锑炉渣玻璃陶瓷的研究

文中概述了玻璃陶瓷及炉渣玻璃陶瓷的发展与开发以锑炉渣为主要原料的锑渣玻璃陶瓷材料的意义,介绍了该炉渣玻璃陶瓷的配方设计、热处理工艺制度确定的方法及其对材料的微晶化作用,结构与性能的影响,用差热分析、x-射线衍射及扫描电镜分析方法探讨了添加氧化物晶核剂Cr_2O_5、ZrO_2、P_2O_5及TiO_2的锑炉渣玻璃陶瓷的微晶化机理、晶相组成与微观结构,测定了所研制的锑炉渣玻璃陶瓷材料的主要性能。研究表明,TiO_2为锑炉渣玻璃陶瓷的一种最有效的晶核剂,当添加量为10％时可按本研究确定的基础玻璃配方及热处理工艺得到一种熔制温度低(1360℃～1380℃)、易实现微晶化且材料性能好的锑炉渣玻璃陶瓷。该材料以硅灰石、榍石和辉石为主晶相,配方中锑炉的用量高于50％。显然,锑炉渣玻璃陶瓷的开发具有较好的社会与经济效益。     

复合晶核剂TiO2/ZrO2对MgO-Al2O3-SiO2系统微晶玻璃的影响研究

本文制备了Mg0-Al2O3-SiO2系微晶玻璃,用XRD、DTA等方法对该系统微晶玻璃材料进行了研究;讨论了复合晶核剂对材料热膨胀性能及热处理温度的影响.结果表明TiO2/ZrO2复合晶核剂中,少量ZrO2(＜0.5wt%)能够降低微晶玻璃材料的热处理温度和热膨胀系数.     

锑炉渣玻璃陶瓷热处理工艺的研究

本文采用差热分析、X-射线衍射分析、扫描电镜技术与正交试验设计相结合的方法研究了锑炉渣玻璃陶瓷的热处理工艺对其微晶化过程的影响。研究确定,该锑炉渣玻璃陶瓷的最佳热处理条件为:核化温度与晶化温度分别为840℃与1020℃,核化与晶化时间分别为2小时与1小时。依此工艺获得了具有良好性能的锑炉渣玻璃陶瓷材料。     

Cr2 O3、TiO2对高炉渣制备微晶玻璃晶化方式的影响

以包钢高炉渣为主要原料,采用熔融法制备CaO-SiO2-MgO-Al2O3系微晶玻璃,主要通过差热分析方法,并借助于Augis-Bennett方程和Ozawa方程研究了分别添加2%Cr2O3和8%TiO2作晶核剂时基础玻璃的晶化方式.研究结果表明:添加2%Cr2O3作晶核剂时,晶体生长指数均可实现大于3,晶化方式为整体晶化;而添加8%TiO2作晶核剂时,晶体生长指数均不可能大于3,晶化方式为表面晶化.因此,Cr2O3是高炉渣制备透辉石类微晶玻璃适宜的晶核剂成分,可单独用作晶核剂,而TiO2无法使基础玻璃整体晶化,不能单独用作晶核剂.研究结果为利用高炉渣成功研制开发透辉石类微晶玻璃在晶核剂种类选择确定方面提供了理论指导.     

Cr_2O_3、ZrO_2、P_2O_5、TiO_2晶核剂对锑炉渣玻璃陶瓷微晶化过程的影响

研究中利用CaO—Al_2O—SiO_2三元相图确定了锑炉渣玻璃陶瓷的基础配方,并运用差热分析,x-射线衍射和扫描电镜分析方法比较了Cr_2O_3、ZrO_2、P_2O_5及TiO_2四种晶核剂的作用效果。研究表明,上述晶核剂对该系统的炉渣玻璃陶瓷的作用机理不尽相同,因而对这类炉渣玻璃陶瓷的析晶形式、析晶程序和晶相组成有不同影响。TiO_2被证明是其中最有效的晶核剂,其最佳用量有为10％。     

Cr2O3、Fe2O3对高炉渣粘熔特性的影响

以高炉渣为主要原料采用熔融法制备微晶玻璃,通过试验研究了晶核剂Cr2O3、Fe2O3对高炉渣粘度及熔化性能的影响规律.结果表明:晶核剂Cr2O3使高炉渣熔点升高,粘度增大,加入2％ Cr2O3作晶核剂时,炉渣浇注温度需要控制在1400℃以上;晶核剂Fe2O3能够降低高炉渣的熔点,但对粘度影响不大,加入2％ Fe2O3作晶核剂时,需要将炉渣温度控制在1325℃以上;加入2％ Cr2O3和2％ Fe2O3组成的复合晶核剂时,需要将温度控制在1375℃以上才能保证渣液的良好流动性,以实现顺利浇注、压延成型,为采用熔融高炉渣直接制备微晶玻璃工艺的研发提供了基础的工艺技术参数.     

MgO-Al2O3-SiO2系硬盘基板用微晶玻璃析晶动力学研究

MgO-A l2O3-SiO2系微晶玻璃是一种优良的磁盘基板备选材料,该材料具有良好的力学性能,能够满足高性能硬盘基板用材料的要求。采用差热分析方法(DTA),得到了以TiO2作为晶核剂的MgO-A l2O3-SiO2系微晶玻璃的析晶动力学参数,研究了该体系微晶玻璃的析晶动力学;利用X射线衍射技术(XRD)确定了经合适热处理后得到的样品的主晶相。结果表明:引入TiO2降低了该体系玻璃的析晶活化能Ea,当TiO2质量分数达到7%时,Ea达到最小值,玻璃析晶晶化指数n达到最大值,这表明TiO2在一定范围内促进了该系统玻璃的析晶。     

复合晶核剂TiO2/ZrO2对微晶玻璃晶化行为的影响

采用差热分析、X-射线衍射分析和扫描电镜观察等测试方法,对以TiO2/ZrO2为复合晶核剂的MgO-Al2O3-SiO2系微晶玻璃材料进行了研究,讨论了晶核剂TiO2/ZrO2添加量对微晶玻璃晶化行为的影响.结果表明,适当提高晶核剂的含量有利于晶体在低温下析晶,且有利于晶态致密化,随着温度的升高,玻璃中会依次析出镁铝钛酸盐、假蓝宝石、尖晶石、α-堇青石、顽辉石等晶体;但晶核剂含量过高则会导致微晶玻璃力学性能的下降.     

粉煤灰和自然冷却黄磷炉渣协同制备微晶玻璃

以粉煤灰和自然冷黄磷炉渣为研究对象,采用熔融法制备CaO-Al2 O3-SiO2 (CAS)系微晶玻璃.利用Kissinger方程和Augis-Bennett方程计算了粉煤灰-自然冷却黄磷炉渣微晶玻璃玻璃析晶活化能(E)和晶化指数(n).借助差热分析(DTA),X射线衍射仪(XRD)和扫描电子显微镜(SEM)研究了晶核剂TiO2,CaF2,P2O5(由KH2 PO4引入)对粉煤灰-自然冷却黄磷炉渣微晶玻璃析晶的影响.结果表明:利用粉煤灰和自然冷却黄磷炉渣并添加一定量的辅料可以制备CAS系微晶玻璃.当分别添加2wt％的TiO2,CaF2,P2 O5时,主晶相不发生改变,均为硅灰石(CaSiO3),但添加2wt％ TiO2或2wt％ CaF2具有降低析晶活化能、促进析晶的作用,而添加2wt％P2O5具有增加析晶活化能、抑制析晶的作用.     

包钢高炉渣制备微晶玻璃的析晶方式研究

以包钢高炉渣为主要原料,采用熔融法制备CaO-MgO-Al2O3-SiO2系微晶玻璃,通过差热分析(DTA)、X射线衍射(XRD)、扫描电子显微镜(SEM)分析方法,并借助Ozawa方程研究了添加不同数量晶核剂时的析晶方式.研究结果表明:分别加入8％ CaF2、8％ TiO2和4％ P2 O5作晶核剂时,晶化指数n均小于3,析晶方式为表面析晶;当加入晶核剂为8％ P2O5时,晶化指数n大于3,析晶方式为整体析晶.     

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.     

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.     

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.     

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.