聚酯超分散剂改性纳米碳酸钙及其应用研究

研究了聚酯超分散剂改性纳米碳酸钙．探讨了不同改性剂和改性温度对活化指数的影响，考察了改性前后纳米碳酸钙DOP糊粘度和吸油量的变化。结果表明：聚酯超分散剂干法改性纳米CaCO3比NDZ-201偶联剂湿法改性纳米CaCO3更有效，其最佳用量为4％，最佳改性温度为110℃。聚酯超分散剂改性纳米CaCO3的DOP糊粘度降低了87．6％，吸油值降低了53．9％。聚酯超分散剂改性纳米CaCO3对PVC材料具有增强、增韧作用。     

聚酯型超分散剂在聚合物中的应用

采用聚酯型超分散剂对碳酸钙(CaCO3)进行表面处理，并用其填充改性聚氯乙烯(PVC)和聚丙烯(PP)，研究了超分散剂用量、聚合度对复合材料性能的影响。结果表明：超分散剂处理CaCO3的最佳用量与碳酸钙的粒径和表面特性密切相关，处理纳米CaCO3、轻质CaCO3、重质CaCO3的最佳用量分别为4％、2．0％和1．5％；超分散剂处理的纳米CaCO3填充改性PVC具有明显的增强增韧作用，对PVC的改性效果比PP好；超分散剂的最佳聚合度为7。     

复合偶联剂改性纳米CaCO3工艺研究

采用正交试验法对钛酸酯和硬脂酸复合改性纳米CaCO3工艺进行了研究,探讨了改性剂用量、乳化温度、乳化时间和保温时间等因素对纳米CaCO3改性的影响,并优化出了最佳操作工艺条件：钛酸酯用量为纳米ca0。3的1,2％(质量分数)、硬脂酸用量为纳米CaCO3 4％(质量分数)、乳化温度70℃、乳化时间90min和保温时间80min。测定了改性纳米CaCO3和未改性纳米CaCO3的活化指数、吸油量、沉降体积以及在邻苯二甲酸二辛酯(DOP)中的粘度,结果表明钛酸酯和硬脂酸复合改性纳米CaCO3活化指数可达99．90％,吸油量降为15．23mL／100g,CaCO3／DOP糊粘度显著降低,亲油性得到显著提高。     

烷基化聚酯超分散剂改性水滑石的合成及其在PVC中的应用

用烷基化聚酯超分散剂改性水滑石,探讨了改性剂种类和用量、改性温度和改性时间对活化指数的影响,重点考察了改性水滑石与钙/锌热稳定剂并用时PVC体系的热稳定性能。结果表明:烷基化聚酯超分散剂干法改性水滑石比NDZ-201偶联剂湿法及干法改性水滑石更有效,其最佳用量为4份,最佳改性温度为110℃,最佳改性时间为90min。改性水滑石用量1～2份与钙/锌热稳定剂并用时能大幅度提高PVC体系的热稳定时间。     

纳米碳酸钙在运动草坪纤维中的应用研究

利用硅烷偶联剂A和超分散剂B对纳米CaCO3进行干法表面处理,通过熔融纺丝的方式制得纳米CaCO3改性的线性低密度聚乙烯(LLDPE)运动草坪纤维.借助电子织物强力机、差示扫描量热仪、扫描电子显微镜等手段,研究了改性纳米CaCO3在纤维中的分散状况及其对纤维性能的影响.结果表明,填充硅烷偶联荆A和超分散剂B复配处理纳米CaCO3的纤维性能最好,断裂伸长率最多可达131%,比未填充纳米CaCO3时高22.8%;干热收缩率最低可达27%,比未填充纳米CaCO3时降低了5.2%;纤维的结晶度随着CaCO3填充量的增加有上升的趋势,由30.5%增加到32.5%;纳米CaCO3粒子在纤维中达到了较好的分散效果.     

纳米碳酸钙复合丙烯酸涂料的流变性

制备了纳米CaCO3复合丙烯酸涂料，通过对其主要性能进行检测表明，当改性纳米CaCO3的添加量为1.5%（质量）时，涂料的耐光性、耐水性、自洁性和贮存稳定性等显著改善。研究了添加轻钙、未改性纳米CaCO3、改性纳米CaCO3及其用量对丙烯酸涂料流变性的影响，结果表明，该体系的流动特性均符合Casson模型；当在丙烯酸涂料中添加1.5%改性纳米CaCO3时，其黏度对温度的敏感性下降，黏度显著降低，剪切稀化能力较强，Casson屈服应力较小，触变性增大，涂料性能改善与其流变性变化基本一致。此外，固体分改变或添加丁醇对添加改性纳米CaCO3复合丙烯酸涂料和传统丙烯酸涂料流变性的影响规律基本相同。     

纳米碳酸钙增韧HDPE的研究进展

近年来，纳米CaCO3填充聚合物改性已成为材料改性的热点，引起人们的极大关注。本文综述了纳米碳酸钙改性HDPE复合材料增韧改性的主要研究成果。介绍TCaCO3从普通数量级到微米级再到现在的纳米级的应用，以及CaCO3从普通分散剂到现在的超分散剂表面改性的研究。指出了现阶段研究中亟待解决的问题并对发展趋势进行了展望。     

ODP诱导下疏水性纳米碳酸钙的合成研究

采用磷酸酯(ODP)表面活性剂对纳米碳酸钙进行表面改性研究,探讨了改性温度、ODP用量对碳酸钙的影响。样品形貌和晶相通过TEM、FESEM、XRD等手段进行表征。通过接触角、在DOP中糊粘度等对样品性能进行测试。结果表明,在改性温度为60℃,ODP用量为CaCO3质量2.0%的条件下,改性纳米CaCO3由亲水性变为亲油性,接触角达105.09°,糊粘度明显降低。     

PTT／纳米CaCO3复合材料流变行为及结晶性能研究

以毛细管流变仪研究了聚对苯二甲酸丙二酯(PTT)/纳米CaCO3复合材料的流变行为,讨论了复合材料的组成、剪切应力和剪切速率及温度对熔体流变行为、熔体黏度的影响,测定了不同配比的复合材料熔体的非牛顿指数 n。结果表明,PTT/纳米CaCO3复合材料熔体为假塑性流体,表观黏度随着剪切速率增加而降低。纳米CaCO3的加入量较少(1％)时,熔体黏度较纯PTT迅速下降;随着纳米CaCO3含量增加(2％-20％),熔体黏度随之上升,但都小于纯PTT的;直到含量为30％时,熔体黏度才超过纯PTT的。差示扫描量热仪测定复合材料的结晶和熔融性能发现,复合材料的熔体结晶温度Tpc和熔融温度Tm较纯PTT、都有所升高,说明纳米CaCO3的加入对PTT的结晶起到了异相成核作用。     

超重力反应结晶法纳米碳酸钙浆料及粉料的表面处理

研究了脂肪酸盐A、水溶性铁酸酯偶联剂B（B1)以及铁酸酯偶联剂C对新型超重力反应结晶法所得的纳米CaCO3浆料及粉料的湿法表面处理的配方与工艺，确定了A体系的最佳改性时间为30～40min、改性温度为40～50℃、改性剂用量(质量分数)为3%～5％；B(B1)体系搅拌强度必须很高，改性时间30～40min，改性温度80℃左右，改性剂用量(质量分数)3％～5％；C体系的最佳改性时间为30～40min，改性剂用量(质量分数)为3％～5％。同时，采用红外光谱对改性前后的纳米碳酸钙进行了表征，表明改性刑已连接至CaCO3表面。最后，用分散稳定模型简要分析了改性机理。     

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.     

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.