凹凸棒石增强环氧树脂的摩擦性能

采用离子液体和硅烷偶联剂对凹凸棒石纳米粉体进行表面功能化改性,进而制备了功能化改性凹凸棒石增强环氧树脂复合材料。利用TRM-1000销-盘摩擦磨损试验机,系统研究了干摩擦条件下不同功能化改性凹凸棒石增强环氧树脂材料与轴承钢共同作为摩擦对偶的摩擦学性能,结合摩擦表面的微观形貌表征和界面摩擦化学分析,阐释了其摩擦学机理。结果表明:表面功能化改性可显著抑制凹凸棒石的团聚、提高其在树脂基体中的分散以及与树脂基体的结合;填充质量分数为3%离子液体功能化改性凹凸棒石,环氧树脂复合材料的耐磨性显著提升,较纯环氧树脂提高了60%;在界面形成的铁氧化物和硅氧化物基转移膜,避免了摩擦副的直接接触并显著提高界面承载能力,是提高材料润滑性能和降低磨损的关键。     

聚合物基复合材料摩擦与磨损性能的研究进展

介绍了聚合物及其复合材料的摩擦与磨损性能,包括聚四氟乙烯(PTFE)、含PTFE及其他聚合物基复合材料的耐磨性能,讨论了填料的种类、尺寸、含量以及填料的协同作用对聚合物基复合材料耐磨性能的影响.结果显示:填料能较好地改善聚合物基复合材料的摩擦磨损性能.并总结了聚合物基复合材料摩擦磨损性能的研究方向.     

陶瓷粉增强HDPE复合材料干摩擦性能

采用熔融共混注射法制备了陶瓷粉/高密度聚乙烯复合材料;研究了不同陶瓷粉加入量的复合材料在干摩擦(50、110 N)条件下的摩擦系数及磨损率,测试了复合材料的硬度及热稳定性能,并利用扫描电镜观察了陶瓷粉与基体的界面形貌及磨损表面形貌。结果表明:陶瓷粉的加入改善了复合材料的干摩擦性能;当陶瓷粉加入量为20%、载荷为110 N时,复合材料的摩擦系数比未添加陶瓷粉的高密度聚乙烯增大了11. 5%,而磨损率降低了38. 8%;复合材料的磨损机理由纯高密度聚乙烯的粘着磨损(50 N)或粘着磨损和疲劳磨损共存转变为磨粒磨损(110 N)。复合材料干摩擦性能的改善是由于陶瓷粉与基体具有良好的界面结合,陶瓷粉提高了复合材料的硬度及热稳定性。     

煤矸石填充改性聚酰亚胺复合材料的研究

以廉价的煤矸石为填料,利用原位聚合法制备了一种煤矸石填充改性聚酰亚胺(PI)复合材料.用傅立叶变换红外光谱仪和偏光显微镜研究了PI/煤矸石复合材料的微观结构,并测试了复合材料的力学性能和热性能.结果表明,加入适量煤矸石能提高PI/煤矸石复合材料的力学性能,当煤矸石的质量分数为10%时,PI/煤矸石复合材料的降解温度比纯PI提高了34.8℃;煤矸石在PI基体中分散较均匀,粒径为几微米到几十微米.     

界面改性对HDPE木塑复合材料性能的影响

采用二辊开炼和压制成型的方法,以马来酸酐接枝聚乙烯(MAPE)、马来酸酐(MAH)和(或)过氧化二异丙苯(DCP)处理木粉制备高密度聚乙烯(HDPE)基木塑复合材料(WPC),考察了几种方法对复合材料力学性能、动态热机械性能及加工性能的影响,并借助扫描电子显微镜( SEM)对复合材料界面进行了形貌分析.结果表明:MAH和DCP共同改性HDPE基WPC,在改善复合材料界面相容性的同时也提高了基体强度,材料综合性能最佳.     

植物纤维改性聚乳酸的研究进展

综述了植物纤维改性聚乳酸(PLA)基复合材料的国内外研究现状及进展,分别探讨了植物纤维的种类、界面改性方式以及加工工艺对PLA复合材料性能的影响,并对植物纤维改性PLA基复合材料的发展方向进行了展望。     

聚酰亚胺(PI)/无机纳米复合材料的制备、结构与性能

依据国内外聚酰亚胺（PI）／纳米复合材料的最新研究进展，重点阐述PI复合材料的制备、结构、性能及应用，展望了PI复合材料的发展趋势。列举了几种常用纳米粉体的特性，介绍了聚酰亚胺（PI）纳米复合材料的3种制备方法：溶胶一凝胶法、插层复合法、直接分散法，由于纳米粉体在PI材料中的分散性良好，使整个聚合物基体形成新的网络结构，利用纳米粉体改变了PI材料的性能，如力学性能、热学性能、加工流动性等，插层剂的加入对PI纳米复合材料的复合体系有明显改善作用。     

聚酰亚胺的合成及其SiO_2复合材料摩擦磨损性能研究

以2,3',4,4'-联苯四酸二酐、4,4'-二氨基二苯甲烷和4-苯乙炔基苯酐为原料合成聚酰亚胺(PI)树脂,采用红外光谱对其结构进行了表征。采用SiO_2为耐磨改性剂,对聚酰亚胺进行改性,制备PI/SiO_2复合材料,研究其摩擦磨损性能,结果表明当SiO_2含量为10%时,PI/SiO_2复合材料具有较好的摩擦磨损性能,摩擦系数为0.145,磨损量为3.8mg。     

聚丙烯基石墨导电复合材料研究进展

阐述了国内外聚丙烯基石墨导电复合材料制备方法的研究现状,以及石墨类型、界面相容剂和加工条件等因素对复合材料性能的影响,介绍了聚丙烯基石墨导电复合材料在制备双极板方面的应用进展,并对其发展前景进行了展望。     

基于粘着摩擦理论的塑料微观摩擦特性研究

利用纳米压痕仪测试ABS塑料的弹性模量,为了研究塑料材料微观摩擦性能,设计了一套测试制样方案,采用纳米划痕技术实测了ABS塑料的微观摩擦性能,并结合粘着摩擦理论对塑料摩擦特性进行了分析。纳米压痕结果,ABS塑料弹性模量均值约为4.20 GPa;纳米划痕结果,弹性接触和塑性接触时摩擦因数分别约为0.1和0.25;对比理论分析和实验结果发现,粘着摩擦理论用于解释塑料材料微观摩擦行为是可行的。     

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。