纳米光催化剂TiO_2/Fe_3O_4的制备及表征

采用两步法制备磁性负载纳米光催化剂TiO2/Fe3O4。首先用液相共沉淀法制备磁性纳米Fe3O4颗粒;然后用溶胶-凝胶法,以钛酸四正丁酯为先驱体,通过水解缩聚在Fe3O4纳米颗粒表面包覆TiO2层,得到易于磁分离回收的复合纳米光催化剂TiO2/Fe3O4,粒径大约为30 nm。利用TEM、XRD、FT-IR、VSM对Fe3O4和TiO2/Fe3O4的结构和性能进行了表征,结果表明,制备的Fe3O4为面心立方晶体(FCC)结构,具有超顺磁性;TiO2为锐钛矿相,包覆在Fe3O4的表面,形成了核-壳式结构的TiO2/Fe3O4复合光催化剂。     

硬脂酸对纳米Al2O3的有机表面修饰研究

为提高纳米α-Al2O3粒子在有机体系中的分散性和相容性,对纳米α-Al2O3进行了有机表面改性.首先制备了纳米α-Al2O3水分散液,然后把纳米Al2O3水分散液转移到溶有硬脂酸的正丁醇溶液中,升温到一定温度,将纳米Al2O3浆体中的水分蒸馏出去,使纳米Al2O3在有机相中进行表面改性,使得纳米Al2O3有机表面改性和防团聚处理一步完成,得到了团聚程度较小的纳米Al2O3粉体.采用红外光谱(IR)、热分析(TG-DTA)、透射电镜(TEM)、润湿性实验、分散性实验等手段对表面改性前后的纳米Al2O3进行表征.红外光谱和TEM表明,在纳米Al2O3表面包覆有硬脂酸的有机层,并且可能有硬脂酸铝的生成.热分析显示,包覆量约为16.7%.润湿性实验及分散性实验表明,经硬脂酸改性的纳米Al2O3的表面性质由亲水变为疏水.     

用二氧化硅表面改性纳米二氧化钛的制备及表征

针对二氧化钛(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TiO2分散稳定性为目的,用并流中和法,以锐钛矿型纳米TiO2粉体为载体,硅酸钠(Na2SiO3)为包覆剂,用硫酸(H2SO4)调节pH值,成功地在纳米TiO2表面包覆致密的SiO2膜.借助Fourier变换红外光谱(Fourier transform infrared spectroscopy,FTIR)、X射线衍射技术(X-ray diffraction,XRD)和X射线能量散射谱(X-ray energy dispersive spectroscopy,EDS),表征样品的键合情况、相态结构、表面的化学成分,同时测定包覆改性前后的纳米TiO2比表面积和酸溶性.FTIR和EDS结果表明:该包覆方法可行,氧化硅(SiO2)以化学键合的方式沉积在纳米TiO2表面,在包覆层和纳米TiO2颗粒之间的界面上形成了Ti-O-Si键.酸溶实验分析和XRD结果证实:在TiO2纳米颗粒表面包覆了一层致密SiO2膜.比表面测定的结果显示:改性后TiO2的比表面积随质量分数m(SiO2):m(TiO2)增加而减小.     

MoO3/TiO2纳米复合催化剂的合成及催化脱氢性能

采用溶胶-凝胶法合成MoO3/TiO2、K2O-MoO3/TiO2、V2O5-MoO3/TiO2、Al2O3-MoO3/TiO2、K2O-V2O5-MoO3/TiO2系列纳米催化剂。借助TEM、XRD、IR等技术对催化剂进行了表征,并利用环己烷催化氧化脱氢成环己烯的反应进行活性测试。结果表明,MoO3在载体TiO2呈单层和多层分布,单层分布时发生了Mo与O—Ti的键合作用,同时使TiO2表面水分子发生解离反应,活化时脱去—OH产生Mo6+和Mo—O-活性中心;多层分布时以Mo[FY=,1]O、Mo—O-活性物种为主。脱氢中心和供氧中心之间存在协同作用,K、Al、V均能影响其协同作用。     

IS-RPB反应器包覆硅膜纳米TiO_2的表征及过程分析

以纳米TiO2Na2SiO3为实验体系,分析了IS RPB反应器内纳米TiO2颗粒的分散和混合过程以及操作参数对纳米颗粒包覆的影响。利用透射电子显微镜(TEM)对粉体颗粒的团聚进行了观测,红外光谱(FT IR)定性分析了纳米TiO2颗粒表面包覆物结构。实验结果表明,雾化射流对撞和“雾面切割”混合过程中硅酸微核在纳米TiO2颗粒表面沉积,形成表面薄层包覆。但IS RPB反应器的操作参数应控制在一定的范围内,其最佳操作参数为流量60 L/h,转速800 r/min。     

纳米TiO_2复合载体催化剂的制备及表征

采用溶胶 凝胶法分别在γ Al2O3和ZRP 5分子筛上负载纳米TiO2制得复合载体,通过不同的方法在载体上负载纳米V2O5,运用XRD、TEM、IR等对催化剂进行了表征。结果表明:TiO2在载体上分散良好,粒子颗粒均匀,粒径大小在25～35nm之间,TiO2在ZRP 5上粒径比在γ Al2O3小,且Ti Al、Ti Si间存在相互作用,有利于产生新的性能。V2O5粒径大小在8～9nm。     

镍包覆Al2O3纳米颗粒对氧化铝陶瓷与铝之间润湿性的影响

采用Ni(NO3)2·6H2O前驱体液相包覆技术对纳米Al2O3颗粒进行金属化处理,经过干燥、加热分解和高温氢气还原处理后,前驱体完全转化为金属Ni晶体,从而获得镍涂覆的Al2O3颗粒。X射线衍射、透射电子显微镜和能谱分析结果表明:金属镍包覆在纳米Al2O3颗粒表面。包覆的纳米Al2O3颗粒经过热压烧结制备的陶瓷体与金属铝之间的润湿角为72.5°,明显改善了陶瓷与金属之间的润湿性。     

纳米氧化锌包覆SiO2和SiO2/Al2O3改性粉制备及表征

采用液相沉积法对纳米氧化锌进行表面包覆SiO2和SiO2/Al2O3改性,并用IR、XRD、TG-DSC对其表面结构进行了表征,用紫外-可见分光光度计对其紫外屏蔽性能进行了检测,采用Zeta电位测定仪、静态沉降实验等分析手段考察了改性前后纳米氧化锌在水体系中的分散稳定性。结果表明,在ZnO表面形成的包覆物是以非晶态形式存在的,通过表面包覆SiO2和SiO2/Al2O3改性后纳米氧化锌对紫外光的屏蔽性能有所下降,明显提高了氧化锌的表面羟基含量,有效改变了氧化锌的等电点,显著提高了纳米氧化锌在水中的分散稳定性。     

TiO2改性Al2O3微滤膜荷电性及其对膜水通量的影响

以硫酸钛、尿素为主要原料，采用均相沉淀法在Al2O3，微滤膜孔表面成功制备了一层纳米TiO2改性涂层。采用显微电泳法通过测定Al2O3，微滤膜颗粒表面TiO2涂层的zeta电位表征了TiO2涂层改性Al2O3微滤膜表面的荷电性，并探讨了微滤膜荷电性其对其水通量的影响。宏观电泳测试和Zeta电位分析表明，经TiO2改性后，Al2O3微滤膜表面荷电性能发生了明显改变，未改性膜Zeta电位等电点为pH=6．3，而改性后膜在pH=2-12时均荷负电。经TiO3改性Al2O3微滤膜的纯净水渗透通量较未改性时明显提高；当pH=6．6时，经TiO2改性后Al2O3微滤膜表面zeta电位绝对值的变化规律与相应的改性Al2O3微滤膜的纯净永渗透通量的变化趋势完全一致， 表明微滤膜水过滤通量的提高与改性涂层改变了膜孔表面的电动性质密切相关。     

TiO_2包覆硅灰石填充对PA1010复合材料的影响

以硅灰石为原料,钛酸四正丁酯为包覆剂,采用溶胶-凝胶法制备了一种纳米TiO2包覆硅灰石复合颗粒,并用电子显微镜(SEM),红外光谱仪(FTIR)等对TiO2包覆硅灰石颗粒进行表征。结果表明:硅灰石表面均匀地包覆了一层厚度约为60nm的非晶态纳米TiO2,进而将TiO2包覆硅灰石复合颗粒填充尼龙1010(PA1010)。用差示扫描量热仪(DSC)对填充后复合材料的聚集态结构进行分析后发现,硅灰石表面包覆TiO2膜改善了硅灰石与尼龙基体的界面结合状况,同时对PA1010产生了诱导结晶作用。     

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。