高固体分丙烯酸树脂相对分子质量的研究

采用溶液聚合法合成高固体分丙烯酸树脂,用凝胶渗透色谱(GPC)法分析引发剂的种类和用量、反应温度及聚合工艺对丙烯酸树脂的相对分子质量及其分布的影响。结果表明,选用偶氮二异丁腈和过氧化苯甲酰两种引发剂进行复配可提高聚合物的相对分子质量;采用“饥饿态”聚合工艺进行聚合反应可有效控制聚合物的相对分子质量,且相对分子质量分布均匀,分散度小于2;当引发剂用量为2%,在110℃的反应条件下制得的丙烯酸树脂的综合性能优异,固含量超过70%,相对分子质量可达4万。     

溶剂型丙烯酸树脂相对分子质量分布的控制

从溶剂型丙烯酸树脂的分子结构和施工性能等方面分析了不同类型丙烯酸树脂相对分子质量分布的影响,并介绍了相对分子质量分布的控制理论和对不同相对分子质量分布的丙烯酸树脂聚合的控制方法。     

ACR中壳层PMMA相对分子质量对PVC／ACR共混物性能的影响

采用种子乳液法制备了核壳型聚丙烯酸酯(ACR),并分别采用十二烷基硫醇和正辛基硫醇作为链转移剂对 ACR壳层的聚甲基丙烯酸甲酯(PMMA)进行相对分子质量调节,并用于PVC共混改性。黏度法对PMMA的相对分子质量测定表明,正辛基硫醇的相对分子质量调节能力较强。采用差示扫描量热分析测定PMMA的玻璃化转变温度(Tg),并对共混树脂进行动态力学性能测试。当ACR壳层PMMA平均相对分子质量低于12×104时,PVC/ACR 共混树脂的缺口冲击强度大大提高。与纯PVC相比,共混树脂的Tg均略有提高,其增量随ACR壳层PMMA平均相对分子质量的降低而减小。动态力学性能测试结果表明,ACR壳层聚合物平均相对分子质量越低,共混物分子链段运动活化能提高越少。     

塑料用涂料

<正>201410019具有金属质感且耐水性优异的汽车内饰塑料件及其涂装方法:JP2013-215 887[日本专利公开]/日本:Nippon Bee Chemical Co.,Ltd.(Kanemura,Satoshi等).-2013.10.24.-16页.-2012/85 545(2012.08.04);IPC B32827/20题述塑料件由透明塑料基材和背涂层及屏蔽层构成。其中,(a)背涂层由一种组合物(含有树脂和非浮型沉积铝颜料)经涂覆而制得;(b)屏蔽层由一种清漆组合物(含有玻璃化转变温度在30~120℃、质均相对分子质量为40 000~200 000的丙烯酸树脂)经涂覆而制得。     

水性丙烯酸改性环氧树脂性能的影响因素研究

采用二步酯化工艺,制得不同相对分子质量及不同丙烯酸用量的水性丙烯酸改性环氧树脂。研究了数均相对分子质量、羧基含量对改性树脂性能的影响,为涂料性能的进一步优化与改善提供了依据。     

薄膜专用PP树脂加工性能的凝胶渗透色谱评价

用凝胶渗透色谱测定了不同批号的薄膜专用聚丙烯(PP)树脂T38F的相对分子质量及其分布,评价了产品的相对分子质量及其分布对加工性能的影响.测定结果的重复性和再现性良好.根据分析结果调整相关工艺条件后生产的PP T38F能够满足用户的加工要求.实验结果表明:薄膜专用PP树脂的重均分子量(Mw)控制在(25.0～29.0)...     

氨基烤漆用羟基丙烯酸树脂的制备及性能

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(n-BA)、丙烯酸(AA)、甲基丙烯酸羟乙酯(HEMA)、苯乙烯(St)和4-叔丁基环己丙烯酸酯(TBCH)为聚合单体,巯基乙醇(β-ME)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,醋酸丁酯(BAC)为溶剂,采用溶液聚合法合成了一系列低相对分子质量的羟基丙烯酸树脂。以氨基树脂作为固化剂,研究了丙烯酸树脂的羟值、酸值及玻璃化转变温度对制成的氨基烤漆漆膜的摆杆硬度、光泽、耐水性、耐酸性及耐碱性的影响。结果表明,当树脂的羟值(以KOH计)为147 mg/g,酸值(以KOH计)为21 mg/g,玻璃化转变温度为25°C时,所制漆膜的综合性能最佳。     

正性光致抗蚀剂用酚醛树脂的制备

采用4-甲基苯酚、3-甲基苯酚与甲醛,经两步法反应制备了一系列正性光致抗蚀剂用酚醛树脂。制备的酚醛树脂的重均相对分子质量及相对分子质量分布分别在(5～17)×10~3和2.75～11.67范围内。探讨了甲醛用量、反应时间、催化剂用量、水选对相对分子质量及相对分子质量分布的影响。增加甲醛和催化剂用量将使相对分子质量增大、相对分子质量分布变宽。延长反应时间也将使相对分子质量分布变宽。但增加水洗次数将使相对分子质量减小、相对分子质量分布变窄。结果表明,通过改变反应条件可有效地控制酚醛树脂的相对分子质量及相对分子质量分布。     

聚酯丙烯酸杂化多元醇水分散体的制备

以间苯二甲酸-5-磺酸钠(5-SSIPA)与新戊二醇缩聚,制备亲水性中间体.用该中间体与羟基丙烯酸树脂、新戊二醇、三羟甲基丙烷和己二酸进一步缩聚,制得聚酯丙烯酸杂化树脂,加水分散后得其水分散体.研究了反应温度、羟基丙烯酸树脂的玻璃化温度及含量对杂化多元醇水分散体及其相应涂膜性能的影响.结果发现,适宜的杂化反应温度为22...     

反式 -1,4-聚异戊二烯相对分子质量的调节

采用负载钛本体沉淀聚合法,以氢气作链转移剂,制备了不同相对分子质量的反式-1,4-聚异戊二烯(TPI),讨论了老化、氢气调节及塑炼对其相对分子质量的影响,以及不同相对分子质量TPI的结构与性能。结果表明,本体系合成TPI的数均相对分子质量为(5～15)×104,相对分子质量分布为2.00～3.00;门尼粘度为20～120时,随着TPI相对分子质量的降低,其结晶速度提高,结晶度无明显变化,拉伸强度明显降低,扯断伸长率、屈服强度和邵尔A型硬度无明显变化。     

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.     

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.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。