水性丙烯酸酯复膜胶的制备

以丙烯酸异辛酯(2-EHA)和丙烯酸正丁酯(n-BA)为软单体,甲基丙烯酸甲酯(MMA)为硬单体,甲基丙烯酸羟丙酯(HPMA)和丙烯酸(AA)为功能单体,正十二烷基硫醇(NDM)为分子量调节剂,乙酸乙酯(EAc)为溶剂,采用溶液聚合法制备了一种水性丙烯酸酯复膜胶,并讨论了单体、溶剂、引发剂、NDM、反应温度和时间对合成树脂及复膜胶性能的影响。研究结果表明:当反应时间为5 h、采用半连续加料方式、w(EAc)=50%和w(NDM)=1%(均相对于单体总质量而言)时,聚合体系稳定,单体转化率为89%,复膜胶的剥离强度为0.64 k N/m。     

相反转乳化法制备无皂苯丙水溶胶

以1,4-二氧六环为溶剂,偶氮二异丁腈(AIBN)为引发剂,采用相反转乳化法合成了苯乙烯/丙烯酸丁酯/甲基丙烯酸/丙烯酸羟乙酯(St/BA/MAA/HEA)四元共聚物无皂水溶胶。考察了水溶胶制备过程中亲水性单体配比、中和度、助溶剂用量对水溶胶性能的影响。结果表明,亲水性单体MAA对苯丙共聚物的自乳化起了主要作用,随着MAA用量的增多,水溶胶粒子的粒径减小,HEA用量的增多使得水溶胶的贮存稳定性增强,中和度的提高和助溶剂用量的增大将会使得水溶胶的粘度急剧增大。     

水溶性丙烯酸树脂的制备研究

用于水性油墨的水溶性丙烯酸树脂由丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、丙烯酸(AA)三种单体采用传统的自由基溶液聚合方式合成,通过大量的对比实验筛选了各种不同的反应条件,获得了最佳合成工艺,包括引发剂、溶剂、加料方式、聚合时间和温度。对影响树脂性能的指标如共聚物组成、玻璃化转变温度Tg等各种因素,采用DSC、IR等分析方法进行了详尽的分析和表证。     

丙烯酸/丙烯酸甲酯共聚物聚合工艺研究及其表征

以丙烯酸(AA)、丙烯酸甲酯(MA)为共聚单体,以过硫酸铵和亚硫酸氢钠为氧化还原体系引发剂,异丙醇为链转移剂,以水为溶剂,采用溶液聚合方法,合成P(AA-MA)共聚物,利用红外光谱对合成的共聚物结构和组成进行表征,研究了各因素对共聚物的特性粘数的影响程度,确定了最佳聚合条件为:单体比例为8∶1,加料时间0.5 h,聚合温度80℃,聚合时间2.5 h,过硫酸铵用量6%,亚硫酸氢钠用量2%,异丙醇100%(以单体质量计)。     

水溶性丙烯酸树脂的合成及表征

用于水性油墨的水溶性丙烯酸树脂可以由丙烯酸丁酯（A），甲基丙烯酸甲酯（MMA），丙烯酸（AA）3种单体采用传统的自由基溶液聚合方式合成，通过大量的对比实验，获得了最佳合成工艺，包括引发剂，溶剂，加料方式，聚合的时间和温度，对影响树脂性能的指标如共聚物组成，玻璃化转变温度（Tg)等因素，采用DSC，IR等分析方法进行了表征。     

有机氟改性阴极电泳涂料的制备及性能

以丙烯酸酯类单体和有机氟单体(全氟烷基乙基丙烯酸酯,TEAc-N)为原料,采用溶液聚合的方式制备了阳离子型有机氟改性丙烯酸树脂并用其制成阴极电泳涂料。通过FT-IR、接触角仪、电导率仪等手段对共聚物树脂及其所配漆液与所得漆膜的性能进行表征,探讨了不同有机氟单体的添加量对电泳涂料性能的影响。结果表明:当有机氟单体的添加量(质量分数)为12%时,漆膜接触角达到了107.5°。改性后的阴极电泳涂料漆膜具有优良的耐腐蚀性。     

丙烯酸-丙烯酸甲酯无规共聚物的聚合及表征

以丙烯酸(AA)、丙烯酸甲酯(M A)为共聚单体,以过硫酸铵和亚硫酸氢钠为氧化还原引发体系,以异丙醇为链转移剂,以水为溶剂,采用溶液聚合法合成了P(AA-M A)无规共聚物。采用红外光谱仪、表面张力仪、透射电子显微镜、热分析仪对共聚物的组成、结构、表面张力、透射形貌和热性质进行了表征。结果表明聚合条件为单体AA/M A(摩尔比)=6/1,异丙醇、过硫酸铵、亚硫酸氢钠添加量都为2%(均以单体计),加料时间30m in,聚合温度60℃,反应时间1.5h。产物为浅黄色黏稠液体,有两头尖的椭球形和球形的两种形态、较好的表面活性和热稳定性。     

5-异氰酸酯-异肽酰氯的合成

5-异氰酸酯-异酞酰氯(ICIC)作为一种关键功能单体可用于制备耐污染的聚酰胺-脲复合反渗透膜。采用反加料方式,以5-氨基-异酞酸为基本原料,在催化剂作用下与酰氯化剂三光气(BTC)反应得到中间体5-氯甲酰胺基-异酞酰氯,再经回流得产品ICIC。对合成工艺如加料方式、催化剂组成及溶剂组合进行了优化,并分析了反应机理。研究结果表明,反加料方式是确保反应顺利进行的首要条件,复合催化剂三乙胺(TEA)/咪唑(Imidazole)的催化效果最佳,而四氢呋喃/氯苯则是反应最理想的溶剂组合。此外,采用红外光谱(IR)、氢核磁(1HNMR)和质谱(MS)分析了产品的化学结构。     

含磺酸基三元聚合物MA-SAS-AM的合成及其阻垢性能研究

用水作溶剂、过硫酸盐为引发剂,以马来酸酐(MA)、烯丙基磺酸钠(SAS)和丙烯酰胺(AM)为单体,通过溶液聚合制备了水溶性高分子MA-SAS-AM。用红外光谱和热分析方法对聚合物进行了表征和分析。探讨了单体配比、引发剂用量、反应温度和分子量调节剂对聚合物阻垢性能的影响。结果表明,MA-SAS-AM三元聚合物对水系统的磷酸盐、硫酸盐和锌盐具有优异的阻垢效果。     

稳定的阳离子型聚合物纳米粒子胶乳的研制

以甲基丙烯酸甲酯 ( MMA)和丙烯酸乙酯 ( EA)为主单体 ,甲基丙烯酰氧乙基三甲基氯化铵( DMC)为功能单体 ,分别采用 4种阳离子乳化剂和阴离子引发剂过硫酸铵 ( A PS)进行自由基乳液共聚合。探讨了乳化剂种类和用量、聚合温度及加料方式对乳胶粒大小、胶乳稳定性和胶膜耐水性的影响。研究发现 ,当采用十六烷基三甲基氯化铵 ( 16 31)作乳化剂 ,用量为 1.75%～ 2 .0 % ,聚合温度为 70℃ ,采用种子半连续法可以成功研制出粒径为 57.5nm、稳定的耐水性较好的阳离子型聚合物纳米粒子胶乳     

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.     

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.