N-酰化改性胺扩链剂合成聚脲弹性体的研究

采用N-酰化方法对扩链剂己二胺进行改性.以己二胺、冰乙酸为原料,磷酸为催化剂合成了新型位阻型扩链剂二乙酰己二胺.将扩链剂与4,4'-二苯甲烷二异氰酸酯(MDI)反应,制备了芳香族新型聚脲.结果表明,由二乙酰己二胺合成聚脲的凝胶时间大大延长,同时软段和硬段的相容性较好,扩链的聚脲热稳定性不变,并显示出较高力学性能.     

停放条件对氯丁橡胶性能的影响

研究了停放温度和停放时间对氯丁橡胶混炼胶门尼粘度、门尼焦烧、力学性能及硫化特性等的影响。结果表明,停放温度和停放时间对氯丁橡胶混炼胶力学性能和交联程度的影响不大;门尼粘度随停放时间的延长呈线性增大,在32℃室温下增长明显,停放温度越高,增长越加明显;门尼焦烧时间随停放时间的延长先缩短后延长;焦烧时间随停放时间的延长逐渐缩短,且在32℃室温下缩短程度较为明显;工艺正硫化时间随停放时间的延长轻微缩短。     

芳香族聚脲的合成与表征

采用4,4’-二苯甲烷二异氰酸酯和间苯二胺为单体,经两步法溶液聚合制备了芳香族聚脲。采用FTIR、^1H NMR,表征了聚脲样品的化学结构。对样品力学性能的测试表明,聚腺的断裂强度及其弹性模量随二异氰酸酯与二胺摩尔比(NCO／NH2)的增加先是有所增强,但随之又明显下降;通过对样品的热重分析,估算了样品的初始热分解活化能为51．3kJ／mol。     

强抑制性改性杂聚糖在钻井液中的作用效能与机理研究

为提高天然植物聚糖的水溶性及其胶液粘度，以植物聚糖衍生物为原料，通过磺化反应制得了改性植物聚糖。采用红外光谱和差示扫描量热分析对磺化前后的植物聚糖进行了表征，证实了磺化结果。通过正交实验确定了磺化改性的反应条件：反应温度90℃，反应pH=12，反应时间12h，磺化剂与植物聚糖质量比为0.6∶1。与原糖相比，改性植物聚糖具有更好的水溶性，经改性植物聚糖处理后的钻井液增黏率为135.1%，降滤失率为22.9%。经改性植物聚糖处理后的钻井液在90℃以下流变性能稳定，具有一定的抗温性。线性膨胀率实验及泥球实验表明，与改性前的原糖相比，改性磺化后的植物聚糖具有良好的抑制防塌作用。     

聚脲涂层性能研究进展

综述了聚脲涂层宏观性能的影响因素,以及聚脲涂层的耐老化性、耐腐蚀性及附着力研究进展。影响因素研究结果表明:端氨基聚醚的官能度越高,相对分子质量越大,凝胶时间越长;涂层的力学性能随硬段含量的增加而显著提高;采用氨基化碳纳米管改性的聚脲涂层具有超高拉伸强度。聚脲涂层具有优异的耐老化性、良好的耐各种酸、碱、盐腐蚀性。聚脲涂层的附着力与基材处理、底漆及施工环境等因素密切相关。     

水热酸处理解离凹凸棒土晶束的研究

为了解离天然凹凸棒土棒晶束,采用水热酸处理工艺技术对其进行改性,以改性样品粘度为指标,考察了固液比、改性时间、改性温度和酸浓度对改性样品的影响,并对改性样品进行Zeta电位和粒度分析以及红外光谱表征。实验结果表明,盐酸水热处理的最佳工艺条件为固液比为1∶0.5,改性时间为6 h,改性温度为150℃,酸浓度为1.04 mol/L,改性样品粘度为329.8 mPa·s;硫酸水热处理的最佳工艺条件为固液比为1∶0.5,改性时间为6 h,改性温度为200℃,酸浓度为1.10 mol/L,改性样品粘度为291.6 mPa·s。     

二乙酰己二胺与异氰酸酯合成聚脲反应动力学

采用酰基化方法对扩链剂1,6-己二胺进行了改性,并用凯氏定氮法,傅立叶红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)分析了改性产物,确定产物为二乙酰己二胺.以二乙酰己二胺为扩链剂,与半预聚物4,4'-二苯甲烷二异氰酸酯(MDI)反应合成新型聚脲,考察了扩链剂1,6-己二胺改性对聚脲凝胶时间的影响,并采用FT-IR研究聚脲合成的反应动力学.结果表明,采用二乙酰己二胺为扩链剂,反应活性降低,凝胶时问延长,有利于动力学反应研究.在常温下,二乙酰己二胺与MDI合成聚脲的反应为二级反应,表观活化能为43.414 kJ/mol.     

处理温度对酶解木质素改性环氧树脂性能的影响

将玉米秸秆酶解木质素与双酚A环氧树脂混合,在不同温度下预处理一定时间,用以改性环氧树脂。通过改性后树脂黏度、固化反应过程、固化后树脂的玻璃化转变温度、凝胶含量以及老化不同时间后树脂力学性能的测试,研究了处理温度对酶解木质素改性环氧树脂性能的影响。结果表明,改性后环氧树脂的黏度随处理温度的提高而增加,改性树脂/聚酰胺混合体系的固化峰值温度随处理温度的提高而降低;玻璃化转变温度和凝胶含量随处理温度的提高而增大;高温预处理的改性树脂固化物的弯曲强度均有不同程度的提高,老化后,材料的弯曲强度先升高,后降低,冲击强度则随老化时间的延长呈现持续降低的趋势。     

神府煤制备磺化煤的研究及应用

讨论了神府煤制备磺化煤的反应中,磺化温度、时间对煤磺化度和酸性基的影响,用FTIR对磺化煤进行结构表征,用体积溶胀法研究了磺化煤在苯胺中的溶胀特性.结果表明,煤的磺化度随着磺化温度的升高、磺化时间的延长而增大,煤经过磺化反应后其在苯胺中的溶胀性能也得到了改善.     

低温等离子体改性烟草焦脱除烟气中汞的实验研究

以废次烟草为原料,用盐酸溶液对800℃焦进行酸洗,然后采用低温等离子体对酸洗后的焦进行改性,研究低温等离子体改性时间对焦孔隙结构和表面化学特性的影响,以及对烟气中Hg⁰的脱除影响特性。利用氮气吸附/脱附、FTIR等方法对烟草焦改性前后的微观理化特性进行表征,在固定床上测试改性焦的脱汞率。结果表明：低温等离子体改性使烟草焦表面的孔隙结构减少,使有利于脱汞的酸性含氧官能团COOH和C=O的活性位含量随改性时间延长先增加后减小,改性作用使焦表面活性位的密度随改性时间逐渐增加。烟草焦改性后对汞的脱除率显著增加,且随改性时间的增加先增加后减小,改性5 min焦脱汞量最大,在2 h内为126.4μg/g。改性焦表面孔径偏大的微孔和中孔通道内的含氧官能团活性位对脱汞起到主要作用,而极微孔仅在吸附初期起作用,并被快速堵塞。     

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.     

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.     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

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。