聚(丙烯腈/醋酸乙烯酯)/蒙脱土纳米复合材料的流变性能

研究了聚(丙烯腈/醋酸乙烯酯)/蒙脱土[P(AN/VAc)/Clay]纳米复合材料的溶解特性及其在二甲基乙酰胺(DMA)溶剂中的流变性能。结果表明,P(AN/VACc)/Clay在溶液纺丝时最佳的溶剂为DMA; P(AN/VAc)/Clay-DMA溶液的非牛顿流动指数小于1,溶液为假塑性流体;当溶液质量分数为12%-13%、温度为130-150℃时,P(AN/VAc)/Clay-DMA溶液的纺丝性能最佳     

离子液体在静电纺丝中的应用

概述了室温离子液体的特性;介绍了离子液体在静电纺丝及其他方面的应用,详述了纤维素和聚间苯二甲酰间苯二胺的离子液体的静电纺丝;指出离子液体将成为静电纺丝非常重要的溶剂,开发能够溶解各种高聚物的离子液体,探索其溶解的高聚物的静电纺丝条件是今后的研究方向。     

离子液体法纤维素纤维的制备及性能研究进展

对纤维素在离子液体中的溶解、溶解机理、纺丝原液的性质、纺丝工艺及纤维性能等进行了综述,认为离子液体作为一种新型纤维素溶剂,具有溶解速度快、溶解度大、对纤维素降解程度小、溶剂回收简单、回收率高等特点,且再生的纤维素具有良好的光泽和力学性能。     

离子液体再生纤维素纤维工艺技术试验研究

介绍了纤维素在离子液体中的溶解与纤维成形机理和纤维素/离子液体溶体的制备,以及不同纤维素浓度、凝固浴浓度、凝固浴温度、拉伸比等条件的纺丝试验,对成形纤维的物理机械性能、截面形态进行了测试分析。纤维素/离子液体溶体的纺丝试验表明,采用干喷湿纺技术,以离子液体/水为凝固浴体系,成形纤维具有较高的强度。     

沸水再拉伸速率对聚丙烯腈纤维结构与性能的影响

以1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为溶剂溶解聚丙烯腈(PAN)制成PAN纺丝原液,采用干喷湿法纺丝,经过凝固、预拉伸、沸水拉伸制得PAN纤维,对所得PAN纤维进行沸水再拉伸处理,研究了沸水再拉伸速率对PAN纤维结构和性能的影响。结果表明:PAN纤维中残留质量分数为4.38%的离子液体,为沸水再拉伸起到了增塑作用;随着沸水再拉伸速率的增大,PAN纤维的力学性能提高,断裂强度由2.69cN/dtex提高到4.33 cN/dtex,而断裂伸长率由26%减小到20%,纤维的玻璃化转变温度、晶区取向度、双折射率、结晶度、晶粒尺寸均增大。     

利用双螺杆挤出机溶解聚丙烯腈

为了提高生产效率,简化操作步骤,并制得质量稳定的高黏均分子量(M_η)聚丙烯腈(PAN)纺丝原液,研究了利用双螺杆挤出机溶解PAN的新方法。二阶螺杆采用T形搭配方式,并在出料口加装过滤装置。溶剂的选择在PAN溶解理论的基础上综合考虑了不同溶剂的溶解能力,找到了适合螺杆溶解要求的混合溶剂。同时将制得的溶液利用干喷湿纺工艺进行纺丝,得到线密度小、高强度的原丝,以验证此体系的可靠性。结果表明此溶解方式可以满足高性能PAN原丝的纺丝要求,同时产出溶液质量稳定且效率更高。     

室温离子液体的制备及物化性能研究

合成了[bm im]B r和[bm im]BF4室温离子液体,考察了其在不同溶剂中的溶解性能及导电性能,同时对离子液体在不同溶剂中的紫外吸收进行了测定。结果表明,离子液体在水、乙醇、乙酸、丙酮中可以较好的溶解,而在乙醚、苯、正己烷中不溶解;离子液体的电导率随浓度的增大和温度的升高而增大,在不同的溶剂中的电导率K不同,而且相差很大,其顺序为K(水作溶剂)>K(乙醇作溶剂)>K(乙酸作溶剂)。溶剂的极性对离子液体的紫外吸收影响较大,最大吸收波长的顺序为:λm ax(水为溶剂)<λm ax(乙醇为溶剂)<λm ax(乙酸为溶剂)。     

一种在离子液体中制备高性能碳纤维用聚丙烯腈纺丝原液的方法

正一种在离子液体中制备高性能碳纤维用聚内烯腈纺丝原液的方法,将丙烯腈二元共聚体系中的单体或丙烯腈三元共聚体系中的单体依次加入离子液体中,室温溶解,加入引发剂,并通入惰性气体,进行自由基聚合反应。反应结束后用冰浴停止聚合反应,以水凝固聚合产物并反复进行水洗烘干纯化后得到聚丙烯腈粉料。利用二甲基亚砜作为溶剂将上述得到的聚丙烯腈粉料搅拌溶解,得到高性能碳纤维聚内烯腈纺丝原液。该方     

离子液体对丝素蛋白溶解性能的影响

合成了一系列碱性离子液体,其中离子液体1-丁基-3-甲基咪唑乙酸盐([Bmim]AC)对丝素蛋白具有良好的溶解性能。考察了丝素蛋白在该离子液体中的溶解特性及在离子液体中的溶解温度和溶解时间,结果表明,在75℃下,溶解840 min,该离子液体对丝素蛋白的溶解能力达到15%(质量分数)。XRD和FTIR分析表明,再生丝素蛋白的构象以α-螺旋为主,丝素蛋白在溶解过程中没有发生衍生化。因此,[Bmim]AC离子液体是丝素蛋白的优良溶剂。     

离子液体溶剂法制备再生纤维素纤维

离子液体是纤维素的有效溶剂,可以实现快速溶解。以离子液体生产的再生纤维素纤维较多地保留了纤维素的天然特性,易于生物降解,产品性能优于传统的粘胶工艺。介绍了离子液体的物性、作为纤维素溶剂的优点、对纤维素的溶解机理、纺丝原液制备及纺丝工艺。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。