环氧胶膜对聚四氟乙烯薄片和铝合金胶接研究

对新型环氧芳胺结构胶膜进行了固化工艺、耐热性能及微观形貌的研究。研究结果表明：该胶膜的玻璃化转变温度（tanδ法）约为202℃,TGA曲线表明固化后的胶膜质量损失5%的温度约为372℃,DTG曲线表明胶膜的最快热失重速率约为400℃;扫描电镜照片显示,胶膜断面呈现韧性破坏模式。用此胶膜开展了耐磨型聚四氟乙烯薄片和铝合金的胶接研究,分析了固化时间、压力及铝合金表面处理方法对二者胶接强度的影响。研究结果表明：当采用固化工艺为180℃/3 h、压力为0.3 MPa时,耐磨型聚四氟乙烯薄片和铝合金胶接强度较佳,常温（23℃）剪切强度为12.7 MPa,高温（177℃）剪切强度为5.6 MPa;该胶膜在航空发动机上具有潜在的应用价值。     

中温固化氰酸酯树脂发泡胶膜研制

通过加入自制潜伏性促进剂,降低了氰酸酯发泡胶的固化温度,实现了在130~135℃固化。通过加入耐热性工程塑料、环氧树脂、偶氮发泡剂、导热填料制备出具有良好的发泡状态、较低放热温度和较高粘接性能的氰酸酯发泡胶膜。发泡胶膜在-55℃至180℃的范围内具有较高的管剪切强度,在膨胀比为3.20时,室温和180℃管剪切强度分别为10.5MPa和5.9MPa。发泡胶具有较好的耐热老化和耐湿热老化、耐介质和耐空间环境性能,在室温下具有良好的贮存期。     

一种带孔面板与蜂窝芯粘接用热破胶膜的研制

制备了一种带孔面板与蜂窝芯粘接用热破胶膜。该胶膜破孔率大于95%,玻璃化转变温度(Tg)为122.0℃,室温剪切强度为35.3MPa,100℃剪切强度为25.1MPa,90°板-板剥离强度为73.5N/cm,胶膜厚度为0.05mm和0.08mm时,90°板-芯剥离强度为15.5N/cm和22.3N/cm。该胶膜具有良好的工艺稳定性、黏性和铺覆性,可铺覆在蜂窝格孔表面进行热破,解决了现有环氧结构胶粘剂热破率低、耐温性差等问题。     

航空航天用耐高温苯并噁嗪树脂胶粘剂

以苯并噁嗪树脂(BZ)为胶粘剂主体树脂、四官能团环氧树脂为改性剂、聚醚酰亚胺为增韧剂,研制出一种耐高温的BZ胶膜。性能测试结果表明,BZ胶膜可在190℃下固化,能耐高温,其玻璃化转变温度(T)达到224℃。空气中5%的热失重率达到了400℃以上,具有较好的耐烧蚀g性;氮气中800℃时的残炭率为48%。该胶膜粘接可靠性较高,常温剪切强度为23.0 MPa,140℃剪切强度为28.0 MPa,200℃剪切强度达到12.0 MPa。BZ胶膜在贮存和运输过程中无需冷藏,室温贮存60 d,工艺性能及粘接性能保持不变。预期在航空航天等多种型号产品上可得到应用。     

MDI改性PVAc胶黏剂的性能效果评价

用MDI改性用醋酸乙烯酯(VAc)单体聚合的固含量≤40%PVAc胶黏剂。讨论了不同MDI加入量对黏度、干湿态剪切强度、吸水率、接触角和干燥时间等方面的影响,最终确定了最佳MDI添加比例:当MDI添加量为15%时,黏接强度和耐水性均达到最好水平,即干态剪切强度9 MPa,湿态剪切强度1.75 MPa,胶膜吸水率最小值33.1%,胶膜与水的最大接触角为45.5°,MDI改性低固含量PVAc比未改性低固含量PVAc在不同温度下,干燥速度快,提高实际应用效率。     

用于西锐SR20复合材料胶接维修的国产中温固化胶膜性能研究

研究了自制中温胶膜J-12和西锐SR20复合材料维修手册提供的AF-163-2M中温胶膜的固化工艺、力学性能及使用温度差异。结果显示:两胶膜在120℃~130℃时具有较好的固化速率,均能在150℃长期使用,满足SR20复合材粘接维修需要;室温下J-12胶膜固化物AF-163-2M胶膜单搭接拉伸剪切强度分别为30.1 MPa、27.4 MPa,J-12胶膜固化物的剪切强度优于AF-163-2M胶膜固化物。综上所述,国产J-12胶膜性能与AF-163-2M胶膜性能相当,可作为替代性产品应用于西锐SR20复合材料粘接维修。     

利用PCB碱性蚀刻废液制备纳米铜导电胶

以碱性蚀刻废液为原料,采用液相还原法制备了纳米铜粉,将制备的纳米铜粉作为导电填充料添加到环氧树脂中制备出纳米铜导电胶。研究了纳米二氧化硅、硅烷偶联剂KH570和纳米铜粉的添加量对导电胶剪切强度以及纳米铜粉添加量对导电胶体积电阻率的影响,探讨了环氧树脂与固化剂聚酰胺适宜的反应时间。实验结果表明,所制备的铜粉为球状,粒径在40～100nm之间;当环氧树脂与固化剂聚酰胺树脂650的质量比为4∶1,纳米二氧化硅、硅烷偶联剂和纳米铜粉的加入量分别占环氧树脂–聚酰胺树脂体系质量的1.5%、4.0%和70%时,在90°C下固化1.0h,可以制备出体积电阻率为3.05×10-3Ω·cm、剪切强度达8.04MPa的导电胶。     

J-199热熔胶膜的研制

讨论了不同VA含量不同熔体指数的EVA和各种增粘剂对热熔胶膜耐热性、软化点、剪切强度、拉伸强度、剥离强度等性能的影响。通过采用不同材料试验和配方的筛选，研制出一种90℃剪切强度0．07MPa、拉伸强度0．47MPa、耐热性好、粘接强度高的热熔胶膜，从而拓宽了热熔胶的使用范围。     

石英纤维布的界面处理对氰酸酯基胶膜性能的影响

分别采用烧蚀法和KH550/乙醇溶液对石英纤维布表面进行处理,将处理后的石英纤维布与改性氰酸酯树脂复合制备了氰酸酯/石英纤维布载体胶膜。研究结果表明,经过0.5%KH550溶液处理后的石英纤维表面形成一层均一的界面层,与氰酸酯树脂间的界面强度(IFSS)为62.1MPa,相比经过烧蚀法处理纤维的IFSS提高约90%。随着KH550浓度增加,氰酸酯/石英纤维布载体胶膜的剪切强度和石英纤维布界面硅元素的含量均呈现先增高后降低的趋势。采用0.5%KH550溶液对石英纤维布处理后,制备的氰酸酯/石英纤维布载体胶膜的综合性能最佳,400℃剪切强度为6.4MPa,400℃老化1h后强度保持率为90.2%。     

一种高弹性环氧基胶粘剂材料的制备

采用自制的端环氧基丁腈橡胶为主增韧剂,PEK(聚芳醚酮)为辅助增韧剂,制备出一种环氧树脂为主体的弹性胶膜。研究结果表明:当环氧基丁腈橡胶用量为60 phr,PEK用量为25 phr时,该弹性胶膜获得了较高的弹性和良好的粘接性能;其常温断裂伸长率达到了26.48%,常温和150℃下的剪切强度分别达到了20 MPa和8 MPa以上。同时该胶膜具有良好的耐热性能,其5%热失重时的温度达到了349.5℃。     

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。