相变储能致密微胶囊的制备

分别采用界面聚合法、自由基聚合法首次制备了以聚脲为第一层壁材,以苯乙烯-二乙烯苯共聚物为第二层壁材,相变点16℃的石蜡为芯材的相变储热致密微胶囊.采用激光粒度分布仪、红外光谱分析仪.差示扫描量热分析仪、热重分析仪分析了制备的致密微胶囊的粒径分布、结构组成以及热性能.结果表明,相变储热致密微胶囊是复合相变材料,微胶囊的粒径均匀,热稳定性好,致密性优良不渗漏,其蓄热能力较好、可广泛应用于节能储能的目的.     

十四醇相变微胶囊的合成与表征

以丙烯腈、丙烯酸丁酯和甲基丙烯酸的共聚物为壁材,十四醇为芯材,通过悬浮聚合法合成相变储能微胶囊材料。研究了单体组成、均化速率、芯壁比对微胶囊形貌和性能的影响,并利用红外光谱、光学显微镜、扫描电子显微镜、激光粒度仪、差示扫描量热仪、热重分析仪分别对微胶囊进行了表征。通过实验优化,当芯壁比为1.5∶1(质量比),均化速率为1 500 r/min,反应温度为70℃时,制备的相变微胶囊球形圆整,粒径均匀,相变焓为113.53J/g,并具有良好的热稳定性。     

基于聚多巴胺包覆的光热相变微胶囊的制备及性能

以正十八烷(n-OD)为芯材,二氧化硅(SiO2)和聚多巴胺(PDA)为复合壁材,采用界面水解缩合法成功制备光热相变微胶囊n-OD@SiO2/PDA.采用FESEM、FETEM、FTIR、DSC、TG、UV-Vis-NIR和模拟光源等对所制备了微胶囊的表面形貌、化学结构、热性能、光吸收性能和光热转换性能进行了分析和表征.在探究了不同芯材与硅源〔正硅酸四乙酯(TEOS)〕质量比对相变微胶囊储热性能影响的基础上,确定了以m(n-OD):m(TEOS)=2:1制备光热相变微胶囊.结果表明,所制备的光热相变微胶囊具有规整的表面形貌和明显的核壳结构,具有良好的耐热性能,复合壁材可以有效保护芯材.与相变微胶囊n-OD@SiO2相比,光热相变微胶囊仍具备良好的储热性能,其熔融热焓值为151.2 J/g,展现出较好的光热转换性能,其光热转换与存储效率为91.8％.     

基于聚多巴胺包覆的光热相变纳胶囊的制备及性能

以正十八烷（n-OD）为芯材，二氧化硅（SiO2）和聚多巴胺（PDA）为复合壁材，采用界面水解缩合法成功制备光热相变微胶囊n-OD@SiO2/PDA。采用FESEM、FETEM、FTIR、DSC、TG、UV-Vis-NIR和模拟光源等对所制备微胶囊的表面形貌、化学结构、热性能、光吸收性能和光热转换性能进行了分析和表征。在探究了不同芯材与硅源（正硅酸四乙酯）质量比对相变微胶囊储热性能影响的基础上，确定了以m(n-OD):m(TEOS)为2:1制备光热相变微胶囊。实验结果表明，所制备的光热相变微胶囊具有规整的表面形貌和明显的核壳结构，具有良好的耐热性能，复合壁材可以有效保护芯材。与相变微胶囊n-OD@SiO2相比，光热相变微胶囊仍具备良好的储热性能，其熔融热焓值为151.2 J/g，展现出较好的光热转换性能，其光热转换与存储效率为91.8%。     

聚氨酯微胶囊相变材料的制备及性能

以硬脂酸丁酯为芯材,2,4-甲苯二异氰酸酯(TDI)和三乙醇胺(TEA)为反应单体制备壁材,采用界面聚合法制备具有储热能力的聚氨酯微胶囊相变材料,并对所制微胶囊的表面形貌、红外结构、热稳定性、相变性能和致密性进行表征分析。结果表明,所制微胶囊呈球形结构均匀分布,熔融温度(ΔT_m)和熔融热焓(ΔH_m)分别为20. 60℃和84. 09 J/g,储热性能优异。热稳定性和致密性分析表明,当TEA质量为4. 5 g、芯材完全失重时,微胶囊的质量保留率最高为52. 6%,120℃持续烘干6 h,质量损失率最低仅为21. 8%,表明所制备的微胶囊具有良好的热稳定性和致密性。     

微胶囊复合相变材料的制备及性能表征

以低熔点的相变材料为芯材,三聚氰胺脲醛树脂为囊壁材料,用原位聚合法制备了相变储能微胶囊。采用红外光谱、扫描电子显微镜、差示扫描量热分析和热重分析测试技术表征了制备的相变微胶囊的结构组成、形貌特征及热性能。实验结果表明,相变储能微胶囊复合相变材料热稳定性好,在160℃以下无质量损失,其相变温度和焓值分别为15.3℃,132.3 J/g。制备得到的微胶囊呈球形,平均粒径小于20μm,固化剂滴加速度为0.5 mL/m in时微胶囊形貌较佳,优化的芯/壁质量比为1∶1.5,且微胶囊的亲水性随芯材含量增加而降低。     

棕榈酸/二氧化硅相变微胶囊的制备及性能研究

采用乳液模板自组装法通过界面缩聚制备了以棕榈酸（PA）相变材料为核、二氧化硅（SiO2）为壳的相变微胶囊，研究了不同核／壳质量比对PA/SiO2相变微胶囊的表面形貌、微观结构、相变储能性能、热稳定性和热循环性能的影响规律。结果表明:随着核／壳质量比增加，PA/SiO2相变微胶囊呈现更完整的核／壳结构和更均匀的球形外观，其最佳核／壳质量比为60:40；所形成的微胶囊的最高相变储热能力可达98.78%；研究显示，致密SiO2包覆层的形成能够有效阻止相变芯材融化后的泄露和流失，同时也提升了相变微胶囊的热稳定性能，该相变微胶囊在快速热冲击下仍保持良好的形态稳定性，并展示了良好的相变可逆性和相变耐久性，该相变微胶囊可广泛应用于工业及民用各领域的潜热储存和热管理。     

纳米SiO_2改性脲醛树脂/十二醇相变微胶囊的制备及性能

利用原位聚合法制备了以纳米SiO_2改性脲醛树脂为壁材、十二醇为芯材的相变微胶囊。考察了芯壁质量比、固化终点pH和纳米SiO_2质量分数对微胶囊包封率和芯材质量分数、渗透率的影响,采用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和热重分析仪(TG)等分别对微胶囊相变材料的表面形貌、粒径和热性能进行了表征。研究结果表明,纳米SiO_2改性脲醛树脂/十二醇相变微胶囊的最佳制备条件为:芯壁质量比为1∶2、固化终点p H=1.5~2、纳米SiO_2质量分数为3%。制备的微胶囊为表面光滑的球形,粒径大小为1.85~5μm,包封率和芯材质量分数分别为62.5%和79.3%,相变潜热为148.4 J/g。     

棕榈酸/二氧化硅相变微胶囊材料的制备及性能研究

采用化学沉淀法合成以棕榈酸为芯材,二氧化硅为壁材的相变微胶囊材料,研究盐酸浓度对棕榈酸/二氧化硅相变微胶囊性能的影响.通过红外光谱(FTIR)、扫描电镜(SEM)、X射线衍射仪(XRD)、差示量热(DSC)等手段对合成的相变微胶囊的微观形貌和相变性能进行分析表征.结果表明:棕榈酸被成功的包覆到了二氧化硅壳材中;盐酸浓度...     

用于自内冷溶液除湿的复配石蜡微胶囊的特性

以三聚氰胺?甲醛树脂为胶囊壁材、固液复配石蜡为胶囊芯材,采用原位聚合法制备了用于自内冷溶液除湿的相变材料微胶囊,研究了单一或不同类型乳化剂复配、乳化剂用量对相变材料微胶囊粒径、微观形貌及热性能的影响. 结果表明,非离子乳化剂NP-10与阴离子乳化剂SDBS复配所制微胶囊相变潜热较低,非离子乳化剂Span80和Tween80按质量比1:1复配、乳化剂占芯材质量的60%、乳化转速为1000 r/min时,所制微胶囊综合性能最佳,表面光滑致密,分散性良好,粒径均一,平均粒径为0.45 ?m,相变潜热为52.48 J/g,囊芯含量为58.44%,相变温度适用于以LiCl溶液为除湿剂的自内冷溶液除湿系统.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。