多巴胺改性空心玻璃微珠表面化学镀银工艺

先采用多巴胺溶液活化空心玻璃微珠(HGM),再化学镀银。研究了硝酸银质量浓度、葡萄糖质量浓度和装载量对银利用率和镀银HGM导电性的影响。采用扫描电镜(SEM)和能谱仪(EDS)分析了镀银HGM的形貌和表面成分。结果表明,经多巴胺活化后,HGM表面成功附着了一层聚多巴胺膜。当硝酸银质量浓度为15 g/L、葡萄糖质量浓度为30 g/L和装载量为4 g/L时,镀液中的银利用率达71.5%,镀银HGM的导电性良好(体积电阻率为34 mΩ·cm),表面银层均匀、致密。     

空心玻璃微珠偶联化学镀银的研究

使用氨丙基三乙氧基硅烷偶联剂改性空心玻璃微珠表面,然后直接实施化学镀银,借助红外光谱、扫描电镜和X-射线衍射测试手段对偶联改性效果、镀层表面形貌和结构进行了表征.测试结果表明,与胶体钯活化法和硝酸银活化法化学镀银相比,空心玻璃微珠偶联表面改性直接化学镀银的镀层更为致密、均匀,银利用率高,导电性好,结合力强.     

电磁屏蔽剂银/镍/玻璃微珠粉体的制备与性能

采用化学镀法在玻璃微珠表面先沉积镍镀层、再化学镀银,制备了Ag/Ni/玻璃微珠复合粉体。讨论了活化剂氯化钯和主盐硫酸镍的浓度、镀液pH对玻璃微珠表面化学镀镍层表面形貌的影响,得出了较佳的镀镍工艺条件:PdCl20.3g/L,NiSO4·6H2O30g/L,pH11。在此基础上化学镀银,采用扫描电镜和能谱分析对Ag/Ni/玻璃微珠结构进行了表征,测试了粉体的体积电阻率、介电常数、磁导率和磁性能。结果表明,镀镍玻璃微珠表面成功包覆一层银,Ag/Ni/玻璃微珠复合粉体的体积电阻率由Ni/玻璃微珠的2.28×104·cm降低至7.64×105·cm,导电性、介电损耗和磁损耗均提高;Ag/Ni/玻璃微珠粉体的饱和磁化强度为27.2emu/g,可以作为一种宽频电磁屏蔽材料的填料。     

电磁屏蔽材料用银包玻璃微珠核-壳粒子的制备及其性能

采用自组装化学镀银技术制备了银包玻璃微珠核-壳粒子,并且运用X射线衍射仪、扫描电镜和电子能谱仪等对该核-壳粒子的物相和形貌等进行了表征.分析了该核-壳粒子的介电性能与结构的关系,并以此为屏蔽填料,研究了电磁屏蔽涂料的相关性能.结果表明,银粒子在玻璃微珠的表面包覆均匀且致密,该粒子的介电常数较包覆前大幅度提高.该电磁屏蔽涂料的导电性能随着填料的体积分数(下同)的增加而增加,达到25%时,其表面电阻率为0.050 7Ω/cm2.同时,在电磁波的频率范围为30～1 500MHz时,屏蔽效能达40～65 dB,并且该材料具有较好力学性能和耐环境性能.     

空心玻璃微珠无钯活化化学镀银的研究

基于银镜反应原理,不经过粗化和活化直接对空心玻璃微珠进行化学镀银。采用单因素分析法,研究了硝酸银、葡萄糖、装载量、氢氧化钠和无水乙醇对银的利用率以及镀层的增重率、导电性能和结合强度等的影响,并借助扫描电镜和X射线衍射仪对镀层的表面形貌和结构进行了分析。结果表明:与胶体钯活化工艺相比,无钯活化化学镀银工艺的银的利用率高,镀层均匀、致密,导电性好,结合强度高。     

微细镍粉化学镀银工艺及性能研究

在水-乙醇介质中,以氨水为配位剂,葡萄糖为还原剂,对微细镍粉进行化学镀银。考察了硝酸银浓度、葡萄糖浓度、还原液pH、反应时间等工艺条件对镀银镍粉的含银量和包覆效果的影响。采用扫描电镜、X射线衍射仪和激光粒径分析仪对镍粉化学镀银前后的微观形貌、相组成和粒径进行分析。结果表明,在较佳的工艺条件下制得的镀银镍粉表面为均匀、致密、连续的单质银镀层,平均粒径为99μm,含银量为23%左右。     

玻璃微珠表面镍铁氧体包覆层的制备和性能

采用高分子凝胶法在玻璃微珠表面制备了镍铁氧体包覆层.分别用X射线衍射仪、扫描电镜和HP8510网络分析仪表征复合材料的结构、表面形貌和电磁性能.复合材料中玻璃微珠质量分数(下同)分别为15%,40%,和65%.复合粉是由镍铁氧体、石英和莫来石相组成.随着微珠含量的增加,镍铁氧体衍射峰强度逐渐降低,莫来石衍射峰强度逐渐增强.当玻璃微珠含量为40%时,在玻璃微珠表面可获得完整的镍铁氧体涂层.玻璃微珠含量为40%的复合材料在X波段具有较好的介电损耗和磁损耗性能,其介电损耗角正切值和磁损耗角正切值分别可达0.30和0.10.     

镀银空心玻璃微珠柔性导电膜的研制

采用化学镀方法在空心玻璃微珠表面包覆金属银,获得镀银空心玻璃微珠(Ag@HGMs)复合粒子。利用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、透射电子显微镜(TEM)和半导体粉末电阻率仪对Ag@HGMs复合粒子的微观形貌、尺寸、结构、组分和导电性进行表征。结果显示,最佳工艺条件下所得Ag@HGMs粉末的体积电阻率为2.85×10^-4Ω·cm,表面镀银层致密、完整。将Ag@HGMs粉末作为导电填料,以液体硅橡胶为柔性基体,制备了具有三明治结构的柔性导电膜,Ag@HGMs复合粒子夹在两层硅胶中间。当导电填料的质量分数为4.76%时,膜的体积电阻率为2.33×10^-3Ω·cm。在反复拉伸、折叠后,Ag@HGMs复合粒子依然粘合在导电网络中,且其表面镀银层未脱落,膜的导电性变化微小。     

镀银SiO_2纳米纤维的制备及其导电性能的研究

利用纳米二氧化硅(SiO_2)的结构特性,将其作为镀银基体材料,结合静电纺丝技术制备了SiO_2纳米纤维,进一步在其表面沉积多巴胺,再采用硝酸银(Ag NO3)进行镀银处理,得到了镀银SiO_2纳米纤维,研究了镀银SiO_2纳米纤维的表面形貌、结晶结构及导电性能。结果表明:表面沉积多巴胺后的SiO_2纳米纤维有利于接下来的镀银处理,能够在纤维表面形成形貌良好的银纳米粒子镀层;随着Ag NO3浓度的增加,镀银SiO_2纳米纤维的电阻率呈下降趋势,当AgNO_3浓度达到10 g/L时,纤维电阻率下降至0. 1 mΩ·cm,并趋于稳定,纤维表面形成均匀致密的银纳米粒子镀层,具有良好的导电性能。     

镜制品化学镀银

1　前言含有硝酸银的银氨溶液与含有葡萄糖酸钠、山梨醇、酒石酸等还原剂和ＮａＯＨ等强碱性物质的还原性溶液接触玻璃基板时 ,就会在玻璃基板上发生化学镀反应而析出银镀层。但镀银效率较低 ,难以形成均匀致密、结合力好的镀银层。鉴于上述状况 ,本文就镀银效率高 ,均匀致密性、耐蚀性、附着性和反射像精密性等性能优良的化学镀银工艺加以叙述。2　工艺概述化学镀银液是由含有ＡｇＮＯ3的银氨溶液为一组份溶液 ,含有葡萄糖酸钠、山梨醇、葡萄糖、酒石酸、甲醛等还原剂和ＫＯＨ、ＮａＯＨ等强碱性物质 ,作为化学镀银的另一组份溶液。其特征…     

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。