不同二胺后扩链对聚酯/聚醚型水性聚氨酯性能的影响

以异佛尔酮二异氰酸酯(IPDI)、聚醚二元醇(N210)、聚酯二元醇(PBA)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,一缩二乙二醇(DEG)为小分子扩链剂,乙二胺(EDA)、异佛尔酮二胺(IPDA)为后扩链剂,合成了一系列水性聚氨酯(WPU)乳液。主要考察了后扩链对水性聚氨酯乳液的稳定性,乳液粒径以及胶膜吸水率和力学性能的影响。结果表明,用二胺后扩链之后,乳液稳定性变好,乳液粒径变小,胶膜吸水率减小,耐水性变好,胶膜拉伸强度增加,当采用IPDA后扩链且质量含量为2.7%时,膜的综合性能较好,吸水率相对较低(16.7%),拉伸强度为31.23MPa,断裂伸长率为1022.31%。     

阴离子型水性聚氨酯的合成及其性能研究

以甲苯二异氰酸酯(TDI)、聚丙二元醇(N210)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,1,4-丁二醇(BDO)和乙二胺(EDA)为小分子扩链剂,采用预聚体法合成了系列阴离子型水性聚氨酯乳液。讨论了硬段含量、DMPA用量、-NCO／-OH物质的量比值及扩链剂用量对水性聚氨酯乳液及胶膜性能的影响,得出了制备阴离子型水性聚氨酯的最佳配方。     

水性聚氨酯相对分子质量的影响因素及胶膜力学性能

采用异佛尔酮二异氰酸酯(IPDI)和聚醚二元醇(N-220)为主要原料,二羟甲基丙酸(DMPA)为亲水扩链剂,乙二胺(EDA)为后扩链剂,合成了一系列聚醚型聚氨酯(WPU)水分散体。考察了nNCO/nOH和中和度的变化对聚氨酯相对分子质量的影响以及聚氨酯相对分子质量与聚氨酯胶膜的力学性能和耐水性的关系。结果表明,随着nNCO/nOH的降低,聚氨酯的相对分子质量呈现先上升后下降的规律;随着中和度的增加,聚氨酯的相对分子质量增加;当nNCO/nOH为1.25时,水性聚氨酯相对分子质量最高,胶膜的力学性能和耐水性最好。     

单组分聚氨酯乳液胶粘剂的制备与性能研究

采用分子量为1000的聚丙二醇与甲苯二异氰酸酯反应制得一定异氰酸酯基含量的预聚体,然后加入亲水扩链剂进行扩链,最后加水乳化中和后得到单组分聚氨酯乳液胶粘剂.研究了异氰酸酯指数(R值)、亲水扩链剂和中和剂对聚氨酯乳液胶粘剂性能的影响.当R=3.5,亲水扩链剂用量为7％,中和度为100％时,单组分聚氨酯乳液胶粘剂综合性能较...     

乙二胺扩链剂对水性聚氨酯性能的影响

以聚醚220、异佛尔酮二异氰酸酯(IPDI)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,丁二醇(BD)和乙二胺(EA)为小分子扩链剂,按不同配比合成了系列水性聚氨酯分散体。主要考察了乙二胺扩链剂用量对水性聚氨酯乳液的稳定性、乳液粒径、粘度以及膜吸水性和力学性能的影响。结果表明,随乙二胺扩链剂用量的增加,乳液粒径增大、分散稳定性变差、粘度减小、胶膜的拉伸强度增加、断裂伸长率减小、耐溶剂性增加、吸水率变化不明显、硬段相Tg升高,软硬段相分离程度增加。胶膜的ATR红外表现为PPG类聚醚型聚氨酯典型的红外光谱。     

热红外隐身涂料用水性聚氨酯的制备研究

以聚碳酸酯二元醇(PCDL)为软段,异佛尔酮二异氰酸酯(IPDI)为硬段,二羟甲基丙酸(DMPA)为亲水扩链剂,三乙胺为成盐剂,乙二胺为二次扩链剂,采用自乳化法合成了聚碳酸酯基低红外发射率水性聚氨酯。采用红外光谱仪(FI-IR)、红外发射率测试仪等对聚氨酯的结构和红外性能进行了表征。研究了PCDL/IPDI比例、亲水扩链剂、中和剂和二次扩链剂对合成水性聚氨酯胶膜红外发射率的影响。结果表明:PCDL/IPDI质量比为2.5∶1,DMPA的量为单体总量的6%,中和度为100%,控制二次扩链剂乙二胺的加入量使得—NH3与—NCO的物质的量比为1.5∶1时,所合成的乳液粘合剂在8～14μm波段红外基本透明,红外发射率可低至0.825,涂膜物理综合性能良好,可以应用于隐身涂层。     

疏水型阳离子水性聚氨酯的合成与性能研究

以甲苯二异氰酸酯,聚酯、聚醚混合多元醇为基本原料,N-甲基二乙醇胺(MDEA)为亲水扩链剂,羟丙基聚二甲基硅氧烷、单硬酯酸甘油酯为改性剂,通过醋酸中和反应制备出疏水型自乳化阳离子水性聚氨酯乳液;研究了改性剂用量、R值(体系中—NCO和—OH的物质的量比)、MDEA含量和中和度对乳液耐水性的影响。结果表明:羟丙基聚二甲基硅氧烷和单硬酯酸甘油酯加入到聚氨酯体系中,均能显著提高聚氨酯的耐水性;胶膜吸水率随MDEA含量增加呈先降低后升高的趋势;当中和度小于100%时,胶膜吸水率随中和度的增大而减小;当中和度大于100%时,中和度对胶膜吸水率无明显影响。     

MDI型水性聚氨酯乳液的合成及性能研究

以二苯基甲烷二异氰酸酯、聚酯二醇、二羟甲基丙酸等为原料合成了水性聚氨酯预聚体,用三乙胺中和制备了水性聚氨酯的透明乳液.通过FT-IR、TEM、拉力机等测试手段对所制水性聚氨酯进行了形貌观察、力学及耐水性测试.结果表明,当n(-NCO):n(-OH)比值为1.8～1.9,DMPA含馈在6.5%～7%,中和度在100%～120%时可制得性能稳定的水性聚氨酯乳液,若在乳化阶段用乙二胺进行扩链,则胶膜的吸水率会进一步降低至4%.     

阳离子水性聚氨酯乳液的合成方法及条件探讨

主要研究了通过多异氰酸酯(TDI)与聚醚多元醇(210)进行预聚反应,再加入小分子扩链剂(一缩二乙二醇)和亲水扩链剂(MDEA),用乙酸中和,乳化制取阳离子水性聚氨酯乳液的合成方法,并讨论了反应过程中各种因素对乳液及胶膜各方面性能的影响。     

小分子扩链剂对水性聚氨酯胶粘剂性能的影响

采用聚己二酸丁二醇酯二醇(PBA)作为软段,异佛尔酮二异氰酸酯(IPDI)作为硬段,通过亲水扩链剂2,2-二羟甲基丙酸(DMPA)在分子链上引入亲水基团.分别使用1,4-丁二醇(BDO)、乙二醇(EG)、乙二胺(EDA)为小分子扩链剂进行扩链反应,经自乳化合成水性聚氨酯胶粘剂乳液,并对水性聚氨酯乳液及胶粘剂的结构和性能...     

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。     

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.     

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。