减磨填料及表面处理对氟醚橡胶密封材料性能的影响

从橡胶密封材料减磨配合体系和表面减磨处理两个方面对氟醚橡胶密封材料性能进行了研究。试验结果表明,将石墨和聚四氟乙烯(PTFE)粉体作为减磨填料,可以提升氟醚橡胶材料的基础力学性能和摩擦磨损性能,但材料的压缩永久变形性能随填料用量增加而变差。试验同时还比较了表面氟化、表面沉积类金刚石涂层、表面喷涂PTFE涂层三种表面处理工艺的影响。研究发现,表面喷涂PTFE涂层可以显著减小材料的摩擦系数,且耐磨性较好,在试验范围内材料的摩擦特性较为稳定。     

填充型氟醚橡胶导热性能研究

以氟醚橡胶为基体.通过添加不同无机导热填料制备填充型导热氟醚橡胶,并考察填料热导率、用量及表面改性处理对氟醚橡胶导热性能的影响.结果表明.填料本身热导率大于21 W·(m·K)-1时对氟醚橡胶导热性能的影响已不明显;增大填料用量可显著提高氟醚橡胶导热性能,但会带来加工和使用性能方面的问题;采用硅烷偶联剂对填料进行表面处理能够增强橡胶与填料间的界面结合,提高氟醚橡胶导热性能.     

玻璃纤维及石墨增强聚四氟乙烯复合材料摩擦磨损性能的研究

用机械混合、冷压成型和烧结的方法制备了不同质量分数(5%~30%)的玻纤和石墨填充聚四氟乙烯(PTFE)复合材料制品。用M-2000型磨损试验机评价了不同样品在干摩擦下的磨损性能,揭示了填料玻纤和石墨对PTFE复合材料磨损性能的影响,并对磨损机理进行了探讨。用扫描电镜(SEM)对试样磨损形貌进行观察。结果表明:对玻纤进行改性能极大地提高PTFE复合材料的耐磨性能,同时可提高复合材料硬度;玻纤和石墨协同作用,对改善PTFE摩擦磨损性能有比较显著的效果;20%玻纤 10%石墨填充PTFE复合材料有着较好的摩擦磨损性能。     

两种补强填料对氟醚橡胶性能的影响

设计补强填料（炭黑N990/硫酸钡）用量和并用比不同的9个试验配方,研究炭黑N990/硫酸钡用量和并用比对氟醚橡胶胶料硫化特性、耐低温性能、物理性能、耐热空气老化性能、耐介质性能和压缩永久变形的影响。结果表明：炭黑N990/硫酸钡用量和并用比对氟醚橡胶硫化胶性能影响较大;随着炭黑N990/硫酸钡用量的增大,氟醚橡胶硫化胶的力学性能更好;氟醚橡胶硫化胶的耐低温性能主要由橡胶的分子结构决定,同时含胶率越高,硫化胶的耐低温性能越好;氟醚橡胶硫化胶的耐介质性能与其交联程度有关,当炭黑N990/硫酸钡用量增大时,橡胶与其形成的交联网络更加密集,硫化胶的耐介质性能提高。     

抗辐照酚酞聚芳醚酮基自润滑复合材料的研制

采用二硫化钼、石墨、碳纤维和氟化镧研制了一种抗辐照的酚酞聚芳醚酮基自润滑复合材料。介绍了此材料的制备工艺和性能,研究了几种添加剂的配比对复合材料的影响。结果表明,在酚酞聚芳醚酮中添加二硫化钼和石墨可明显改善材料的摩擦磨损性能,加入碳纤维和氟化镧不仅可提高复合材料的机械强度,而且还使摩擦磨损性能在一定程度上得到改善。加入上述添加剂均可提高复合材料的抗辐照性。     

PTFE填充氟橡胶的摩擦磨损特性研究

研究了聚四氟乙烯(PTFE)填充量对氟橡胶(FKM)的力学性能和摩擦磨损性能的影响.并用扫描电子显微镜分析了PTFE表面形貌和PTFE填充氟橡胶的磨损表面.结果表明,PTFE的加入提高了FKM的摩擦磨损性能.力学性能下降不大.     

聚醚砜酮复合材料摩擦性能的研究

以杂环取代聚聚醚砜酮（ＰＰＥＳＫ）为基体,研究了石墨、二硫化钼（ＭｏＳ２）等无机填料,以及聚四氟乙烯（ＰＴＦＥ）对复合材料力学性能和摩擦性能的影响。结果表明,填充石墨和ＭｏＳ２后,可民时改善复合材料的弯曲强度和摩擦性能,两者具有协同作用,加入ＰＴＦＥ后可大幅度降低复合材料的摩擦系数及弯曲强度。     

SiC一石墨填充PTFE复合材料的摩擦磨损性能研究

在聚四氟乙烯（ＰＴＦＥ）中分别填充碳化硅（ＳｉＣ）,石墨及不同配比的ＳｉＣ－石墨混合物,制备了具有不同力学和摩擦学性能的ＰＴＦＥ基复合材料。探讨了填料组成对材料硬度及干摩擦条件下与不锈钢环对磨时摩擦磨损性能的影响,并研究了ＰＴＦＥ基复合材料的磨损表面和磨屑形貌。结果表明,填充适量的ＳｉＣ－石墨混合物既能增加ＰＴＦＥ的承载能力,又可保持良好的摩擦学性能;不同复合材料的磨损机理不同,磨损表面有磨屑形貌     

改性石墨/丁腈橡胶复合材料的性能

采用十六烷基三甲基溴化铵、硅烷偶联剂KH 570以及聚乙二醇分别对石墨表面进行了有机改性,通过机械共混法制备了改性石墨/丁腈橡胶复合材料,考察了改性剂种类以及改性石墨用量对复合材料物理机械性能及摩擦性能的影响,并用扫描电子显微镜表征了石墨在橡胶基体中的分散情况及复合材料磨损表面情况。结果表明,随着改性石墨用量的增加(20份以内),复合材料的物理机械性能有所上升,摩擦系数不断下降;3种改性剂中,KH 570改性石墨所制备复合材料的物理机械性能及摩擦性能较优,当添加20份KH 570改性石墨时,其在橡胶基体中分散较好,磨损表面最为光滑、平整,复合材料的物理机械性能最佳,摩擦系数达到最低值(0.7)。     

环氧树脂基复合涂层摩擦磨损性能研究

研究了不同质量分数石墨、碳纤维、纳米ZrO2对环氧树脂(EP)涂层摩擦磨损性能的影响,并用扫描电子显微镜观察了涂层磨损表面形貌并探讨了磨损机理。结果表明:石墨质量分数为20%时复合涂层的磨损率仅为纯EP的7.75%;纳米ZrO2质量分数为4%时复合涂层的磨损率为纯EP的30%;纳米ZrO2与碳纤维以及石墨的协同作用提高了EP的摩擦磨损性能。EP复合涂层的磨损机理以粘着磨损、磨粒磨损以及疲劳磨损为主。     

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.     

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.     

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。