微波法合成葡萄糖三聚氰胺树脂胶黏剂

合成了一种不含甲醛、无毒的绿色环保型胶黏剂.以葡萄糖代替甲醛,在酸性条件下用微波法合成了类似于脲醛树脂的绿色环保型葡萄糖三聚氰胺树脂,通过正交实验法获得了合成的最佳条件,同时对树脂的固化条件进行了研究.葡萄糖三聚氰胺树脂合成的最佳反应条件为:pH=3,催化剂用量:0.40g,n(三聚氰胺)∶n(葡萄糖)=4∶0.3,反应时间:6min.催化剂用量和反应配比对葡萄糖三聚氰胺树脂的合成反应的影响较大,其次是pH值,对反应影响最小的是反应时间.但反应时间也不应过长,以免碳化.     

果糖对甲酚树脂胶黏剂合成

以果糖代替甲醛,在酸性条件下合成了绿色环保型果糖对甲酚树脂胶黏剂。用正交实验法对反应物配比、反应温度、反应时间和pH进行了优化,得到的果糖对甲酚树脂胶黏剂合成的最佳反应条件为：n（果糖）：n（对甲酚）=7：1,反应温度为95℃,反应时间为7．Oh,pH值为3。同时以邻苯二甲酸酐作为固化剂,对树脂的固化条件进行了研究,得到的最佳固化条件为：国化剂用量为16％,固化温度为120℃,固化时间为1h。     

果糖尿素树脂胶黏剂的合成

以果糖代替甲醛合成类似于脲醛树脂的绿色环保型果糖尿素树脂胶黏剂。用正交实验法对反应物配比、催化剂用量、反应温度和反应时间及固化条件进行了优选。通过红外（IR）对果糖尿素树脂的结构进行了表征,并对反应机理进行了探讨,基本证实了Viswanathan所推测的机理。果糖尿素树脂胶黏剂合成的最佳工艺条件为：n（果糖）：n（尿素）=6：1,催化剂用量为1．0％,反应温度为95℃,反应时间为3h。该树脂以邻苯二甲酸酐作固化剂时的最佳固化条件为：120℃,固化剂用量为8％,固化时间为2h。     

葡萄糖缩二脲树脂胶黏剂的合成

以葡萄糖代替甲醛合成类似于脲醛树脂的绿色环保型葡萄糖缩二脲树脂.用正交实验法对反应的pH值、反应温度、催化剂用量、反应配比和反应时间及固化条件进行了优选.通过红外光谱(IR)对葡萄糖缩二脲树脂的反应机理进行了探讨,基本证实了Viswanathan所推测的机理.葡萄糖缩二脲树脂胶黏剂合成的最佳工艺条件为:pH值为1.0,n(葡萄糖):n(缩二脲)=10:1,催化剂用量为0.6%,反应温度为95 ℃,反应时间为11 h.该树脂以苯酐作固化剂的最佳固化条件为:120 ℃,固化剂用量为8%,固化时间为2.0 h.     

响应面优化法研究果糖苯酚树脂胶黏剂的合成

以果糖代替甲醛,在碱性条件下合成了果糖苯酚树脂胶黏剂。用响应面优化法对果糖苯酚树脂的合成条件进行了优化。以树脂黏度为考察指标,根据Box-Behnken的中心组合设计原理对实验进行设计和结果分析。用响应面优化法研究了温度、时间和催化剂用量对反应的联合影响,得出最佳工艺条件为:反应温度72.36℃,反应时间6.96h,催化剂用量7.98%。在此条件下,树脂的黏度为27.67s。同时用红外光谱(IR)对树脂结构进行了分析。     

微波法合成葡萄糖缩二脲树脂胶粘剂

以葡萄糖代替甲醛,在酸性条件下通过微波加热法合成了类似于脲醛树脂的绿色环保型葡萄糖缩二脲树脂胶粘剂。并通过正交试验法获得了树脂合成的最佳反应条件:pH=2;n(缩二脲)∶n(葡萄糖)=4∶0.6;催化剂用量0.75%;反应时间6 min。对树脂的固化条件进行了优选。     

花生壳苯酚液化产物-尿素-甲醛树脂胶黏剂的研究

以花生壳苯酚液化产物为原料,制备花生壳苯酚液化产物-尿素-甲醛（PLPUF）树脂胶黏剂。采用正交试验探讨了制备PLPUF树脂胶黏剂的最优配比,以提高其综合性能,结果表明：第一批尿素（U₁）/第二批尿素（U₂）物质的量比、液化产物（PL）/尿素（U_总）物质的量比以及液化产物和尿素总用量（PL+U_总）与甲醛（F）物质的量比为3：1、1：1.5和1：1是PLPUF树脂胶黏剂制备的最佳配比;此配比下胶合强度达到了0.83 MPa,含固体量为47.11%,游离甲醛的量为0.05%,以酚醛树脂胶黏剂为标准,PLPUF树脂胶黏剂能满足木材工业树脂的使用要求。PLPUF树脂在贮存过程中黏度逐渐上升,贮存5~15 d胶合强度为0.87~1.15 MPa,22 d后胶合强度降低至0.74 MPa,仍可满足使用条件。PLPUF树脂的FT-IR图中出现酰胺C=O和C—N等伸缩振动峰,表明尿素参与反应、改性树脂,而加入固化剂前后树脂的FT-IR吸收峰相同,结合DSC曲线表明固化剂的加入不改变树脂结构,但可以改善PLPUF树脂的固化过程,降低固化温度和固化反应热。     

一种单组份环保型环氧树脂胶黏剂的制备

本实验以双酚A型环氧树脂为基体树脂,双氰胺为固化剂,咪唑为固化促进剂,BN(氮化硼)和A1₂O₃为填料,再添加适量的其他助剂,制备单组份环保型环氧树脂胶黏剂。通过对粘接强度,热性能、储能模量、玻璃化转变温度的测试,研究了基体树脂、填料、固化剂用量等因素对环氧树脂胶黏剂性能的影响,制备了单组份环保型环氧树脂胶黏剂。     

SBS胶黏剂热老化性能的研究

胶黏剂的性能不仅和胶黏剂本身的化学结构、合成方式有关,而且使用条件对其性能影响很大.采用SBS弹性体、增黏树脂、接枝剂及按一定比例配合而成的混合溶剂制备了一种价廉物美的新型环保型胶黏剂.考查了热老化行为对SBS装饰胶黏剂性能的影响,通过热分析仪考查了300h内胶黏剂的玻璃化温度、剥离强度的变化.并通过扫描电子显微镜(SEM法)和X射线能谱(EDX法)考查了SBS装饰胶表面形貌和表面碳元素组成在50h、,100h、200h和300h热老化的微观变化情况,结果表明此种胶黏剂热老化性能良好.     

葡萄糖苯酚树脂胶粘剂的合成

以葡萄糖代替甲醛,在碱性条件下合成了葡萄糖苯酚树脂胶粘剂。用红外光谱(IR)对其结构进行了分析,并通过正交实验获得了该树脂合成的最佳反应条件:pH=11,n(葡萄糖):n(苯酚)=8:1,反应温度120℃,催化剂用量14．3%,反血时间4 h;同时对树脂的固化条件进行了系统研究。     

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.     

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.