ZTA陶瓷注凝成型工艺中浆料性能的研究

对ZTA陶瓷注凝成型工艺中分散剂、pH值、氧化锆含量、固相体积分数、有机单体含量对浆料流变性的影响进行了研究.研究表明:合适的分散剂加入量可使浆料粘度降低;pH值的改变对浆料粘度有较大影响;随氧化锆含量、固相体积分数、有机单体含量增大,浆料粘度也会增大.     

氧化锆陶瓷注凝成型浆料流变性研究

陶瓷浆料流变性能是注凝成型工艺的关键,注凝成型要求浆料固含量高,粘度低.本文主要研究了固相含量、浆料pH值、分散剂、交联剂、单体等在制备低粘度高固含量氧化锆陶瓷浆料时,对浆料流变性的影响.实验结果表明:控制浆料的pH值为10左右,加入0.3wt％聚丙烯酸铵作为分散剂、1 wt％ AM作为单体,单体和交联剂比例为20∶1时,可制得粘度为2.12 Pa·s、流动性好适宜于复杂形状制品注模的陶瓷浆料.     

PZT压电陶瓷浆料注凝成型中的分散和聚合反应

为得到凝胶注模成型所需的高固相低粘度的锆钛酸铅压电陶瓷浆料,进行沉降试验和流变性实验,研究了分散剂柠檬酸三铵、浆料pH值和固相含量对浆料粘度的影响,实验结果表明其分散剂最佳用量为陶瓷粉体质量分数1.5%～2.0%、浆料最佳pH值为10.0左右。此时,可制备粘度小于1Pa·s,体积分数为50%适于凝胶注模的稳定锆钛酸铅浆料。研究了聚合反应的影响因素,结果表明浆料pH对聚合反应有一定的影响。     

HfB_2-Si_3N_4复合材料浆料流变性的研究

采用注凝成型技术研究了HfB2-Si3N4复合材料浆料的流变性能.主要讨论了pH值、分散剂、固相含量、球磨时间等对HfB2-Si3N4复合材料浆料粘度的影响.结果表明:当分散剂用量为8%(体积分数),pH值为10.9,球磨时间控制在15～20 h时,可制得固相体积含量为38%,粘度为600 mPa·s的HfB2-Si3N4复合浆料.     

氧化锆陶瓷注凝成型研究

本文对ZrO2注凝成型工艺中分散剂、固相体积含量对浆料流变性的影响进行了研究.研究表明分散剂的加入可以使浆料的Zeta电位值提高近40mv,浆料粘度降低;随固相体积含量增加,浆料粘度增加,但使浆料粘度降至最低所需分散剂的量减少.     

凝胶-注模成型技术制备碳纤维/HA复合材料的研究

本文研究了pH值、分散剂、有机单体和碳纤维含量对碳纤维/HA陶瓷浆料粘度的影响,观察了复相陶瓷浆料的凝胶固化过程,研究了烧结温度和碳纤维含量对复合材料烧结密度、抗弯强度和断裂韧性的影响.研究结果表明:当pH =9、有机单体含量为10wt％、分散剂含量为5wt％、固相含量为50wt％的碳纤维/HA陶瓷浆料具有良好的分散性.随引发剂、催化剂含量的增加,复相陶瓷浆料的凝胶固化时间缩短.复合材料的烧结密度、抗弯强度和断裂韧性均随烧结温度的升高而升高.复合材料的抗弯强度和断裂韧性均随着碳纤维含量的增加呈现先增加而后降低趋势.当碳纤维含量为2wt％和2.5wt％时,凝胶注模成型所制备的复合材料的抗弯强度和断裂韧性分别为80.6 MPa和1.87 MPa·m1/2,较干压成型样品提高了24.9％和19.8％.     

溶胶-凝胶法制备ZrB2-SiC复合材料的研究

采用溶胶-凝胶法制备ZrB<,2>-SiC复合材料,主要分析pH值、分散剂、固相含量、有机单体含量对ZrB<,2>-SiC浆料粘度的影响.实验结果表明,当pH值为10.3,分散剂含量为0.92 wt%,有机单体含量为3.2 wt%时,就可以制得固相含量为45 vol%,粘度为608 mPa·s的ZrB<,2>-SiC浆料.     

注凝成型工艺的研究进展

介绍了陶瓷的注凝成型工艺原理、工艺流程、浆料分散机理、凝胶固化过程和素坯干燥理论,分析了pH值、分散剂、固相含量及粉体特性对注凝成型浆料流变性能的影响,指出了陶瓷注凝成型工艺的发展趋势及存在的问题。     

氧化铝陶瓷注凝成型的研究

本实验探究了氧化铝陶瓷注凝成型工艺,综合分析了分散剂和浆料的固相含量对氧化铝陶瓷浆料粘度的影响,实验证明:当分散剂的加入量为0.6%,浆料的固相含量为50%时,浆料适宜注浆,得到的陶瓷产品颗粒分布均匀,结构致密。     

注凝成型制备HfB2-SiC复合陶瓷

采用注凝成型制备HfB2-SiC复合陶瓷,讨论了分散剂、pH值、固相体积含量对HfB2-SiC复合陶瓷浆料粘度的影响,并采用X射线衍射仪、扫描电镜、能谱等手段对制备烧结体的物相组成和显微结构进行了分析研究。结果表明,在HfB2中添加质量分数为20%的SiC,pH为10.6,分散剂体积分数为8%的条件下,HfB2-SiC复合粉体浆料的固相体积分数为40%,粘度为600mPa.s;在烧结体中HfB2和SiC以主晶相的形式存在于复合材料中,二者存在良好的界面结合,显微结构致密。     

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.     

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.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.