聚氨酯泡沫塑料化学镀银工艺

研究了化学镀银液中银离子、葡萄糖、pH值、稳定剂硫脲对聚氨酯泡沫塑料上银沉积速率的影响,优选了在聚氨酯泡沫塑料上化学镀银工艺条件.聚氨酯泡沫塑料化学镀银后再经电沉积和烧结处理可制得质量优良的发泡银.     

三种有机泡沫材料的吸放水性及微观结构研究

采用重量法和扫描电镜研究了硬质聚氨酯泡沫塑料、硅橡胶泡沫材料、半硬质自结皮聚氨酯泡沫塑料的吸、放水性能和微观结构,比较了这三种泡沫材料的吸、放水性能及其机理。结果表明,这三种有机泡沫材料的吸、放水能力不同,硬质聚氨酯泡沫塑料的吸、放水能力<硅橡胶泡沫材料<半硬质自结皮聚氨酯泡沫塑料,其吸、放水机理与泡沫开孔有关,密度越小且泡孔开孔率越高,吸、放水能力越强。     

国外聚氨酯泡沫塑料工业(连载)

三、聚氨酯泡沫塑料制品 (一)软质聚氨酯泡沫塑料软质聚氨酯泡沫塑料(简称软质泡沫或软泡)的消费量仍占聚氨酯总消费量的绝大部分。1971年世界软质泡沫总产量为100万吨/年以上,而硬质泡沫约为20—30万吨/年,     

聚氨酯

第三代聚氨酯软泡品种高回弹聚氨酯泡沫塑料高回弹聚氨酯泡沫塑料(H R泡沫体)是在七十年代初期工业化的聚醚型软聚氨酯泡沫体第三代品种。回顾聚氨酯泡沫塑料的发展过程,开始是五十年代初以聚酯型泡沫体投入市场,由于石油化工的发     

醇-磷酸酯法降解废旧聚氨酯的研究

选用不同的降解剂,采用醇-磷酸酯法降解废旧聚氨酯泡沫,对降解产物进行性能测试。结果表明：以一缩二乙二醇和磷酸三正丁酯为降解剂降解聚氨酯软质泡沫效果较好。以降解产物作为部分原料制备聚氨酯硬质泡沫塑料体,对其性能测试并与不加降解产物制备的聚氨酯硬质泡沫体比较,结果表明：降解产物作为部分原料对聚氨酯硬质泡沫塑料的性能影响不大。     

电沉积法制备泡沫铜

以聚氨酯软泡沫为基体,经预处理、化学沉积、电沉积和焚烧及热还原工艺制备了均匀分布三维网状孔结构的、高空隙率（＞９５％）且具有一定拉伸强度的泡沫铜材料．通过电子显微镜及生物显微镜观察了制备过程各步骤产品的形貌,用图像分析仪测定了泡沫铜的孔径分布,并运用线性电位扫描法对在泡沫上电沉积的阴极过程进行了研究．     

聚氨酯预聚物改性酚醛泡沫塑料脆性的研究

采用聚氨酯预聚物对酚醛泡沫塑料进行改性，研究了预聚物粘度、用量对泡沫粉化程度和回弹性的影响。结果表明：预聚物的粘度越低，对酚醛泡沫的粉化性的改善效果越好；当预聚物的质量分数为3％时，改性泡沫的粉化程度仅为未改性的40％，且使泡沫具有一定的弹性，回弹率大于60％；聚氨酯预聚物对酚醛泡沫塑料的改性机理不是简单的物理共混，同时伴有共聚反应发生。     

一种聚氨酯泡沫塑料切块机

正本发明涉及一种聚氨酯泡沫塑料切块机,利用圆形送料桶和圆盘锯的刀齿使聚氨酯泡沫块经过垂直切割和水平切割后仍保持圆柱形,泡沫条相对位置保持不变,不会出现泡沫条与圆盘锯大面积接触造成切割刀组抱死的情况,泡沫条经横切刀组切断后成为聚氨酯泡沫塑料块,通过气流吹送至包装袋中。本发明所提出的聚氨酯泡沫塑料切块机在一次送料过     

三种泡沫材料的吸放水性及微观结构

采用重量法和扫描电镜研究了硬质聚氨酯泡沫塑料、硅橡胶泡沫、半硬质自结皮聚氨酯泡沫的吸、放湿水性能和微观结构,比较分析和探讨了3种泡沫材料的吸、放水性及其机理,并提出减少泡沫材料中水份的有效途径.研究结果表明3种泡沫材料的吸、放水性不同,即硬质聚氨酯泡沫塑料＜硅橡胶泡沫＜＜半硬质自结皮聚氨酯泡沫,其吸、放水机理是由于开孔所致,如果密度越小且泡孔开孔率越高,则吸、放水能力越强.减少泡沫材料中水份的有效途径(1)提高材料密度和闭孔率;(2)在材料表面镀金属膜或保留表皮;(3)进行适当干燥处理,并尽可能降低存放环境湿度.     

聚氨酯泡沫塑料工业的进展

近年来聚氨酯塑料工业正向着原料系列化、制品多样化、生产设备自动化发展.对国外近期的聚氨酯泡沫塑料工业的发展及特点进行了评述分析与预测.介绍了国内聚氨酯泡沫塑料的应用结构及其发展现状,同时对聚氨酯泡沫塑料的开发提出了自己的建议,加强聚氨酯泡沫行业的管理,集中技术优势,建立起研究开发、加工的一个完整有序的工业体系,以期提高我国泡沫工业的整体实力.     

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.     

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.     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.