聚烯烃用有机成核剂的合成研发进展

介绍了二苄叉山梨醇衍生物类、羧酸及其金属盐、有机磷酸金属盐、酰胺类成核剂的合成方法及国内外发展水平,讨论了有机类成核剂对聚烯烃制品的改性效果。     

二苄叉山梨醇类透明剂合成技术及发展

综述了国内外二苄叉山梨醇类透明剂的发展及合成技术;分别介绍了有关第一代二苄叉山梨醇类透明剂二苯亚甲基山梨醇(DBS),第二代二苄叉山梨醇类透明剂双(对-甲基-二苯亚甲基山梨醇) (MDBS)、双(对-乙基-二苯亚甲基山梨醇)(EDBS)和第三代二苄叉山梨醇类透明剂双(3,4-二甲基-二苯亚甲基山梨醇(DMDBS)的合成方法。     

聚烯烃用有机成核剂的合成研发进展

介绍了二苄叉山梨醇衍生物类、羧酸及其金属盐、有机磷酸金属盐、酰胺类成核剂的合成方法及国内外发展水平，讨论了有机类成核剂对聚烯烃制品的改性效果。     

综合信息

烟台只楚合成化学有限公司投资2000多万元在APEC中国烟台(芝罘)科技工业园内建成年产400t第三代聚丙烯成核透明剂ZC-3的现代化工厂。近年来国内外许多企业对聚丙烯成核剂的研究开发相当活跃,已商品化的种类很多,其中尤以山梨醇苄叉衍生类与有机磷酸盐对PP的透明性有显著的改进作用,因此又称成核透明剂。目前,山梨醇苄叉衍生物系列已成为国内外开发最为活跃,品种最多,产销量最大的一类PP成核透明剂。国内外市场的山梨醇苄叉衍生物类主要分为第一代DBS、第二代MDBS和第三代DMDBS,第三代山梨醇成核透明剂已获得美国PDA、德国BCS等…     

成核剂

改善二苄叉山梨醇系成核剂稳定性的方法；含结晶成核剂的聚乳酸组成物；甲基三乙氧基硅烷偶联剂的制备；分散性，相容性良好的成核剂。[编者按]     

高效聚烯烃用成核剂的合成研究

本文介绍高效聚烯烃用成核剂二苄叉山梨醇的合成过程，通过对投料量、反应时间、搅拌速度等因素的控制，得到了纯度大于98％的产品，质量稳定。产品熔点为206～225℃，达到国外同类产品指标。     

山梨醇二苄叉对等规聚丙烯结晶的影响

本文阐明了山梨醇二苄叉对聚丙烯结晶的影响,它与典型的成核剂苯甲酸钠相似,但其作用机理更复杂。     

成核剂对聚乙烯蜡结晶形态及熔点的影响

分别以硬脂酸钙、硬脂酸锌、硬脂酸和1,3:2,4-二苄叉山梨醇(ID)为成核剂,采用熔融法对聚乙烯蜡(PEW)进行了重结晶实验,并通过偏光显微镜和显微熔点测定仪研究了成核剂的种类、用量、结晶温度对PEW的结晶形态和熔点的影响.结果表明,成核剂增大了PEW的成核密度,降低了球晶尺寸,提高了熔点;成核剂1,3:2,4-二苄叉山梨醇的效果最好,所形成的晶粒最小,晶片最厚,当其添加量为0.2%,结晶温度为80℃时,PEW的球晶尺寸最小,PEW的初熔点达到了110.6℃,比原料提高了27.7℃.     

成核剂在PP中的应用

介绍了成核剂的种类及其在国内外的研究开发进展,重点阐述了国内传统成核剂二苄叉山梨醇及其衍生物、有机磷酸盐类成核剂对PP透明性及力学性能的影响。在PP中添加成核剂不仅提高了PP的透明性,同时还可改善PP的力学性能     

DBS类凝胶因子的合成及性能

以取代的苯甲醛和山梨醇为原料,环己烷为溶剂和夹带剂,甲醇为促进剂,对甲苯磺酸为催化剂,用共沸脱水法合成了1,3∶2,4-O-二苄叉-D-山梨醇(DBS),收率91.2%;1,3∶2,4-O-二(4-甲基苄叉)-D-山梨醇(MDBS),收率90.5%;1,3∶2,4-O-二(3,4-二甲基苄叉)-D-山梨醇(DMDBS),收率89.0%。用原甲酸三甲酯作化学脱水剂,合成了1,3∶2,4-O-二(2,4,6-三甲基苄叉)-D-山梨醇(2,4,6-TMDBS),收率37.1%;1,3∶2,4-O-二(2,4,5-三甲基苄叉)-D-山梨醇(2,4,5-TMDBS),收率30.9%;1,3∶2,4-O-二(5,6,7,8-四氢萘-2-亚甲叉)-D-山梨醇(DTHNS),收率74.1%。其结构经1HNMR确认。测定了它们对21种有机溶剂的凝胶性能。发现苯环上取代基的位置、数量、大小等因素对凝胶性能有重要影响。2,4,6-TMDBS无凝胶性能,其余化合物对多种溶剂具有良好的凝胶性能,DTHNS对非极性化合物有极优良的凝胶性能。测试并比较了上述化合物的最低凝胶浓度,证实了凝胶-溶胶解缔温度随凝胶因子质量分数增加而增加;随着溶剂(一元直链伯醇)碳原子数的增加而增加。     

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.     

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.     

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.