聚乙烯醇改性水性硝化纤维乳液的性能

以1,5-二氨基-3-戊磺酸钠、硝化纤维和异佛尔酮二异氰酸酯为主要原料制得了自乳化磺酸盐型水性硝化纤维乳液(SWNC),再与聚乙烯醇(PVA)进行物理共混制备出PVA/SWNC复合乳液。通过乳液稳定性测试、粒子分布测量以及膜的水接触角、吸水率和力学性能测试,考察了PVA用量对复合乳液及其胶膜性能的影响。发现当PVA含量为5%时,PVA/SWNC乳液具有良好的室温贮存稳定性,胶膜拉伸强度为10.4 MPa,断裂伸长率为359.4%。采用扫描电子显微镜、傅里叶变换红外光谱仪、透射电子显微镜和热重分析仪比较研究了最优含量下所制复合乳液与SWNC乳液。与SWNC乳液相比,PVA/SWNC复合乳液的粒径有所减小,其胶膜的热稳定性和力学性能均有所提高。     

水性聚氨酯/聚乙烯醇复合材料的制备与性能

将水性聚氨酯（WBPU）乳液与聚乙烯醇（PVA）溶液共混制备了WBPU/PVA复合材料。通过FTIR、透光率、AFM、拉伸测试、吸水率、TG等表征方法研究了材料的相容性以及PVA含量对复合材料的力学性能、耐水性和热性能的影响。实验结果表明,WBPU与PVA间存在分子间氢键作用;当PVA含量为80%时,两组分具有相对较高的相容性,且此时复合材料具有最大的拉伸强度61.9 MPa,相对于WBPU（24.9 MPa）和PVA（44.7 MPa）分别提高了149%和38%;随着PVA含量的增加,复合材料的断裂伸长率和耐水性呈现降低的趋势。     

Na-MMT/醋丙复合乳液的制备及其性能研究

在剥离态钠基蒙脱土悬(Na-MMT)浮液中,通过原位乳液聚合法制备Na-MMT/醋丙(PVA)复合乳液,研究了Na-MMT含量对复合乳液聚合稳定性和存稳定性的影响,通过吸水率和紫外光老化等方法分别表征Na-MMT/PVA复合乳液的抗水性和抗老化性能,并通过透射电镜观察复合乳胶粒的形貌。实验结果表明:Na-MMT含量在2.0%以内有利于制备得到稳定性良好的复合乳液,复合乳液乳胶粒粒径和复合乳液涂膜吸水率均先减小后增大;复合乳液呈现层状与球状结合的复合结构,Na-MMT/PVA复合乳液涂层具有更好的耐水性和抗紫外老化性能。     

环氧氯丙烷改性水性硝化纤维乳液的制备及性能

以硝化纤维(NC)、异佛尔酮二异氰酸酯(IPDI)和二羟甲基丙酸(DMPA)等为主要原料,制得自乳化型WNC(水性硝化纤维)乳液;然后以环氧氯丙烷(ECH)为交联改性剂,制成改性WNC乳液胶粘剂。研究结果表明:当w(DMPA)=3.5%、w(ECH)=7%时,改性WNC乳液具有优良的储存稳定性,其胶膜耐水性(吸水率为9.1%)、T型剥离强度(7.1 N/mm)、拉伸强度(14.9 MPa)和断裂伸长率(529.3%)俱佳,柔韧性和耐热性优异。     

大豆蛋白/聚乙烯醇共混材料的制备及性能的研究

在丙三醇增塑下,将大豆分离蛋白(SPI)与聚乙烯醇(PVA)通过溶液法共混,经模压成型制备SPI/PVA共混材料,采用差示扫描量热仪、热失重分析仪、扫描电子显微镜等研究了其性能。结果表明,当PVA含量较低时,SPI/PVA是具有较好相容性能的共混聚合物。随着PVA含量的增加,SPI/PVA共混物在130℃附近出现第2个Tg,且逐渐向高温方向移动,PVA的共混大大增加了SPI的热稳定性能;当PVA含量为30份(质量份,下同)时,其拉伸强度比纯SPI提高了237%;加入PVA对SPI/PVA共混材料的吸水性也有明显改善,其24h吸水率从85.5%下降到54%。     

高粘度苯丙乳液的制备与性能研究

采用一步乳液聚合法制备出一种具有高粘度的苯丙乳液,通过傅里叶红外光谱(FTIR)研究高粘度苯丙乳液的微观结构,探讨了聚乙烯醇(PVA)含量对聚合物乳液粘度、固含量、吸水率、力学性能等物理性能的影响。结果表明,实验成功合成了固含量稳定的高粘度苯丙乳液;当PVA含量为2.2%时,乳液粘度达到3 346.5 m Pa·s,增幅为288.32%;断裂伸长率高达2 478%,增幅为251.21%。与纯苯丙乳液相比,所制备的高粘度苯丙乳液综合性能得到明显提高。     

高粘度苯丙乳液的制备与性能研究

采用一步乳液聚合法制备出一种具有高粘度的苯丙乳液,通过傅里叶红外光谱(FTIR)研究高粘度苯丙乳液的微观结构,探讨了聚乙烯醇(PVA)含量对聚合物乳液粘度、固含量、吸水率、力学性能等物理性能的影响。结果表明,实验成功合成了固含量稳定的高粘度苯丙乳液;当PVA含量为2.2%时,乳液粘度达到3 346.5 m Pa·s,增幅为288.32%;断裂伸长率高达2 478%,增幅为251.21%。与纯苯丙乳液相比,所制备的高粘度苯丙乳液综合性能得到明显提高。     

PVA/石榴皮粉复合薄膜的制备及性能研究

以聚乙烯醇(PVA)为基材、石榴皮粉为填充材料,采用溶液共混的方法制备了不同石榴皮粉含量的PVA/石榴皮粉复合薄膜。通过扫描电子显微镜(SEM)、红外光谱、紫外可见光谱、力学性能测试、水蒸气透过率测试、热重差热分析等手段考察了石榴皮粉含量对PVA复合薄膜性能的影响。结果表明:石榴皮粉与PVA相容性良好,与纯PVA薄膜相比,PVA/石榴皮粉复合薄膜的热稳定性显著增强,并表现出优异的紫外光阻隔性能,同时,随着石榴皮粉含量的增加,复合薄膜的水蒸气透过率提高,脆性增大。     

有机硅改性水性硝化纤维乳液的研究

以甲基硅油对水性硝化纤维(WNC)进行改性,制备了改性水性硝化纤维乳液。通过傅里叶变换红外光谱(FT-IR)、粒径分析和热重分析(TGA)等测试手段,研究了IPDI三聚体(TriIPDI)、甲基硅油的含量对WNC乳液及其涂膜性能的影响。结果表明:当n(Tri-IPDI)∶n(NC)为0.50左右,w(甲基硅油)=7%时,乳液贮存稳定性良好,涂膜的耐水性、表面疏水性和热稳定性较未改性乳液涂膜都得到提高。     

含氟丙烯酸酯改性水性硝化纤维乳液的制备及其性能

以硝化纤维(NC)、异佛尔酮二异氰酸酯(IPDI)、丙烯酸(AA)、丙烯酸羟乙酯(HEMA)、全氟辛基乙基丙烯酸酯(FA)、三乙胺(TEA)为主要原料,采用自乳化法制备含氟丙烯酸酯改性水性硝化纤维乳液(WNC)。通过傅里叶变换红外光谱(FTIR)、透射电子显微镜(TEM)、纳米粒度仪、动态流变仪以及视频光学接触角测定仪对所制乳液及薄膜进行了结构和性能表征,并考察了单体聚合温度、n(AA)∶n(HEMA)、含氟丙烯酸酯质量分数(占反应物AA、HEMA、NC、IPDI总质量的百分数)对乳液及其薄膜性能的影响。结果表明,所得WNC乳液性能稳定,乳液胶粒呈球形,具有核-壳结构。当单体聚合温度为60℃,n(AA)∶n(HEMA)=3∶1,含氟丙烯酸酯用量为1.0%时,所得乳液粒径较小且分布窄,平均粒径和分散系数分别是54 nm和0.023;改性后的乳液薄膜吸水率降低至2.0%,薄膜接触角增加至120°,相比较未改性的WNC乳液,改性后的WNC乳液薄膜具有优异的耐水性。     

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.     

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。     

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。