羟基碳纳米管对氟硅树脂涂层防腐性能及耐水稳定性的影响

研究了一种海洋用铝合金6061基材低表面能防腐涂层的制备方法,利用空气喷涂法将氟硅树脂、固化剂、改性纳米材料羟基碳纳米管(CNT-OH)等形成的混合液喷涂在基材上形成涂层。对CNT-OH/氟硅树脂复合涂层的接触角/滚动角、表面能、硬度、附着力、表面形貌、耐水性、耐腐蚀性等性能进行了表征测试。结果表明:当添加0.3%CNT-OH(以氟硅树脂质量计)时,复合涂层的接触角/滚动角分别为121°/21°,表面能为22 m N/m;复合涂层表面具有一定的微观粗糙结构,均方根粗糙度达到3.078 nm;涂层的硬度和附着力分别达到5H和0级;不同温度和盐度条件下,经过浸泡试验和盐雾箱试验25 d后,复合涂层仍表现出良好的耐水性和耐盐水腐蚀性。可认为,CNT-OH对氟硅树脂具有良好的改性作用。     

有机氟低表面能涂料的研究进展

简要介绍了新型、环保的有机氟低表面能涂层的现状及国内外的最新研究进展;同时,结合有机氟低表面能涂层优良的环保特性,分析、讨论了在舰船上使用的可行性;最后,展望了有机氟低表面能涂料应用前景及发展动向。     

低表面能材料上海洋生物附着的研究

考察了不同表面状态的聚四氟乙烯材料和含有机氟、有机硅涂层的防污性能。低表面能材料上的污损生物附着不牢。聚氨酯、醇酸、氯醋乙烯等树脂为基料的涂层防污性差;而涂层中有机硅橡胶的含量比聚四氟乙烯更有利于防止海洋生物的附着。     

氟硅溶胶-气相纳米SiO2复合超疏水涂层的制备

以气相纳米SiO2和氟硅溶胶为原料,通过多层堆积法在玻璃表面制备复合超疏水涂层,涂层的表面形貌和疏水性分别通过扫描电镜和接触角测量仪进行表征,重点考察了氟硅溶胶与气相纳米SiO2质量比及涂装层数对涂层疏水性、附着力和硬度的影响.结果证明:氟硅溶胶可在无定型气相纳米SiO2表面形成团簇状微球结构,形成兼具低表面能和高粗糙...     

低氟含量低表面能自清洁氟碳涂料的研究

以氟单体和丙烯酸酯类单体通过聚合物的分子结构设计，合成了一类总氟含量不超过12％的低氟含量的含氟丙烯酸树脂，所制备的氟碳涂料的涂层的表面能低，具有自清洁功能。分析了该涂层中极性与非极性官能团的分子取向机理，测定了纯水水珠在不同含氟单体均聚物和共聚物清漆漆膜上以及在含氟丙烯酸树脂涂层上的接触角，探明了含氟丙烯酸树脂涂层的总氟含量与表面能的关系、含氟官能团在涂层中的分布，探讨了低氟含量的含氟丙烯酸树脂涂料的涂层自清洁机理。     

氟硅低聚物杂化疏水表面的盐水污垢特性

采用溶胶-凝胶法制备了一种氟硅低聚物杂化疏水材料并在铜基表面上涂覆了疏水涂层.基于动态热阻法,在盐度为0%和7%的条件下,测试了改性表面的盐水抗垢性能.结果表明,涂覆了氟硅低聚物杂化疏水涂层具有较低的表面能,垢层与金属表面之间的附着力差,污垢不易沉积.不同盐度下涂覆涂层的污垢热阻的渐进值低于铜表面的渐进值,抗垢效果明显.     

纳米二氧化钛/氟树脂超疏水涂层的制备及性能

以金红石型纳米TiO2及自制的氟树脂制备了氟碳涂料,采用刷涂法于铁片表面构筑了超疏水涂层。考察了纳米TiO2与氟树脂用量、热处理温度等对涂层疏水性的影响,并分别用扫描电镜(SEM)、接触角测量仪观察和测试了涂层表面的微观结构及疏水性。结果表明,涂层表面的水接触角随着氟树脂用量的增加而增大,随纳米TiO2用量的增加呈先增后减的趋势。涂层的吸水率随着氟树脂用量的增加而减少,随纳米TiO2用量的增加呈先减后增的趋势。随着热处理温度的升高,涂层的水接触角先增后减,吸水率先减后增。最佳工艺条件是TiO2及氟树脂的质量分数分别为12%与40%,热处理温度170℃。此条件下得到的涂层表面具有微/纳二元粗糙结构,对水静态接触角达152°,为超疏水涂层,并具有优异的耐水、耐酸碱、耐洗刷、耐沾污及自清洁性能。     

短氟碳链含氟硅烷偶联剂及其疏水涂层的构建

以三氟丙基甲基环三硅氧烷(D3F)、二甲基氯硅烷、甲基二氯硅烷、乙烯基三甲氧基硅烷(VTMS)为主要原料,通过阴离子开环聚合和硅氢加成反应合成了一系列短氟碳链含氟硅烷偶联剂。载玻片表面经纳米二氧化硅溶胶涂膜和硅烷偶联剂表面修饰得到疏水涂层。探究了不同硅烷偶联剂对于涂层疏水性、附着力、硬度、透过率等性能的影响。结果表明,同类型含氟硅烷偶联剂中氟含量越大,其修饰的涂层接触角越大;相似相对分子质量及氟含量情况下,直链型含氟硅烷偶联剂修饰的涂层疏水性优于支链型修饰的涂层。经含氟硅烷偶联剂修饰的疏水涂层中,接触角最大的是由聚合度为9的支链型含氟硅烷偶联剂(DF3)修饰的涂层,可达141.6°。疏水涂层的附着力均达1级,硬度均达H,可见光透过率高于82.9%,具有良好的自清洁性能。     

超疏水氟硅涂层的制备及性能研究

文章采用溶胶凝胶法将GPTM、TEOS、氟硅烷等前驱体通过表面烷基化来制备杂化超疏水涂层。通过多种实验表征手段对超疏水涂层进行分析,发现前驱体GPTM与TEOS摩尔比为2,氟硅涂层经8%TMCS正己烷溶液修饰后,可得到水接触角为153.54°,透光率为76.2%的透明超疏水涂层。     

不同颜色色浆对氟树脂/铝低红外发射率涂层的影响

研究了大红、深黄、水紫、黑色4种颜色色浆对氟树脂/铝低红外发射率涂层光泽、附着力、硬度、粗糙度、耐冲击性、色差、红外发射率、耐腐蚀性等性能的影响。研究结果显示:深黄色色浆涂层的发射率最低,约为0.1;不同色浆对氟树脂涂层色差明度影响不同,相对于其他色浆,水紫能够使涂层偏暗;大红、深黄、水紫色浆的涂层硬度均为6H;加深黄色浆的涂层附着力最好,其次是大红色浆和水紫色浆;深黄色浆对涂层的耐冲击性影响最大,其次是大红色浆和水紫色浆;相对于大红、深黄、黑色色浆,水紫色浆涂层具有最低的粗糙度,表面比较光滑;水紫色浆和深黄色浆的红外波峰比较持平,有利于减小表面发射率;水紫色浆氟树脂涂层的耐腐蚀性能最好。耐盐水腐蚀测试后4种涂层均没有明显失光,水紫涂层没有发生明显变色,深黄和黑色涂层起泡密度较低。水紫色浆因其粒径均匀细小,在氟树脂涂料中易分散,与氟树脂相容性好,因此具有相对较优的综合性能。     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.