E/VAC对PC/PBT共混体系性能的影响

针对聚碳酸酯(PC)／聚对苯二甲酸丁二酯(PBT)共混体系相容性差的缺点,采用(乙烯／乙酸乙烯酯)共聚物(E／VAC)作增容剂对其进行改性。研究了E／VAC对PC／PBT共混体系结晶性能和力学性能的影响,并用扫描电子显微镜观察了共混体系的形态结构。结果表明,E／VAC可以提高PC／PBT共混体系的相容性,当E／VAC含量为2％时共混体系的综合性能较好。试验还发现加入E／VAC后PC／PBT共混体系有良好的成型加工性能。     

阿克玛法国E／VAC装置投产

据美国《化学周刊》12月7日消息，阿克玛（Arkema）日前表示旗下位于法国Ain的Balan工厂内的一套高容量（乙彬乙酸乙烯酯）共聚物（E／VAC）装置已开始试运行。公司方面虽然没有透露该装置的产能细节，但是表示该装置的产能可以供应欧洲E／VAC市场需求的35％，同时30％的产品将出口，主要出口至北美和亚洲。据悉该装置的建设成本约5700万美元，是阿克玛公司追求增长型市场战略的一部分。E／VAC主要用于热熔胶、电缆和多层包装。     

LLDPE/LDPE/(E/VAC)/Mg(OH)2无卤阻燃电缆料的研制

采用线性低密度聚乙烯（LLDPE），低密度聚乙烯（LDPE），（乙烯／乙酸乙烯酯）共聚物（E／VAC）为基体树脂，Mg(OH)2，微胶囊化红磷为主，辅助阻燃剂，制备了无卤阻燃电缆料，探讨了Mg(OH）2阻燃剂用量，粒径大小，表面处理方法及红磷的阻燃协同效应等对体系力学性能，阻燃性能的影响。研究表明，在配比为8／20／30的LLDPE／LDPE（E／VAC）体系中加入适量的经偶联剂处理的Mg(OH)2的微胶囊化红磷，可制得阻燃性好的电缆料。     

EVA/TPU共混物热氧老化性能研究

研究4种不同组合的乙烯-乙酸乙烯酯共聚物（EVA）／热塑性聚氨酯（TPU）共混物热氧老化前后物理性能的变化规律。结果表明，EVA／TPU共混物老化后总体趋势是邵尔A型硬度、100％定伸应力和拉伸强度增大，拉断伸长率减小；在EVA／聚醚型TPU（T8）并用比为50／50时，共混物老化后出现气泡，老化规律异常。乙酸乙烯酯质量分数为0．4的EVA（E4）／T8共混物在E4／T8并用比为75／25时，老化前后平均的物理性能变化率较小，为较佳组合。     

埃克森美孚向PTT Chem转让技术

埃克森美孚不久前与泰国PTT Chem签署协议，向其转让Autoclave技术。PTT Chem将用该技术建设一座年产量为10万t的工厂，生产低密度聚乙烯（LDPE）和（乙烯／乙酸乙烯酯）共聚物（E／VAC）。     

(E/VAC)-g-MAH/PA6共混物的热致形状记忆功能

采用马来酸酐接枝(乙烯／乙酸乙烯酯)共聚物[(E／VAC)-g-MAH]与尼龙6(PA6)共混制备了具有微晶物理交联结构的(E／VAC)—g—MAH／PA6形状记忆体系。研究了PA6含量与聚合度、形变拉伸温度与形变回复温度及回复次数等因素对形状记忆功能的影响。结果表明,形状回复率随着PA6含量的增加而上升,在形变回复温度为80—100℃时达到最大值(大于95％),并随着回复次数的增多而显著下降。     

无卤阻燃硅烷交联POE复合材料的制备及性能研究

以硅烷交联聚烯烃弹性体（POE）为基体、Mg（OH）2为阻燃剂、（乙烯／乙酸乙烯酯）共聚物（E／VAC）为增容剂,制备了一种应用于无卤阻燃电缆料的高性能复合材料。考察了Mg（OH）2、E／VAC用量对复合材料拉伸性能、热延伸率、阻燃性能及耐高温老化性能的影响,利用扫描电子显微镜研究了复合材料断面的形貌特征。结果表明,当引发剂为0．1份、交联剂为2份、Mg（OH）2为140份、E／VAC为10份时,制备的无卤阻燃硅烷交联POE复合材料具有优异的力学性能、阻燃性能和耐高温老化性能,符合无卤阻燃聚烯烃电缆护套料的技术标准。     

PVC/SMAH共混物的研究

研究了聚氯乙烯（PVC）与（苯乙烯／马来酸酐）共聚物（SMAH）的共混改性,测定了共混物的冲击强度、熔体流动速率和维卡软化点。SMAH可以显著地提高PVC的熔体流动速率和维卡软化点,但共混物的制品冲击强度降低。加入第三组分（乙烯／乙酸乙烯酯）共聚物（E／VAC）后,PVC／SMAH共混物的制品冲击强度提高。结构分析表明,PVC／SMAH共混物体系是典型的两相体系。     

MAH接枝E/MAK对PC增韧的研究

采用一种含有强极性官能团的新型增韧剂马来酸酐接枝（乙烯／甲基丙烯酸酯）共聚物[（E／MAK）-g-MAH]对聚碳酸酯（PC）进行增韧研究。实验结果表明,随着（E／MAK）-g-MAH含量的增加,PC／（E／MAK）-g-MAH共混体系的冲击强度显著提高。当（E／MAK）-g-MAH质量分数为20％时,冲击强度达59．6kJ／m^2,是纯PC冲击强度的近6倍。另外（E／MAK）-g-MAH还使共混体系的断裂伸长率提高,流动性得到明显改善。     

POE/PE反应挤出接枝马来酸酐

研究了辛烯-乙烯共聚物，聚乙烯（POE／PE）的掺混比例、马来酸酐（MAH）单体和过氧化二异丙苯（DCP）用量、第二单体的种类、反应温度、螺杆转速、真空度对接枝产品性能的影响情况以及接枝产品与尼龙共混注塑制得的样品的性能，得到了使该种接枝产品使用性能最佳的配方和工艺条件，即POE／PE为75／25；MAH用量1．3％～1．5％（质量分数），DCP用量：0．04％-0．06％（质量分数），第二单体苯乙烯用量为1．2％-1．5％（质量分数），螺杆转速：40-50r／min，真空度0．01MPa,螺筒温度：140～195℃。     

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.     

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.