锡偶联S-SBR/BR并用胶性能的研究

研究了国产锡偶联Ｓ－ＳＢＲ／ＢＲ并用胶料的加工性能、物理性能及动态生热特性。研究结果表明,锡偶联Ｓ－ＳＢＲ加入适量均匀剂后门尼粘度可与ＢＲ相近;随ＢＲ并用量的增大,共混胶料的耐屈挠以及耐磨性能都有所提高,生热略有降低,强力性能下降;锡偶联Ｓ－ＳＢＲ／ＢＲ并用比为６０／４０,填充体系选用炭黑Ｎ２３４时,硫化胶综合性能达到最佳。     

锡偶联SSBR流变性能的研究

以丁二烯，苯乙烯为单体，改性萘锂为引发剂，ＳｎＣｌ４为偶联剂，采用负离子聚合，制备了锡偶联型溶聚丁苯橡胶（ＳＳＢＲ）。结果表明，随偶联度和结合苯乙烯含量增加，ＳＳＢＲ的流动性变化，偶联度对ＳＳＢＲ混炼胶流动性的影响明显低于生胶，其值以２．０为宜，与乳聚丁苯橡胶（ＥＳＢＲ）相比，ＳＳＢＲ具有流动性好，挤出膨胀比小，挤出物外观优异等特点，但ＳＳＢＲ对温度的敏感性较强，生胶的辊筒加工性略逊于ＥＳＢＲ。     

白炭黑和炭黑在轮胎胎面胶配方中的比较

首先，我们通过比较ＳＢＲ炭黑和ＳＢＲ白炭黑硫化胶的各种物理性能，研究了ＳＢＲ炭黑硫化胶的滚动阻力［ｔｇδ（５０℃，１５Ｈｚ）］和耐湿滑性［ｔｇδ（０℃，１５Ｈｚ）］的实验室指标是否也适用于ＳＢＲ白炭黑硫化胶。ＳＢＲ白炭黑硫化胶的移动因子（ｌｏｇａＴ）、ｔｇδ值（０℃，１５Ｈｚ）以及摩擦系数μ值对温度的依赖关系几乎与ＳＢＲ炭黑硫化胶的相同。因此，我们决定将这些指标用作ＳＢＲ白炭黑硫化胶性能实验室试验的量度。接着，我们研究了ＳＢＲ的微观结构及其改性方法对ＳＢＲ白炭黑硫化胶的这些指标和蓝朋（Ｌａｍｂｏｕｒｎ）磨耗性能的影响。苯乙烯含量及玻璃化温度（Ｔｇ）对ｔｇδ（５０℃，１５Ｈｚ）和蓝朋磨耗性能有影响。分批聚合溶液丁苯橡胶（Ｓ－ＳＢＲ）的ｔｇδ（５０℃，１５Ｈｚ）比乳液丁苯橡胶（Ｅ－ＳＢＲ）和连续聚合Ｓ－ＳＢＲ低。Ｔｇ对０℃，１５Ｈｚ时的ｔｇδ具有显著影响。在ＳＢＲ白炭黑硫化胶中未观察到改性方法对物理性能的影响。这是ＳＢＲ白炭黑硫化胶和ＳＢＲ炭黑硫化胶的主要差别。通过Ｓ（动态应变振幅），Ｇ′（动态贮存模量）和ｔｇδ（１５０℃）可以解释ＳＢＲ白炭黑硫化胶的滚动阻力为何较低。     

导电炭黑在NBR中的应用研究

对导电炭黑（ＣＳＦ）作为ＮＢＲ的填料时，其填充量、硫化时间和增塑剂用量等因素对ＮＢＲ／ＣＳＦ混炼胶加工性能和硫化特性及硫化胶物理性能和电性能的影响进行了研究，并与乙炔炭黑（ＡＣＥＴ）进行了对比。结果表明，随着ＣＳＦ用量的增大，混炼胶的炭黑结合ＮＢＲ量、门尼粘度［ＭＬ（１＋４）１００℃］、屈服强度和拉伸强度均增大，扯断伸长率和挤出膨胀率降低，挤出物外观变优，焦烧时间和正硫化时间延长，硫化速度放慢，硫化胶的物理性能有所降低，导电性能提高；硫化胶体积电阻率随硫化时间延长和施加负荷的增大而降低，随温度升高和增塑剂ＤＯＰ用量增大而升高。ＮＢＲ／ＣＳＦ混炼胶的结合橡胶量、门尼粘度和混炼胶应力应变性能及硫化胶导电性能等均高于ＮＢＲ／ＡＣＥＴ混炼胶。     

胶料介电特性的全填充短路波导测试和分析

采用微波测试法中的全填充短路波导测试法测试炭黑胶料硫化过程中介电特性———介电常数εｒ和介电损耗因子ｔａｎδ的变化。测试分析结果表明,随着胶料交联密度增大,εｒ增大;炭黑粒径越小、比表面积越大、结构越高,胶料的ｔａｎδ越大;同一硫化条件下,ＮＲ、ＢＲ、ＳＢＲ、充油顺丁橡胶和充油丁苯橡胶胶料的εｒ顺次减小。     

改性溶聚丁苯橡胶在轮胎中的应用

研究了聚合物链端改性对降低炭黑填充硫化胶滞后损失的影响。测试了用几种不同方法改性的ＳＢＲ硫化胶的物理性能。从这些结果中看出，用锡化合物或异氰酸酯改性的ＳＢＲ，在５０℃下的ｔｇδ值较小，表明它们的滞后损失小。此外，这两种体系还表现出良好的Ｐａｙｎｅ效应、耐磨性和加工性能。     

用正交旋转设计法探讨绿色轮胎胎面胶配方设计

用三元二次通用正交旋转设计法研究了变量偶联型Ｓ－ＳＢＲ／ＢＲ,促进剂ＤＭ／Ｄ、炭黑／白炭黑与硫化胶物理性能的关系,得到一系列变量与性能的等高图,揭示了诸因素之间的内在规律。研究表明,增大白炭黑用量及偶联型Ｓ－ＳＢＲ／ＢＲ的并用比例有利于提高胶料的抗撕裂性能,炭黑与促进剂的用量直接影响着胶料的３００％定伸应力。     

显微照相法测定炭黑分散度的研究

ＲＣＴＶＬＭ橡胶彩色电视显微镜系统和ＤＩＳＰＥＲＧＲＡＤＥＲ１０００型炭黑分散度仪均是根据光反射原理,用显微照相法测定炭黑分散度的。通过测试结果的分析和比较得出,对于未加硫黄和促进剂的混炼胶和硫化胶的炭黑分散度等级,其测定结果基本准确;对于加入硫黄和促进剂的混炼胶的炭黑分散度等级,由于硫黄和促进剂的干扰,其测定结果不太准确     

导电炭黑在NBR中的应用

用导电炭黑作填充剂，研究了它对ＮＢＲ混炼胶加工行为，硫化特性，硫化胶性能及导电性能的影响，并与填充乙炔炭黑的ＮＢＲ胶料性能进行了对比。结果表明，随着ＣＳＦ用量增加，炭黑结合ＮＢＲ含量，门尼粘度，屈服强度和拉伸强度的均增加，而扯断伸长率及挤出物出口膨胀比降低，挤出物外观变优。     

稀土BR／SBR共混胶的性能

研究了４种共混比的ＬｎＢＲ／ＳＢＲ共混生胶、混炼胶及硫化胶的性能，并与ＮｉＢＲ／ＳＢＲ共混胶进行了对比。结果表明，共混生胶的ＭＬ均低于ＬｎＢＲ及ＳＢＲ；当ＬｎＢＲ／ＳＢＲ共混混炼胶的ＭＬ、剪切应力、出口膨胀及硫化速度均低于ＮｉＢＲ／ＳＢＲ共混胶，挤出物外观优于后者；共混硫化胶的拉伸强度、热空气老化、拉伸疲劳、湿滑、耐磨等性能均明显优于后者，生热和透气率高于后者。     

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.     

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。     

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.     

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.     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。