壳聚糖-硅藻土-聚丙烯酸高吸水性树脂

以丙烯酸,硅藻土为原料,过硫酸铵为引发剂,N,N’-亚甲基双丙烯酰胺为交联剂,通过接枝壳聚糖制备了壳聚糖-硅藻土-聚丙烯酸高吸水性树脂,并对高吸水性树脂的结构进行了红外光谱的表征,系统研究了引发剂、交联剂、硅藻土的用量,丙烯酸与壳聚糖的质量比,丙烯酸的中和度,反应温度以及反应时间对高吸水性树脂吸水率的影响。实验结果表明,丙烯酸与壳聚糖的质量比为12∶1,硅藻土的含量为1%,引发剂和交联剂的用量分别为2.5%和0.16%,中和度为70%,反应温度为60℃,反应时间为5.5h时,合成的壳聚糖-硅藻土-聚丙烯酸高吸水性树脂吸水(盐)率最高,分别为145g/g和30g/g。     

水溶液聚合小麦淀粉接枝丙烯酸高吸水性树脂的研究

以小麦淀粉与丙烯酸为原料,以N,N′-亚甲基双丙烯酰胺为交联剂,过硫酸铵为引发剂,采用水溶液聚合法合成高吸水性复合树脂。考察了丙烯酸的中和度、淀粉/单体比例、引发剂、交联剂等对聚合反应和树脂性能的影响。通过正交试验优选出物料的最佳配比:丙烯酸的中和度为90%,引发剂用量为0.5%,交联剂用量为0.05%,淀粉含量为10%。制备得到的吸水性复合树脂吸水率达1060g.g-1,性能优于聚丙烯酸钠高吸水性树脂。     

淀粉接枝丙烯酸／丙烯酰胺影响因素的研究

探索了以过硫酸钾为引发剂,以N,N,-亚甲基双丙烯酰胺为交联剂,将淀粉与丙烯酰胺、丙烯酸在水溶液中聚合制备高吸水性树脂。结果表明：当m（丙烯酰胺）：m（丙烯酸）为1：24,单体总用贵为12g,反应温度30％,反应时间2h,丙烯酸中和度94％,引发剂用量0.02g,交联剂用量为0.0015g时,可以合成具有较好的吸水性的高吸水性树脂,在蒸馏水中吸水倍率可达699.99g／g。     

具有高通液性能高吸水性树脂的制备及性能研究

以丙烯酸、功能单体为聚合单体,N,N-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,采用水溶液聚合法合成了一种具有优异通液性能和吸液性能的高吸水性树脂,研究了自制功能单体用量、交联剂用量、引发剂用量、中和度、引发温度对高吸水性树脂吸液能力和通液能力的影响,并使用扫描电镜对高吸水性树脂的颗粒形态进行表征。结果表明,合成最佳条件为：丙烯酸用量为250 g,功能单体用量为25 g,交联剂用量为1.5 g,引发剂用量为0.375 g,氢氧化钠用量为97.2 g,引发温度为55℃。此条件下制备得到的高吸水性树脂具有良好的吸液性能和通液性能,吸盐水倍率为103.25 g/g,通液速度为201.55 mL/min。扫描电镜结果表明高吸水性树脂由于分子链的刚性变强,颗粒表面形状更规则。     

淀粉-丙烯酸-丙烯酰胺高吸水性树脂的紫外光聚合及性能研究

采用紫外光引发聚合的方法制备淀粉-丙烯酸-丙烯酰胺高吸水性树脂,研究了淀粉用量、单体配比、丙烯酸中和度、交联剂、光引发剂等因素对吸水率的影响。当固化时间15min,淀粉用量10%(占丙烯酸用量的质量百分比).光引发剂用量0.4%,交联剂用量0.02%,中和度85%,丙烯陂/丙烯酰胺(摩尔比)10.可制得吸水率为985.1g/g的吸水树脂。     

丙烯酸钠-丙烯酰胺高吸水树脂的合成与性能

以过硫酸钾为引发剂、N,N-亚甲基双丙烯酰胺(NNMBA)为交联剂,采用水溶液聚合法制备聚丙烯酸钠-丙烯酰胺高吸水性树脂,研究了丙烯酸与丙烯酰胺比例、单体浓度、引发剂用量、交联剂用量以及聚合温度对树脂吸水性能的影响。制备的高吸水性树脂吸蒸馏水为593g·g-1,吸自来水为260g·g-1,吸0.9%Na Cl溶液为66.7g·g-1。     

丙烯酸/丙烯酰胺/丙烯腈三元共聚制备耐盐高吸水性树脂的研究

采用过硫酸铵作为引发剂,N,N-二甲基双丙烯酰胺作为交联剂,通过水溶液共聚法制备了丙烯酸、丙烯酰胺、丙烯腈高吸水性共聚物,探讨了合成过程中各种影响因素对高吸水性树脂性能的影响。结果表明,当反应单体配比n(丙烯酸)∶n(丙烯酰胺)∶n(丙烯腈)=15∶4∶6,引发剂用量为单体总质量的0.05%,交联剂用量为单体总质量的0.015%,反应温度为80℃,反应时间为3 h,中和度为75%的条件下,所得高吸水性树脂的吸去离子水能力可达990 g/g以上,吸0.9%氯化钠溶液能力达190 g/g以上。     

环保型木薯淀粉接枝丙烯酸共聚物的合成研究

以N,N'-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,采用水溶液聚合法制备了木薯淀粉接枝丙烯酸高吸水性树脂.考察了淀粉含量、中和度、引发剂用量、交联剂用量等因素对反应的影响.结果表明:在木薯淀粉含量为10%,引发剂用量为0.3%,交联剂用量为0.025%,丙烯酸与氢氧化钠的中和度为85%的条件下,制备得到的吸水性树脂吸水率达1355 g·g-1,其吸水速率快、加压保水能力强、热稳定性好.     

淀粉基高吸水性树脂的制备及吸水性影响因素研究

以玉米淀粉和丙烯酸为原料,N,N-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,采用水溶液聚合法制备淀粉接枝丙烯酸高吸水性树脂,用红外光谱对其结构进行了表征.适宜的工艺条件为:丙烯酸中和度90%,淀粉用量、交联剂用量及引发剂用量分别为丙烯酸质量的50%、0.01%和0.1%,反应温度50℃、反应时间3h时,制备的高吸水性树脂吸蒸馏水倍率为340g/g,常压10℃放置10d后保水率为47%.     

木薯淀粉-硅藻土-丙烯酸复合高吸水树脂的制备

以木薯淀粉、硅藻土、丙烯酸为原料,N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸铵为引发剂,通过水溶液聚合法制备了木薯淀粉-硅藻土-丙烯酸复合高吸水树脂。分别对引发剂用量、交联剂用量、丙烯酸与淀粉的摩尔比、中和度、硅藻土用量进行单位因素实验和正交实验,并通过极差分析对影响材料吸水率的因素做统计分析。最佳的反应工艺条件为:以丙烯酸单体质量为基准,引发剂用量0.55%,交联剂用量0.06%,丙烯酸与淀粉摩尔比10.5,中和度75%,硅藻土用量18%。在此条件下合成的木薯淀粉-硅藻土-丙烯酸高吸水性树脂吸水、吸盐率分别为912 g/g,94 g/g。     

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.     

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.