PTT/MMT纳米复合材料的制备及性能的研究

采用熔融共混的方法制备了聚对苯二甲酸丙二醇蘸/蒙脱土(PTT/MMT)纳米复合材料,并用红外光谱表征了PTT/MMT纳米复合材料的结构.通过DSC、热台偏光显微镜等研究了PTT/MMT纳米复合材料的结晶行为,测定了纳米复合材料的力学性能.结果表明,随着PTT/MMT纳米复合材料中蒙脱土含量的增加,PTT/MMT纳米复合材料的熔融结晶温度增高.其结晶过程为异相成核,纳米复合材料的力学性能有一定的提高.     

原位聚合PE/MMT纳米复合材料的流变行为研究

采用蒙脱土(MMT)负载的Ziegler-Natta催化剂,通过原位聚合法制备了不同MMT含量的聚乙烯(PE)/MMT纳米复合材料。利用热重分析(TGA)确定了PE/MMT纳米复合材料中MMT的含量,并使用Haake流变仪分析了MMT含量对PE/MMT纳米复合材料流变行为的影响。结果表明:PE/MMT纳米复合材料的熔体流变行为与高密度聚乙烯(HDPE)和低密度聚乙烯(LDPE)基本一致;复合材料的黏度随MMT含量的增加先升高后降低,其中当MMT含量为4.58%时,其黏度明显低于HDPE和LDPE,该性质有利于复合材料的成型加工;PE/MMT纳米复合材料属于假塑性流体,其非牛顿指数(n)随着温度的升高而增大,随着MMT含量的增加先降后升。     

PTT/MMT纳米复合材料的研究

采用熔融共混的方法制备了聚对苯二甲酸丙二醇酯/有机蒙脱土（PTT/MMT）纳米复合材料,通过DSC、热台偏光显微镜等研究了PTT/MMT纳米复合材料的结晶行为,测定了纳米复合材料的力学性能,并用熔体流变仪研究了PTT/MMT纳米复合材料熔体流变性能。结果表明：随着PTT/MMT纳米复合材料中蒙脱上含量的增加,PTT/MMT纳米复合材料的熔融结晶温度增高,纳米复合材料的力学性能有一定的提高;PTT-蒙脱土纳米复合材料熔体的流变性能随MMT含量的增加非牛顿性减弱,熔体的粘流活化能减小。     

PEN／MMT纳米复合材料结晶动力学的研究

采用熔融插层法制备聚2,6-萘二甲酸乙二酯(PEN)/蒙脱土(MMT) 纳米复合材料,用Avrami方程和张志英方法对所得数据进行了等温结晶和非等温结晶动力学的研究.结果表明,在PEN/MMT共混物中由于MMT的加入,降低了PEN/MMT的结晶活化能,导致共混物的结晶速率提高;MMT含量影响共混物的结晶速度,加入少量的MMT可以明显提高共混物的结晶速率;共混物的表面活化能的变化与Avrami方程得出的n值变化相似,MMT的含量影响共混物成核结晶速度.     

PTT/蒙脱土复合材料非等温结晶行为的研究

采用差示扫描量热仪对熔融共混制备的聚对苯二甲酸丙二醇酯(PTT)/蒙脱土(MMT)复合材料非等温结晶行为进行了测试分析。研究结果表明:在相同的降温速率时,随着MMT含量的增加,PTT/MMT复合材料的结晶峰温向高温方向移动,结晶峰变窄,半结晶期也缩短;随着降温速率的增大,PTT/MMT复合材料的结晶峰温向低温方向移动,半结晶期变短。采用Ozawa法处理了PTT/MMT复合材料的非等温结晶过程,结果表明:MMT的加入改变了PTT的成核机理,加快了PTT的结晶速率。     

聚甲基丙烯酸/蒙脱土纳米复合材料的制备及性能

用甲基丙烯酸(methacrylic acid,MAA)在钠基蒙脱土(montmorillonite,MMT)层间直接原位插层聚合制备了聚甲基丙烯酸/蒙脱土(polymethacrylic acid/montmorillonite,PMAA/MMT)纳米复合材料.以蒙脱土的层间距、插层进入蒙脱土层间的聚合物含量及应用于皮革鞣制的实验结果为考察指标,对制备过程中的引发剂用量及蒙脱土用量进行了单因素实验研究.结果表明:所制备的PMAA/MMT纳米复合材料属于剥离型纳米复合材料,应用于皮革鞣制所得坯革的增厚率及湿热稳定性均有较大提高.     

聚乙烯-乙烯醇/蒙脱土纳米复合材料结晶行为研究

以十六烷基季铵盐有机化蒙脱土(MMT)为无机相,以乙烯-乙烯醇共聚物为基体,通过熔融插层法制备了聚乙烯-乙烯醇/有机蒙脱土(EVOH/MMT)纳米复合材料,利用示差扫描量热仪(DSC)研究了EVOH/MMT复合材料的结晶行为.结果表明:MMT与EVOH插层后使EVOH/有机蒙脱土纳米复合材料的熔点和熔融热降低.经季铵盐处理过的蒙脱土片层在EVOH/有机蒙脱土纳米复合材料结晶过程中的异相成核作用不明显.在相同结晶条件下,EVOH/MMT纳米复合材料的结晶速率比EVOH慢.MMT的加入使EVOH/MMT纳米复合材料的熔融温度(Tm)从EVOH的180.7℃降低到175.2℃,结晶温度(Tc)从EVOH的157.9℃降低到153.1℃,而玻璃化转变温度(Tg)却较EVOH升高了大约2.6℃.     

PET/PTT/MMT复合材料的制备及其非等温结晶行为

采用双螺杆挤出机制备了聚对苯二甲酸乙二醇酯/聚对苯二甲酸丙二醇酯(PET/PTT)合金以及该聚酯合金基蒙脱土(MMT)复合材料。采用扫描电镜(SEM)观察了聚酯合金以及聚酯合金基蒙脱土复合材料的结构,通过差示扫描量热仪(DSC)对其非等温结晶行为进行了研究。结果表明:PET/PTT/MMT复合材料结构比聚酯合金致密,并且MMT的分散比较均匀;相同的降温速率下,随着蒙脱土含量的增加,PET/PTT/MMT复合材料的结晶温度向高温方向移动。随着降温速率增大,聚酯合金与聚酯合金基复合材料的结晶峰温度都向低温方向移动。     

原位聚合制备聚丁烯-1/蒙脱土纳米复合材料及其性能

通过使用一种新型Ziegler-Natta催化剂/蒙脱土(MMT)复合型催化剂与丁烯-1进行原位聚合制备了剥离型聚丁烯-1(PB-1)/MMT纳米复合材料。通过广角X射线衍射(WAXD)和透射电子显微镜(TEM)对纳米复合物验证结构,通过热重分析(TGA)和差示扫描量热(DSC)对复合材料进行性能表征。结果显示,蒙脱土片层在聚丁烯-1基体中以纳米尺寸均匀分散,呈现剥离状态。随着蒙脱土含量增加,复合材料热分解温度升高,结晶度也升高。随着外给电子体含量增大,全同聚合物的含量增大。     

聚丙烯/共聚酯/蒙脱土复合材料结晶行为的研究

采用热台偏光显微镜研究了聚丙烯(PP)/共聚酯(COPET)以及PP/COPET/蒙脱土(MMT)复合材料等温结晶时的结晶形态,结果表明:两样品均呈现清晰的球晶所特有的黑十字消光图像,PP/COPET/MMT复合材料的球晶尺寸比PP/COPET样品的球晶尺寸大大减小。采用差示扫描量热法对PP/COPET以及PP/COPET/MMT复合材料的非等温结晶行为进行了研究,结果表明:随着MMT含量的增加,复合材料样品的结晶初始温度和结晶峰温基本呈现逐渐降低趋势,结晶放热焓随MMT含量增加先增加后减小;在不同的降温速率下结晶,两种样品结晶峰温均随降温速率的增大而降低,结晶放热焓也随着结晶速率的增大而降低。采用Jeniorny法处理了PP/COPET和PP/COPET/MMT样品的非等温结晶过程,得出了两体系的结晶速率总体上随着冷却速率的增加而加快,为多维结晶生长体系。     

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。