掺锡氧化铟纳米粉体的制备及表征

以InCl3·5H2O和SnCl4·5H2O为原料,以NH3·H2O作共沉淀剂,采用表面活性剂及有机脱水的方法防团聚,制备了纳米掺锡氧化铟(ITO)粉体,并用X-射线衍射、透射电子显微镜、扫描电子显微镜、比表面测定、傅立叶红外吸收光谱等对制得的粉体进行了表征.结果表明,制得的球形ITO粉体分散性好、粒度均匀,具有单相立方In2O3晶体结构,其平均粒径约40 nm,在714～3333 cm-1范围内对红外光的平均透过率小于5%,是一种优良的红外吸收材料.     

铌酸钾织构陶瓷用模板粉体的制备

以Nb2O5和KOH为原料,采用水热法成功制备了铌酸钾(KNbO3)织构陶瓷用的片状模板粉体K8Nb6O(19)·10H2O.通过X射线衍射分析(XRD)、扫描电镜(SEM)分析了粉体的晶相和表观形貌,考察了水热反应条件和表面活性剂对粉体制备的影响.实验结果表明:在140℃、反应2 h,KOH的浓度为9 mol/L时,...     

纳米ZAO复合粉体的制备及性能表征

以Zn(Ac)2·2H2O和Al(NO3)3·9H2O为原料,用溶胶-凝胶法制备了ZnO/Al2O3(ZAO)复合粉体.研究了Al2O3掺杂浓度、锌离子浓度、反应温度、pH值、反应时间和烧结温度等对粉体平均粒径的影响,用正交实验得到最佳制备方案.用激光粒度分析(LPA)、能谱分析(EDAX)、热重-差热分析(TG-DTA)和X-射线衍射分析(XRD)对粉体的性能进行了表征.结果表明:制备的纳米ZAO粉属于六方晶系纤锌矿结构.其X-射线衍射图谱中并没有氧化铝的衍射峰,Al3 取代了Zn2 的位置,形成固熔体.Al2O3掺杂浓度、锌离子浓度、pH值和烧结温度等对粉体平均粒径的影响较大,在最佳条件下,制得的ZAO复合粉体粒径分布均匀、平均粒径约为22 nm.     

一种新型W/O型微乳液制备超细Al2O3粉体的实验研究

向PEG+正丁醇/正庚烷/水溶液 (NaAlO2 )超声乳化后的W/O微乳液中通入CO2,将制得的凝胶焙烧后制备出了粒度100nm左右的Al(OH)3凝胶与Al2O3超细粉体,实验结果表明:乳化温度、表面活性剂与助表面活性剂之比及偏铝酸钠浓度是影响粉体粒度的主要影响因素.     

原料表面改性对微波合成TiC粉体的影响

通过调节p H值和添加分散剂(聚丙烯酸),对微波合成Ti C的原料Ti O2和乙炔炭黑进行表面改性处理,将处理后的原料通过湿磨混料,并在微波窑中利用碳热还原反应合成Ti C粉体。利用Zeta电位测试、X射线衍射、激光粒度分析等手段,研究p H值、分散剂、球磨等原料表面改性及混料工艺对微波合成Ti C粉体的物相组成、化学计量、粒度分布的影响。结果表明:Ti O2和乙炔炭黑的较佳改性p H值均为4,其较佳分散剂用量分别是2.4 wt%和9.0 wt%;湿磨混料的较佳时间为6 h;与未经表面改性处理相比,原料经表面改性处理后,微波合成Ti C粉体的温度较低(合成温度降低150℃),粉体粒度较小,化学计量更准确。     

制备条件对碳酸钡沉淀粒度分布的影响

一种功能陶瓷用碳酸钡的制备方法。采用正交试验法考察加料次序、反应温度、加料速度与表面活性剂这4种因素对制备的碳酸钡沉淀颗粒大小及粒度分布的影响。找出了功能陶瓷用碳酸钡制备的较佳条件：慢速反加料、反应温度25℃、添加表面活性剂。     

氟硅酸铵氨化制备纳米二氧化硅的实验研究

实验以氟硅酸铵和氨水为原料,通过化学沉淀法制备纳米二氧化硅粉体。考察了表面活性剂、反应温度、物料配比等不同工艺条件对纳米二氧化硅粉体的粒度分布、反应收率等的影响。实验结果表明:分散剂十二烷基苯磺酸钠可以有效改善粉体粒度的分布;综合考虑二氧化硅粉体的粒度、反应收率、反应效率和生产成本,确定氟硅酸铵氨化制备二氧化硅的反应温度为常温、反应时间为60 min、物料配比(氟硅酸铵与氨水物质的量比)为1∶4.8、氨水的加料速度为96 m L/min、搅拌速度为200~300 r/min。     

以尿素为沉淀剂制备超细α-Al2O3粉体

以硫酸铝为原料,尿素为沉淀剂,采用均匀沉淀法制备了a-Al2O3超细粉体.系统考察了反应温度、Al2SO4·18H2O初始浓度以及沉淀剂用量对产率的影响.通过DTA-TG,XRD与SEM分析,研究了前躯体胶体的脱水过程及粉体的结构与形貌.结果表明,当前躯体在1200℃下煅烧时可得到结晶完善,纯度高,粒径均匀的球形超细a-Al2O3粉体.     

水热法制备(Na0.82K0.18)0.5Bi0.5TiO3陶瓷粉体及其介电性能研究

以NaNO3,KNO3,Bi(NO3)3·5H2O和Ti(OC4H9)4为原料,NaOH为矿化剂,采用水热法成功制备了(Na0.82K0.18)0.5Bi0.5TiO3 (NKBT)粉体.研究了反应温度、反应时间和NaOH浓度对NKBT粉体制备的影响.运用XRD、SEM对制备的NKBT粉体进行了测试.测试结果显示,通过调整水热反应条件可对NKBT粉体的微观形貌进行控制.采用传统烧结法可将水热法制备的NKBT粉体烧结为致密的NKBT陶瓷.     

工艺条件对ZrO2粒度的影响

以工业ZrOCl2·8H2O和分析纯Nh3·H2O为主要原料,采用化学沉淀法制备了ZrO2纳米粒子,研究了不同阶段添加表面活性剂聚乙二醇(PEG)对ZrO2粉体颗粒尺寸的影响机理.通过测定ZrO2粉体比表面积计算出其粒度在10～40nm之间.     

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。