原位乳液聚合制备丙烯腈聚合物/纳米氧化硅复合粒子

利用2,2'-偶氮(2-脒基丙烷)二氯化氢(AIBA)引发剂与纳米氧化硅粒子的静电作用而使AIBA吸附在纳米氧化硅表面,进而引发丙烯腈-甲基丙烯酸甲酯(AN-MMA)原位乳液聚合.考察了AIBA浓度和反应温度对AN-MMA原位乳液聚合动力学的影响以及氧化硅含量对AN-MMA共聚物/纳米氧化硅复合乳胶粒径分布和形态的影响.结果表明:聚合速率随AIBA浓度和聚合温度的升高而增大; AIBA浓度相同时,原位乳液聚合速率小于普通乳液聚合;AN-MMA共聚物/纳米氧化硅复合粒子粒径随纳米氧化硅含量增加而增大;原位乳液聚合得到的复合胶粒表面粗糙,当纳米氧化硅质量分数为10%时,纳米氧化硅与聚合物乳胶粒子复合良好;当纳米氧化硅质量分数为20%和30%时,有部分纳米氧化硅粒子与乳胶粒子分离而分散在连续相中.     

KH-550对水性聚氨酯性能的影响及机理分析

以2,2-二羟甲基丙酸(DMPA)为亲水扩链剂,聚四氢呋喃二醇(PTMG)和聚己二酯1,4-丁二醇酯(PBA)为软链段,异佛尔酮二异氰酸酯(IPDI)为硬链段,成功制备了固含量50%以上低黏度γ-氨丙基三乙氧基硅烷(KH-550)改性的水性聚氨酯(WPU)乳液。对乳液和胶膜进行了物性表征和研究,分析了KH-550改性WPU的作用机理。实验发现当KH-550加入量为预聚体质量分数2%时,其改性的WPU的综合物性最佳,此时乳液固含量在50%左右,乳液粒径小于130 nm,黏度低于400m Pa·s;胶膜的拉伸强度大于35 MPa,断裂伸长率大于750%,吸水率低于5%。     

用磺酸型亲水扩链剂制备高固含量聚氨酯乳液

以聚(四氢呋喃-co-氧化丙烯)二醇为软段、异佛尔酮二异氰酸酯为硬段,以1,2-二羟基-3-丙磺酸钠(DHPA)作为亲水扩链剂,用自乳化法合成了一系列稳定的高固含量聚氨酯乳液,分析了DHPA用量对乳液及其胶膜性能的影响。结果表明:所得聚氨酯乳液的粒径呈多元分布,乳胶粒子呈球形;乳液为假塑性流体;随着DHPA用量的增加,乳液平均粒径逐渐减小,粒径分布变窄,固含量不断增大,当DHPA质量分数为7%时,乳液的总固物质量分数可达61%。乳液具有较好的高、低温及贮存稳定性能。随着DHPA用量的增加,聚氨酯乳液胶膜的拉伸强度逐渐增大,扯断伸长率则先增大后减小;当DHPA质量分数为5%时胶膜的综合力学性能最佳;DHPA用量对胶膜的热稳定性没有明显影响。     

乙二胺扩链剂对水性聚氨酯性能的影响

以聚醚220、异佛尔酮二异氰酸酯(IPDI)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,丁二醇(BD)和乙二胺(EA)为小分子扩链剂,按不同配比合成了系列水性聚氨酯分散体。主要考察了乙二胺扩链剂用量对水性聚氨酯乳液的稳定性、乳液粒径、粘度以及膜吸水性和力学性能的影响。结果表明,随乙二胺扩链剂用量的增加,乳液粒径增大、分散稳定性变差、粘度减小、胶膜的拉伸强度增加、断裂伸长率减小、耐溶剂性增加、吸水率变化不明显、硬段相Tg升高,软硬段相分离程度增加。胶膜的ATR红外表现为PPG类聚醚型聚氨酯典型的红外光谱。     

磺酸-羧酸型水性聚氨酯的制备及性能研究

采用预聚体合成法,以二羟甲基丙酸(DMPA)和自制1,2-二羟基-3-丙磺酸钠(DHPA)为亲水扩连剂制备一系列含有磺酸基团的水性聚氨酯微乳液。利用FTIR对DHPA和PU的结构进行表征,证实了目标产物DHPA的生成,并作为亲水扩链剂引入PU链上。研究表明：随着DHPA含量增大,乳胶粒平均粒径逐渐减小,粒径分布宽度变窄;TEM照片显示,乳液分散 均匀,形貌规整,呈圆球状。乳液表观黏度随着剪切速率增加而下降,呈假塑性流体特征。     

HDI/IPDI物质的量比对PPG型水性聚氨酯性能及微观形貌的影响

将聚氧化丙烯二醇(PPG)、1,6-己二醇(HDO)、二羟甲基丙酸(DMPA)与不同物质的量比的六亚甲基二异氰酸酯(HDI)和异佛尔酮二异氰酸(IPDI)反应,通过预聚体混合法制备了一系列环境友好的PPG型水性聚氨酯。利用FT-IR、DSC、SEM等研究了HDI/IPDI物质的量比对水性聚氨酯的性能和微观形貌的影响。结果表明:随着HDI/IPDI物质的量比的增加,水性聚氨酯链段的氨基甲酸酯键之间的氢键密度增加,水性聚氨酯分散体的平均粒径增大,硬段的结晶性和柔韧性随之提高,同时促进了软段的拉伸诱导结晶。     

改性纳米碳化硅/聚氨酯弹性体复合材料的制备

采用KH-560与KH-550反应得到新的硅烷偶联剂改性纳米碳化硅(SiC);再以2,4-甲苯二异氰酸酯(TDI)、聚氧化丙烯醚二醇(PPG2000)为原料合成预聚体,改性纳米SiC为填料、3,3’-二氯-4,4’-二氨基二苯甲烷(MOCA)为扩链剂,制备了改性纳米SiC/聚氨酯弹性体(PUE)复合材料。讨论了改性前后的纳米SiC添加量对复合材料的力学性能、耐磨性能和热稳定性的影响,并用扫描电镜分析了改性前后的纳米SiC在基体中的分散性。结果表明,改性后的纳米SiC在基体中的分散性优于纳米SiC,当改性纳米SiC质量分数为9%时,改性纳米SiC/PUE复合材料的力学性能达到最佳,耐磨性能明显改善,热失重温度提高了33℃。     

含有磺酸基团的水性聚氨酯的制备及性能

采用预聚体合成法,以二羟甲基丙酸(DMPA)和自制1,2-二羟基-3-丙磺酸钠(DHPA)为亲水扩链剂制备一系列含有磺酸基团的水性聚氨酯微乳液。利用FTIR对DHPA和聚氨酯的结构进行表征,证实了目标产物DHPA的生成,并作为亲水扩链剂引入PU链上。研究结果表明,随着DHPA含量增大,乳胶粒平均粒径从139.31 nm减小至57.75 nm,且粒径分布宽度变窄,胶膜的拉伸强度由43.0 MPa增加至55.7 MPa,断裂伸长率从361%增加至430%。TEM照片显示,乳液分散均匀,形貌规整,呈圆球状。乳液表观黏度随着剪切速率增加而下降,呈假塑性流体特征。     

硅烷偶联剂改性水性聚氨酯的合成与性能研究

以聚醚210、异佛尔酮二异氰酸酯(IPDI)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,胺类硅烷偶联剂为后扩链剂,按不同配比合成了系列有机硅改性水性聚氨酯分散体。主要考察了硅烷偶联剂质量分数对水性聚氨酯乳液的稳定性、乳液粒径以及胶膜吸水性和耐热性的影响。结果表明,随硅烷偶联剂质量分数的增加,乳液粒径增大,分散稳定性良好,胶膜的耐水性明显提高;胶膜的耐热性能明显提高,并且发生了交联反应;胶膜的ATR红外显示体系中形成的脲键随硅烷偶联剂的质量分数增加而增多。     

DHPA扩链剂合成磺酸型水性聚氨酯的性能研究

合成了一种新型磺酸型扩链剂1,2-二羟基-3-丙磺酸钠(DHPA),并通过红外光谱法证明了其化学结构。利用这种扩链剂与异佛尔酮二异氰酸酯、聚醚多元醇等反应,制备出固含量高、热稳定性好和力学性能好的磺酸型水性聚氨酯(SWPU)乳液及薄膜。与同时合成的羧酸型水性聚氨酯(CWPU)对比发现,SWPU乳液的固体质量分数可达50%以上,而CWPU乳液固体质量分数不超过40%;SWPU乳液的粒径比CWPU小,粒径分布窄;SWPU薄膜具有更好的热稳定性和弹性模量;SWPU薄膜耐溶剂性比CWPU薄膜好,但耐水性比CWPU薄膜差。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

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.