球形纤维素珠体-AN-AM接枝共聚物的制备

以球形纤维素珠体为原料,丙烯腈(AN)和丙烯酰胺(AM)为单体,硝酸铈铵和过硫酸钾(KPS)为引发剂,制备纤维素珠体-AN-AM接枝共聚物,并通过正交单因素实验,研究了反应温度、引发剂用量、单体用量、反应时间等因素对接枝效果的影响。实验结果表明:当反应温度为60℃,引发剂硝酸铈铵用量为20%,KPS用量为15%(引发剂与单体AN的质量百分比),单体AN浓度为0.75 mol/L,AM浓度为0.28 mol/L,硝酸浓度为0.14 mol/L,反应时间为3 h时,接枝效果最好。此条件下,AN、AM与纤维素的接枝率可达259.4%,接枝效率可达49.40%。     

一种油田防垢剂的合成及评价实验研究

以过硫酸铵-亚硫酸氢钠为氧化还原引发体系、亚硫酸氢钠同时作链转移剂合成低相对分子量的聚丙烯酸钠,作为一种油田防垢剂。研究了单体、引发剂及链转移剂的用量、反应温度和时间等对产物相对分子质量的影响,并对不同相对分子量的产物进行了防垢性能的评价。结果表明反应温度为60℃、单体质量分数30%、引发剂用量0.6%、链转移剂用量5%、反应时间2 h时,可制得聚丙烯酸钠的粘均相对分子质量在2 000~3 000,作为油田防垢剂防垢效率高、效果好。     

沉淀聚合制备低分子量聚丙烯酸及残液循环利用

以偶氮二异丁腈(AIBN)为自由基引发剂,石油醚为溶剂,异丙醇为链转移剂,通过沉淀聚合制备了低相对分子质量(简称分子量,下同)的聚丙烯酸。考察了引发剂用量、链转移剂用量、单体质量浓度对聚合收率的影响,确定最佳聚合条件为:AIBN用量为单体质量的10%,链转移剂用量为单体质量的100%,单体质量浓度100g/L,反应温度80℃,反应时间4 h。反应结束后产品在底部沉淀析出,溶剂可循环利用,在最佳聚合条件下,残液循环利用5次,单体的累计转化率达到92.6%。凝胶渗透色谱(GPC)分析表明,通过残液循环制备的产品重均分子量(Mw)变化不大,保持在1 000～1 300,多分散性(PDI)为1.92～3.38。     

制备聚丙烯酸钠分散剂的最佳工艺条件探究

以丙烯酸为单体,采用过硫酸铵和亚硫酸氢钠为氧化还原引发剂,同时亚硫酸氢钠又作为链转移剂来制备低分子量的聚丙烯酸钠.研究了单体浓度、引发剂用量、链转移剂用量以及反应温度对分子量和分散性的影响.通过正交设计实验确定了最佳反应条件:过硫酸铵用量为5.56%,亚硫酸氢钠为4.44%,单体浓度为33.3%,温度70℃,反应时间为3h.     

制备聚丙烯酸钠分散剂的最佳工艺条件探究

以丙烯酸为单体,采用过硫酸铵和亚硫酸氢钠为氧化还原引发剂,同时亚硫酸氢钠又作为链转移剂来制备低分子量的聚丙烯酸钠.研究了单体浓度、引发剂用量、链转移剂用量以及反应温度对分子量和分散性的影响.通过正交设计实验确定了最佳反应条件过硫酸铵用量为5.56%,亚硫酸氢钠为4.44%,单体浓度为33.3%,温度70℃,反应时间为3h.     

高温本体聚合合成ACS树脂的接枝率研究

研究了聚合条件、配方组成及氯化聚乙烯(CPE)的氯化度对高温本体聚合合成丙烯腈(AN) CPE苯乙烯(St)接枝共聚物（ACS）树脂接枝率的影响。结果表明,本体聚合合成ACS树脂过程中接枝反应主要发生在聚合转化率低于50 %的低转化率阶段;反应温度、引发剂及链转移剂用量是影响本体聚合合成ACS接枝率的主要因素;提高聚合反应温度、增加引发剂和链转移剂浓度均会导致接枝率显著下降;St/AN的质量比、CPE橡胶的含量及氯化度对接枝率的影响较小。     

制备聚丙烯酸钠分散剂的最佳工艺条件探究

以丙烯酸为单体,采用过硫酸铵和亚硫酸氢钠为氧化还原引发剂,同时亚硫酸氢钠又作为链转移剂来制备低分子量的聚丙烯酸钠。研究了单体浓度、引发剂用量、链转移剂用量以及反应温度对分子量和分散性的影响。通过正交设计实验确定了最佳反应条件:过硫酸铵用量为 5 56%,亚硫酸氢钠为 4 44%,单体浓度为 33 3%,温度 70℃,反应时间为 3h。     

链转移剂调控DMDAAC均聚物分子量

以工业级二甲基二烯丙基氯化铵(DMDAAC)为反应单体、甲酸钠或甲醇为链转移剂,选择过硫酸铵-亚硫酸氢钠氧化还原引发体系,采用水溶液聚合法得到分子量在800～9000的PDMDAAC.通过正交实验考察了单体质量分数、聚合温度、聚合时间、聚合体系pH值、引发剂用量、还原剂用量和链转移剂用量对聚合产物特性粘数和单体转化率的影响.研究了链转移剂对PDMDAAC分子量的调控作用及其用量对聚合物特性粘数和单体转化率的影响规律.     

IA/AA/AMPS三元共聚物的合成及阻垢性能研究

以水作溶剂,过硫酸铵为引发剂,衣康酸(IA)、丙烯酸(AA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,合成了IA/AA /AMPS三元共聚物.探讨了引发剂用量、链转移剂用量、反应温度等对共聚物阻垢性能的影响.结果表明,引发剂用量为单体总质量的4.5%,链转移剂用量为单体总质量的9.5%,反应温度为95℃时,共聚...     

低分子量聚丙烯酸钠的合成与分析

低分子量的聚丙烯酸钠具有良好的分散性能,本文以丙烯酸为单体,过硫酸铵为引发剂,异丙醇为链转移剂,通过中和法合成了低分子量的聚丙烯酸钠,用端基法测得其数均分子量。通过改变单体浓度、引发剂用量、链转移剂用量和反应温度等反应条件,得出了各合成因素对聚丙烯酸钠分子量影响的趋势。     

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.     

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。