不对称交流脉冲电位法制备聚8–羟基喹啉薄膜工艺

采用不对称交流脉冲电位法在镀镍工件表面制备聚8–羟基喹啉薄膜。研究了阶跃电位、阶跃时间、重复次数和溶液中8–羟基喹啉含量等工艺条件对电沉积聚8–羟基喹啉薄膜的影响。分别采用塔菲尔曲线测量、扫描电镜和能谱分析对电沉积后工件的耐蚀性、薄膜的表面形貌和组成进行分析。最佳工艺条件为:8–羟基喹啉0.002mol/L,氢氧化钠0.4mol/L,正阶跃电位0.55V,负阶跃电位0.05V,正阶跃时间0.2s,负阶跃时间0.1s,重复次数100。采用最佳工艺处理后,工件的腐蚀电位、腐蚀速率分别为0.32V和4.1581×103g/(m2·h),耐蚀性优于未处理的工件,且与铬钝化处理的工件相当。     

恒电位法电沉积聚8-羟基喹啉薄膜

采用恒电位法在镀镍工件表面制备聚8-羟基喹啉薄膜。研究了沉积电位、8-羟基喹啉浓度、Na OH浓度、沉积时间等工艺条件对薄膜耐蚀性的影响。分别采用盐水周浸泡试验、三氯化铁缝隙试验和Tafel极化曲线法对比研究了恒电位法电沉积试样、循环伏安法电沉积试样和空白工件的耐蚀性。采用扫描电镜表征了聚8-羟基喹啉薄膜的表面形貌。恒电位法沉积的最佳工艺条件为:8-羟基喹啉2 mmol/L,Na OH 0.4 mol/L,电位0.5 V,时间300 s,室温。采用最佳工艺所得薄膜的耐蚀性略优于循环伏安法试样,远优于空白工件。     

镍基电沉积制备聚8-羟基喹啉薄膜

采用8羟基喹啉的碱性水溶液,分别通过循环伏安法和恒电位法在镍基体上电沉积制备了聚8羟基喹啉薄膜。探讨了2种方法制备聚8羟基喹啉薄膜的电化学行为,并对比研究了不同方法所得试样的表面形貌和耐蚀性。结果表明,循环伏安法电沉积聚8羟基喹啉的氧化峰为0.563 V和0.481 V,还原峰则位于0.318 V;恒电位法电沉积聚8羟基喹啉包含聚合物成核和长大2个过程。恒电位法所得聚8羟基喹啉薄膜较循环伏安法所得膜更平整,耐蚀性更好。聚8羟基喹啉薄膜增大了基体表面的电荷转移电阻,隔绝了腐蚀介质,从而有效增强了镍基体的耐蚀性。     

聚吡咯/聚苯胺复合膜的制备及耐腐蚀性能

采用循环伏安法在304不锈钢表面电沉积聚苯胺(PANI)、聚吡咯(PPY)及其复合膜(PANI/PPY)。用扫描电镜(SEM)和红外光谱(FT-IR)观察膜的表面形貌和组成,通过动电位极化曲线和电化学阻抗谱(EIS)研究了空白钢片、纯PAN膜、纯PPY膜以及苯胺(AN)与吡咯(PY)不同用量所得复合膜在0.30mol/LH2SO_4+3.5%NaCl溶液中的腐蚀行为,并利用三氯化铁点腐蚀试验印证了最优条件下所制复合膜对不锈钢的保护作用。结果表明:苯胺与吡咯的浓度比、扫描速率和循环次数对PANI/PPY复合膜的耐蚀性影响显著。当苯胺与吡咯的浓度比为7:3,扫描速率为50mV/s,循环次数为30圈时,可制得致密度高、表面均匀和结合力良好的PANI/PPY复合膜,该复合膜在0.30 mol/L H2SO_4+3.5%NaCl溶液中具有良好的耐蚀性,可以明显改善不锈钢在氯离子环境中的耐孔蚀能力。     

导电聚苯胺膜的合成及其防腐性能

为了增强不锈钢(SS)双极板的耐腐蚀性能,采用循环伏安法(CV)在316L不锈钢(SS)表面电合成聚苯胺(PANI)薄膜。以0.2 M H_2SO_4+x NaCl水溶液为腐蚀介质,通过测量开路电位(OCP)、Tafel极化曲线和电化学阻抗谱(EIS),研究Cl-浓度对PANI/316L SS复合体系腐蚀行为的影响。结果显示:随着CV循环次数的增加PANI薄膜逐渐变厚;Cl~-浓度对PANI/316L SS耐腐蚀性能影响显著,随Cl~-浓度的增大,PANI/316L SS体系的耐蚀性降低。     

铜表面聚多巴胺辅助功能化防腐涂层的构建及性能

为了提高金属铜在中性盐环境中的耐腐蚀性,采用聚多巴胺（PDA）辅助共沉积法构建了高性能防腐涂层。通过引入聚乙烯亚胺（PEI）促进多巴胺单体（DA）的交联聚合,并利用 8-羟基喹啉（8-HQ）缓蚀剂强化涂层防腐稳定性。采用衰减全反射傅立叶变换红外光谱（ATR-FTIR）、扫描电子显微镜（SEM）和电化学测试系统探究了不同种类PDA基涂层及不同DA/PEI比例的 PDA/PEI/8-HQ复合涂层成分、形貌和耐腐蚀性,并剖析了涂层的防腐机理。结果表明：DA与 PEI浓度比为1∶1时,结构致密的 PDA/PEI/8-HQ涂层可充分发挥 PDA、PEI与 8-HQ缓蚀剂的协同作用,涂层体系自腐蚀电流密度低至 0. 48 μA/cm²,并可对铜提供稳定、优异的腐蚀防护作用。     

聚三聚氰胺导电聚合物薄膜修饰电极用于高酸度水溶液测定

在含有三聚氰胺单体的溶液中,采用循环伏安法电聚合成功制备了导电聚合物聚三聚氰胺薄膜修饰玻碳电极,研究了该修饰电极在不同浓度的盐酸溶液中电化学响应。研究表明,循环伏安图中具备一对可逆性良好的氧化还原峰,且氧化峰的峰电位与盐酸浓度在0.1~10.0 mol/L范围内分两段呈线性关系:在0.1~1.2 mol/L和1.4~10.0 mol/L,线性回归方程分别为Epa(V)=0.5256CH++0.1977,R2=0.9936;Epa(V)=0.01908 CH++0.2421,R2=0.9935;并进一步考察了对模拟强酸稀土提取液的酸度检测,具有良好的选择性和稳定性。该导电聚合物薄膜修饰电极制备方法简单快捷,可广泛应用于高酸度水溶液酸度的直接测定。     

ZrO2颗粒浓度对钕铁硼Ni-P/ZrO2复合镀层耐蚀性的影响

采用化学镀技术在钕铁硼表面制备出Ni-P/ZrO2复合镀层,并研究了ZrO2颗粒浓度对复合镀层中ZrO2颗粒含量、复合镀层的形貌、孔隙率和耐蚀性的影响.结果表明,ZrO2颗粒浓度在0.5～4.0 g/L范围内时,复合镀层的耐蚀性随着ZrO2颗粒浓度增加逐步改善,在不同腐蚀介质中的平均腐蚀速率都呈现减小的趋势,主要归因于...     

2,4,6-三氯苯酚在多壁碳纳米管修饰电极上的电化学行为研究

利用多壁碳纳米管较高比表面积、良好导电性和生物相容性等优良性能,制备多壁碳纳米管修饰玻碳电极,并研究2,4,6-三氯苯酚在多壁碳纳米管修饰电极上的电化学行为及其测定方法。采用滴涂法制备的多壁碳纳米管修饰玻碳电极作为工作电极,用循环伏安法测定2,4,6-三氯苯酚。结果表明,在最优的实验条件:pH=6.0的磷酸盐缓冲液,分散液的修饰量为5μL,扫描速率为50 mV/s下,2,4,6-三氯苯酚的浓度在10～110μmol/L内与对应的峰电流呈线性关系,相关系数为0.995 8,检出限为1.81×10^(-5)μmol/L。并且进行实际水样测试,回收率在95.72%～103.25%。所建立的检测2,4,6-三氯苯酚新方法灵敏度高、操作简单、测定线性范围宽,可用于2,4,6-三氯苯酚的快速检测。     

电化学阻抗谱在电沉积研究中的应用(三)

文章的第三部分介绍了电化学阻抗谱在Ni–SiC复合镀、化学镀镍和镀层性能(耐蚀性、电化学行为和腐蚀行为)研究中的应用。     

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.     

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.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。