紫胶改性酚醛树脂胶粘剂的研究

紫胶是一种具有多种用途的天然树脂,利用紫胶改性酚醛树脂胶粘剂,有利于扩大紫胶的应用范围,提高对可再生资源的综合利用。研究了对紫胶改性酚醛树脂胶粘剂的固化时间、粘接胶合板的粘接强度和甲醛释放量进行了测定。结果表明:紫胶改性酚醛胶的固化时间与普通酚醛胶接近,粘接胶合板的粘接强度达到Ⅰ类胶合板的要求,胶合板的甲醛释放量降低。因此,用紫胶改性酚醛树脂胶粘剂是可行的。     

秸秆乙醇副产物酚醛树脂的制备与应用

以秸秆乙醇副产物、苯酚、甲醛为原料,NaOH为催化剂,通过逐步共聚制备了秸秆乙醇副产物改性酚醛树脂胶粘剂,并进行了中试放大试验和人造板生产试验。通过工艺优化发现,秸秆乙醇副产物最高可替代50%质量的苯酚,且不影响酚醛树脂胶粘剂的性能,其游离甲醛含量0.22%;制备的桉杨三层胶合板100℃水煮3 h,粘接强度为0.98 MPa,达到国家Ⅰ类板要求;甲醛释放量为0.23 mg/L,达到E0级。     

涂附磨具用的新型树脂粘合剂

贵州省化工研究所研制的SF型酚醛树脂粘合剂,主要是以苯酚和甲醛为原料的缩聚化合物。它粘接力强,耐热性能好。由于SF树脂粘合剂是以水为溶剂,故产品无毒,生产使用安全,对环境污染小。用SF树脂粘合剂生产的磨具质最长期稳定,能长期防潮、防霉。目前,涂附磨具行业除使用SF树脂粘合剂外还使用环氧树脂粘合剂及动物胶,但环氧树脂及动物胶都不及SF树脂理想。在相同条件下通过对比,用SF树脂制作的钢     

多元酚—甲醛树脂粘合剂的研究

一、概述 1、多元酚——甲醛树脂简介多元酚甲醛树脂是一种以粗酚为原料,经过物理过程与化学反应研制而成的水溶性、热固型的粘合剂,它主要用作Ⅰ类胶合板、水泥模板(俗称壳子板)、防水防潮刨花板、纤维板的粘接。用它粘接Ⅰ类胶合板与水泥模板,其粘接强度,达到国际GB738—75规定之标准。多元酚——甲醛树脂属酚醛树脂的系列,它的主要优点是粘接强度高,耐水性、耐热性强与防     

酚醛树脂胶粘剂研究进展

酚醛树脂胶粘剂具有优良的耐水性、耐热性、耐候性,粘接强度高及化学稳定性好等优点而被用于诸多领域。但是其还存在固化温度高、热压时间长、易透胶、有甲醛释放、原料成本高且不可再生等缺点。综述了快速固化和低游离甲醛含量酚醛胶粘剂,三聚氰胺、尿素、木质素、生物质焦油以及其他改性酚醛树脂胶粘剂,并对其存在问题和发展前景作了分析和展望。     

木质素改性酚醛树脂的研究进展

人造板工业用的酚醛树脂胶,虽然粘接性能好,但在制造和使用的过程中都会释放出污染物甲醛,而木质素分子中有酚羟基和醛基,使用木质素,既可改善胶粘剂的性质,又可节约苯酚的用量,降低甲醛释放量,达到废物利用与保护环境的目的本文综述了木质素磺酸盐、碱木质素、甘蔗渣木质素、酶解木质素等代替部分苯酚应用于环保树脂胶的制备工艺及研究发展现状,并对其发展前景作了展望     

低甲醛释放量“MF环保型脲醛胶”合成新工艺

产品经四川省产品质检所检测达到了环保型标准。新工艺的技术关键是1、该所自行研制的“ＭＦ酸碱催化剂”取代传统工艺的酸碱助剂 ,在加成聚合反应中能使甲醛与尿素全部聚合并能吸收余下的游离甲醛 ,是传统工艺基础上的一个重大突破。制成的胶液仍然乳白透明 ,水溶性、涂刷性、粘接力和耐水性等均符合应用要求。2、制胶时无需脱水 [无填料 ]含固量在 4 8%以上。粘度 30 - 5 0ｍＰａ·ｓ,胶合的板材粘接强度和游离甲醛释放量 ,符合ＧＢ/4897- 92规定的许可值 ,并达到Ｅ1级 .Ｅ2级标准。3、广泛应用于胶合板 ,装饰板 ,刨花板 ,木地板及复合地…     

有机硅改性热塑性酚醛树脂制备的研究

以苯酚和甲醛为原料。采用草酸作为催化剂,通过有机硅改性合成的热塑性酚醛树脂。讨论了催化剂草酸的含量、反应时间和有机硅的含量对改性酚醛树脂性能的影响。结果表明：当草酸含量为2．0,wt%,反应时间为2．5h,有机硅含量为3．0wt％时,合成改性酚醛树脂的固化时间、流动距离和挥发度等综合性能较好,合成的酚醛树脂可用作摩擦材料粘合剂。     

高温无机粘合剂研制成功

一种新型耐高温无机粘合剂日前在中国石油吉林石化公司研究院研制成功。该种新型耐高温无机粘合剂是以硅酸盐为粘接剂,高分子缩合磷酸盐为固化剂,硅化物、碳化物等高熔点物质为填料组成的新型粘合剂。具有机械强度高、粘接力强、化学稳定性好、无毒无污染、不燃烧、室温固化及高温使用等特点。可广泛用于石油、化工、冶金、电力等行业中的高温设备、烟道炉窑的粘接密封等领域。该产品在国家86 3攻关项目的高温碳化炉内进行应用试验,在使用温度高达10 0 0～130 0℃,连续使用5 0 0h后,仍具有良好的粘接密封性能。该新型无机粘合剂的研制成功为…     

粘合剂的耐候性

在玻璃钢产品中,不同结构件之间需要连接。连接方法很多,其中应用最普遍的是粘合剂粘接。在产品应用中,不仅玻璃钢会老化,粘合剂也会老化,特别是钢与玻璃钢粘接时,粘接寿命如何,是人们十分关心的问题。我们对JF-1粘合剂和HYJ-6粘合剂粘接的玻璃钢/普通碳钢试样进行了大气老化试验。 1.粘合剂配方及试样制备 JF-1和HYJ-6粘合剂粘接玻璃钢/普通碳钢,试样形式如下图:     

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.     

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.