双子季铵盐表面活性剂的制备及性能研究

以十二烷基二甲基叔胺C12H25(CH3)2N、盐酸、环氧氯丙烷为原料合成了一种双子季铵盐表面活性剂GC12,经红外光谱和核磁共振氢谱证实其结构并研究了其表面活性、泡沫性能、乳化性能、HLB值及乳液的粒径分布。结果表明,GCl2具有较高的表面活性,良好的乳化能力和泡沫性能,临界胶束浓度(cmc)值仅为1.07×10-3mol/L,γcmc值为36.5 m N/m,HLB值为12.5,在15⁵5℃下乳液颗粒平均直径为120 nm,是良好的O/W型乳化剂。     

双子季铵盐表面活性剂的制备及性能研究

以十二烷基二甲基叔胺C12H25(CH3)2N、盐酸、环氧氯丙烷为原料合成了一种双子季铵盐表面活性剂GC12,经红外光谱和核磁共振氢谱证实其结构并研究了其表面活性、泡沫性能、乳化性能、HLB值及乳液的粒径分布。结果表明,GCl2具有较高的表面活性,良好的乳化能力和泡沫性能,临界胶束浓度(cmc)值仅为1.07×10-3mol/L,γcmc值为36.5 m N/m,HLB值为12.5,在15~55℃下乳液颗粒平均直径为120 nm,是良好的O/W型乳化剂。     

新型糖基酰胺非离子表面活性剂的制备及性能研究

以葡萄糖酸内酯和十二胺为原料,合成了N-十二烷基葡萄糖酰胺(C₁₂GA)非离子表面活性剂。通过红外光谱和¹H NMR对其结构进行了表征。优选出了能使C₁₂GA在水溶液中溶解的表面活性剂十二烷基苯磺酸钠（LAS）和十二烷基硫酸钠（SDS）,并对其复配溶液的溶解性、表面张力、润湿、乳化、泡沫、黏度和去污等物化性能进行测试,且与N-十二烷基-N-甲基葡萄糖酰胺（MEGA）的复配性能进行了对比。结果表明,C₁₂GA可以与磺化/硫酸化产品发生协同增效作用,对其表面活性、乳化、泡沫和增稠性能都有明显的提高,特别是增稠性能高于椰子油脂肪酸二乙醇酰胺（6501）,且与MEGA的增效作用基本相同,表明在一定条件下C₁₂GA可以取代MEGA产品。     

双癸基二甲基羧酸铵反离子碳链长度对其表面活性和应用性能的影响

通过对不同反离子碳链长度(n=2,4,6,8,10,12)的双癸基二甲基羧酸铵的表面活性及泡沫性能、乳化性能和润湿性能进行测定,探讨反离子碳链长度对季铵盐表面活性剂的表面活性及应用性能的影响。结果表明:随着反离子碳链长度(n=2,4,6,8,10,12)的增加,双癸基二甲基羧酸铵的表面活性逐渐增强,其临界胶束浓度(cmc)逐渐减小,最低表面张力(γcmc)先降低后升高,当反离子碳链长度n=10时,γcmc达到最低,降低水表面张力20 m N/m的效能(pc20)逐渐增大,饱和吸附量(Гtotal)逐渐增大,单个分子占有面积(Am)逐渐减小;泡沫性能和乳化性能均随着反离子碳链长度的增加先增强后减弱;润湿性能随着反离子碳链长度的增加而逐渐增强。     

松香基季铵盐Gemini表面活性剂的合成及性能研究

以脱氢枞胺为原料合成了一系列松香基季铵盐Gemini表面活件剂,用IR及1H-NMR光谱对产物进行了结构表征,并对该系列表面活性剂的性能进行研究.松香基季铵盐Gemini表面活性剂具有很强的表面活性性能:临界胶束浓度(CMC)在(2.5～5.5)×10-5mol/L,表面张力23.7～30.3 Mn/m,松香基季铵盐Gemini表面活性剂还具有很强的乳化性能及泡沫性能.     

磺酸盐双子表面活性剂乙撑-双(N-乙磺酸-十二酰胺)钠盐的合成与性能

以乙二胺、月桂酸、三氯化磷和2-溴乙基磺酸钠等为原料,制备磺酸盐双子表面活性剂乙撑-双(N-乙磺酸-十二酰胺)钠盐,对其中间体合成工艺进行优化,对产物结构进行表征,并对其相关性能如表面活性、起泡性以及乳化性进行测定。结果表明:该表面活性剂的水溶液在24℃条件下,其临界胶束浓度(cmc)为0.53 mmol/L,相应表面张力(γcmc)为29.73 m N/m,该表面活性剂的表面活性、起泡性以及乳化性较好。     

新型季铵盐双子表面活性剂12-PZ-12的合成及性能研究

以哌嗪为连接基团,依次经过酰基化、氢化铝锂还原和季铵化反应,合成了新型季铵盐双子表面活性剂12-PZ-12。用1 H NMR和元素分析进行了结构表征,并研究了其表面活性以及不同种类和浓度的反离子对其表面活性的影响。结果表明,12-PZ-12的水溶液在25℃时的临界胶束浓度cmc=4.68×10-4 mol/L,临界胶束浓度下的表面张力γcmc=24.0 mN/m,优于传统的表面活性剂。随着反离子浓度的增加,12-PZ-12的cmc值降低,且Iˉ比Clˉ对其cmc值的影响更为显著。     

多季铵盐表面活性剂的合成及流变性能研究

以二乙胺盐酸盐、环氧氯丙烷、长链烷基二甲基叔胺为原料,合成了3种多季铵盐表面活性剂CD3N-n(n=12,16,18,代表烷基链碳原子个数);测定了上述多季铵盐表面活性剂的表面活性,并研究了碳链长度、温度、浓度以及反离子对多季铵盐水溶液流变性的影响。结果表明,合成的多季铵盐水溶液的临界胶束浓度(cmc)分别为2.0×10-4,1.0×10-4和8.0×10-5mol/L,临界胶束浓度下的表面张力(γcmc)分别为39.05,37.45和34.12 m N/m,cmc和γcmc均随着烷基链长度的增加而减小;CD3N-18的增黏效果显著,溶液黏度随CD3N-18浓度的增大而增大,随温度升高和反离子的加入先增加后减小,反离子助剂氯化钾的增黏效果较好,而水杨酸钠有助于提升产品的耐温性。     

Gemini表面活性剂与月桂醇醚羧酸盐的复配性能研究

研究了Gemini阳离子表面活性剂双十二烷基季铵盐(12-3(OH)-12)与阴离子表面活性剂月桂醇聚氧乙烯醚羧酸钠(AE9C)复配体系的稳定性、表面活性、泡沫性能、润湿性和乳化性能。结果表明,12-3(OH)-12与AE9C复配体系稳定性好,表现出很好的协调增效作用。当n(12-3(OH)-12)∶n(AE9C)=1∶2时,增效作用最为明显,其临界胶束浓度CMC为1.49 mmol/L,最低表面张力γCMC=30.15 m N/m,均低于任一单组分。复配体系的泡沫、润湿和乳化性能均要优于任一单组分,并且都在n(12-3(OH)-12)∶n(AE9C)=1∶2时表现出最佳性能。     

季铵盐有机硅双子表面活性剂的物理化学及抗菌性能的研究

以丙酮和正己烷为溶剂,聚乙二醇二缩水甘油醚和不同粘度羟基封端聚二甲基硅氧烷为主要原料在四丁基溴化铵（TBAB）和氢氧化钠（NaOH）的催化下合成不同硅氧链长的环氧基聚醚改性硅氧烷EP-PSix-EP(x=30,100,800),再与N,N二甲基十二烷基叔胺在无水乙醇、盐酸催化下进行季铵化反应,制备联结基长度不同的季铵盐有机硅双子表面活性剂C12-PSix-C12（x=30,100,800),研究C12-PSix-C12中联结基长度对其表面张力、润湿性能、乳化稳定性等物化性能及抗菌性能的影响,结果表明,随着C12-PSix-C12中联结基长度的减小,C12-PSix-C12的表面活性、乳化稳定性及润湿性能逐渐增强;抗菌实验结果显示3种表面活性剂均表现出一定的抗菌性能,且随着C12-PSix-C12中联结基长度的降低,抗菌能力增强。     

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.     

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.     

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.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.