可再分散乳胶粉的研究进展及应用前景

介绍了可再分散乳胶粉的研究进展、性能特点以及在现实中的应用。随着对可再分散乳胶粉研究的深入，可再分散乳胶粉的应用因其优良的性能已从原来在建筑材料行业的应用扩展至许多新的领域。     

疏水性可再分散聚合物乳胶粉的研究进展

对可再分散聚合物乳胶粉进行疏水性改性是提高其应用性能的重要方法。本文概述了疏水改性的可再分散聚合物乳胶粉的制备技术,对脂肪酸及其衍生物、硅烷等疏水改性的可再分散聚合物乳胶粉的特性和应用进行了论述,指出了疏水性可再分散乳胶粉用于水泥砂浆、新型内外墙干粉涂料等建筑材料可赋予材料良好的疏水性,从而提高其性能和使用寿命。     

可再分散乳胶粉的研究进展及其应用

本文简述了可再分散乳胶粉的性能。着重介绍了可再分散乳胶粉的制备,包括单体及配方的选择、聚合方法和干燥工艺,综述了可再分散乳胶粉的改性及其在建筑腻子、外墙外保温材料、内外墙装饰材料、地坪材料等方面的应用。指出以水溶性高分子为乳液聚合主要稳定剂的乳液聚合是一种新的思路。     

可再分散聚合物乳胶粉研究进展

介绍了可再分散乳胶粉的制备工艺、作用机理及应用现状,着重阐述了核壳结构聚合物乳胶粉在喷雾干燥时的独特性能优势并指出这种结构的聚合物乳胶粉将是未来重点研究的方向之一.     

可再分散聚合物乳胶粉的性能及其应用

介绍了可再分散聚合物乳胶粉的性能、市场现状及改性机理,重点讨论了可再分散聚合物乳胶粉在建筑腻子、自流平地坪材料、外墙外保温及饰面系统、外墙外保温系统、灰膏、瓷砖粘结剂和零VOC干粉涂料中的应用。     

丙烯酸酯可再分散乳胶粉的性能与表征

丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、甲基丙烯酸(MAA)和甲基丙烯酸羟乙酯(HEMA)为共聚单体合成了具有软核硬壳结构的丙烯酸酯乳液,经喷雾干燥法制得了丙烯酸酯可再分散乳胶粉.通过测试再分散液粒径及其分布、吸光度表征了乳胶粉再分散性及再分散液稳定性,并用扫描电镜(SEM)观察了再分散液的微观成膜效果,最后用傅立叶红外光谱(FT-IR)、透射电镜(TEM)、差示扫描量热(DSC)等测试对乳胶粉进行了表征.实验结果表明,制备的乳胶粉具有良好的再分散稳定性,再分散液和原乳液粒径大小及其分布基本相同,SEM显示再分散液具有良好的成膜性,FT-IR表明乳胶粉的分子结构与原乳液相比未发生明显改变,TEM显示再分散液粒子未发生变化仍保持核壳结构,DSC验证了制得的乳胶粉具有核(25℃和壳55℃两个玻璃化温度(T_g).所有分析表明乳胶粉再分散液与原乳液的性能和结构基本相同.     

瓦克在华最大可再分散乳胶粉生产厂投产

最近，瓦克化学集团新的可再分散乳胶粉及VAE乳液生产基地在南京正式投入使用。工厂可再分散乳胶粉年生产能力达3万t，是中国同类工厂中规模最大的。该项投资致力于确保长期充分的VINNAPAS可再分散乳胶粉生产能力，同时为亚太地区客户提供可靠的供应和稳定的品质。瓦克化学是世界上最大的建筑用可再分散乳胶粉生产商之一。     

制备可再分散苯-丙乳胶粉的干燥温度探讨

采用喷雾干燥法制备苯-丙可再分散乳胶粉.探讨了干燥室进口温度对制备苯-丙可再分散乳胶粉及其性能的影响.结果表明,进口干燥空气的温度对乳胶粉的外观、粒径、含水率、再分散性、成膜性能、吸水率有较大影响.干燥温度升高,可再分散乳胶粉含水率降低,再分散液粒径减小,再分散性、成膜性都变好,吸水率提高.但温度过高(160 ℃)和过低(100 ℃)会使乳胶粒子在干燥过程中形成粒径较大的聚合物颗粒,导致粉体滤渣含量增加,对于苯-丙乳液来说,适当的喷雾干燥温度是120～140 ℃.红外光谱图表明:在100～160 ℃下的干燥没有明显改变乳胶粒子的分子结构.SEM图分析表明:干燥温度越高,再生膜越致密.     

含有机硅改性聚合物的水泥腻子

比较了普通可再分散乳胶粉聚合物和有机硅改性可再分散乳胶粉聚合物对水泥破子吸水性、水蒸气透过性、气合量及抗折强度的影响。结果发现，掺入有机硅改性可再分散乳胶粉聚合物的水泥腻子具有良好的粘接性、憎水性和透气性，施工性好、无毒、无刺激性，是传统破子的优良替代品。     

影响可再分散聚合物乳胶粉性能的因素分析

采用喷雾干燥法制备可再分散聚合物乳胶粉。探讨了干燥室进口温度、喷雾液黏度、雾化轮转速及喷雾液进料速率对制备可再分散乳胶粉及其性能的影响,并用扫描电镜对乳胶粉进行表征。结果表明:进口温度为120～140℃、喷雾液黏度在15～20 s、雾化盘转速24 000 r/min、进料泵转速为30～35 r/min时,制备的乳胶粉流动性好、无结块,再分散性优良,满足制备乳胶粉的性能要求。     

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。