碳酸盐热解法制备氧化镁晶须

以氯化镁和碳酸氢铵为原料, 加入适当添加剂聚乙烯醇, 在60 ℃反应条件下得到制备氧化镁晶须的前驱体--正碳酸镁晶须(MgCO3*3H2O).以正碳酸镁晶须为原料, 通过控制正碳酸镁的分解条件保持碳酸镁的晶体形状不被破坏, 并在高温下转变成氧化镁晶体结构, 得到氧化镁晶须.利用扫描电镜和X射线衍射对氧化镁晶须作了形貌观察和结构分析, 表明所得氧化镁晶须直径分布均一, 晶体结晶良好, 对氧化镁晶须的生成机理也作了初步探讨.     

利用菱镁矿制备氧化镁晶须

从镁盐产品的开发和解决镁资源综合利用的角度出发，以菱镁矿制备的氧化镁浆液为主要原料，加入沉淀剂碳酸钠，在室温下得到氧化镁晶须的前驱物（碳酸镁晶须）。通过控制碳酸镁的分解条件保持晶须形状不被破坏，在煅烧情况下转变为氧化镁晶须。采用X射线衍射仪和扫描电子显微镜观察氧化镁晶须的结构和形貌，结果表明所制备的氧化镁晶须表面光滑，直径分布均匀，结晶良好。     

不同镁盐对氧化镁晶须形貌的影响

为考察不同镁盐对氧化镁晶须形貌的影响，以3种镁盐为原料，碳酸钠为沉淀剂制备了不同形貌的氧化镁晶须。采用X射线衍射仪和扫描电子显微镜对产物进行了表征。结果表明，采用不同镁盐为原料虽均可得到纯相的氧化镁晶须，但以氯化镁为原料制备的晶须表面光滑，质量较高，而以硝酸镁和硫酸镁为原料制备的晶须表面较粗糙。研究发现，这些形貌上的差别主要是由于溶液中pH的差异而引起的。     

CaSO_4晶须对聚氨酯胶粘剂性能影响的研究

用实验室自制的相对分子质量为2500的聚己二酸-1,4-丁二醇酯二醇和甲苯二异氰酸酯、混合扩链剂配制聚氨酯胶粘剂,并使用实验室自制的改性和未改性200nm硫酸钙晶须对聚氨酯胶粘剂进行改性,考察不同硫酸钙晶须及其加入量、加入方式对聚氨酯胶粘剂综合力学性能的影响。根据实验结果,200nm改性硫酸钙晶须当加入量为3％时,聚氨酯胶粘剂的拉伸强度、初粘性和最终剥离强度均有明显提高。     

高温熔剂法制备氧化镁晶须

以氯化镁为原料，氯化钾为助熔剂，采用高温熔剂法制备出氧化镁晶须。通过正交实验，利用极差、方差分析法对生长氧化镁晶须的反应条件进行了优化，找出了生长氧化镁晶须的最佳工艺条件：脱水时间1h、温度400℃；灼烧时间6h、温度900℃。因素影响顺序：灼烧温度〉脱水时间〉灼烧时间〉脱水温度。实验结果表明：在高温熔剂法制备氧化镁晶须的过程中，灼烧温度和脱水时间为主要因素，在最佳工艺条件下制得晶须的形貌较好，产率可达76．6％。     

碱式硫酸镁烧结法制备氧化镁晶须

以价格低廉的硫酸镁和氢氧化钠为原料,通过前驱体烧结法制备氧化镁晶须。首先以硫酸镁和氢氧化钠为原料,通过常温反应—水热晶化,制得了结晶良好、具有纤维状外形的前驱体碱式硫酸镁[MgSO4.5 Mg(OH)2.2 H2O]的单一物相。通过控制前驱体的分解速度使其在低温下缓慢分解以保持晶须状外形,然后在高温下烧结,得到烧结良好、分散均匀、长径比大的氧化镁晶须。利用SEM和XRD对产物进行表征,氧化镁晶须是由纳米氧化镁颗粒烧结而成的“假象”体,直径在0.2~1.5μm,长径比≥50。实验证明该工艺简捷、易行、条件温和,为氧化镁晶须的工业化生产提供了有效可行的新途径。     

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。     

导热弹性硅橡胶垫片的性能研究

试验研究氧化铝和氧化镁晶须对导热弹性硅橡胶垫片性能的影响.结果表明,当氧化铝用量为150份时,甲基乙烯基硅橡胶胶料的导热系数达到1.08 W·(m·K)-1,约为未加导热填料硅橡胶胶料的5倍;氧化铝与少量氧化镁晶须(氧化镁晶须质量分数为0.06)并用填充的硅橡胶导热性能优于氧化铝粒子填充硅橡胶,热稳定性明显提高,热膨胀系数明显减小;以氧化铝/氧化镁晶须填充的硅橡胶为基体、电子级玻璃布为增强材料制得的导热弹性垫片具有优良的导热性能和较高的撕裂强度.     

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...     

以氯化镁为原料制备氧化镁晶须的工艺研究

以氯化镁和碳酸钠为原料,通过前驱体烧结法制备氧化镁晶须.首先以氯化镁和碳酸钠为原料合成了前驱体碳酸镁晶须,接着将碳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:氯化镁溶液的浓度为0.6mol/L,氯化镁和碳酸钠的摩尔比为1:1,陈化时间2h.在此条件下制得了前驱物碳酸镁晶须,将碳酸镁晶须焙...     

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.     

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。     

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.