pH响应黏弹性油酰胺丙基二甲胺/邻苯二甲酸氢钾胶束体系流变性研究

通过考察油酰胺丙基二甲胺(PKO-O)/邻苯二甲酸氢钾(PHP)黏弹性胶束体系的稳态剪切黏度、流动曲线、剪切触变性、黏弹性、热触变性等流变学性质,研究了该胶束体系的pH响应性。结果表明,200 s-1下,pH=7.47时胶束体系稳态剪切黏度较大,为122.3 mPa·s;在pH=7.61,7.47,6.40 3个状态间,稳态剪切黏度可循环切换多次,表明该胶束体系具有良好的pH响应性;PKO-O/PHP胶束体系为剪切变稀的正触变性流体,其流动曲线可用Cross本构方程进行表征;该体系是典型的黏弹、热触变性流体,pH=7.47时体系具有较大的复模量和显著的热触变性。     

高黏度聚酯流变行为的研究

采用毛细管流变仪研究了高黏度聚酯(PET)的表观黏度及黏流活化能随温度(280～300℃)及剪切速率(20～104s-1)的变化。结果表明:高黏度PET熔体随着剪切速率的增加出现切力变稀现象,随着熔体温度升高,剪切速率对熔体的表观黏度的影响降低;高黏度PET的黏流活化能随着剪切速率的提高而降低;在温度为300℃,剪切速率为3 000 s-1时,高黏度PET熔体具有较好的流动性。     

压裂用疏水缔合聚合物溶液性质及减阻性能

以功能性疏水单体甲基丙烯酸长链酯与丙烯酰胺(AM)、丙烯酸(AA)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为原料,合成了疏水缔合聚合物HAWP-18。采用流变仪考察了HAWP-18的耐剪切性能、黏弹性及触变性。结果表明:HAWP-18属于假塑性流体,临界缔合质量浓度为2.31 g/L,随着剪切速率增加,HAWP-18的表观黏度缓慢下降后不变,剪切速率降低后,表观黏度可再度恢复,表现出较强的耐剪切性能;黏弹性测试表明:HAWP-18是典型的黏弹性结构流体,具有较宽的线性黏弹区,该体系的储能模量G'大于损耗模量G″,并且黏度越大,弹性特征越强。采用稳态剪切测试考察了不同质量浓度HAWP-18的剪切应力与剪切速率的关系,结果表明:HAWP-18具有触变性,并且触变性随质量浓度增大而增强。使用自制摩阻测试仪测定了不同质量浓度HAWP-18的减阻性能,结果表明:HAWP-18减阻率随质量浓度的增加先上升后降低。     

PSM/PP复合材料的流变性能研究

应用毛细管流变仪研究了可塑性淀粉生物基材料(PSM)/聚丙烯(PP)体系的流变学性质。讨论了挤出成型温度、剪切速率、线性聚丙烯(LPP)含量和PP支链结构对PSM流动性能的影响。结果表明:140～170℃,0～103 s-1下流动曲线具假塑性流体特点;表观黏度随温度、剪切速率增加而降低,黏度随剪切速率下降逐渐减少;170℃后曲线有向牛顿型流体变化的趋势;PSM/短支链PP(SCBPP)比PSM/LPP的表观黏度低,PSM/长支链PP(LCB-PP)比PSM/LPP的表观黏度高;PSM对剪切速率的敏感性低于PP。     

低电荷密度聚丙烯酰胺水分散体的触变性研究

从流变学的角度,利用静态剪切法对低电荷密度聚丙烯酰胺（D-amPAM）水分散体触变性进行了研究.考察了分散稳定剂浓度、分散稳定剂黏均分子量、共聚物单体浓度以及硫酸铵浓度对D-amPAM体系触变性以及触变强度的影响.结果表明,随分散稳定剂浓度的增加,体系的触变性越来越明显,触变强度越来越大;随分散稳定剂黏均分子量的增加,体系的静态剪切黏度及触变强度先增加后减小;共聚物单体浓度越大,体系的触变形态越稳定单一,触变强度以及静态剪切黏度越大;不同硫酸铵浓度下制取的分散体系触变性及触变强度变化较大.     

UHMWPE/石蜡油溶液体系的黏度特性

以石蜡油(LP)为溶剂配制超高相对分子质量聚乙烯(UHMWPE)/LP溶液,运用正交设计方法,研究低剪切速率下UHMWPE的黏均相对分子质量(Mη)、溶液浓度和温度对UHMWPE/LP溶液体系黏度特性的影响。结果表明:UHMWPE/LP溶液的黏度随Mη及溶液浓度的增加而增加,随溶液温度的升高而降低;正交试验结果为UHMWPE的浓度对UHMWPE/LP溶液体系的黏度影响最大,Mη次之,在190~220℃下,温度影响较小。     

聚丙烯酰胺水溶液的流变特性

通过测定聚丙烯酰胺(PAM)水溶液不同状态下的表观黏度,研究了质量浓度、剪切速率和温度对PAM溶液流变特性的影响。结果表明,在浓度范围1.0～4.0 g/L时,PAM溶液表观黏度随浓度的增加呈线性递增。在浓度范围2.0～4.0 g/L时,PAM溶液表现为假塑性流体特性,其表观黏度随剪切速率的升高而降低,且两者的对数值呈线性关系,非牛顿指数n随稠度系数K的增加而降低;溶液表观黏度随温度的升高而降低,其黏流活化能约为10 kJ/mol。PAM溶液表现为明显的正触变性。     

可逆交联聚合物压裂液黏弹性及变剪切性能研究

可逆交联聚合物压裂液的携砂能力不仅与黏度有关,而且与其黏弹性相关,因此研究可逆交联聚合物压裂液的黏弹性显得十分必要。文章对可逆交联聚合物压裂液进行了应力扫描和频率扫描实验,讨论了可逆交联聚合物压裂液的黏弹性,评价了压裂液的变剪切性能。结果表明:随着聚合物浓度的增加,可逆交联聚合物压裂液线性黏弹区的范围变宽,储能模量和耗能模量增加,黏弹性提高;当温度为120~160℃,经170s-1、剪切100 min后的平均尾黏分别为56、52和40mPa·s,说明体系具有良好的耐温耐剪切性能。     

美白洁面乳泵送工艺流变学研究

主要研究泵送工艺对美白洁面乳流变学性质的影响,包括流动曲线及黏弹性。研究发现,泵送工艺可显著影响产品的流变学性质,不同转子泵频率下的产品流变学性质相差较大。选取复模量为衡量指标,确定转子泵频率的合适范围为20~25 Hz。这与实际生产中转子泵的频率23 Hz相符合。     

棉浆粕/NMMO·H_2O溶液的流变性能研究

以N-甲基吗啉-N-氧化物的水溶液(NMMO·H_2O)为溶剂溶解棉浆粕制成棉浆粕/NMMO·H_2O溶液,研究了棉浆粕质量分数为4%~8%的棉浆粕/NMMO·H_2O溶液在85~100℃的流变性能。结果表明:在低剪切速率(γ)下,棉浆粕/NMMO·H_2O溶液的表观黏度(ηa)随温度上升而下降,一定温度时γ达到一定值后,ηa出现转折点呈急速下降趋势,且随着温度的升高,ηa出现转折点的γ增大;棉浆粕/NMMO·H_2O溶液体系为切力变稀的假塑性流体,一定γ下,棉浆粕浓度越高,体系黏度越大,但γ达到一定值后,体系黏度出现转折点呈急剧下降趋势,且随着浓度的增大,ηa出现转折点的γ减小;溶液体系在85~100℃内,其非牛顿指数小于1,且随温度升高而减小,随着棉浆粕浓度的增加,溶液体系的黏流活化能减小,溶液体系的黏-温敏感性减小。     

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.     

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。     

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。