在微波辐射作用下制备纳米CeO2及其表面改性研究

本文以Ce(SO4)2·4H2O和NaOH为反应原料,用表面活性剂聚乙二醇(PEG)分散和保护产品,在微波辐射作用下制备了纳米CeO2.采用红外光谱仪、X射线衍射仪和差热热重联用分析仪对所制得的产品进行表征,产品颗粒粒径为24.9 nm.为了扩大所制备的纳米CeO2的应用范围,用表面活性剂月桂酸钠对其进行表面改性研究,结果表明该工艺具有高效、环保、产品分散性好、粒径小和易于推广等优点.     

用WPSt制备大颗粒聚合物P(PS/VAc)的工艺研究

以聚苯乙烯(PSt)泡沫为原料,采用悬浮法制备大颗粒聚合物P(PS/VAc)。着重探讨了分散剂加入方式及用量、引发剂用量、水介质的用量、聚苯乙烯泡沫的用量等对其粒径及分布的影响,确定了产品粒径主要位于2~4mm的聚合工艺条件。     

MgCl_2溶液中杂质离子的存在对氨气法制备Mg(OH)_2粒径的影响

MgCl_2是Mg(OH)_2 (MH)化学沉淀中常用的前驱体,但来自海水、菱镁矿和白云石等的MgCl_2中可能存在一些杂质,可能会影响所制备MH的质量。介绍了在MgCl_2溶液中分别加入不同种类的杂质离子,通过氨气沉淀法制备Mg(OH)_2(MH)产品,以此研究杂质离子的存在对所制备MH产品粒径的影响规律。实验结果表明,在MgCl_2溶液中阳离子的存在对所制备MH的粒径没有明显的影响,但阴离子的存在对所制备MH的粒径有显著的影响。当多价阴离子或单价AC~-存在时,甚至当杂质离子与MgCl_2的摩尔比低至1:120时,所制备的MH的平均粒径也可显著增加,而且其粒径分布也明显变宽。但是当阴离子杂质为单价的NO_3~-或Br~-时,对所制备的MH的粒径却没有明显的影响。     

利用新型膜乳化器制备粒径均一的PLGA微球

用恒流泵替代气瓶给压装置得到新型膜乳化器,以改善膜乳化法制备微球的工艺稳定性;以聚乳酸-羟基乙酸共聚物(PLGA)为膜材,利用水包油(O/W)乳化法制备PLGA微球,研究了新型膜乳化器与传统膜乳化器对微球形貌、粒径及粒径分布的影响,考察了搅拌速度、稳定剂浓度、PLGA浓度及分散相流速对微球形貌、粒径及其分布的影响.结果表明,在微孔膜孔径2mm、搅拌速度300 r/min、稳定剂浓度1.0%(w)及PLGA浓度60 mg/m L、分散相流速20mL/h的条件下,可制得表面光滑、粒径均一(粒径分布系数Rspan0.50)的PLGA微球,各批产品的粒径相对标准偏差为1.99%,产品批次重复性良好.     

溶胶-凝胶-冷冻干燥技术制备纳米二氧化锡及其表征

采用溶胶-凝胶-冷冻干燥技术制备了纳米SnO2粉体,并用X-射线衍射(XRD)、透射电镜(TEM)和热分析(TG-DTA)对产品进行了表征,同时考察了pH值、反应物浓度以及焙烧温度对产品粒径及形貌的影响。结果表明,在优化的反应条件下,溶胶-凝胶-冷冻干燥技术可以制得粒径均匀的10nm以内的SnO2粉体。     

复合剪切力场下纳米SiO_2的制备及原位改性

以工业硅酸钠为前驱物、盐酸为沉淀剂、聚乙二醇为表面活性剂、硅烷偶联剂为改性剂,在复合剪切力场下,用化学沉淀法制备纯纳米二氧化硅(SiO2)和原位改性纳米SiO2,并进行放大实验。分析复合剪切力场下纳米SiO2的形成过程以及不同剪切力场、进料方式等对纳米SiO2型貌的影响。用Fourier红外光谱、透视电子显微镜、热重分析及粒径分析仪等对产品进行表征,结果表明:在复合剪切力场下制备的纳米SiO2的形貌近似为球形、平均粒径为19.5nm且粒径分布窄,原位改性纳米SiO2的分散效果良好。     

聚乙二醇对纳米氧化锌合成的影响

采用均匀沉淀法,以尿素与无水氯化锌为原料,聚乙二醇(PEG)为表面活性剂,探讨聚乙二醇分子量分别是800、2000、4000和8000以及不同用量对纳米氧化锌颗粒合成的影响,并采用沉降法、斯托克斯(St?ckes)定律计算粒径,SEM表征产品粒径形貌。由实验结果知,当PEG分子量为4000,n(PEG):n(CO(NH_2)_2):n(ZnCl_2)=0.037:4:1(摩尔比)时,合成纳米氧化锌颗粒粒径小,平均粒径约为55.78 nm,粒径分布窄;均匀沉淀法所制备的产品锌含量均高于79.3%,接近理论锌含量(80.7%),产品纯度高。     

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.     

萃取-超临界法制备纳米TiO2

以硫酸法钛白生产过程的中间产品钛液(TiOSO4)为原料,经过萃取、酸洗和反萃得到TiO(OH)2白色浆料,用乙醇置换大部分水分后,采用超临界流体干燥制备纳米TiO2。用TEM、XRD等手段对其表征,所得粒子粒径为20～30 nm, 干燥和晶化一步完成。     

硅酸乙酯为原料反相微乳液法制备纳米二氧化硅

采用NP-5/环己烷/去离子水体系制备反相微乳液,绘制了该体系的三元相图,并以正硅酸乙酯(TEOS)为原料,在碱性条件下受控水解反应制备了纳米SiO2粒子,探讨了[n(水)∶n(表面活性剂)](用R表示)和[n(水)∶n(TEOS)](用H表示)对SiO2纳米粒子粒径的影响。通过扫描电镜(SEM)和激光粒度仪对样品形貌和粒子大小和粒径分布进行了表征。结果显示:扫描电镜下观察到的SiO2粒子为无定型球形颗粒,粒径在200～500 nm的范围,激光粒度仪分析得到的平均粒径随着R和H的增大而增大。     

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。