热处理温度对核-壳型SiO2@TiO2复合纳米材料光催化性能的影响

采用溶胶-凝胶法在二氧化硅(SiO2)纳米微球表面负载纳米二氧化钛(TiO2),制备核-壳SiO2@TiO2复合纳米颗粒.采用X射线衍射仪(XRD)、环境扫描电子显微镜(SEM-EDS)、比表面积测定(BET)等研究手段对样品的矿物组成、结构形貌进行了表征,并考察了其光催化活性.结果 表明:溶胶-凝胶法后期的热处理明显提高了核-壳SiO2@TiO2复合纳米颗粒光催化降解亚甲基蓝溶液的能力,其中,经过400℃热处理的样品催化效果最好,对质量浓度为20 mg/L的亚甲基蓝溶液90 min的降解率达到96.27％.     

光催化PVC糊的制备及其对亚甲基蓝的光催化降解

将纳米TiO2加入PVC糊中制备光催化PVC糊,研究不同种类及含量的纳米TiO2、亚甲基蓝溶液的浓度对光催化PVC糊制品光催化性能的影响.实验结果表明:含掺钨改性纳米TiO2的先催化PVC糊降解效果最明显;当纳米TiO2含量为8份时,亚甲基蓝溶液降解率最高;亚甲基蓝溶液的浓度为5 mg/L时,降解效果明显.     

锌掺杂TiO2超微粉的溶胶-凝胶法制备及光催化性能研究

以钛酸四丁酯为原料,采用溶胶-凝胶法制备了锌掺杂纳米TiO2光催化剂,探讨了锌掺杂对TiO2光催化活性的影响.用X射线衍射仪(XRD)、扫描电子显微镜(SEM)表征了产品的微观结构和晶相组成,用综合热分析仪对前驱体凝胶进行了差热分析;以亚甲基蓝为降解对象,考察了锌掺杂、掺杂浓度对TiO2光催化活性的影响.结果表明:锌掺杂对TiO2晶由锐钛矿型向金红石型的相转变有抑制作用,并能够提高纳米TiO2的光催化活性;锌掺杂量具有一个相对最佳比例,当掺杂量3%、热处理温度550℃时,用溶胶-凝胶法可得到粒径分布均匀、锐钛矿晶型含量高、具有较高光催化活性的锌掺杂纳米TiO2.     

玻璃纤维负载纳米TiO2的制备及光催化性能

采用浸渍-提拉法在玻璃纤维(GF)表面负载纳米TiO2,制备TiO2/GF复合光催化剂.通过X射线衍射(XRD)、热重-差热分析(TG-DSC)、扫描电镜(SEM)及能谱元素分析(EDS)对TiO2/GF复合光催化剂的结构进行了表征.结果表明,经550 ℃以下热处理,TiO2的晶型为锐钛矿相,随着热处理温度的升高,TiO2的晶型逐渐转化为金红石相.以亚甲基蓝的光催化降解为探针反应,评价TiO2/GF复合材料的光催化活性.复合材料的光催化降解活性与P25相当,且经多次使用后,复合光催化剂对亚甲基蓝的降解率仍保持在80%以上.     

天然炭纤维负载二氧化钛颗粒的制备与光催化活性

以棉花制备的炭纤维为载体,钛酸丁酯为钛源,采用水热法制备炭纤维负载二氧化钛复合材料(CF/TiO2),利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)等对CF/TiO2复合材料进行结构表征.用紫外-可见光吸收光谱(UV-vis)分析比较了TiO2、炭纤维和CF/TiO2,热处理温度以及溶液的pH值在紫外光照下对甲基蓝溶液的光催化降解性的影响,以及对CF/TiO2复合材料的失活性能研究.结果表明:炭纤维负载TiO2对甲基蓝光催化降解性较好,有效利用了炭纤维的吸附性与TiO2的催化活性;当热处理温度为220℃,pH =5时,甲基蓝溶液的吸附-光催化性能最大为85.9％;复合光催化剂使用后在紫外线照射后,其活性恢复,可以循环利用.     

LDO负载纳米二氧化钛复合物的制备及其光催化性能研究

以碳酸根型镁铝层状双氢氧化物(LDH)为载体,采用溶胶-凝胶法利用酞酸丁酯水解负载纳米TiO2于LDH片层获得TiO2/LDH前驱体,通过低温焙烧前驱体获得纳米二氧化钛/层状双金属氧化物复合物(TiO2/LDO).以亚甲基蓝溶液模拟染料污染物,在波长291 nm紫外光条件下测定吸光度,评价了光催化剂不同投加量,体系pH值以及光照时间条件下对亚甲基蓝降解率的影响,研究了TiO2/LDO的光催化性能.结果表明:通过溶胶-凝胶法可以获得高分散纳米级(<10 nm)TiO2负载型TiO2/LDH复合物,TiO2/LDH中TiO2负载率达8.01wt%(质量分数);TiO2/LDO的光催化性能较纯LDO高,TiO2负载于LDO层板对亚甲基蓝具有协同催化作用;在pH值为9的80 mL亚甲基蓝溶液(浓度为5 mg/L)中投入0.20 g TiO2/LDO,催化反应8 h后降解率高达81.7%,TiO2/LDO对亚甲基蓝溶液的光催化反应符合一级动力学方程.     

漂浮型纳米TiO2/EP的制备及其光催化性能

以膨胀珍珠岩为载体,钛酸四丁酯为原料,用溶胶-凝胶法制备漂浮型纳米TiO2光催化剂,并用该光催化剂在太阳光下对亚甲基蓝进行光催化降解实验.结果表明,在450℃焙烧2h,负载3次的条件下制备的漂浮型催化剂光催化活性较好.150 mg漂浮型纳米TiO2/EP在30 mL亚甲基蓝溶液(4 mg/L)液面平铺,经120 min太阳光照射,亚甲基蓝的降解率为97.6％.XRD和SEM分析结果表明,二氧化钛为结晶良好的锐钛矿型,粒径大约为8nm.漂浮型纳米TiO2/EP有较广阔的工程应用前景.     

高炉渣纤维负载TiO2光催化材料的制备及其光催化性能

以高炉渣纤维(BFSF)为载体,采用溶胶凝胶法,在BFSF表面负载TiO2,制备BFSF负载TiO2(TiO2/BFSF)光催化材料.利用差热-热重(TG-DTA)、X射线衍射仪(XRD)、场发射扫描电镜(SEM)及能谱元素分析(EDS)等近代测试方法对TiO2/BFSF的显微结构和相组成进行了表征.以模拟印染废水的亚甲基蓝(MB)的降解,评价样品的光催化活性.实验结果表明:TiO2溶胶负载3次,煅烧温度为450℃时,TiO2/BFSF光催化材料表面负载了一层均匀密实的锐钛矿型TiO2,当紫外光照射180 min时,亚甲基蓝的降解率达到92.5％.循环利用TiO2/BFSF光催化材料4次,亚甲基蓝的降解率依然能够达到63％.     

TiO2薄膜的低温制备以及工艺优化和性能研究

采用改进溶胶-凝胶法,通过浸渍-提拉工艺在载玻片表面低温制备了锐钛型纳米TiO2薄膜,探讨了水量、pH、水浴时间等工艺参数对TiO2的晶型及光催化活性的影响.利用XRD、FT - IR、SEM和UV - Vis光谱等手段对薄膜的物相、结构、表面形貌以及光吸收特性进行了表征,并利用紫外光激发下降解亚甲基蓝溶液来评价TiO2薄膜的光催化活性.结果表明:在低温条件下,所得TiO2薄膜表面均匀平整;随着水量的增加和pH的降低,TiO2晶化程度逐渐提高;水浴前后所制备的TiO2薄膜对紫外光都表现出了极强的吸收特性;水浴处理有利于提高纳米TiO2薄膜的催化活性,80 ℃水浴8h后TiO2薄膜对亚甲基蓝溶液的降解率从20.9％提高到72.1％.     

纳米TiO2的复合改性及其光催化性能

采用甲基丙烯酸甲酯、硝酸镧对纳米TiO2进行复合改性,以亚甲基蓝作为光催化降解对象,讨论改性条件对纳米TiO2光催化性能的影响.结果表明,纳米TiO2经过改性后,其光催化性能均有所提高,尤其是经过硝酸镧复合改性后,其光催化性能明显好于未改性纳米TiO2和单一改性纳米TiO2.甲基丙烯酸甲酯用量、硝酸镧用量、热处理温度、热处理时间对纳米TiO2光催化性能均有影响.复合改性纳米TiO2的较佳工艺条件为:甲基丙烯酸甲酯用量为44.09%,硝酸镧用量为2.31%,热处理温度为500℃,热处理时间为5 h.     

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。