防老剂挥发性及其轮胎胶料气味的研究

分析防老剂在模拟轮胎生产工序工艺条件下的挥发特性,并将其挥发性物质与整车厂家关注的挥发性有机化合物(VOCs)和REACH法规高度关注的物质(SVHC)清单进行比对;分析不同防老剂组合轮胎胎侧胶,确定胎侧胶的挥发性物质以及挥发量与放置时间的关系,判定影响胎侧胶气味的主要因素。结果表明:在轮胎生产过程中防老剂的VOCs挥发量较小,与受热温度呈正相关性;不同防老剂的稳定性不同,挥发性物质气味也有差异;促进剂是胎侧胶主要挥发性物质的产生体,经高温(80℃)停放一定时间后胎侧胶的挥发量明显减小;加强原材料控制、保证原料供应的连续性和稳定性、优化配方和工艺是减小轮胎VOCs挥发量及气味的方法。     

汽车座椅泡沫VOC主要来源的实验研究

采用一立方箱式法对汽车座椅泡沫(聚氨酯软泡)中的挥发性有机物质进行测试,找出其主要挥发性有机物质,并对各类挥发性有机物质的气味进行了评价。采用10 L袋式法对合成汽车座椅泡沫的原材料中的挥发性有机物质进行测试,找出汽车座椅泡沫主要挥发性有机物质的来源。结果表明,苯系物、醇醚类物质、胺类物质、烷烃、硅氧烷以及醛类物质为汽车座椅泡沫中主要的挥发性有机物质,其中烷烃主要来自于脱模剂。通过对汽车座椅泡沫的挥发性有机物质的溯源研究,可以为相关工作者降低其挥发性有机物以及气味提供参考。     

乘用车橡胶密封条气味研究

为找到密封条气味的来源,采用气相色谱-质谱联用仪对气味成分进行检测和分析,将气味的来源锁定在与成分相关的三元乙丙橡胶(EPDM)配方中的发泡剂、石蜡油、促进剂三种物质。通过进一步的对比实验,确认改进这三种物质的措施对降低气味是有效的:发泡剂的含量减少0.92份,气味等级平均值提升0.9级;若不使用发泡剂偶氮二甲酰胺ADCA,则气味等级提高0.3级;用闪点高、芳香烃含量低的石蜡油,气味等级平均值提升1.6级;使用无亚硝胺硫化体系,气味等级提高0.8级。这三种措施都能使气味等级达到标准要求的6级及以上。     

聚氨酯泡沫塑料VOC及气味性研究

以3种软质聚氨酯泡沫塑料样品为研究对象,分别采集其散发的气体,采用高效液相色谱分析DNPH管中的醛酮类物质,采用热脱附-气相色谱-质谱-嗅觉检测器联用装置分析Tenax-TA管中采集的气体,详细分析出了不同聚氨酯泡沫塑料中的散发物质、各散发物质的气味强度和气味类型,并说明了聚氨酯泡沫塑料的气味与各散发物质的关联。结果表明,聚氨酯泡沫塑料中散发的挥发性有机物(VOC)主要包括醛类化合物、醇羟基化合物、胺类化合物、烷烃、脂类化合物和苯系化合物等;其中,氨臭味主要来源于胺类化合物,溶剂味主要来源于苯系化合物、醇羟基化合物和烷烃;可通过降低目标气味物质含量或增加特定的香味物质改善材料的VOC和气味。     

软聚氯乙烯塑料的气味分析研究

采用气相色谱-质谱法(GC-MS)对3种软聚氯乙(烯S-PVC)试样的挥发性有机物进行了测试,分析了产生气味的物质。结果表明:试样产生的挥发性有机物为烃类化合物、醇和醛、酯等羰基化合物,产生气味的化合物主要是羰基化合物;添加抗氧剂可阻止增塑剂和其他烃类的氧化,减少S-PVC塑料气味的产生。     

不同促进剂气味分析及低气味替代方案研究

测试4种促进剂TBSI,TBBS,CBS,CBBS的气味,并研究促进剂CBBS不同用量或与硫黄不同配比在橡胶中的应用效果,探索促进剂TBSI,CBBS替代促进剂CBS,TBBS的低气味解决方案。结果表明,促进剂TBSI可改善胶料在加工过程中的气味,但在硫化胶及成品中对气味的改善有限,而促进剂CBBS可同时改善加工过程和轮胎成品的气味。     

过氧化氢减少聚醚多元醇中挥发性醛类物质的工艺研究

使用过氧化氢对聚醚多元醇进行特殊工艺处理,检测处理前后聚醚多元醇挥发性醛类物质。结果表明,工艺处理可以有效减少聚醚多元醇中挥发性醛类物质(甲醛、乙醛、丙烯醛),显著降低聚醚多元醇气味,满足了聚氨酯行业对聚醚多元醇低气味的要求。     

基于GC-MS对鸭绒鹅绒的气味成分分析

羽绒有无异味直接影响羽绒品质。为了快速准确的检测羽绒气味成分,采用GC-MS技术对鸭绒鹅绒进行气味分析,由NIST 98质谱数据库检索,采用峰面积归一法,得到挥发性气味成分的种类及含量。结果显示鸭绒、鹅绒中分别含67、62种挥发性物质,鸭绒鹅绒产生异味的主要成分种类基本相同,鸭绒比鹅绒异味更明显,其主要产生异味的可能是酯类和含氮化合物,主要包括戊烯酸乙酯、丁酸-2-甲基丙酯、4-乙基苯甲酸环戊酯、1,2-苯二甲酸二乙酯、乙酸铵等物质。     

汽车用PVC材料的气味溯源

对某车型的3种聚氯乙烯(PVC)材料进行了气味测试,并用热脱附气质联用的方法测定PVC中的挥发性有机物(VOC),分析出了影响气味的关键物质及其来源。研究结果发现,影响PVC气味的挥发性物质主要是PVC生产过程中使用的溶剂类和添加剂类物质。     

住友研发新型低气味天然橡胶技术

正近日,住友橡胶工业株式会社正式宣布,新型"低气味天然橡胶"技术研发成功。该技术通过抑制天然橡胶原材料中引发气味的非橡胶成分(例如蛋白质和脂类)的分解,大幅降低了天然橡胶散发出的气味。目前,住友橡胶集团在泰国的天然橡胶加工厂已引入该项技术。现如今,全球约有70%的天然橡胶被用于轮胎生产,住友橡胶作为全球知名轮胎企业,始终秉     

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.     

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.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.