端羧基液体丁腈橡胶增韧环氧树脂研究

制备了由端羧基液体丁腈橡胶（cTBN）增韧环氧树脂（ER）于室温下固化的双组分胶黏剂。研究了CTBN与ER配比、甲组分处理温度及其保温时间对胶黏剂剪切强度的影响并用扫描电子显微镜（SEM）观察了其微观形态。实验结果表明CTBN：ER=8：1、甲组分于200℃下反应2．5h时,胶黏剂剪切强度可以达到25．34MPa,耐介质性能良好。同时SEM测试结果表明端羧基液体丁腈橡胶对ER增韧作用明显,为提高环氧树脂的粘接性和韧性提供了技术依据。     

室温固化耐热150度环氧树脂结构胶粘剂

介绍了一种以液体端羧基丁腈橡胶（CTBN）改性环氧树脂为主体,改性聚硫橡胶为固化剂的结构胶粘剂,该胶强度高,韧性好,室温固化10d,室温剪切强度23．6MPa,150℃剪切强度为13．3MPa,200摄氏度剪切强度为5．6MPa,室温剥离强度6．0kN.m^-1,综合性能优异,用于,航天工业耐热结构部件的粘接。     

耐久性室温固化环氧树脂结构胶的性能研究

以端羧基丁腈橡胶(CTBN)作为EP(环氧树脂)的增韧剂、聚醚胺(D-230)作为固化剂的主要成分,研制了3种室温固化型EP胶粘剂(J-133、J-153和J-164)。研究结果表明:J-133具有较高的剪切强度(27.0 MPa)和较好的韧性(剥离强度4.0 kN/m),可用于板-板和板-芯结构的胶接;J-153具有较低的黏度,是一种灌注型胶粘剂,可用于蜂窝夹层板上安装固定元器件,其压缩强度为81.0 MPa、断裂伸长率为5.3%~6.8%;J-164的密度(0.6~0.8 g/cm~3)较低,是一种蜂芯拼接胶,其压缩强度为25.5 MPa、90°剥离强度为2.3 kN/m。这3种胶粘剂均具有较高的胶接强度、较宽的使用温度范围,并且在水、航空煤油、液压油及高湿气等环境中均具有很好的耐久性。     

J-241室温固化耐150℃胶黏剂的制备与性能

采用丙烯酸酯原位聚合物增韧改性多官能环氧树脂,制备了J-241室温固化耐150℃结构胶黏剂。研究了胶黏剂的对金属材料和环氧碳纤维复合材料的粘接性能。制备的胶黏剂具有良好的室温固化性能,固化后室温剪切强度33.2MPa、150℃剪切强度13.6MPa,剥离强度35.2N/cm,对环氧碳纤维复合材料具有良好的粘接性能,可用于环氧碳纤维复合材料结构的修补和二次连接成型。     

室温固化耐热150℃环氧树脂结构胶粘剂

介绍了一种以液体端羧基丁腈橡胶 (CTBN)改性环氧树脂为主体 ,改性聚硫橡胶为固化剂的结构胶粘剂。该胶强度高 ,韧性好 ,室温固化 10d ,室温剪切强度 2 3.6MPa,15 0℃剪切强度为 13.3MPa ,2 0 0℃剪切强度为5 6MPa ,室温剥离强度 6.0kN·m-1,综合性能优异。用于航空、航天工业耐热结构部件的粘接。     

新型增韧改性环氧胶粘剂问世

天津城建学院与河北大学联合攻关，采用液体丁腈-40橡胶对环氧树脂进行增韧，研制出可室温较快固化、剪切强度较高的改性环氧胶粘剂。环氧树脂与液体丁腈橡胶的最佳质量比为10：1，制得的结构胶粘剂室温24h固化后，具有良好的力学性能，室温剪切强度高达22．4MPa，一般的丁腈橡胶虽然也能增韧环氧树脂，但改性后的粘接强度提高不大。端羧基液体丁腈橡胶（CTBN）对环氧树脂增韧效果很好，可是原料价格太高，受到制约。而采用液体丁腈-40橡胶，对E-44环氧树脂／低分子聚酰胺体系进行增韧，可得到室温固化、剪切强度较高的改性环氧胶粘剂。     

黑龙江省科学院石油化学研究院结构与耐热研究中心

正蜂窝夹心胶黏剂J-71、J-123、J-80蜂窝夹芯胶粘剂J-71:多节点T型剥离强度(kN/m)室温:≥2.3 150℃,1.0多节点T型剥离强度(kN/m)J-123:多节点T型剥离强度(kN/m)室温:≥2.8 150℃≥1.0 175≥0.7多节点T型剥离强度(kN/m)特点:粘接强度高,工艺性能好,耐热性优良。J-123胶可用于制造高密度的铝蜂窝芯材。J-80:T型剥离强度室温:≥3.0kN/m特点:表面适应性好,节点强度高,耐久性能优异,主要用于Nomex纸蜂窝的制造,可在-100℃-175℃长期使用。固化工艺:固化温度180℃±5℃;时间为2～3h;固化压力:0.5 MPa±0.1MPa。     

端羧基液体丁腈(CTBN)对环氧树脂的增韌作用(一)

本文研究了端羧基液体丁腈橡胶(CTBN)与环氧树脂不同配比下的粘接强度。经红外光谱分析,端羧基液体丁腈的羧基基团与环氧基团发生了化学反应。通过偏光显微结构观察,证实了端羧基液体丁腈橡胶与环氧树脂固化后呈两相体系,并研究了不同配比下的形态结构。     

一种高性能芳纶纸蜂窝节点胶黏剂的研制

研制了一种芳纶纸蜂窝节点胶黏剂,该胶黏剂以环氧树脂和高邻位酚醛树脂为主体树脂,以活性端基的丁腈橡胶弹性体为增韧剂,以核壳橡胶和无机填料为流动控制剂,可在180℃固化。25℃剪切强度为34.6MPa,150℃剪切强度为14.1MPa,25℃蜂窝节点强度为5.6N/cm。该胶黏剂有较好的耐热性能和耐湿热性能,在150℃经过400h的热老化或是经过1000h的湿热老化后,依然具有良好的力学性能。     

用改性环氧胶黏剂粘接硫化丁腈橡胶

以端异氰酸基聚氨酯预聚体改性环氧树脂和双氰胺为主要原料制备了一种单组分耐热环氧树脂胶黏剂，该胶可以对表面未处理的丁腈橡胶进行粘接。文中考察了增韧剂种类、增韧剂用量对粘接强度的影响，同时考察了促进剂种类和用量对凝胶时间和贮存期的影响。实验结果表明，该胶黏剂对丁腈橡胶的粘接强度好，具有较好耐热性和较长贮存期。     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.