一种新的非离子型乳化液膜体系的稳定性研究

制备了一种新的非离子型乳化液膜体系OP-4/D2EHPA/液体石蜡/煤油/盐酸,通过测定乳液电导率、破损率、溶胀率、乳滴粒径大小等,研究了乳化剂浓度、油内比、D2EHPA皂化度、内相盐酸浓度以及温度等因素对乳液稳定性的影响,并与以液膜传统专用乳化剂Span80、ENJ-3029、兰-113A所制得的W/O型乳液进行了加热破乳对比实验。结果表明该乳液体系表现出两个异常的稳定特性:(1)随着OP-4浓度的增加,乳液稳定性呈现先增加后下降的现象,OP-4在油相中的浓度为3%～5%(wt)时,乳液的稳定性较好。(2)当温度低于45℃时乳液表现出相当好的稳定性,温度超过50℃后乳液稳定性急剧下降。加热破乳对比实验表明,该乳液在60℃加热破乳10min,破乳率达100%,而分别以专用乳化剂Span80、ENJ-3029、兰-113A制备的乳液在60℃下加热60min仍不能破乳。通过控制适当条件,可以制备常温稳定性好而加热条件下容易破乳的乳化液膜体系。     

硅丙微乳液的合成与性能研究

以丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)和有机硅(KH-560)为共聚单体,十二烷基硫酸钠(SDS)和辛基酚聚氧乙烯醚(OP-10)为复合乳化剂,采用种子乳液聚合法制备硅丙微乳液。通过单因素试验法优选出制备硅丙微乳液的最佳工艺条件。结果表明:当聚合反应温度为80℃、反应时间为3 h、m(BA)∶m(MMA)=4∶3、w(KH-560)=8%、复合乳化剂中m(OP-10)∶m(SDS)=1∶2且w(复合乳化剂)=3%时,单体转化率超过70%,硅丙微乳液具有良好的稳定性和耐介质性能。     

微波辐照下聚硅氧烷微乳液的制备及动力学研究

以八甲基环四硅氧烷(D4)为原料,十二烷基苯磺酸(DBSA)为催化剂,十二烷基苯磺酸钠(SDBS)和聚乙二醇辛基苯基醚(OP-10)为复配乳化剂,在微波辐照下制备聚硅氧烷微乳液。讨论了反应条件对微乳液制备的影响,结果表明,反应温度80℃,D4、DBSA、SDBS和OP-10分别为微乳液质量的15%,3%,4%和1%时微乳液的流体力学半径最小。进一步研究了反应条件对反应动力学的影响,结果表明,温度越高,催化剂用量越大,D4转化速率越快,但最终的平衡转化率接近。     

苯丙乳液聚合稳定性研究

采用乳液聚合的方式,以十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)和壬基酚聚氧乙烯醚(OP-10)为乳化剂,合成了含功能性单体丙烯酸的苯乙烯/丙烯酸丁酯的共聚乳液.考察了不同的反应温度、不同的引发剂用量、不同的乳化剂用量和配比等因素对聚合反应工艺的影响,发现当引发剂质量分数0.5%,乳化剂质量分数4%,SDS、SDBS和OP-10的质量比为2:1:9,反应温度为80 ℃±2 ℃,丙烯酸含量为2%时乳液的凝聚率最低.     

微乳液法制备导电聚苯胺及其在防腐涂层中的应用

采用微乳液聚合法,以十二烷基苯磺酸(DBSA)和盐酸(HCl)为掺杂剂、OP-10为助乳化剂、过硫酸铵为氧化剂,制备了聚苯胺悬浮液。探讨了主要原料用量和工艺参数对聚苯胺电导率的影响,确定最优反应条件为:n(DBSA):n(HCl)=3:2,n(酸):n(苯胺)=2:1,n(氧化剂):n(苯胺)=1:1,m(OP-10):m(苯胺)=2:3,反应时间9 h,反应温度30℃。将所制聚苯胺悬浮液直接与水性环氧乳液混合均匀后加入配套固化剂,通过电化学测量和浸泡试验研究了所得涂层的防腐性能。结果表明其防腐性能相比纯环氧涂层得到非常大的提高。     

苯乙烯-丙烯酸乙酯微乳液制备工艺研究

以苯乙烯、丙烯酸乙酯为主要单体,以十二烷基硫酸钠(SDS)和辛基苯酚聚-氧乙烯醚(OP-10)组成混合乳化体系,以过硫酸钾(KPS)为引发剂,采用半连续微乳液聚合的方式制备丙烯酸酯微乳液。考察了单体配比、聚合温度、乳化体系配比、引发剂等因素对乳液性能的影响。当单体配比为m(EA)∶m(MMA)=1∶1、聚合温度为75～76℃、乳化剂用量共计25 g且SDS/OP-10=3∶2、引发剂用量为1.0g,且采取聚合中期补加KPS溶液的方式补加、丙烯酸用量为3%,体系的p H值在7～8时制得的微乳液的产品性能最好。     

低乳化剂含量丙烯酸酯微乳液的合成与性能

以脂肪醇聚氧乙烯醚硫酸钠(AES)/辛基酚聚氧乙烯醚(OP-10)为阴/非离子型复合乳化剂,制备了低乳化剂含量的丙烯酸酯微乳液。探讨了搅拌速率、聚合温度、复合乳化剂类型和用量、pH值及聚合中期引发剂补加方式等对丙烯酸酯微乳液的稳定性、透光率、粒径及其分布等影响。结果表明:当搅拌速率为120~160 r/min、聚合温度为75~76℃、复合乳化剂中w(AES+OP-10)=2%且m(AES)∶m(OP-10)=3∶1时,丙烯酸酯微乳液的稳定性最高(凝胶率为0),并且其透光率为68.7%、平均粒径为37.8 nm且粒径分布较均匀。     

环氧改性水性聚氨酯涂料印花粘合剂的研制

用环氧树脂改性水性聚氨酯(WPU)乳液来提高胶膜的耐水性、耐溶剂性、耐化学品性以及力学性能。讨论了环氧树脂的加入量和加入方式对乳液性能的影响。确定了水性聚氨酯乳液的制备工艺条件:nNCO/nOH=2:1,预聚温度65～70℃,反应2h;使用3.71%～4.63%的DMPA进行亲水改性,且DMPA要用N-甲基-2-吡咯烷酮溶解后加入;扩链时间2h;乳化温度<5℃。得到了共聚法制得的环氧树脂改性WPU性能较优、且环氧树脂加入量6%为宜的结论。     

OP-10/n-C5H11OH/c-C6H12/H2O体系W/O微乳液稳定条件的研究

对OP-10／n-C5H11OH／c-C6H12／H2O体系W／O微乳液的相组成和性质进行研究,并分析了液晶相出现的原因,结果表明,当OP-10／n-GH5H11OH质量比为4：1时。具有较宽范围的W／O微乳相区域,且该微乳液体系对整个pH变化不敏感,在10℃--32℃范围内,温度变化对微乳液稳定区无太大的影响。     

甲醇柴油微乳液制备及稳定性的实验研究

复配油酸,二乙醇胺,span80,op-4四种表面活性剂,将其加入到加甲醇柴油混合体系中,制备甲醇柴油微乳液,并采用正交试验方法与粘度指数法,考察了制备温度,搅拌时间,搅拌速度,助表面活性剂用量,甲醇含量5种因素对甲醇柴油微乳液稳定性的影响程度。实验结果表明,当m(油酸)/m(二乙醇胺)/m(span80)/m(OP-4)=10∶2∶3∶2时,可增溶甲醇量最大,正交试验结果表明:样品粘度指数最小,50℃恒温前后的粘度变化最小,为稳定性最佳的甲醇柴油微乳液配方,显著性检验结果表明影响因素作用程度依次为:甲醇含量制备温度搅拌时间助剂用量搅拌速度。在试验温度为30℃,搅拌时间为12 min,搅拌速度为300 r/min时,添加甲醇质量分数为5%的实验条件下制备甲醇柴油微乳液。     

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.