阳离子化魔芋葡甘聚糖插层蒙脱石的制备与表征

采用季铵化魔芋葡甘聚糖(CMKGM)对钠基蒙脱石(MMT)进行改性制备有机蒙脱石(CMKGM-MMT),并对改性后的蒙脱石进行红外光谱(FT-IR)和X射线衍射(XRD)等分析表征.结果表明,当制备季铵化魔芋葡甘聚糖改性蒙脱石时,反应条件pH值为4.6、反应温度为60 ℃,且CMKGM的用量是MMT的1.0倍阳离子交换容量时(CMKGM和MMT的质量比为0.9),形成的插层型有机蒙脱石的有机化程度最高,并考察了改性蒙脱石的体外细胞毒性及其对牛血清白蛋白(BSA)的载药性能.     

插层改性蒙脱石及其在醇酸树脂中分散性能的研究

为了提高蒙脱石在醇酸树脂中的分散性能，需对蒙脱石进行有机改性来改善其表面的疏水性。为此，本文选用系列季铵盐表面活性剂对蒙脱石进行插层改性，以 X射线衍射分析方法对表面活性剂插层状态进行表征，同时对改性蒙脱石在醇酸树脂中的直接分散性能进行对比研究。结果表明：在本文所用改性工艺条件下，用单链烷基铵盐或双链烷基铵盐改性蒙脱石时，改性剂在蒙脱石层间的存在状态均以倾斜双层排列为主。其中双十八烷基甲基苄基氯化铵（ D1817）改性蒙脱石在醇酸树脂中的增稠、触变性能最佳，其次是十六烷基三甲基氯化铵（ 1631）。对比单长链烷基季铵盐，双长链烷基季铵盐改性有机蒙脱石在醇酸树脂体系中有更好的分散状态。     

改性蒙脱石对海藻酸钠载药凝胶微球的结构及释药性能的影响

以双十二烷基二甲基溴化铵(DDAB)作为改性剂对钠基蒙脱石进行插层改性,并以此改性蒙脱石吸附啶虫脒,然后包覆在海藻酸钠微球中。通过红外光谱、X射线衍射、扫描电子显微镜和释药实验对改性蒙脱石的结构、形貌和载药微球的释药性能进行了表征。结果表明:经DDAB改性后的蒙脱石的层间距由原来的1.21 nm增加到3.64 nm。改性蒙脱石对农药啶虫脒的吸附能力显著增强;且改性蒙脱石的加入使海藻酸钠凝胶微球的内部呈多孔结构,提高了其对药物的缓释性能,在50 h内微球仅释药约16%,其释药过程符合Non-Fickian扩散模型。     

聚酰胺改性用插层蒙脱石制备和性能研究

介绍了聚酰胺改性用插层蒙脱石制备方法、性能和应用。其中将自制的非反应型插层蒙脱石用熔体挤出法制备蒙脱石／尼龙6纳米复合材料,其拉伸强度为84．41MPa、抗弯强度为115．40MPa、热变形温度(0．45MPa)为189℃。     

改性剂及高密度聚乙烯插层和剥离蒙脱石的分子动力学模拟

为研究高密度聚乙烯/有机改性蒙脱石(PE-HD/OMMT)复合材料中改性剂及PE-HD对蒙脱石(MMT)插层和剥离的影响,采用分子动力学方法模拟了OMMT中不同负载量的十八烷基三甲基氯化铵阳离子(OTAC+)在MMT中的排列方式以及对MMT插层的影响.此外,搭建了PE-HD/OMMT复合材料模型,编写MS Perl脚本...     

蒙脱石对胰岛素吸附行为的研究

以胰岛素为模型药物、钠基蒙脱石为载体材料,在一定条件下制备出胰岛素/蒙脱石(INS/MMT)复合物,并通过X射线衍射(XRD)、红外光谱(FT-IR)和热重(TGA)等分析表征手段对该复合物进行表征.结果表明,胰岛素确实插层进入了钠基蒙脱石的片层,但由于分子体积太小,胰岛素对钠基蒙脱石层间距的影响并不显著.     

三丁基正十四烷基氯化膦插层蒙脱石的制备与表征

用三丁基正十四烷基氯化膦(TTPC)对蒙脱石(MMT)进行改性制备有机蒙脱石(TTPC-MMT)。研究了超声波作用下反应时间、反应温度和TTPC用量等对TTPC-MMT吸油值的影响,并用傅立叶变换红外光谱(FTIR)、X射线衍射(XRD)、透射电子显微镜(TEM)和热重(TG)分析等手段对改性蒙脱石进行表征。结果表明,超声波作用能明显缩短处理时间,并提高TTPC-MMT的吸油值,在TTPC与MMT质量比为1∶5,65℃处理1 h条件下,TTPC-MMT的吸油值最高。TTPC的有机链插入到蒙脱石的片层之间,层间距由原土的1.24 nm增加至2.08 nm,形成了插层型有机蒙脱石,其在260℃前的热失重仅为3.7%。     

钙基蒙脱石对聚苯乙烯纳米复合材料阻燃性能的影响

钙基蒙脱石(Ca MMT)是自然界存在的主要蒙脱石形态。分别采用十六烷基三甲基溴化铵(CTAB)和双十二烷基二甲基溴化铵(DDAB)对Ca MMT进行插层改性,制备了有机钙基蒙脱石(Ca OMT)。采用熔融共混法制备了聚苯乙烯(PS)/Ca OMT纳米复合材料。通过X射线衍射法评估了Ca MMT的改性效果;采用热重法和锥型量热法研究了复合材料的热稳定性和燃烧过程中的释放速率、生烟速率以及CO释放速率等阻燃性能。研究表明,CTAB和DDAB均可对Ca MMT有效插层改性,其中,DDAB改性的Ca MMT对PS的阻燃性能提高较大。与纯PS相比,PS/Ca OMT纳米复合材料的相对最大热释放速率可降低42.9%,生烟速率可降低7.5%,CO释放率可降低16%。     

PDM-AM/纳米插层复合蒙脱石和PDM-AM-GL/纳米插层复合蒙脱石性能的对比

以单体转化率、聚合物的特性黏度和复合材料旋转黏度为指标,对聚二烯丙基二甲基氯化铵-丙烯酰胺(polymer diallyldimethylammonium chloride-acryhmide,PDM-AM)/纳米插层复合蒙脱石(montmorillonite,MMT)和聚二烯丙基二甲基氯化铵-丙烯酰胺-乙二醛(glyoxal,GL)(PDM-AM-OL)/纳米插层复合MMT分别进行了研究,并对其进行了Fourier红外光谱(Fourier transform infrared spectrometer,FTIR)分析和X射线衍射(x-raydiffraction,XRD)检测.将PDM-AM/纳米插层复合MMT和PDM-AM-GL/纳米插层复合MMT分别应用于皮革预鞣,再用质量分数为2%的标准铬粉鞣制.FTIR结果表明:单体在蒙脱石的存在下成功聚合,通过离心处理能够将聚合物与蒙脱石成功分离.XRD结果表明:PDM-AM/纳米插层复合MMT和PDM-AM-GL,纳米插层复合MMT中蒙脱石的层间距的变化规律相一致.PDM-AM/纳米插层复合MMT与GL的反应使得蒙脱石的层间距有所增加.应用结果表明:采用PDM-AM/纳米插层复合MMT预鞣不利于2%铬粉鞣制;然而当引入醛基之后,采用PDM-AM-GL/纳米插层复合MMT预鞣后,坯革的耐湿热稳定性、填充性均优于单独采用2%铬粉鞣制的坯革.     

木质纤维素基吸油树脂插层有机蒙脱石吸油性能

采用悬浮接枝聚合法合成了木质纤维素–g–甲基丙烯酸丁酯插层有机蒙脱石(LNC–g–BMA/OMMT)吸油性树脂,对汽油的吸油率可达9 873.1 mg/g。采用Fourier红外光谱、X射线衍射、扫描电子显微镜和孔隙比表面积分析仪等对吸油性树脂的形貌和结构进行表征,分析了有机蒙脱石、引发剂、交联剂、分散剂用量以及水油比对树脂吸油性能的影响。结果表明,LNC―g―BMA/OMMT吸油性树脂表面疏松,有利于汽油分子在树脂内扩散;蒙脱石经有机化改性后层间距扩大,聚合物插入到有机蒙脱石片层中,通过破坏有机蒙脱石的片层结构使有机蒙脱石基本单元均匀分散于聚合物基体中。     

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。