用脱镁海泡石制备介孔分子筛MCM-41

以脱镁海泡石为硅源,在水热条件下合成介孔分子筛MCM-41.考察了晶化时间、晶化温度、pH值等因素对介孔分子筛MCM-41的影响.用X射线衍射分析、Brumauer-Emmett-Teller法和红外分析表征MCM-41.结果表明:在pH值为12,晶化温度为100℃,晶化时间为24h时,所得MCM-41的结晶度最好,比表面积为860m2/g,孔体积为0.77 cm3/g,孔径为2.9nm,孔壁厚为1 nm.红外分析表明:脱镁海泡石在合成介孔分子筛MCM-41过程中生成了≡SiO-CTA 络合物.     

酸性条件下介孔分子筛MCM-41的合成与表征

以十六烷基三甲基溴化铵为表面活性剂,正硅酸乙酯为硅源在酸性条件下合成了具有完好的六方结构介孔分子筛MCM-41.考察了pH值、酸性介质、反应物比例、晶化温度等对介孔分子筛MCM-41合成的影响,并用XRD对其进行了表征.     

硼酸钠缓冲体系下制备介孔分子筛AlMCM-41及其水蒸汽热稳定性

硼酸钠缓冲体系下,在pH值为9. 5条件下,水热合成了硅铝比(简称Si/Al)分别为25、10、8、6的介孔分子筛Al MCM-41,在Si/Al为10时,在p H值分别为8. 5、9. 5、10. 8的条件下也水热合成了Al MCM-41,对合成后的样品进行XRD表征,得到结论:随着Si/Al的增加,Al MCM-41的有序性提高,p H值为9. 5得到的Al MCM-41结晶度最高。还考察了以上不同Si/Al和pH值介孔分子筛Al MCM-41的水蒸汽热稳定性,在Si/Al为25时,p H值为9. 5条件下合成介孔分子筛的水蒸汽热稳定性最好。     

晶化过程中无机盐及pH值调节对介孔分子筛水热稳定性的影响

以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,在碱性条件下合成了介孔分子筛MCM-41.借助XRD,SEM等检测手段考察了晶化过程中加入无机盐对介孔材料稳定性的影响.实验结果表明:加入NaF的样品其XRD衍射峰较强,表现出较好的结构有序性;在最初凝胶晶化24h后引入(NH4)2SO4,同样可获得有序的介孔结构;晶化过程中降低体系pH值能使硅酸盐的聚合度增大,孔壁厚度增加.由于所得产物具有完整的介孔结构,很好的结晶度及较大的孔壁厚度,因而在一定程度上提高了介孔分子筛的水热稳定性.     

低质量分数表面活性剂作模板合成MCM-41中孔分子筛

以硅酸钠为硅源,表面活性剂十六烷基三甲基溴化铵(CTMABr)为结构模板剂,用水热晶化法在w(CTMABr)=1%～3%下制备全硅MCM-41中孔分子筛。采用染料吸附脱色实验比较了原料配比、反应体系pH值、晶化时间、晶化温度、脱模温度对MCM-41合成的影响。结果表明,合成MCM-41中孔分子筛时表面活性剂CTMABr质量分数必须达到1%以上;pH=10～12;晶化温度以125℃左右为好;前驱体脱模温度控制在600～800℃。在较优的工艺条件w(CTMABr)=1 5%、pH=11、晶化温度125℃、晶化时间24h、脱模温度640℃下得到了具有完美晶型结构、BET比表面积=1370m2/g、平均孔径3 28nm的全硅MCM-41中孔分子筛。     

硼酸钠缓冲体系下制备介孔分子筛AlMCM-41及其水蒸汽热稳定性

硼酸钠缓冲体系下,在pH值为9. 5条件下,水热合成了硅铝比(简称Si/Al)分别为25、10、8、6的介孔分子筛Al MCM-41,在Si/Al为10时,在p H值分别为8. 5、9. 5、10. 8的条件下也水热合成了AlMCM-41,对合成后的样品进行XRD表征,得到结论:随着Si/Al的增加,AlMCM-41的有序性提高,pH值为9. 5得到的AlMCM-41结晶度最高。还考察了以上不同Si/Al和pH值介孔分子筛AlMCM-41的水蒸汽热稳定性,在Si/Al为25时,p H值为9. 5条件下合成介孔分子筛的水蒸汽热稳定性最好。     

以离子液体为模板剂合成MCM-41介孔分子筛

以离子液体1-十六烷基-3-甲基溴代咪唑为模板剂,合成介孔分子筛MCM-41。考察了不同硅源[、C16mim]Br/SiO2配比、pH值、晶化时间等条件对合成MCM-41的影响。采用XRD和低温氮吸附对产物进行表征,结果表明该方法合成的样品具有较大比表面积和规整介孔孔道结构。     

MCM-41介孔分子筛合成与改性的研究进展

简要介绍了MCM-41介孔分子筛的特点,应用和改性原因.综述了MCM-41介孔分子筛的合成方法,主要包括水热合成法,室温合成法,微波合成法等,列出了每种合成方法的优缺点和合成过程中的影响因素,pH值、晶化时间、晶化温度、模板剂的种类及用量等都会对MCM-41介孔分子筛的结构和孔径产生很大影响.阐述了MCM-41介孔分子筛的改性方法,包括金属杂原子取代法,如主族金属、过渡金属、稀土金属等,有机修饰或功能化法,负载型改性法,如负载金属氧化物、无机酸、杂多酸、有机碱、金属的配合物等.最后就MCM-41介孔分子筛的应用前景做了展望.     

直接合成中孔材料MCM-41

以水玻璃为硅源，三甲基十六烷基溴化胺(cetyltrimethylammonium bromide，CTAB)为模板剂，10％的H2SO4为pH调节剂，在敞开体系中直接合成中孔分子筛MCM-41。利用XRD和孔径分布测定对合成的分子筛进行了结构表征，研究了料浆的n(Si)／n(CTAB)比值，体系的pH值，晶化温度和时间对MCM-41合成的影响。根据实验给出合成条件为：n(Si)／n(CTAB)=5～7，浆料pH值10．5～10．7，合成温度373K，晶化时间12～24h。     

强酸性介孔晶体分子筛的制备

实验室合成了未脱除模板剂的MCM-41分子筛,然后通过焙烧使模板剂炭化,生成碳纳米丝,留在孔道中。将产物溶解在碱中,用合成ZSM-5的方法处理,最终使无定型硅铝在碳纳米丝表面结晶、生长,晶化后,再将其焙烧,得到了强酸性介孔晶体分子筛。对MCM-41、ZSM-5和最终产物进行了XRD表征,结果显示,晶化温度140 ℃、晶化时间24 h以及较佳焙烧条件下制得的最终产物的酸性、热稳定性和水热稳定性较强。     

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。