改性胶清橡胶及其复合材料的性能研究

采用有机改性钠基蒙脱土对胶清橡胶进行复合改性,制备改性胶清橡胶,并与杂胶、喇叭口胶、泡沫胶和废水胶复合,研究改性胶清橡胶及其复合材料的各项性能.结果表明,改性胶清橡胶塑性初值(P0)和塑性保持率(PRI值)与胶清橡胶相比大幅度提高,物理性能和热性能也明显改善;改性胶清橡胶/杂胶等复合材料的物理性能与杂胶等相比显著提高,P0和PRI值也有不同程度的增大.     

两种补强填料对氟醚橡胶性能的影响

设计补强填料（炭黑N990/硫酸钡）用量和并用比不同的9个试验配方,研究炭黑N990/硫酸钡用量和并用比对氟醚橡胶胶料硫化特性、耐低温性能、物理性能、耐热空气老化性能、耐介质性能和压缩永久变形的影响。结果表明：炭黑N990/硫酸钡用量和并用比对氟醚橡胶硫化胶性能影响较大;随着炭黑N990/硫酸钡用量的增大,氟醚橡胶硫化胶的力学性能更好;氟醚橡胶硫化胶的耐低温性能主要由橡胶的分子结构决定,同时含胶率越高,硫化胶的耐低温性能越好;氟醚橡胶硫化胶的耐介质性能与其交联程度有关,当炭黑N990/硫酸钡用量增大时,橡胶与其形成的交联网络更加密集,硫化胶的耐介质性能提高。     

杜仲橡胶硫化胶交联密度与结晶性能关系研究

采用差示扫描量热(DSC)法分析杜仲橡胶硫化胶交联密度对其物理性能和结晶性能的影响。结果表明:随着硫黄用量的增大,杜仲橡胶硫化胶的交联密度增大,邵尔A型硬度减小,100%定伸应力、拉伸强度和拉断伸长率先增大后减小;消除热历史后杜仲橡胶生胶的结晶特征减弱;随着交联密度的增大,硫化胶的DSC特征熔融峰减弱直至消失,结晶峰钝化,峰面积减小。     

聚酯/聚醚混合型增塑剂对乙烯丙烯酸酯橡胶性能的影响

研究不同牌号乙烯丙烯酸酯橡胶(AEM)及聚酯/聚醚混合型增塑剂种类和用量对硫化胶性能的影响。结果表明:AEM Vamac G硫化胶的耐低温性能较好,而AEM Vamac GLS硫化胶的物理性能、耐老化性能和耐油性能较好,选择并用比为50/50的AEM Vamac G/AEM Vamac GLS并用胶作为主体材料,硫化胶的物理性能、耐油性能和耐低温性能可更好地平衡;添加增塑剂TP-759的硫化胶的耐低温性能较好,添加增塑剂RS-735的硫化胶的耐热老化性能较好,两者耐油性能相当;随着增塑剂用量的增大,硫化胶的耐低温性能提高,拉伸强度降低,拉断伸长率和压缩永久变形增大,油浸泡后体积变化率减小。     

热氧老化对氯丁橡胶化学结构及性能的影响

对氯丁橡胶（CR）硫化胶进行热氧老化试验,研究100 ℃下老化时间对CR硫化胶化学结构、交联密度、溶胶质量分数和相对分子质量分布、氯质量分数、拉伸性能的影响。结果表明,在热氧老化过程中,CR硫化胶的橡胶分子链发生氧化反应,化学结构发生明显变化。在老化初期,CR硫化胶的交联密度增大,溶胶质量分数和相对分子质量减小,橡胶分子链以交联为主;老化时间超过192 h后,CR硫化胶的交联密度减小,溶胶质量分数、相对分子质量及其分布指数增大,橡胶分子链氧化断裂增多;在老化过程中,交联及脱氯使CR硫化胶结构化越来越严重,导致CR硫化胶的拉伸性能明显降低。     

金属离子钝化剂添加工艺对胶清橡胶性能的影响

通过3种添加工艺将乙二胺四乙酸二钠(EDTA-2Na)、柠檬酸钠(Na CA)和三聚磷酸钠(STPP)3种金属离子钝化剂加入胶清橡胶,研究金属离子钝化剂对胶清橡胶硫化特性、物理性能和热氧老化性能的影响。结果表明:加入金属离子钝化剂对胶清橡胶硫化特性和物理性能影响较小,但能明显提高胶清橡胶的热氧老化性能;Na CA和EDTA-2Na在凝固前加入胶清对提高胶清橡胶热氧老化性能和热稳定性效果更好,STPP则在混炼过程中添加效果更好。     

环保橡胶增塑剂HJA0810在工业橡胶板胶料中的应用

研究高芳烃含量的环烷基环保橡胶增塑剂HJA0810(以下简称增塑剂HJA0810)在工业橡胶板胶料中的应用,并与现用机油进行对比。结果表明:与添加机油的胶料相比,添加增塑剂HJA0810的胶料混炼工艺性能和硫化特性相当,硫化胶的物理性能和耐热老化性能提高;随着增塑剂HJA0810用量增大,硫化胶的物理性能和耐热老化性能提高,耐压缩疲劳性能先提高后降低;增塑剂HJA0810可等量或适当增量替代机油应用于工业橡胶板胶料中,改善工业橡胶板胶料的环保性能。     

抗硫化返原剂WK-901在橡胶隔震支座胶料中的应用

研究抗硫化返原剂WK-901用量对橡胶隔震支座胶料及成品性能的影响。结果表明:抗硫化返原剂WK-901对胶料的t_(10)和t_(90)基本无影响,但对硫化平坦性有显著影响;抗硫化返原剂WK-901对胶料老化前的物理性能有一定影响,对老化后的物理性能有显著影响;随着抗硫化返原剂WK-901用量的增大,成品橡胶隔震支座内层胶的拉伸强度增大,拉断伸长率降低,支座的屈服后刚度和等效水平刚度均增大。     

氢氧化镁对氯化聚乙烯橡胶性能的影响

研究单独使用氢氧化镁及氢氧化镁／氯化石蜡／三氧化二锑并用阻燃体系对氯化聚乙烯橡胶（CM）性能的影响。结果表明，单独使用氢氧化镁，随着氢氧化镁用量的增大，CM硫化胶氧指数增大，但氢氧化镁用量过大，CM硫化胶物理性能明显下降；与单独使用氢氧化镁相比，达到相同的阻燃效果时，采用氢氧化镁／氯化石蜡／三氧化二锑并用阻燃体系的CM硫化胶物理性能较好；采用配方优化设计系统确定氢氧化镁，氯化石蜡和三氧化二锑的用量分别为66．3，4．7和11．8份时，CM硫化胶的阻燃性能和物理性能较好。     

乙烯-乙酸乙烯酯橡胶基吸油膨胀橡胶的制备与性能

采用低乙酸乙烯酯质量分数的乙烯-乙酸乙烯酯橡胶(EVM)制备吸油橡胶,考察硫化剂DCP用量、补强填料种类及用量对其吸油膨胀性能和物理性能的影响,并对其耐老化性能、饱和吸油后稳定性能和保油率进行研究。结果表明:当硫化剂DCP用量为1.5份时,EVM硫化胶的物理性能和吸油膨胀性能较好;与白炭黑填充的硫化胶相比,炭黑填充EVM硫化胶的吸油膨胀性能较优;EVM吸油膨胀材料在酸、碱、盐环境中具有优异的耐老化性能和稳定性能,且保油率高。     

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.     

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。     

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.     

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.     

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.