯并双噁唑(PBO)纤维的改性方法,并对今后PBO纤维的改性方向进行了展望。PBO纤维的改性主要是采用碳纳米管、石墨烯等纳米粒子及第三单体对PBO纤维进行共混复合及原位共聚改性,从而提高PBO纤维的力学性能、热学性能、表面性能及耐老化性能等。今后应加强改性体PBO基体的共聚改性机理及改性体对PBO聚合、纺丝过程的影响研究,探索多种改性技术的混合使用或新的改性技术,从而制备出更优异的高性能PBO纤维。     

PBO纤维表面改性方法的研究

对PBO纤维表面性能的改善进行了研究,考察了混杂芳纶纤维、电晕处理、偶联剂处理及强酸处理等多种方法对PBO纤维与环氧树脂表面粘接强度及其复合材料层间剪切性能的影响程度,比较了各种方法的改性效果及各自优缺点。     

PBO纤维表面改性的研究进展

聚对苯撑苯并双噁唑(PBO)由于其特殊的表层结构,与聚合物树脂基体复合时存在严重的界面不相容性。简要介绍了PBO纤维的结构与性能,综述了化学刻蚀、偶联剂处理、等离子体处理、电晕处理、辐射处理、酶处理、热处理、化学涂层和超临界液体处理等PBO纤维表面改性方法。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.