硅溶胶补强PDMS-PA复合膜的性能

以疏水纳米二氧化硅溶胶作硅橡胶的补强材料,制成了硅橡胶-聚酰胺(PDMS-PA)复合膜;用扫描电镜观察了其断面形态,考察了复合膜对醇-水溶液的渗透蒸发分离效果及耐用性,并与气相法白炭黑补强PDMS-PA复合膜进行了比较.结果表明,与气相法白炭黑补强PDMS-PA复合膜相比,硅溶胶补强的PDMS-PA复合膜的PDMS皮层和PA支撑层之间的结合更紧密,但分离因子和渗透通量下降.在相同条件下进行醇-水分离实验后,气相法白炭黑补强PDMS-PA复合膜出现PDMS皮层与PA支撑层分离现象;而硅溶胶补强PDMS-PA复合膜的PDMS皮层与PA支撑层结合完好.表明用硅溶胶作107硅橡胶的补强填料时能在PDMS-PA复合膜的渗透汽化性能略有下降的情况下改善PDMS皮层与PA支撑层之间的结合,提高复合膜的耐用性,使其具有工业使用价值.     

白炭黑填充PDMS/PVDF复合膜的纳滤分离性能及传质特性

将纳米级白炭黑填充于PDMS制备了白炭黑填充PDMS/PVDF复合膜,采用红外(FT-IR)、热失重(TGA)和接触角(CA)等方法对填充复合膜进行了分析和表征,并采用纳滤的方法系统研究了复合膜对大豆油/己烷混合油的分离性能。结果表明,白炭黑填充能有效促进PDMS的交联,提高PDMS的疏水性、热失重温度以及对溶剂的稳定性;白炭黑填充量增加使复合膜渗透通量降低,但截留率从96%提高到98%;随溶液浓度增加,渗透通量和截留率同时降低;随温度的升高,渗透通量上升,截留率降低。大豆油和己烷在膜中的传质特性可用不完全的溶解-扩散模型描述,溶液渗透压实验值与计算值符合较好。     

纳米白炭黑填充硅橡胶复合膜的制备与渗透汽化分离性能

制备以聚酯(PET)为支撑层,白炭黑填充的聚二甲基硅氧烷(PDMS107)为皮层的硅橡胶复合膜,并以乙醇水物系为料液,对比分析白炭黑增强硅橡胶复合膜的渗透蒸发分离性能,分离因子比空白膜有所提高,在乙醇浓度为3%～5%时,分离因子可达16.09,渗透通量为75.39 g/m2·h;测定填充白炭黑硅橡胶复合膜的拉伸强度,结果表明:拉伸强度可达1.828 MPa,相当于空白膜(0.368 MPa)的5倍.     

聚二甲基硅氧烷-聚偏氟乙烯共混膜制备及其渗透蒸发性能研究

为增强聚偏氟乙烯(PVDF)膜的疏水性能和膜选择性能,在PVDF基膜材料中添加了不同质量的聚二甲基硅氧烷(PDMS),制备了PVDF-PDMS共混复合膜。考察了PDMS、PVDF质量比对复合膜结构性能的影响,并用扫描电子显微镜、比表面积孔径分析仪、接触角测量仪、傅里叶变换红外光谱仪、X射线光电子能谱仪等仪器对复合膜进行了表征;采用低含量苯酚水溶液研究了复合膜的渗透蒸发性能。结果表明,随着PDMS添加量的增加,复合膜的疏水性能、苯酚渗透通量以及分离因子都会逐渐增大,复合膜渗透蒸发性能明显优于未改性膜;在PDMS、PVDF质量比为1:10时,复合膜具有最好的形态结构,表面接触角达到82.92°,苯酚渗透通量为39.31 g/(m~2·h),分离因子增加到4.68。     

支撑层结构对PTFE-PDMS复合膜渗透汽化性能的影响

以不同结构的聚四氟乙烯(PTFE)平板膜为支撑层、聚二甲基硅氧烷(PDMS)为活性层,通过表面涂覆方法制备PTFE-PDMS复合膜,并用于渗透汽化过程,以实现乙醇-水混合溶液的分离;研究了支撑层结构及制膜参数对其分离性能的影响。结果表明,支撑层结构对复合膜分离因子几乎无影响,对孔径大孔隙率高的支撑层,制膜时,PDMS聚合物向支撑层中渗入过多会使复合膜的渗透通量降低。PDMS聚合物向支撑层渗透形成的过渡层是复合膜传质阻力的重要部分,且过渡层厚,复合膜的耐溶胀性好。综合考虑渗透通量及分离因子,复合膜优化制备条件是交联剂正硅酸乙酯的质量分数4%,交联温度80℃,交联时间为5 h。     

偶联剂对纳米二氧化硅/PDMS复合膜渗透汽化性能影响的研究

用3种硅烷偶联剂3-氨丙基三乙氧基硅烷(AMES)、γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(MEMS)、十六烷基三甲氧基硅烷(HEMS)分别对纳米二氧化硅粒子进行改性,利用制备的改性粒子与PDMS制备了一系列平板复合渗透汽化分离膜,用于乙醇/水溶液分离.实验结果表明:复合膜的渗透汽化性能得到显著的提高.3种改性粒子在提高渗透通量方面:HEMS＞MEMS＞ AMES;在提高分离因子方面,MEMS与AMES对复合膜的影响十分接近,而HEMS远小于前两者.当MEMS改性二氧化硅的质量分数为4％时,在40℃质量分数为10％的乙醇/水溶液中,复合膜的分离因子达到最高值11.17,渗透通量为216.1g/(m2 ·h).     

疏水性SiO2-PDMS渗透汽化膜溶解-扩散性能

制备了疏水性纳米SiO2填充聚二甲基硅氧烷(PDMS)渗透汽化膜,研究了其溶解-扩散性能,计算了复合膜的溶解度参数(δM)及乙醇渗透系数(PE)。结果表明,填加SiO2提高了PDMS膜的乙醇溶解度(SE),SiO2填加量为10%(质量分数,下同)时,复合膜在30℃时的SE为0.0064,而未填加时仅为0.0026;PE值随SiO2含量的增加呈先增加后减小的趋势,SiO2填加量5%时,PE在60℃时为2.52×10-13 m2/s,而未填加时仅为1.42×10-13 m2/s;提高温度有利于乙醇的渗透。以乙醇/水物系为研究对象,结果表明,SiO2-PDMS复合膜渗透汽化性能与其渗透系数的变化趋势基本相同。     

PDMS/陶瓷复合膜用于乙醇回收的中试研究

采用中试装置，测评商业化PDMS/陶瓷复合膜回收乙醇的分离性能，考察了进料流量、操作温度及进料液乙醇质量分数对乙醇分离性能的影响，其中，详细研究了进料液乙醇质量分数连续变化时，膜的分离因子和渗透侧乙醇质量分数及水通量等数据的变化趋势。结果表明：在测试范围内，进料流量对膜分离性能的影响不大；随着操作温度的增加或进料液乙醇质量分数的提高，渗透通量增加，渗透侧乙醇质量分数呈现出不同的变化趋势。进料液乙醇的质量分数从9.86%连续降至0.55%的过程中，乙醇/水分离因子逐步提高，乙醇通量逐步降低，水通量基本保持不变。     

沸石填充硅橡胶渗透汽化膜的制备及其优先透醇性能研究

由ZSM-5沸石和聚二甲基硅氧烷(PDMS)制备超薄沸石填充PDMS复合膜,考察沸石填充量、沸石结构中硅铝比和操作温度对沸石填充硅橡胶膜渗透汽化性能的影响。结果表明,超薄复合膜的制备可以改善渗透通量小的缺陷。沸石填充量30%时分离因子最大;具有相同填充量的PDMS膜,硅铝比较大的填充膜,其分离因子和渗透通量均较高;随着操作温度的升高,复合膜分离因子先升高后降低,在50℃达到最大值,其渗透通量呈升高趋势。     

沸石填充硅橡胶渗透汽化膜的制备及其优先透醇性能研究

由ZSM-5沸石和聚二甲基硅氧烷(PDMS)制备超薄沸石填充PDMS复合膜,考察沸石填充量、沸石结构中硅铝比和操作温度对沸石填充硅橡胶膜渗透汽化性能的影响。结果表明,超薄复合膜的制备可以改善渗透通量小的缺陷。沸石填充量30%时分离因子最大;具有相同填充量的PDMS膜,硅铝比较大的填充膜,其分离因子和渗透通量均较高;随着操作温度的升高,复合膜分离因子先升高后降低,在50℃达到最大值,其渗透通量呈升高趋势。     

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。