纳米炭粉改性苯并噁嗪树脂烧蚀性能研究

为进一步提高苯并噁嗪树脂的烧蚀性能,采用纳米炭粉对其进行了改性研究。采用透射电镜(TEM)和场发射电子显微镜(SEI)观察了纳米炭粉在苯并噁嗪树脂的中的分散状态;通过热失重分析研究了纳米炭粉质量分数对苯并噁嗪树脂残炭率的影响并测试了烧蚀性能;同时采用X-射线衍射法(XRD)对炭层结构进行了分析。结果表明,质量分数为10%纳米炭粉的改性苯并噁嗪800℃残炭率可达到63.6%,该体系700℃炭化后的压缩强度为纯树脂的3.8倍。改性后的苯并噁嗪树脂炭化层结构致密,裂纹小,石墨化度与炭结构的有序度大大提升,最终使树脂的耐烧蚀性能与抗热震性获得改善。     

纳米炭粉改性苯并嗯嗪树脂烧蚀性能研究

为进一步提高苯并嗯嗪树脂的烧蚀性能，采用纳米炭粉对其进行了改性研究。采用透射电镜（TEM）和场发射电子显微镜（SEI）观察了纳米炭粉在苯并嗯嗪树脂的中的分散状态；通过热失重分析研究了纳米炭粉质量分数对苯并嗯嗪树脂残炭率的影响并测试了烧蚀性能；同时采用X-射线衍射法（XRO）对炭层结构进行了分析。结果表明，质量分数为10％纳米炭粉的改性苯并嗯嗪800℃残炭率可达到63．6％，该体系700℃炭化后的压缩强度为纯树脂的3．8倍。改性后的苯并嗯嗪树脂炭化层结构致密，裂纹小，石墨化度与炭结构的有序度大大提升，最终使树脂的耐烧蚀性能与抗热震性获得改善。     

碳纤维/聚苯并(噁)嗪复合材料的界面与力学性能的关系研究

本文采用含不同上胶剂的碳纤维与苯并(噁)嗪树脂复合,制备碳纤维/聚苯并(噁)嗪单向复合材料,研究了碳纤维表面上胶剂对于复合材料的层间剪切强度(ILSS)、弯曲性能、断口形貌及动态机械性能的影响.结果表明,含有环氧树脂上胶剂的碳纤维/苯并(噁)嗪树脂基复合材料(EPCF/PBZ)的ILSS和弯曲性能优于含非环氧类树脂上胶剂的碳纤维/苯并(噁)嗪树脂基复合材料(VECF/PBZ)和不含上胶剂的碳纤维/苯并(噁)嗪树脂基复合材料(USCF/PBZ).环氧树脂上胶剂改善了纤维与苯并(噁)嗪树脂的粘结性能,使复合材料的内耗峰峰高降低,能量损耗减小.电镜照片同样验证了这一结果.     

SW280玻璃布/苯并噁嗪热熔法预浸料的性能研究

本文采用热熔法制备SW280玻璃布/苯并噁嗪预浸料,并对苯并噁嗪树脂工艺性、热失重性能,及复合材料动态热机械性能、高温力学性能保持率、阻燃性能等进行工艺试验和性能评价.结果表明,苯并噁嗪树脂软化点在41～42℃,最低黏度点为1835mPa·s,满足热熔法预浸料的制备要求;氮气氛围下起始分解温度280℃左右,800℃时残碳率可达61.3％.SW280玻璃布/苯并噁嗪复合材料力学性能优异,界面粘接良好,玻璃化转变温度为200℃,其200℃高温下的压缩强度、弯曲强度、弯曲模量和层剪强度保持率分别为90.6％、59.4％、83.2％和62.7％.SW280玻璃布/苯并噁嗪复合材料阻燃性能优异,无焰和有焰模式下最大烟密度均为0,氧指数＞58％,燃烧等级为V-1.     

纳米改性碳/酚醛树脂基复合材料性能研究

针对碳/酚醛树脂基复合材料层间剪切强度低的缺点,采用纳米填料进行改性。测试了2种纳米填料(纳米碳纤维、碳纳米管)改性后酚醛树脂的热解性能,研究了纳米填料对复合材料力学性能、烧蚀性能以及高温炭化后力学性能的影响,并观察分析了复合材料测试后的微观形貌。研究结果表明,纳米填料改性后,复合材料的力学性能、烧蚀性能均有所改善。其中,纳米碳纤维改性后复合材料的常温层间剪切强度达到24.9 MPa,氧乙炔线烧蚀率为22.75μm/s,质量烧蚀率为23.58 mg/s。纳米碳纤维表面粗糙,与树脂基体的界面强度高,因此其改性后的力学性能和烧蚀性能优于碳纳米管。     

苯并噁嗪树脂基芳砜纶纤维及玻璃纤维复合材料性能的研究

本文对苯并噁嗪、苯并噁嗪/芳砜纶纤维、苯并噁嗪/玻璃纤维树脂基复合材料的结构和性能进行了研究,并考察了该树脂的力学性能及耐热性,测试了苯并噁嗪/芳砜纶纤维、苯并噁嗪/玻璃纤维树脂基复合材料的力学性能及介电性能,并对芳砜纶纤维表面进行了电镜扫描。结果表明,树脂的耐热指数为199℃,其耐热性能和稳定性好,芳砜纶纤维与树脂之间形成了一个互溶体系,导致了芳砜纶纤维/苯并噁嗪复合材料的力学性能比玻璃纤维/苯并噁嗪复合材料的低,与树脂浇铸体的力学性能接近。     

纳米炭粉改进碳/酚醛材料层间性能研究

本文研究了纳米炭粉对碳/酚醛材料层间性能的改善，尤其是在高温和湿热环境下的效应，分析了纳米炭粉的增强机理。结果表明，纳米炭粉含量为10％(质量分数)时，碳/酚醛材料层间性能最佳。添加纳米炭粉可显著提高碳／酚醛材料高温层间性能，改善耐湿热性。900℃碳化后，层间剪切强度为5．4MPa，而不含纳米炭粉时仅为1．7MPa。     

纳米炭纤维含量对其酚醛复合材料性能影响

采用纳米炭纤维对酚醛树脂改性,通过力学性能、烧蚀性能测试以及电镜和X-射线光电子能谱(XPS)分析研究了纳米炭纤维含量对炭/酚醛树脂基复合材料性能的影响。结果表明,当纳米炭纤维质量分数为15%时,其改性复合材料的层间剪切强度最大,达到31.17 MPa,氧乙炔线烧蚀率最小,为0.020 mm/s。分析了其改性机理,指出纳米炭纤维在树脂中的分散均匀程度是获得理想复合材料性能的关键。     

碳纤维增强苯并噁嗪树脂基复合材料的研究进展

苯并噁嗪是近年来发展起来的一种新型的高性能复合材料基体树脂。本文较系统地综述了国内外碳纤维增强苯并噁嗪复合材料的研究进展,介绍了苯并噁嗪树脂及其复合材料的性能特点,指出了进一步的发展趋势。     

硅氧烷改性苯并噁嗪材料的合成及研究进展

苯并噁嗪树脂存在脆性大、成膜性低、开环温度过高以及与复合材料的相容性差等缺点,可用硅氧烷对其进行改性.概括了硅氧烷改性苯并噁嗪的方法及硅氧烷的引入对苯并噁嗪性能的影响;综述了硅氧烷改性苯并噁嗪的研究进展(作为紫外光固化、热致性形状记忆及人体运动检测材料),并展望了未来硅氧烷改性苯并噁嗪的发展方向.     

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。