Wettability of Highly Fluorinated Polymer Coatings

Wettability of a linear polymer is a function of backbone structure, side-chain substitution, and fluorination. For a polymer to be suitable as a thin coating, a convenient method of application is mandatory to insure continuity and adherence to the respective substrate. Wetting properties of highly fluorinated ethylenic and methacrylic polymers are examined. The latter have proven to be effective barrier films for the prevention of liquid spreading in certain applications, and the effect of solvents on the wetting and adhesion of such films and on their stability with a variety of liquids are discussed.     

一类高透明含氟共聚型聚酰亚胺的合成与表征

以2,2′-双(三氟甲基)-4,4′-二氨基联苯(TFMB)、4,4-二氨基二苯醚(ODA)和3, 3′,4,4′-二苯醚四甲酸二酐(ODPA)为原料,间甲酚为溶剂,按不同的配比,采用一步法制备了一系列低成本含氟共聚型聚酰亚胺CPI-1～CPI-4,进一步制备成膜。通过红外光谱仪、核磁共振波谱仪对该系列含氟聚酰亚胺的结构进行了表征确认。采用UV光度计、TGA、DSC、拉伸性能试验机对其溶解性能、光学性能、热性能、机械性能进行了测试。结果表明,该系列含氟聚酰亚胺室温下能溶于二甲基亚砜(DMSO)、N,N-二甲基乙酰胺(DMAc)、三氯甲烷(CHCl_3)等有机溶剂,具有较好的溶解性和成膜性。所制薄膜具有优良的光学透明性,在紫外光波长400nm时的透光率均在70%以上。CPI-1～CPI-4的起始分解温度均大于500℃,N_2氛围下800℃的质量残留百分数均在52%以上,玻璃化转变温度在166～170℃。此外,CPI-1～CPI-4薄膜的拉伸强度在89.8～105.3MPa,弹性模量在1.3～1.7 GPa,断裂伸长率在9.7%～18.4%,表现出较好的机械性能。     

Radical Copolymerization of a Highly Fluorinated Cyclic Olefin Octafluorocyclopentene with Alkyl Vinyl Ethers

Summary Fluoropolymers are potential candidates for use in the fields of specific coating and lithography. Their versatility could be enhanced by increasing their glass transition temperature, T _g . In order to achieve this, the copolymerization of a highly fluorinated cyclic monomer, octafluoro-cyclopentene (OFCPE), with three kinds of alkyl vinyl ethers was investigated with a radical initiator in bulk. It was found that OFCPE and cyclohexyl vinyl ether (CHVE) copolymerized successfully, and the weight average molecular weight and T _g of the copolymer reached values of 12,000 and 124.9°C, respectively. Copolymer composition was close to a OFCPE:CHVE unit ratio = 0.5:0.5. The monomer reactivity ratios estimated by the Yamada-Itahashi-Otsu nonlinear least-squares procedure were found to be r _1,OFCPE = 0.005 ± 0.020 and r _2,CHVE = 0.154 ± 0.017.     

全氟丁基磺酰氟季胺盐的合成研究

含氟表面活性剂作为特种表面活性剂的一种,正凭借其高表面活性、优良的耐热性、稳定性以及憎水、憎油的特性,在工业生产中起到不可替代的作用.选择比较了几种常用的表面活性剂合成方法,并合成了全氟丁基磺酰氟季铵盐.     

Highly Diastereo‐ and Enantioselective Vinylogous Mannich Reactions of Fluorinated Aldimines with Siloxyfurans

A highly regio‐ and enantioselective asymmetric vinylogous Mannich reaction of readily available fluorinated aldimines bearing a chiral auxiliary [(S)‐1‐phenylethyl group] with siloxyfurans to afford chiral fluorine‐containing γ‐butenolide or γ‐lactone derivatives has been developed in the presence of silver acetate (10 mol%) and axially chiral phosphine‐oxazoline ligand L1 (11 mol%). In most cases, the corresponding fluorinated adducts were obtained in high yields, good to excellent enantiomeric excesses and up to>20:1 dr.     

Carbocations as Lewis Acid Catalysts: Reactivity and Scope

One class of potential Lewis acids that has received negligible attention as a catalyst is the carbocation. Here we show the potential of triarylmethylium ions as highly powerful Lewis acid catalysts for organic reactions. The Lewis acidity of the triarylmethylium ion can be easily tuned by variation of the electronic properties of the aromatic rings and the catalytic activity of the carbocation is shown to correlate directly to the level of stabilization of the empty p_C‐orbital at the cationic carbon. The versatility of triarylmethylium ions as efficient Lewis acid catalysts for organic reactions is demonstrated in Diels–Alder, aza‐Diels–Alder, conjugate addition, halogenation, epoxide rearrangement and intramolecular hetro‐ene reactions.

     

碳氟表面活性剂

介绍了碳氟表面活性剂的主要物理化学性质,合成方法,国际,国内碳氟表面活性剂的发展及现状。介绍了碳氟表面活性剂的最新进展,特别是一些新型碳氟表面活性剂的主要性质和用途。分析了我国碳氟表面活性剂发展缓慢,与国外形成巨大反差的原因,并对进一步发展我国的碳氟表面活性剂工业提出了自己的看法。     

纳米级ATO在含氟聚丙烯酸酯乳液中的应用研究

通过原位聚合法制备得到ATO/含氟聚丙烯酸酯(PA-F)复合乳液,其中纳米级ATO加入量分别为PA-F树脂质量的0、2%、4%、6%、8%、10%,考察了ATO用量对复合乳液平均粒径及乳液胶膜的光学性能及其他常规性能的影响。结果表明:随着ATO用量的增加,乳液的粒径趋于增大,但体系足够稳定;胶膜的可见光部分的平均透过率并没有太大的影响,平均透过率均高于80%,而近红外部分的平均透过率却急剧下降。当ATO含量为10%时,红外波段的平均透过率仅为39.95%,比纯PA-F胶膜下降了54%,而可见光透过率为81.43%,降幅只有4%。     

氟表面活性剂和氟聚合物(X)——氟涂料

氟涂料是含氟化学品的重要应用领域之一。介绍了氟涂料的性能特点、发展历程、类型、制备方式和应用领域,分析了国内氟涂料市场现状、发展趋势和研究热点,并对我国在该领域的发展前景进行了展望。     

The Protonation of Aromatic π Carbocations. The Behavior of 2-Hydroxy- and 9-Hydroxyphenalenone in Trifluoromethanesulfonic Acid

In continuation of work on the protonation of aromatic π carbocations, the behavior of 1,2-dihydroxyphenalenyl cation ( 7 ) and 1,9-dihydroxyphenalenyl cation ( 8 ) in CF₃SO₃D was investigated. The behavior of carbocation 8 was unexceptional. It underwent a facile exchange at room temperature, with H-2, H-5 and H-8 all exchanging at comparable rates. Carbocation 7 , on the other hand, exchanged at an exceptionally slow rate, even at 100°C. The order of reactivity of the various sites on 7 was found to be H-3 ≫ H-5 ⪖ H-4 ≈ H-6; H-7, H-8 and H-9 did not exchange. These unusual results are best accommodated by assuming that most, if not all, of the exchange actually occurs on 2-hydroxyphenalenone ( 9 ) which is present in very low concentration. Hückel calculations support this contention.     

Fluorinated polyphosphazene polyelectrolytes

Polyphosphazene polyelectrolytes containing various amounts of hydrophobic fluorinated moieties and ionic carboxylic acid groups were synthesized. Polymer compositions and molecular weights were characterized by NMR and gel permeation chromatography. Interestingly, poly[(carboxylatophenoxy)(trifluoroethoxy)phosphazene] containing 60 mol % fluorinated groups was found to be soluble in aqueous solutions. The behavior of fluorinated polyelectrolytes in reactions of ionic complexation with multivalent and monovalent salts was studied in aqueous solutions and ethanol–water mixtures. Such reactions led to the formation of ionotropic hydrogels under mild conditions and, thus, are of importance to the development of microencapsulation processes and controlled release formulations. All of the synthesized polymers underwent phase separation in the presence of multivalent ionic crosslinkers, such as spermine and calcium chloride. This included a water‐soluble polyelectrolyte containing 40 mol % ionic groups and hydrophobic polymer with only 3 mol % carboxylic acid groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 53–58, 2007     

Design and Generation of Highly Diverse Fluorinated Fragment Libraries and their Efficient Screening with Improved 19F NMR Methodology

Fragment screening performed with ¹⁹F NMR spectroscopy is becoming increasingly popular in drug discovery projects. With this approach, libraries of fluorinated fragments are first screened using the direct‐mode format of the assay. The choice of fluorinated motifs present in the library is fundamental in order to ensure a large coverage of chemical space and local environment of fluorine (LEF). Mono‐ and poly‐fluorinated fragments to be included in the libraries for screening are selected from both in‐house and commercial collections, and those that are ad hoc designed and synthesized. Additional fluorinated motifs to be included in the libraries derive from the fragmentation of compounds in development and launched on the market, and compounds contained in other databases (such as Integrity, PDB and ChEMBL). Complex mixtures of highly diverse fluorine motifs can be rapidly screened and deconvoluted in the same NMR tube with a novel on the fly combined procedure for the identification of the active molecule(s). Issues and problems encountered in the design, generation and screening of diverse fragment libraries of fluorinated compounds with ¹⁹F NMR spectroscopy are analyzed and technical solutions are provided to overcome them. The versatile screening methodology described here can be efficiently applied in laboratories with limited NMR setup and could potentially lead to the increasing role of ¹⁹F NMR in the hit identification and lead optimization phases of drug discovery projects.     

Fluorinated siloxane amine oligomers

Fluorine‐containing siloxane oligomers were made from bis(aminopropyl)tetramethyldisiloxane and trimethyltris(trifluoropropyl)cyclotrisiloxane. These materials were characterized by IR spectroscopy, size exclusion chromatography, nonaqueous colorimetric end group titration, and ¹H‐NMR. The end groups of one oligomer were chemically modified for an increased NMR signal for molecular weight determination. The cyclic trimeric siloxane starting material was additionally studied via ¹³C‐, ²⁹Si‐, and ¹⁹F‐NMR. Two forms of it were used: a white solid obtained at room temperature, and a colorless liquid isolated at low temperature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1315–1320, 2000     

Highly Air‐ and Water‐Stable Fluorinated Ferrocenylphosphine‐Aminophosphine Ligands and their Applications in Asymmetric Hydrogenations

Air‐ and water‐stable fluorinated ferrocenylphosphine‐aminophosphine ligands have been synthesized and applied to the Rh‐catalyzed asymmetric hydrogenation of enamides and α‐dehydroamino acid derivatives. These reactions afforded the corresponding products in good to excellent ees (up to 99.7% ee) and nearly quantitative yields. The combination of the remarkable air‐ and water‐stability with excellent catalytic performance makes these catalysts excellent choices for practical applications.