复合插层剂在水滑石增强环氧树脂中的协同作用

以对氨基苯磺酸(AB)和十二烷基磺酸钠(SDS)为插层剂,合成一种新型插层水滑石(LDHs)。X射线衍射(XRD)测试结果表明,成功制得一种复合插层剂插层的超分子水滑石LDHs-AB-SDS。采用LDHs-AB-SDS对环氧树脂(EP)进行改性,得到EP/LDHs-AB-SDS纳米复合材料。同时通过XRD、热重分析(TGA)和力学性能测试考察了LDHs-AB-SDS对EP/LDHs-AB-SDS复合材料结构、热稳定性以及力学性能的影响。结果表明:所得EP/LDHs-AB-SDS复合材料均为剥离型结构;复合材料的初始热分解温度略微下降,但残炭率显著增高;此外,随着LDHs-AB-SDS的加入,复合材料的拉伸强度、模量以及断裂伸长率均有不同程度的提高。     

SBS/粘土纳米复合材料的制备和性能研究

通过溶液插层法制备了苯乙烯—丁二烯—苯乙烯聚合物(SBS)／粘土纳米复合材料，并用X射线衍射透射电子显微镜分析其纳米分散结构及形态。研究结果表明：所得复合材料为插层型纳米复合材料；与SBS相比，SBS／粘土纳米复合材料断裂拉伸强度和300％定伸强度显著提高，储能模量明显提高。     

熔融挤出法制备PA6-66/蒙脱土纳米复合材料的研究

采用聚合物熔融挤出的方法，用自制的有机蒙脱土与PA6—66熔融复合，制备出剥离型PA6—66／蒙脱土纳米复合材料；并对材料的结构与性能进行了测试。TEM结果表明，蒙脱土晶层均匀地分散于基体中，平均厚度约10nm，形成结构均匀的纳米复合材料。DSC、MFR测试结果表明，纳米复合材料的热性能和加工性能优于基体；同时对复合材料的力学性能进行测试，结果表明，纳米级蒙脱土起到了显著增强作用，复合材料拉伸强度升高了17．1％；拉伸模量提高了将近30％；屈服强度是纯PA6／66的1．22倍。     

插层剂对尼龙6/蒙脱土纳米复合材料性能的影响

用3种不同的插层剂有机化蒙脱土,并分别与尼龙6熔融共混制得了尼龙6/蒙脱土纳米复合材料,对热变形温度(HDT)和力学性能进行了研究。结果表明:与纯尼龙6相比,3种复合材料的HDT、拉伸模量、弯曲模量、弯曲强度有明显提高,屈服强度也有所提高,而冲击强度和断裂伸长率则有所下降;其中,含羟基的插层剂对复合材料的综合改性效果最好。     

水滑石(LDH)的合成及其表征

利用“双滴法”成功制备出具有层状结构的镁铝水滑石,并对比确定了最佳反应温度。首先在50℃、80％、95％下制备出三种水滑石,利用XRD分析水滑石的结构,确认制备出了具有典型层状结构的水滑石;然后利用TGA测试三种水滑石的热分解温度,发现95℃下制备出的水滑石晶体强度较高,为进一步研究聚合物基水滑石纳米复合材料奠定了良好的基础。     

不同亚微观形态的聚丙烯/蒙脱土纳米复合材料的研究

通过控制不同的工艺条件，利用双螺杆挤出插层法制备出两种不同微观结构的聚丙烯／蒙脱土纳米复合材料。利用透射电子显做镜观察发现．分别制备出了插层型和半插层型聚丙烯／蒙脱土纳米复合材料，半插层型结构的材料中有机土分散更均匀，尺度更小。对两种纳米复合材料的物理性能测试表明，插层型纳米复合材料的缺口冲击强度提高幅度最大，同时耐热性并没有降低；半剥离型纳米复合材料的熔体质量流动速率降低幅度最大，屈服强度、弹性模量、耐热性提高幅度最大，缺口冲击强度略小于插层型。     

水滑石在二乙基次膦酸铝阻燃PA66/GF材料中的应用

采用双螺杆挤出造粒工艺制备二乙基次膦酸铝(AlPi)阻燃玻璃纤维增强尼龙66(PA66/GF)复合材料，研究水滑石替换传统三聚氰胺聚膦酸盐(MPP)对复合材料综合性能的影响。结果表明：水滑石含量增加会导致复合材料拉伸强度及悬臂梁缺口冲击强度降低，水滑石添加质量分数为6%时，复合材料拉伸强度由122 MPa降低至114 MPa,悬臂梁缺口冲击强度由8.3 kJ/m²降低至7.6 kJ/m²,但弯曲强度及弯曲模量有所增加。当水滑石添加质量分数超过6%时，燃烧后碳层强度及致密性明显提升，材料可获得稳定的V-0阻燃等级。锥形量热测试分析进一步证明水滑石的引入可以降低引燃时间(TTI)、平均热释放速率(mHRR)和总热释放量(THR),参与提升碳层强度及致密性，改善复合材料阻燃性能。     

聚乙烯醇/蒙脱石纳米复合材料的结构与性能

通过溶液插层 流延成膜法,以聚乙烯醇和钠质蒙脱石为原料,制备出了不同蒙脱石含量的聚乙烯醇/蒙脱石纳米复合材料薄膜。用X射线衍射(XRD)、扫描电子显微镜(SEM)、热重分析(TGA)和力学性能测试对复合材料的结构和性能进行了表征。结果表明,聚乙烯醇分子成功进入蒙脱石的层间,实现了在纳米尺度上的复合;蒙脱石含量高于7 5wt%形成插层型的纳米复合材料,低于7 5wt%形成剥离型的纳米复合材料;在SEM图片上还观察到了纳米复合材料的微观结构。纳米复合材料的热稳定性、拉伸强度和直角撕裂强度均比纯聚乙烯醇有很大提高。     

插层剂对PA66/蒙脱土纳米复合材料性能影响

将不同插层剂改性的蒙脱土与尼龙66(PA66)通过熔融共混制得了纳米复合材料,对复合材料的热变形温度和力学性能进行了研究。结果表明,与纯PA66相比,3种插层剂改性的蒙脱土／PA66纳米复合材料的热变形温度、弯曲模量、弯曲强度均有明显提高,拉伸模量和屈服强度也有所提高,但断裂伸长率和缺口冲击强度则明显下降;含极性羟基的插层剂对复合材料的综合改性效果较好,含2个长链非极性烃基的插层剂改性效果较差;加入环氧树脂后,复合材料的热变形温度、拉伸模量和弯曲模量有所降低,屈服强度、弯曲强度、断裂伸长率和缺口冲击强度则有所增加。     

LDPE/纳米水滑石复合材料农用棚膜的研究

将纳米水滑石有机化改性以后，采用插层法制备出LDPE／纳米水滑石复合材料，挤出吹塑农用棚膜。对棚膜的力学性能、透光性能、耐老化性能、流滴消雾性能进行测试，结果表明：纳米水滑石的用量约为3％时．棚膜的拉伸强度、直角撕裂强度和断裂伸长率、透光率、耐老化性、红外光线的阻透性等出现峰值；纳米水滑石的用量约为0．3％时，棚膜的流滴消雾效果好，持效性长。     

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.     

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。     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。