聚天冬氨酸阻垢缓蚀剂的量子化学研究

用量子化学计算的方法,探讨了聚天冬氨酸（PASP）的分子结构和阻垢缓蚀性能的构效关系,计算结果显示,在阻垢性能方面,聚天冬氨酸分子氮原子和羧基团中氧原子呈负电性,这使得羧基上的氧原子易与晶面上的钙离子发生静电交互作用,且PASP分子中两个氮氧原子间距与方解石有关晶面上钙离子间距匹配,因而显著加强了阻垢剂分子与特定晶面之间的吸附力,从而起到了碳酸钙晶体的阻垢效能。在缓蚀性能方面,计算得到了PASP分子最高占据轨道能量、最低空轨道能量以及最低空轨道能量与最高占据轨道能量的差。计算表明结果与机理描述相符合。     

聚天冬氨酸阻垢缓蚀性能量子化学研究

采用量子化学计算方法,研究聚天冬氨酸(PASP)分子结构和阻垢缓蚀性能之间的构效关系。结果表明,PASP分子在阻垢性能方面,由于分子中亚胺基上的氮原子和羧基上的氧原子均具有较强的负电性,使得羧基上的氧原子非常容易与晶面上的钙离子发生静电交互作用,且PASP分子中两个氮氧原子的相对间距与方解石晶面上钙离子间距非常相近,这样良好的匹配性显著增强PASP分子与特定晶面之间的吸附力,从而达到对碳酸钙晶体的阻垢效果,静态阻垢实验结论与计算结果完全一致;PASP分子在缓蚀性能方面,通过量化计算得到PASP分子最高占据轨道能量、最低空轨道能量以及最低空轨道能量与最高占据轨道能量的差值,计算结果与机理描述基本相符,实验验证结论与计算结果完全一致。     

甲叉膦酸型化合物阻垢机理的量子化学研究

运用密度泛函（DFT）理论，在B3LYP／6-31G水平下，系统研究了ATMP，EDTMP，HDTMP，GDMP，MADMP这5种甲叉膦酸类阻垢缓蚀剂分子结构与阻垢性能之间的构效关系。结果表明，5种膦酸分子中的氮原子及膦羧基团中的氧原子上负电荷密度较大，这使得氮原子及膦羧基易与垢晶体中的钙离子发生静电相互作用，如果氮原子与氧原子间距与方解石晶体生长面上的钙离子对间距匹配，将显著增强了阻垢剂分子与特定晶面的Coulomb吸附行为，诱导垢晶体发生畸变，有效地阻止其生长。本文还利用半经验（PM3）方法对分子势能面进行扫描，得出分子能量随二面角改变的变化率，初步探讨了分子柔性、刚性对其阻垢性能的影响。     

聚天冬氨酸与PBTCA的阻垢性能及复合使用效果应用研究

基于聚天冬氨酸优异的缓蚀阻垢性能,试验室人工合成并制得聚天冬氨酸。通过静态阻垢试验可知当聚天冬氨酸与羟基亚乙基二膦酸质量比1∶1混合使用后,阻垢性能优于任一单体。在PASP与PBTCA使用量1∶1(质量比)的条件下,复配制得缓蚀阻垢剂。通过静态缓蚀、阻垢试验和动态模拟试验得出,复合缓蚀阻垢剂投加量为30 mg/L时,缓蚀阻垢效果显著。     

电厂循环水绿色水处理剂阻垢缓蚀性能的研究

采用静态阻垢法、静态挂片法、极化曲线法对绿色水处理剂聚天冬氨酸和聚环氧琥珀酸的缓蚀阻垢性能进行了研究,初步探讨了其缓蚀阻垢机理。通过静态阻垢实验结果可知,聚环氧琥珀酸的阻垢性能好于聚天冬氨酸(PASP),当聚环氧琥珀酸(PESA)和PASP质量浓度达到8mg/L之后阻垢率基本维持在一个水平;通过静态挂片实验结果可以看出PASP的最佳质量浓度为50mg/L,PESA的最佳质量浓度为40mg/L;通过极化曲线法可知PASP和PESA均属于抑制阳极型水处理剂。     

环境友好型聚天冬氨酸水处理剂配方研究

针对聚天冬氨酸(PASP)及其四元复合配方的阻垢缓蚀性能进行研究。聚天冬氨酸具有缓蚀和阻垢双重功能,但用做缓蚀剂时用量较大(100 mg/L)。为了降低成本,对聚天冬氨酸、苯并三氮唑(BTA)、钨酸钠和葡糖酸钠进行四元复配研究,通过正交试验得到最佳配比:PASP∶BTA∶钠钨酸钠∶葡萄糖酸钠是10∶0.5∶20∶10(总浓度为40.5 mg/L),该配方对铜的阻垢率和缓蚀率分别为99.22%和0.000 6 mm/a,具有较好的阻垢缓蚀效果。     

聚天冬氨酸的合成及其性能研究

以马来酸酐和氨水为原料合成聚天冬氨酸.用红外光谱和核磁共振对聚天冬氨酸进行了结构表征,用黏度法测定了聚天冬氨酸的黏均分子量,用静态阻垢法评价聚天冬氨酸的阻垢性能,用旋转挂片法测定聚天冬氨酸的缓蚀性能;比较聚天冬氨酸与水解聚马来酸酐( HPMA)、氨基三甲叉膦酸(ATMP)的阻垢缓蚀性能.结果表明,最适宜合成工艺条件为:n(马来酸酐)∶n(氨水)=1∶1.1,热聚温度160℃,缩聚时间60 min;当阻垢剂浓度大于6.4 mg/L时,PASP和ATMP的阻垢性能相当,均优于HPMA.     

聚天冬氨酸的改性对阻垢分散性能的影响

将聚琥珀酰亚胺(PSI)与天冬氨酸(ASP)、2-氨基乙磺酸(SEA)分别进行反应,对聚天冬氨酸进行改性,并对改性聚天冬氨酸的阻CaCO3垢、分散Fe2O3和缓蚀性能进行了评定。实验结果表明:在PASP分子结构中引入羧基可以提高其阻垢率,而磺酸基的引入则会降低其阻垢率,当引入羧基的改性聚天冬氨酸质量浓度为6mg/L时,阻垢率达到了100%;磺酸基的引入可以大大提高聚天冬氨酸的分散性能,加药质量浓度为10mg/L,分散Fe2O3时上清液最小透光率为40.3%;羧基的引入有助于缓蚀性能的提高,加药质量浓度为100mg/L时,比PASP的缓蚀率提高35%以上。     

聚天冬氨酸阻垢与缓蚀的研究现状与展望

聚天冬氨酸因具有的高阻垢性能、良好的生物降解性和无毒性等优点已成为21世纪缓蚀阻垢剂的发展方向.文章首先从聚天冬氨酸结构上分析了其阻垢与缓蚀机理;然后,阐述了聚天冬氨酸合成方法、改性技术及在阻垢与缓蚀方面的研究现状;最后,介绍了聚天冬氨酸作为缓蚀阻垢剂的发展趋势.     

新型水处理剂聚天冬氨酸缓蚀、阻垢机理的光度分析

采用紫外分光光度法分别测定了新型水处理剂聚天冬氨酸（PASP）、锌与聚天冬氨酸复配物（Zn-PASP）、钙-聚天冬氨酸（Ca-PASP）的吸收光谱,研究了锌与聚天冬氨酸复配物的缓蚀机理及PASP对Ca的阻垢机理。     

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.     

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.