硅酮胶密封的中空玻璃

中空玻璃的边缘密封系统的主要功能是将两片或多片玻璃结构性黏结起来防止水汽进入.通过双重边缘密封系统可以取得最好的密封效果,在该系统中,第一道密封是由聚异丁烯基密封胶提供水汽密封,第二道弹性密封则确保中空玻璃在相应荷载下的结构整体性.硅酮双重密封的中空玻璃比有机胶密封的中空玻璃具有较低的水汽渗透率,因为边缘密封的渗透性几乎完全由第一道密封(PIB)的渗透性决定,并且因为硅酮第二道密封在阻止水汽扩散进入第一道密封方面比有机胶表现得更好.     

硅酮第二道密封的中空玻璃耐久性

中空玻璃的边缘密封系统的主要功能是防止水汽进人中空玻璃内腔和减少腔内冲填气体的扩散,并提供其结构性强度。在双道密封系统中,第一道密封聚异丁烯基密封胶（PIB）提供水汽密封,第二道弹性密封则确保中空玻璃在相应荷载下的结构整体性。硅酮第二道密封的中空玻璃比有机胶二道密封的中空玻璃具有较低的水汽渗透率,是因为边缘密封的渗透性几乎由第一道密封（PIB）的渗透性决定,而且作为第二道密封的硅酮在黏弹性,特别是在实际使用条件下的抗拉强度和弹性恢复率方面要优于有机胶,因此其阻止水汽扩散进入第一道密封方面比有机胶表现得更好。边缘密封的抗气体扩散同时取决于第一道和第二道密封的渗透性。硅酮作为第二道密封的中空玻璃在实际的服务条件下测试也证实具有较高的耐久性和服务年限,是因为硅酮第二道密封的物理和黏接性能几乎不受主要的环境老化因素,也就是紫外线,热量和湿度的影响。     

中空玻璃检验中常见不合格项目及其影响

中空玻璃是由弹性密封胶、丁基胶、干燥剂、间隔条和不同种类的原片玻璃等多种材料复合在一起的系统,其生产流程复杂,生产过程中需要注意的关键节点多.从GB/T11944-2012《中空玻璃》的要求出发,分析标准中对所用原材料、尺寸偏差、外观质量、露点、水气密封耐久性、充气中空玻璃气体含量的要求,对中空玻璃常见不合格项目如胶层宽度不符合要求、内道密封胶不均匀连续、密封胶流淌、间隔条内干燥剂粉尘量不合格、露点、水气密封耐久性出现的原因进行分析,探讨不合格项目对中空玻璃的影响.     

非金属暖边系统在中空玻璃行业的应用和发展

改善中空玻璃隔热和隔声性能的主要途径是采用低辐射镀膜玻璃,填充惰性气体来替换中空玻璃单元内的空气,再就是选择热导率更低的间隔条材料,也就是采用暖边系统来降低边部热损失并提高气密性而最大化的吸声降噪。因为非金属暖边密封体系在隔热效果和使用寿命方面均比含金属暖边效果优异。本文对非金属暖边系统,尤其是Koedispace热塑性间隔条密封体系和Koedispace 4SG反应型热塑性暖边系统进行了系统的介绍与论述。     

中分子量聚异丁烯市场广阔

随着塑钢窗的推广应用,中空玻璃已深入到普通民居,国内市场应用前景广阔。聚异丁烯用于中空玻璃密封胶方面可以增加产品的柔韧性和渗透性,目前市场上中空玻璃的密封结构分为单道密封和双道密封。单道密封指中空玻璃利用舒适胶条密封;双道密封指中空玻璃打两道胶,中分子量聚异丁烯胶作第一道密封胶,强度好的聚硫胶或硅酮胶作第二道密封胶。无论在哪一种结构中,中分子量聚异丁烯由于其可靠的耐水性和优异的密封性能都扮演了重要的角色。通常,密封胶条中聚异丁烯含量约为20％,双道密封结构中第一道密封胶中的含量甚至可达40％以上。     

插层剂对尼龙6/蒙脱土纳米复合材料性能的影响

用3种不同的插层剂有机化蒙脱土,并分别与尼龙6熔融共混制得了尼龙6/蒙脱土纳米复合材料,对热变形温度(HDT)和力学性能进行了研究。结果表明:与纯尼龙6相比,3种复合材料的HDT、拉伸模量、弯曲模量、弯曲强度有明显提高,屈服强度也有所提高,而冲击强度和断裂伸长率则有所下降;其中,含羟基的插层剂对复合材料的综合改性效果最好。     

我国中空玻璃用丁基热熔密封胶发展概况及存在问题

介绍了中空玻璃丁基热熔密封胶的发展历程,以及被用作中空玻璃边部密封的原因和技术要求.指出国内中空玻璃用丁基热熔密封胶存在的问题及解决方案.     

插层剂对PA66/蒙脱土纳米复合材料性能影响

将不同插层剂改性的蒙脱土与尼龙66(PA66)通过熔融共混制得了纳米复合材料,对复合材料的热变形温度和力学性能进行了研究。结果表明,与纯PA66相比,3种插层剂改性的蒙脱土／PA66纳米复合材料的热变形温度、弯曲模量、弯曲强度均有明显提高,拉伸模量和屈服强度也有所提高,但断裂伸长率和缺口冲击强度则明显下降;含极性羟基的插层剂对复合材料的综合改性效果较好,含2个长链非极性烃基的插层剂改性效果较差;加入环氧树脂后,复合材料的热变形温度、拉伸模量和弯曲模量有所降低,屈服强度、弯曲强度、断裂伸长率和缺口冲击强度则有所增加。     

一种新型红磷阻燃母料阻燃玻纤增强尼龙的研究

采用一种新型红磷阻燃母料(RPM3025)作为阻燃剂,玻璃纤维作为增强材料,制备了阻燃增强尼龙材料.研究了这种新型红磷阻燃母料和已经商品化的中低端红磷阻燃母料所制备的阻燃增强尼龙在物理性能、力学性能、阻燃性和热性能等方面的差别.结果表明:RPM3025制备的阻燃增强尼龙密度较轻、流动性较好、热变形温度和热稳定性较高,阻燃性达到了UL94 V-0级(1.6 mm).尽管其拉伸强度、弯曲强度和弯曲模量略有降低,但冲击强度从11.4 kJ/m2大大提高到16.6 kJ/m2.而RPM3025制备的阻燃增强尼龙66的拉伸强度、弯曲强度和弯曲模量下降较大,并且热变形温度和热稳定也明显降低.     

尼龙6-聚乙烯合金/蒙脱土纳米复合材料的制备与物理机械性能

用熔融插层法制备了尼龙6-聚乙烯合金/蒙脱土纳米复合材料.X射线衍射表明,在有机蒙脱土质量分数为4%,6%时,蒙脱土被剥离成片层分散在基体中;进一步提高蒙脱土质量分数至10%,蒙脱土部分剥离,部分插层.物理机械性能测试结果表明,将有机蒙脱土加入尼龙6-聚乙烯合金中能显著提高复合材料的拉伸强度、弯曲强度、冲击强度.其中冲击强度最大可以提高100%以上.     

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。