纳米SiO2粉体的制备与研究

纳米SiO2粉体的制备是以硅酸钠和盐酸为原料，添加适宜的稳定剂(非离子表面活性剂)和分散剂，在适宜的pH值和温度下，采用化学沉淀法合成。要得到性能优良的纳米SiO2粉体，最佳工艺条件为：温度20～40℃，pH6，反应液质量浓度ρ1=20g／L，ρ2=1.20mg／h，反应时间15min。结果表明：制备的纳米SiO2粒径为30～50nm，比表面积大、分散性好、质量优良、可达到产业化的生产。     

用于环境功能涂料的纳米TiO2/SiO2复合光催化剂的制备工艺

针对环境功能涂料制备过程中TiO2纳米颗粒在水性涂料中极易团聚、分散性差的问题,以提高分散稳定性和改善光催化氧化活性为目的,采用溶胶．凝胶法,以锐钛矿型纳米TiO2粉体为载体,Na2SiO3为包覆剂,H2SO4为中和剂,成功地制备了分散性优良、光催化活性可控的纳米TiO2／SiO2复合粉体。结果表明,包覆剂用量、包覆温度及中和时间是影响催化剂分散稳定性和光催化活性的主要因素。通过实验优化确定最佳工艺条件为：分散剂5027用量为2％(wt,5027／H2O)：分散液pH值为9．5左右;中和时间为2h;包覆温度根据对其光催化活性的不同要求可控制为23℃或80℃：Na2SiO3用量6％(wt,SiO／TiO2):陈化液pH值为9．0左右。     

以次磷酸钠为还原剂制备纳米铜粉

研究了以化学还原法与均匀沉淀法相结合的方法制备纳米铜粉。实验以次磷酸钠为制备纳米铜粉的还原性沉淀剂。实验得出较佳工艺条件：硫酸铜浓度0．08～0．5mol／L，次磷酸钠的浓度0．4～1mol／L，还原剂的滴加速度35滴／min，表面活性剂用量占原料质量分数的0．3％，温度50℃，pH=2．0，六偏磷酸钠0．5～2g。对产品进行XRD谱图和TEM电镜分析，证实为纳米级铜粉，但在空气中不稳定，极易被氧化为Cu2O。     

纳米Al2O3-SiO2的分散及颗粒间力的相互作用

研究了纳米γ—Al2O3，SiO2的分散行为及其同相与异相微粒间静电引力与斥力作用。采用Malvern Zetasize 3000HSA自动电位粒度仪测定了纳米γ—Al2O3和SiO2在不同pH值下的表面电位。结果表明：纳米γ—Al2O3的等电点为pH=8．23，纳米SiO2的等电点为pH=1．58，两种粉体混合后的等电点为pH=6．94。研究了悬浮液pH、表面活性剂对纳米粉体团聚体的影响，结果表明：添加FS—20表面活性剂、pH=12时，两种粉体混合后的分散效果较好。采用DLVO(Derjaguin—Landau—Verwey—Overbeek)理论对γ—Al2O3，SiO2和γ—Al2O3—SiO2同相及异相纳米微粒间的分散过程进行了量化研究，理论计算结果与实验结果吻合。     

化学共沉淀法制备纳米四氧化三铁粉体

采用化学共沉淀法制备纳米Fe3O4粉体,并用聚乙二醇表面活性剂进行表面改性,在铁离子浓度比Fe2＋：Fe3＋=1：2时,对制备工艺影响因素进行了讨论。通过实验得到的最佳工艺条件为：控制温度介于40～60℃,最佳的pH取值为9,聚乙二醇的适宜用量取5～10 mL。采用TEM观测制备的纳米Fe3O4颗粒的形貌及其大小,得到的纳米Fe3O4颗粒粒径为20～50 nm之间。     

纳米碳化硅复合化学镀镍-磷合金工艺

以硫酸镍为主盐,次磷酸钠为还原剂,在铁基体上进行了化学镀Ni-P-纳米SiC.研究了镀液温度、pH及硫酸镍质量浓度对镀速的影响,得到较佳工艺条件如下:硫酸镍24～26 g/L,次磷酸钠20～35g/L,柠檬酸10～20 g/L,醋酸钠10～15 g/L,丁二酸钠2～4 g/L,纳米SiC粉体0.6g/L,pH 4.1～...     

共沉淀法制备纳米镁铬尖晶石粉体

镁铬尖晶石具有较高的熔点而被广泛应用于耐火材料中。而常规镁铬尖晶石粉体因烧结温度较高，铬蒸发而使得耐火材料的致密度难以提高。为改善镁铬耐火材料的烧结性能，进行了纳米镁铬尖晶石粉体的研究：以Cr(NO3)3，Mg(NO3)2，PEG-400和CO(NH2)2为原料，采用共沉淀法获得了铬酸镁纳米粉(nc2o3：nMgo=1：1)的前驱体，经过超临界流体干燥(SCFD)制备出镁铬二元纳米气凝胶，经600℃煅烧后获得了纳米级立方相镁铬尖晶石粉体。经XRD，DSC-TG，BET和透射电镜分析，结果表明：前驱体纳米粉的比表面积为350～780m^2／g，平均粒径为1～2nm，煅烧后的纳米粉的比表面积为36～65m^2／g，平均粒径为5～10nm。     

多孔纳米SiO2微粉的制备与表征

多孔状纳米SiO2微粉的制备是以水玻璃和盐酸为原料,添加适宜的稳定剂（非离子表面活性剂）在适宜的pH值和温度下沉淀合成。要得到性能优良的SiO２纳米微粉,最佳工艺的研究尤其重要。用BDL-B型电位仪、BET、EPMA-电子探针及DTA-TGA等手段对其性能进行了表征,结果表明,制得的SiO2超细微粉,颗粒呈多孔状,具有巨大的比表面积,高达1000m2／g以上,孔径为25Å左右。粒度分布均匀,粒度可达纳米级,这种粉末具有特殊的性能。     

聚合硅酸铝铁的制备与应用

用硅酸钠与硫酸中和制得聚硅酸溶液，再与硫酸铝、三氯化铁溶液反应，制得絮凝性能优良的聚硅酸铝铁絮凝剂。对制备过程中Al/Fe、（Al Fe)/SiO2、SiO2的浓度、pH值等参数进行了探讨，结果表明，按Al/Fe=3:1,(Al Fe)/SiO2为1：1，以及20℃、pH=5.5左右，SiO2%=2.5的条件下制得的产品性能良好，投加量为20mL/L、pH=8.0-8.5时，对印染废水有很好的处理效果。     

pH值对ZnWO4粉体的微波水热法合成及光催化性能的影响

以Na2WO4·2H20和Zn（NO3）2·6H2O为原料,采用微波水热法在不同pH值下200℃反应60min制备出ZnW04粉体。分析了pH值对合成样品的物相、形貌和比表面积的影响,并对不同pH值下合成粉体的光催化性能进行了研究。结果表明：pH值为5．0～7．5时适宜合成ZnW04粉体,pH为5．0、6．0和7．5时分别合成了星状、颗粒状及纤维状ZnWO4粉体：制备出的ZnWO4粉体比表面积分别为15．79、28．12m。／g和54．27m^2／g;随着ZnW04粉体比表面积的增加,ZnWO4粉体光催化性能随之提高,其中pH=7．5时合成的纤维状的ZnWO4粉体比表面积最大,在紫外光下,2h的光催化降解罗丹明B降解率达到了98．5％。     

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。