聚己内酯体系聚氨酯弹性体力学性能的研究

通过改变预聚体中异氰酸根含量、扩链剂种类及用量以及异氰酸酯配比,采用预聚体法合成了浇注型聚己内酯聚氨酯弹性体。结果表明,异氰酸根含量越高,聚氨酯弹性体力学性能越好;采用胺类扩链剂得到的弹性体力学性能好于醇类扩链剂的弹性体力学性能;随着异氰酸酯T-100/T-80配比的减小,弹性体凝胶时间逐渐缩短。     

室温固化型MDI体系聚氨酯弹性体力学性能的研究

以不同结构多元醇和4,4′-二苯基甲烷二异氰酸酯(MDI-100)合成预聚体,再与不同扩链剂反应制备室温固化MDI型聚氨酯弹性体。讨论了多元醇种类、扩链剂种类、扩链系数、稀释剂用量、催化剂种类对聚氨酯弹性体力学性能的影响。结果表明,结构规整的多元醇制备的聚氨酯弹性体综合性能较好;二醇类扩链剂1,4-丁二醇(1,4-BDO)和对苯二酚二羟基乙基醚(HQEE)制备的弹性体性能较好,操作工艺可行;扩链系数以0.85~1.0为宜;适宜稀释剂质量分数为5%~10%;MDI室温固化体系的催化剂可选用HDcat。     

安全轮胎用聚氨酯材料耐热性研究

对影响安全轮胎内部填充聚氨酯材料耐热性的因素进行了研究,通过采取复配异氰酸酯、筛选新型扩链剂和稀释剂、加入防老剂等方法,优化了配方,并对固化后的聚氨酯材料进行热重图谱分析。结果表明:采用新型扩链剂LAP–1、T/M(甲苯二异氰酸酯/二苯基甲烷二异氰酸酯)体系异氰酸酯、稀释剂LM–07、防老剂FP–01等材料,可使所制聚氨酯材料的热分解温度由163.46℃升至248.84℃,提高了其耐热性。     

低硬度聚氨酯弹性体的制备及性能

以聚醚多元醇(PPG-2000)/MDI体系为基础,以EG/TMP为扩链剂(扩链系数f=0.95),补加PPG-60和POP-36多元醇,采用半预聚物法合成了低硬度高回弹性浇注型聚氨酯弹性体,考察了异氰酸酯种类、游离异氰酸酯含量、扩链剂种类及其配比和多元醇配比对材料力学性能的影响。结果表明,制得的PPG-2000,PPG-60/POP-36/MDI/EG/TMP聚氨酯弹性体具有良好的综合力学性能。     

热塑性聚氨酯热熔胶的合成与性能研究

以己二酸系聚酯二醇为软段,二异氰酸酯与扩链剂生成的链段为硬段,制备了聚氨酯热熔胶;研究了软硬段组成、结构、相对分子质量、扩链剂、异氰酸酯指数等对聚氨酯热熔胶的力学性能、结晶性能、粘接性能及耐热性能的影响。     

聚氨酯弹性体耐水性影响因素

以两步法工艺合成聚氨酯弹性体,通过改变多元醇、异氰酸酯种类以及扩链剂种类及配比等,考察了原料种类对聚氨酯弹性体力学性能及耐水性能的影响。结果表明,多元醇种类、异氰酸酯种类对聚氨酯弹性体耐水性影响较大,硬段含量与扩链剂种类对试样耐水性影响较弱,提高交联密度对试样耐水性提高有利。     

LED用环氧树脂灌封胶的研究

采用低黏度的混合胺类固化剂和环氧活性稀释剂,并以聚氨酯为增韧剂制得了改性环氧树脂灌封胶,研究了各组分对灌封胶的力学性能和透光性能的影响。该灌封胶黏度低,透光性好,适宜用于LED的灌封。     

TODI和MDI并用对浇注型聚氨酯弹性体性能的影响

以聚四氢呋喃(PTMG)为聚合物多元醇,TODI和MDI并用为异氰酸酯,添加一定量的扩链剂,采用预聚法制备了一系列浇注型聚氨酯弹性体;研究了TODI/MDI不同并用比、扩链剂种类以及扩链系数对弹性体工艺性能和力学性能的影响。结果表明,随着TODI用量的增加,可操作时间延长,弹性体的耐热性能提高;当采用PTMG 1000为聚合物多元醇,TODI/MDI并用比为60/40,1,4-BD为扩链剂,且扩链系数为0.95时,聚氨酯弹性体的综合性能最佳。     

浇注型聚氨酯弹性体的研制

采用2,4-甲苯二异氰酸酯(TDI)、聚醚多元醇或聚酯多元醇、扩链剂等原料通过预聚物法合成了浇注型聚氨酯(PUR)弹性体,分析了柔性链段的分子结构、扩链剂的分子结构及异氰酸酯基的含量等因素对PUR弹性体力学性能的影响。结果表明,以聚己二酸丁二酯为柔性链段、MOCA或TX-2为扩链剂、异氰酸酯基质量分数为5％．5．5％时,所得PUR弹性体具有较好的综合性能。     

高硬度透明聚氨酯材料的研制

选用不同结构的多异氰酸酯、低聚物多元醇、扩链剂等为原料,用半预聚体法和一步法制得一系列高硬度高透明性聚氨酯材料。讨论了合成工艺、多异氰酸酯结构、扩链剂结构和多元醇平均每个羟基所对应的相对分子质量(N值)及其平均官能度对聚氨酯材料性能的影响。结果表明,选择异佛尔酮二异氰酸酯及扩链剂E并控制多元醇平均官能度在2.5～2.7和平均N值在120～150范围内,采用半预聚法制得的高硬度透明聚氨酯材料具有较好的综合力学性能及热稳定性。     

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.     

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.     

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。     

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。