线形-枝状碳硅两亲嵌段聚合物的合成与表面性能

通过对聚乙二醇端羟基烯丙基化及硅氢化加成反应,将疏水性有机硅基团接枝到亲水的聚乙二醇链段两端,得到有机硅接枝单元数量不同的两种线形-枝状两亲聚合物,用NMR、FTIR对其结构进行了表征,并评价了其表面活性。两种聚合物具有良好的表面活性,其临界聚集浓度(CAC)值分别为5.13×10-4mol/L和4.83×10-5mol/L,γCAC值分别为32.48 m N/m和32.21 m N/m。此外,该聚合物水溶液的表面张力-浓度曲线呈现"两段式"变化,说明聚合物分子在空气/水表面上有构象变换过程,而聚合物PEG链段、含硅枝状结构将显著影响吸附层中聚合物的分子构象。     

羧酸盐型Gemini表面活性剂的合成及表征

以脂肪胺、三聚氯氰、二乙醇胺、丁二酸酐为原料,三步法合成了2种表面活性剂,用1 HNMR、ESI-MS、IR对产物进行了表征,并用吊片法考察了目标产物水溶液的表面活性。实验结果表明,目标产物具有较好的表面活性,25℃时DXC6A和DXC8A的最低表面张力(γCMC)分别为31.85mN/m和28.76mN/m,临界胶束浓度(CMC)分别为2.32×10-4 mol/L和1.41×10-5 mol/L,表面活性优于传统表面活性剂十二烷基硫酸钠(SDS)。     

新型含氟季铵盐表面活性剂的合成与表面性能

以N-甲基二乙醇胺(MDEA)和全氟己基乙基碘为主要原料,合成了一种新型的含氟季铵盐表面活性剂。通过单因素和正交实验,考察了溶剂、反应温度、反应物摩尔比、溶剂体积和反应时间对MDEA转化率的影响,探讨优化出最佳工艺条件:溶剂为正丁醇,反应温度90℃,n(全氟己基乙基碘)∶n(MDEA)=2.5∶1,溶剂体积为8 mL,反应时间为42 h,转化率达到93.75%。通过傅里叶红外吸收光谱、质谱和核磁共振谱对目标产物进行表征,并通过测定其水溶液的表面张力研究了产物的表面活性。其临界胶束浓度(CMC)为1.518 mmol/L,临界胶束浓度下的表面张力(γCMC)为9.3 mN/m;单分子饱和吸附量、单分子饱和吸附面积和胶束化标准自由能分别为0.354×10-10 mol/cm2、4.69 nm2和-26.03 kJ/mol。与同类产品相比较,产物具有优异的表面性能。     

烷基糖苷柠檬酸单酯盐水溶液表面张力研究

采用wilhelmy吊片法和最大气泡压力法分别测定了烷烃链碳原子数为8,10,12的三种烷基糖苷柠檬酸单酯盐水溶液的平衡表面张力及动态表面张力。考察了烷基糖苷柠檬酸单酯盐(AG-EC)的烷烃链长和浓度、温度、氯化钠对其动态表面张力的影响。结果表明,AG-EC12、AG-EC10及AG-EC08在25℃时的临界胶束浓度分别为0.226,1.038,5.104 mmol/L,三种烷基糖苷柠檬酸单酯盐在其各自的水溶液中均显示出表面活性。随着疏水碳链长由8增长至12,三种烷基糖苷柠檬酸单酯盐的动态表面活性升高。同一烷基糖苷柠檬酸单酯盐随着浓度增大,其动态表面张力参数n、t*减小,且R1/2增大,动态表面活性增大。随着实验温度的升高(25⁴5℃)或无机电解质Na Cl浓度增加至0.6 mol/L,动态表面活性均升高。     

烷基糖苷柠檬酸单酯盐水溶液表面张力研究

采用wilhelmy吊片法和最大气泡压力法分别测定了烷烃链碳原子数为8,10,12的三种烷基糖苷柠檬酸单酯盐水溶液的平衡表面张力及动态表面张力。考察了烷基糖苷柠檬酸单酯盐(AG-EC)的烷烃链长和浓度、温度、氯化钠对其动态表面张力的影响。结果表明,AG-EC12、AG-EC10及AG-EC08在25℃时的临界胶束浓度分别为0.226,1.038,5.104 mmol/L,三种烷基糖苷柠檬酸单酯盐在其各自的水溶液中均显示出表面活性。随着疏水碳链长由8增长至12,三种烷基糖苷柠檬酸单酯盐的动态表面活性升高。同一烷基糖苷柠檬酸单酯盐随着浓度增大,其动态表面张力参数n、t*减小,且R1/2增大,动态表面活性增大。随着实验温度的升高(25~45℃)或无机电解质Na Cl浓度增加至0.6 mol/L,动态表面活性均升高。     

可断键均三嗪脂肪磺酸盐型表面活性剂的合成与表面活性

以脂肪胺、三聚氯氰、氨基乙磺酸为原料合成了4种不同碳链长度均三嗪脂肪磺酸盐型表面活性剂[2-脂肪胺基-4-(2-磺基乙基)胺基-6-氯-1,3,5-均三嗪]。用元素分析、1HNMR、FTIR对中间体和目标产物的结构进行了表征。测定了25℃时4种表面活性剂的表面张力,研究了它们的表面活性。结果表明,疏水链长为C14时,该类表面活性剂的临界胶束浓度(cmc)和cmc下的表面张力(γcmc)达到最低值分别为:3.58×10-5mol/L和32.53 mN/m。与普通表面活性剂C12-LAS相比,疏水链长为C12~C16的该类表面活性剂的cmc均比C12-LAS低1~2个数量级,即它们降低水溶液表面张力的效率比C12-LAS高;疏水链长为C8、C12和C16时,其在溶液表面的饱和吸附量均比C12-LAS小,饱和吸附面积比C12-LAS大;疏水链长为C14时则相反。     

脂肽类生物表面活性剂Surfactin的乳化性

采用白金板法对Surfactin的表面活性进行研究,并用浊度法和离心法对其乳化性进行研究。结果表明:Surfactin的临界胶束浓度为9.03×10-5mol/L,可将水的表面张力由73.98 mN/m降至最低27.48 mN/m。在浓度为1×10-3~1.2×10-2mol/L的NaC l溶液中,Surfactin溶液的表面张力随盐浓度升高逐渐降低并最终稳定在34 mN/m;Surfactin在121℃处理20 min后,其表面张力仍能保持在37.10 mN/m;在pH=2~12范围内,其表面活性稳定并良好;表明Surfactin具有较强的NaC l浓度、温度、pH的耐受性。浊度法测得Surfactin亲水亲油平衡(hydrophile lipophilic balance,HLB)值为14,对所需HLB值为12~16的油相乳化性能良好。     

α-癸基甜菜碱的表面活性和胶体性质

研究了两性表面活性剂α-癸基甜菜碱的表面活性与溶液性质.α-癸基甜菜碱亲水基团的立体结构有利于正、负电荷的相互作用,使得表面吸附层和胶束中表面活性剂分子排列更加紧密.实验测得溶液的最低表面张力为38.2 mN/m,临界胶束浓度为6.9×10-3mol/L,胶束形成标准自由能为-22.3 kJ·mol-1,胶束聚集数为74;表面活性剂溶液在等电点pH区域具有最低表面张力和临界胶束浓度.     

季铵盐聚氧乙烯醚三硅氧烷表面活性剂的合成与界面性能

以烯丙基聚氧乙烯醚、环氧氯丙烷和氢氧化钠溶液为原料,采用两步法来合成烯丙基聚氧乙烯缩水甘油醚(APGE),然后在铂催化剂作用下,与1,1,1,3,5,5,5-七甲基三硅氧烷(MDHM)进行硅氢化加成反应制得聚氧乙烯基缩水甘油醚三硅氧烷(PGETS),最后将其与三甲胺盐酸盐进行开环反应合成出季铵盐聚氧乙烯醚三硅氧烷表面活性剂(QASPETSS)。用IR和1HNMR对目标产物的结构进行了表征,并通过测定该水溶液的平衡表面张力研究了其表面活性。结果表明,在临界胶束浓度为6.3×10-4mol/L时,可以将水的表面张力降至22.4 mN/m;饱和吸附量、饱和吸附层中每个QASPETSS分子所占的平均面积和形成胶束的标准自由能分别为3.6×10-6mol/m2、0.46 nm2和-28.2 kJ/mol。     

聚锑酸离子交换剂对锶的吸附行为研究

研究了聚锑酸离子交换剂吸附0.01 mol/L HNO_3溶液中锶的热力学特征,通过吸附动力学实验,初步探讨了温度对吸附过程的影响.结果表明,聚锑酸对0.01mol/L HNO_3溶液中锶的吸附符合Freundlich 经验公式,表现为吸热的化学吸附过程.根据毛细孔扩散模型,由平衡数据和动力学曲线计算了锶在聚锑酸离子交换剂颗粒内液相有效扩散系数为8.18×10~(-9)cm~2/s(20℃)和1.33×10~(-8)cm~2/s(30℃).     

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.     

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.     

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。