不同官能度环氧树脂的阳离子光固化研究

对4种不同官能度的环氧树脂在紫外光辐照下用一种二苯基碘钅翁盐或两种二烷基苯甲酰锍盐光引发剂进行阳离子光固化的体系作了系统的研究。研究结果表明,二氨基二苯甲烷环氧树脂AG-80不能阳离子光固化,而E-51,711和TDE-85均可在二苯基碘钅翁六氟磷酸盐或1-甲基-1-十二烷基苯甲酰甲基六氟锑酸锍盐作用下进行紫外光引发阳离子聚合,其中二苯基碘钅翁六氟磷酸盐引发E-51环氧树脂阳离子光固化的效果最好,该树脂体系可用做紫外光固化复合材料的树脂基体。研究还发现,在停止紫外光辐照后,由于阳离子聚合链终止困难而使碘钅翁盐引发的环氧树脂光固化体系存在后固化现象,后固化速度与后固化时的温度有关。     

不同链长杂化单体合成及光聚合性能研究

通过三步反应合成了三种不同链长的新型杂化单体。使用傅里叶红外光谱和核磁共振仪对相应产物进行了表征。同时使用傅里叶实时红外(FT-RTIR)对三种杂化单体的光聚合性能进行了研究。考察了引发剂种类、不同浓度光引发剂以及链长对杂化单体的光聚合性能的影响。结果表明,光引发剂硫钅翁盐的引发性能要优于碘钅翁盐,随着光引发剂浓度的增大,杂化单体双键及环氧基团的转化率都相应提高,随着链长的增长,相应单体中的双键的转化率降低,但是相应单体中环氧基团的转化率随之升高。     

二苯基碘鎓氟硼酸盐引发AGE阳离子光聚合与光交联的研究

用合成的二苯基碘钅翁氟硼酸盐作为光敏引发剂 ,研究了含乙烯基和环氧基两种不同官能基的烯丙基缩水甘油醚 ( AGE)的阳离子光聚合和聚合前后微观结构的变化 ,讨论了其阳离子光聚合的特征和机理 ,测定了光聚合引起光交联的凝胶转化率曲线     

二苯基碘(钅翁)氟硼酸盐引发AGE阳离子光聚合与光交联的研究

用合成的二苯基碘(钅翁)氟硼酸盐作为光敏引发剂,研究了含乙烯基和环氧基两种不同官能基的烯丙基缩水甘油醚(AGE)的阳离子光聚合和聚合前后微观结构的变化,讨论了其阳离子光聚合的特征和机理,测定了光聚合引起光交联的凝胶转化率曲线.     

碘鎓盐引发的环氧—丙烯酸酯复合光敏胶的研制

用合成的二苯基碘钅翁六氟磷酸盐作光引发剂 ,对不同比例的双酚A环氧树脂E5 1 和丙烯酸酯预聚物AE组成的复合树脂进行了光固化研究 ,证明了碘钅翁盐具有同时引发环氧和丙烯酸酯复合树脂按阳离子和自由基两种不同机理进行光固化的能力 ;考察了树脂的不同比例对固化速度的影响 ;同时选择一定比例的光敏复合树脂研究了增感剂 (DA)对光固化速度的影响。结果表明 ,这种复合光敏胶具有粘度低 ,光固化速度快 ,粘合力强 ,玻璃化转变温度低 ,耐水煮沸性好的优点 ,可作为新型UV -固化胶粘剂和防水性密封胶加以应用。     

聚环氧氯丙烷的合成

以乙二醇为起始剂,分别以六氟化磷三乙基氧盐、三氟化硼乙醚络合物和三氟化硼四氢呋喃络合物（THF·BF3）为催化剂,进行环氧氯丙烷阳离子开环聚合,合成端羟基环氧氯丙烷聚醚（PECH）。所得PECH分子量在800～2000之间,收率为60％～75％。实验结果表明,THF·BF3催化体系制备的PECH,相对分子质量1500～2000,平均官能度接近于2。     

N—丁基—2—乙氧基硫代吖啶酮的光化学反应机理

采用荧光光谱研究了N－丁基－2－乙氧基硫代吖啶酮的光化学反应机理。结果表明：在Xe灯光照下，N－丁基－2－乙氧基硫代吖啶酮转变成了相应的吖啶酮，用紫外－可见光谱和质谱证实了吖啶酮的存在；生成的吖啶酮可被二苯基碘翁盐猝灭，它们之间的荧光猝灭遵循电子转移的反应机理，实验又证明了由硫代吖啶酮、二苯基碘翁盐和硫代水杨酸三者组成的光聚合引发体系的引发效果最好。     

分子内敏化鎓盐的合成及光敏性研究

二芳基碘鎓盐和三芳基硫鎓盐是阳离子聚合的光引发剂和光敏产酸物,但他们在300nm以上的光吸收很低,限制了对紫外光的利用效率。为解决此问题,本文合成了一些新的碘鎓盐和硫鎓盐,并用凝胶时间方法考察了它们的光引发效率。实验结果表明,2-苯硫基甲基,2′,4′-二甲基二苯碘鎓盐和9-蒽丙基,二苯基硫鎓盐具有特别高的光引发效率,这归之于光照时这些鎓盐发生了分子内电荷转移反应,即发生了分子内敏化。9-蒽丙基二苯硫鎓盐分子中的蒽基(An)是电子给体也是敏化基团,光照时可发生如下反应:     

DPPH引发丙烯酸酯单体光聚合动力学研究

采用傅立叶红外光谱仪、核磁共振仪对阳离子光引发剂4-(苯硫基)苯基二苯基硫鎓六氟磷酸盐(DPPH)结构进行了表征,紫外光谱分析表明该引发剂在302nm处有最大紫外吸收。通过实时红外(RT-IR)对DPPH引发丙烯酸酯单体光聚合动力学过程进行了研究,考查了引发剂浓度、光强及不同官能度单体对双键转化率及聚合速率的影响。随引发剂浓度增加,最大转化速率先增大后减小,而光强增加,最大转化速率增加。单体官能度越高,双键转化率与最大转化速率越低,达最大转化速率的时间越长。     

丙烯腈光聚合研究

研究偶氮二异丁腈(AIBN)作光引发剂引发丙烯腈(AN)的光聚合,探讨了单体浓度、引发剂浓度、光照时间和环境温度对单体转化率、聚合物黏均相对分子质量的影响。总结出光引发剂C60-(SR)n(C60负载引发-转移-终止剂)与常规光引发剂AIBN引发AN光聚合的区别。     

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.     

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。     

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。     

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.     

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.     

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.