莫来石抑制钛酸铝材料热分解的机理研究

运用扫描电镜（SEM）、X-射线衍射仪（XRD）、能谱仪（EDS）等现代测试手段,从材质的显微结构、晶界晶相组成分析入手,对莫来石抑制钛酸铝热分解的作用机理作了较为详细的分析研究,探明莫来石抑制钛酸铝热分解的作用机理是：（1）在高温下Si^4 进入钛酸铝晶格或间隙中,形成固溶化的钛酸铝晶体,稳定了晶格;（2）因莫来石与钛酸铝间的热膨胀差异,造成较大的压应力（37.65MPa）,致使固溶化的钛酸铝晶体更趋稳定。     

莫来石-钛酸铝高温窑具的研制

在合成莫来石/钛酸铝复相原料的基础上,借助于XRD、SEM和热态模拟试验等手段研究了烧成温度、复相原料添加量对莫来石-钛酸铝高温窑具性能的影响.研究结果表明:合成的莫来石/钛酸铝复相原料适于制备高温窑具;在1600 ℃烧成的窑具试样具有较高的高温抗折强度和良好的抗热震性;复相合成原料添加量为45%时可获得综合性能较好的窑具材料;热态模拟试验表明研制的莫来石-钛酸铝高温窑具适于作为硬磁材料烧成窑具.     

不同莫来石对钛酸铝热分解的抑制作用研究

本文作者运用先进的Ｘ－射线衍射仪、扫描电镜（ＳＥＭ）、能谱仪（ＥＤＸ）等测试手段,对钛酸铝莫来石复合材料的显微结构、热分解性能及热膨胀特性作了详细研究;研究结果表明,不同晶形或以不同方式制备的莫来石都能有效地抑制钛酸铝晶体的高温（１０００℃,２００小...     

添加剂和烧成温度对钛酸铝的合成与烧结性能的影响

研究了添加剂MgO和SiO2 以及烧成温度对钛酸铝的合成及烧结性能的影响。结果表明 ,烧成温度的升高促进了钛酸铝的合成与烧结 ;MgO的引入极大地促进了钛酸铝的合成 ,而对于SiO2 来说 ,这种促进作用在高温下才明显 ;MgO和SiO2 在钛酸铝中均有一定的固溶度 ,超过此固溶极限将有新相 (尖晶石或莫来石 )产生 ,从而导致烧结性能随MgO和SiO2 添加量的变化呈现复杂的变化规律     

莫来石-钛酸铝窑具的制备与性能研究

采用原位合成技术合成莫来石一钛酸铝复相材料(ATM),并以复相材料和烧结莫来石(M60)为主要原料制备莫来石一钛酸铝窑具,借助于XRD、SEM和热态模拟试验等手段研究了烧成温度、复相材料添加量对莫来石-钛酸铝高温窑具性能和显微结构的影响.结果表明:合成的莫来石-钛酸铝复相材料适于制备高温窑具;在1 600℃烧成的窑具试样具有较高的高温抗折强度和良好的抗热震性;合成复相材料的添加量为45%时可获得综合性能好的窑具材料;热态模拟试验表明研制的莫来石-钛酸铝高温窑具适合在低于1 400℃,承重小于8 kg的条件下使用.     

烧成工艺对钛酸铝稳定性影响的研究

本文详细研究了烧成温度和保温时间对钛酸铝热稳定性的影响。结果表明:提高烧成温度和延长保温时间有利于提高钛酸铝的热稳定性。通过%一ray衍射分析和透射电镜分析,揭示了钛酸铝稳定性的提高是由于钛酸铝晶粒的充分发育、长大以及钛酸铝晶体结构中的八面体畸变程度下降的缘故。     

纳米Fe2O3对钛酸铝陶瓷热稳定性能的影响

以溶胶–凝胶法制备的钛酸铝前驱体和固相合成法制备的纳米Fe2O3为原料,在不同温度煅烧保温2h制备出钛酸铝固溶体[Al2(1–x)Fe2xTiO5]。通过X射线衍射、电子探针分析并计算晶格常数和热分解率,研究了纳米Fe2O3含量以及烧成温度对烧后试样热分解性能的影响。结果表明:纳米Fe2O3很容易与Al2TiO5反应,形成固溶体,抑制钛酸铝陶瓷的热分解;随着纳米Fe2O3加入量的增加,Al2(1–x)Fe2xTiO5的晶格常数变大,热分解率降低,但当加入量超过10%时,Al2(1–x)Fe2xTiO5的晶格常数不变甚至减小,热分解率反而会增大;纳米Fe2O3作为添加剂可改善钛酸铝陶瓷的热分解性能。煅烧温度对钛酸铝的热分解率有很大影响,随着温度升高,热分解率降低,当温度大于1350℃时,钛酸铝陶瓷晶格常数保持不变,钛酸铝陶瓷的热分解率变化不大。     

含钛添加剂对堇青石陶瓷热膨胀性能的影响

以粘土、滑石、氧化铝微粉等为原料 ,于1370～ 14 0 0℃烧成 ,合成了堇青石陶瓷。研究了添加 5 %～ 2 0 %的钛酸铝 (AT )或 5 %～ 15 %的氧化铝(A)与氧化钛 (T)的混合物 (A与T的摩尔比 1∶1)对堇青石陶瓷的相组成及热膨胀率的影响。结果表明 :添加AT或A T均能有效地降低材料的热膨胀率 ;XRD分析表明 ,在添加 15 %以上AT或添加10 %以上A T的堇青石试样中形成了莫来石与钛酸铝晶体 ;SEM显微照片表明 ,引入AT或A T均促进了堇青石的合成。从效果和节约能源考虑 ,应添加 10 %～ 15 %的A T ,烧成温度为 14 0 0℃左右。     

基于高铝粉煤灰的堇青石-莫来石复合材料制备

为了实现高铝粉煤灰的高值化利用,以高铝粉煤灰为单一铝硅原料,依次对其进行酸、碱预处理,将处理后的高铝粉煤灰与滑石粉混合,通过一步原位烧成制备堇青石-莫来石复合材料,进一步考察原料配比和烧成条件对烧成样品性能的影响规律。结果表明,烧成温度为1 370℃、烧成时间为2 h、堇青石和莫来石理论质量比为50∶50时,可制备出体积密度为1.96 g/cm~3、显气孔率为30.47%、常温抗折强度为66.44 MPa的堇青石-莫来石复合材料,其主要指标均达到YB/T 4549—2016《堇青石-莫来石窑具》的要求,该方法实现了以粉煤灰为主要原料,灵活制备具有不同堇青石和莫来石配比的复合材料,为高铝粉煤灰的高值化利用提供新途径。     

稳定的钛酸铝陶瓷的研究

钛酸铝瓷是低膨胀高熔点的陶瓷材料。它广泛用于高抗热震性场合以及炼铝工业。本研究利用添加剂使之生成部分莫来石提高了钛酸铝的抗弯强度,部分金属离子固溶到钛酸铝晶体中,使之提高了热稳定性。本研究制得的热稳定性钛酸铝陶瓷既保持了低膨胀性又提高了强度达到了实用水平。     

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。