水溶液法制备氧化镁晶须的工艺研究

为了促进氧化镁晶须的规模化生产与工业应用,采用前驱物煅烧法制备了氧化镁晶须.首先以硫酸镁和氨水为原料合成了前驱体碱式硫酸镁晶须,接着将碱式硫酸镁焙烧成氧化镁晶须.探讨了各个工艺条件对产物的影响,探索出最佳的工艺条件为:硫酸镁溶液的浓度为2mol·L-1,水热反应温度160℃,水热反应时间20h.在此条件下制得了前驱物碱...     

硼酸镁晶须的制备与表征

以氢氧化镁、硼酸为反应物,氯化钠-氯化钾混合作助熔剂,高温固相合成法合成硼酸镁晶须。通过正交实验探讨硼酸镁晶须制备的最佳工艺条件:原料镁硼摩尔比1∶1,原料与助熔剂摩尔比1∶1.5,800℃高温固相合成2 h。采用X射线衍射仪和扫描电镜对硼酸镁晶须结构表征及表面相貌观察分析,所制备的硼酸镁晶须长度20μm,直径1.5μm针状晶体。对硼酸镁晶须合成过程进行了探讨分析。     

以活性氧化镁和氯化镁为原料合成氧化镁晶须

探讨了一种合成氧化镁晶须的新的工艺方法。首先以活性氧化镁和氯化镁为原料合成了前驱体碱式氯化镁晶须，接着将碱式氯化镁焙烧成氧化镁晶须。分别用X射线衍射仪（XRD）、扫描电镜（SEM）、热重分析仪（TGA）和化学分析，分析了中间体碱式氯化镁和产品氧化镁晶须的成分、形貌和热化学行为。探讨了各个工艺条件对产物的影响，探索出最佳的工艺条件：活性氧化镁与氯化镁的物质的量比在0．08左右，氯化镁溶液的浓度为3mol／L，反应温度40～50℃，陈化时间在48-72h，陈化温度50℃。在此条件下制得了形貌良好的前驱物碱式氯化镁晶须。将碱式氯化镁晶须焙烧，控制升温速率在2—5℃／min，采取分段升温方式升温至600℃，即可制得氧化镁晶须。制得的晶须长度在100μm左右，直径约0．5μm。     

硼酸镁晶须的合成及表征

以氢氧化镁和硼酸为原料,利用高温-助熔剂-湿法工艺合成了高品质的硼酸镁晶须。采用XRD、SEM、HR-TEM、SAED等手段表征,系统研究了焙烧温度、焙烧时间、硼镁物质的量比及助熔剂添加量对晶须形貌的影响。结果表明,在焙烧温度为850 ℃、焙烧时间为4 h、n（硼）∶n（镁）=3∶1、n（钠+钾）∶n（镁+硼）=4∶1的条件下,可合成直径为0.5~0.8 μm、长径比为40~240且表面光滑的硼酸镁晶须。还对硼酸镁晶须的高温-助熔剂-湿法工艺合成生长机理进行了探讨。     

溶胶-凝胶法由菱镁矿制备氧化镁晶须的工艺研究

采用溶胶-凝胶法,以菱镁矿、盐酸和尿素为原料,加入成胶剂柠檬酸并烘干,生成前驱体后利用程序升温在高温下煅烧得到氧化镁晶须。结果表明,制备氧化镁晶须的最佳条件为:反应体系温度100℃,溶液pH值为6,并分别加入MXC-2及DXC-3晶形控制剂。晶须长径比为20³0∶1,长度为30μm,并具有良好的结晶状态。     

无水硫酸钙晶须的制备及表征

以某稀土厂生产过程中产生的硫酸铵废水为原料,用氯化钙作为钙源,采用水热法制备高长径比的硫酸钙晶须。首先采用正交实验研究反应时间、反应温度和陈化时间对硫酸钙晶须长径比的影响,确定最佳工艺条件。在正交实验最佳工艺条件的基础上,研究了pH对制备硫酸钙晶须形貌的影响。使用扫描电子显微镜（SEM）、X射线衍射仪（XRD）,红外分析仪（FT-IR）和热重-差热分析仪（TG-DSC）对制得的硫酸钙晶须的表面形貌和物相进行了表征和分析。研究结果表明：在制备硫酸钙晶须的最佳工艺条件下（即反应时间为5 h、反应温度为140℃、陈化时间为4.5 h）,溶液体系pH为1时,制备得到纯态无水硫酸钙晶须,其形貌最佳、长径比最大,平均长度达到117.44μm、平均长径比为40.2。     

淀粉接枝聚丙烯酸钠吸水性树脂的工艺研究

采用反相悬浮聚合法制备聚丙烯酸钠－淀粉吸水性树脂，研究了淀粉加入量、分散剂用量、反应放热等因素对合成工艺的影响，合成的最佳工艺条件为反应升温时间大于1h、反应温度低于70℃、反应及脱水时间6h、淀粉加入量为20％。建立了以环已烷为油相的回流定量脱水新工艺，使溶剂回收率达95％，产品干燥时间缩短到2h，产品总收率达到99．0％。     

硫酸钙晶须的制备及其影响因素

采用低温常压酸化法制备了硫酸钙晶须。通过单因素实验考察了石膏与水的比例、石膏与硫酸的比例、稀硫酸滴加速度、水浴温度4个因素对硫酸钙晶须微观形貌的影响,并运用正交实验优化了工艺参数。通过实验得到制备硫酸钙晶须最佳工艺参数：石膏与水的质量比为1∶10、石膏与硫酸的质量比为1∶5、稀硫酸滴加速度为 3 mL/min、水浴温度为80 ℃。采用最佳工艺条件制备的半水硫酸钙晶须和无水硫酸钙晶须的纯度分别为98.3%、97.2%,长径比分别为60、40,并具有较好的分散性,尺寸分布均匀。     

正交实验设计优化穿心莲总黄酮提取工艺

探讨了用乙醇回流提取穿心莲黄酮类化合物,找出最佳提取条件。通过正交实验探索乙醇回流法提取穿心莲黄酮类化合物的最佳工艺条件,采用紫外分光光度法测定总黄酮含量。影响实验因素的主次顺序是：固液比〉浸提时间〉乙醇浓度〉浸提温度,其中固液比对实验指标有显著性的影响。最佳提取工艺为固液比1：20、浸提时间4h、乙醇浓度60％、浸提温度50℃。     

草酸盐法制备纳米硼酸镁晶须研究

以MgCl2·6H2O、H3BO3和H2C2O4·2H2O为原料,利用草酸盐法制备出形貌良好的纳米硼酸镁晶须,其长度300 ～ 500 nm,直径60 ～ 100 nm,探讨了制备硼酸镁晶须的最佳工艺条件,分析了Mg2B2O5的生长过程中H2C2O4的作用.同时采用高温固相法,以NaCl为助熔剂,制备出长度10 ～ 35 μm,直径1～2 μm针状硼酸镁晶须.通过对比发现,用H2C2O4·2H2O代替NaCl作为添加剂,可以降低煅烧温度,同时大大缩短了煅烧时间,制备得到的晶须更为纯净、长度直径可达到纳米级别.     

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。