花生壳与核桃壳制备活性炭的比较研究

试验对花生壳和核桃壳制备活性炭进行了研究。得出花生壳制备活性炭最佳条件为:液固比2∶1,H3PO4质量分数15%,活化温度500℃,活化时间4 h;核桃壳制备活性炭最佳条件为:液固比2∶1,H3PO4质量分数20%,活化温度700℃,活化时间2 h。研究表明:核桃壳制备活性炭更值得推广。     

膜分离技术制备高纯单宁酸的研究

工业单宁酸经改性活性炭预处理后,用超滤和纳滤技术纯化的方法制备高纯度单宁酸。重点考察了料液质量分数、操作压力差、料液温度对膜分离效果的影响。确定的最佳工艺条件是:料液质量分数 15%、截留相对分子质量为 6000 的超滤膜和截留相对分子质量为600的纳滤膜的操作压力差分别为 0.10 MPa 和 0.08 MPa、料液温度 40℃。同时探讨了颗粒活性炭通过硝酸氧化改性增强其吸附性能的方法。分析结果表明,膜分离技术有效地实现了不同分子质量的物料分级和截留,精品单宁酸的含量为 97.3%,收率为 84.7%。     

塔罗科血橙皮中黄酮类化合物的提取

本实验用单因素法和正交实验法探讨索氏回流提取法提取血橙皮中黄酮类化合物的提取条件。考察了乙醇体积分数、温度、时间及料液比对黄酮类化合物提取率的影响。实验结果表明:乙醇的体积分数为80%,温度为95℃,液料比为1∶40,时间为2.5 h的条件下提取效果最佳。测定总黄酮的提取率可达到1.515%。     

玉米秸秆活性炭改性及复合磁性材料研究

基于玉米秸秆经磷酸活化后制备出的活性炭有较好的吸附效果,解决了环境污染和资源浪费问题。本文通过探究时间、温度、料液比、磷酸浓度等因素对活性炭吸附能力的影响,对比后得出实验室条件下的最佳工艺为:炭化温度400℃、炭化时间1 h、料液比为1:3、磷酸质量浓度60%、活化温度400℃、活化时间2 h;进而通过酸碱试剂对活性炭进行改性表明酸改性剂更加有效;并且用磁性材料将活性炭复合之后,其对金属离子的吸附能力比普通活性炭强。     

多组分共聚酯纤维的碱处理研究

研究了多组分共聚酯纤维的碱处理工艺条件:达到最佳碱处理效果的碱浓度,碱处理时间和碱处理温度及十二烷基苄基季胺盐(1277)的浓度等。结果得到未加1277的最佳碱处理条件为:NaOH质量分数为3.0%,浴比1:40,碱处理温度为90℃,时间为60 min;加入1277时,NaOH质量分数为2.0%,浴比和最佳处理温度和时间不变,1277的质量浓度为0.40 g/L。     

超声辅助优化小麦胚芽中总黄酮提取工艺

超声辅助提取小麦胚芽中黄酮类化合物,考察料液比、乙醇体积分数、提取时间、提取温度对小麦胚芽黄酮得率的影响。结果表明,各因素影响的主次顺序为:乙醇体积分数>料液比>提取温度>提取时间;提取最佳工艺为:料液比1∶30 g/mL,乙醇体积分数40%,提取时间60 min,提取温度50℃。在此最佳条件下,小麦胚芽总黄酮的得率为1.52%。     

超声辅助优化小麦胚芽中总黄酮提取工艺

超声辅助提取小麦胚芽中黄酮类化合物,考察料液比、乙醇体积分数、提取时间、提取温度对小麦胚芽黄酮得率的影响。结果表明,各因素影响的主次顺序为:乙醇体积分数料液比提取温度提取时间;提取最佳工艺为:料液比1∶30 g/mL,乙醇体积分数40%,提取时间60 min,提取温度50℃。在此最佳条件下,小麦胚芽总黄酮的得率为1.52%。     

微波辅助提取山楂中熊果酸的工艺研究

对微波辅助提取山楂中熊果酸的工艺条件进行了研究,通过正交试验对工艺条件进行了优化,结果表明：各因素对熊果酸提取率的影响顺序为：乙醇质量分数〉提取温度〉微波时间〉微波功率〉液料比,乙醇质量分数为显著影响因素;最佳条件为：乙醇质量分数为85%、提取温度为55℃、微波时间为4min、液料比为16∶1、微波功率300W,在此条件下的熊果酸提取率为3.42%。     

响应面法优化荞麦茎中芦丁的提取工艺

以荞麦茎为原料,研究芦丁的最佳提取工艺。通过单因素实验及响应面法实验考察了料液比、提取温度、乙醇体积分数、提取时间4个因素对芦丁提取量的影响。结果表明,各因素对芦丁提取量的影响大小依次为:料液比提取温度乙醇体积分数提取时间;荞麦茎中芦丁的最佳提取工艺条件为:料液比1∶22(g∶mL)、提取温度65℃、乙醇体积分数60%、提取时间2.0h,在该条件下,芦丁提取量达到6.752mg·(100g)~(-1)。     

油茶壳用微波加热磷酸法制活性炭

以油茶果壳为原料,用磷酸作活化剂,采用微波加热法制备粉状活性炭。按4因素3水平的正交表设计试验方案,研究磷酸浓度、料液混合比、活化温度、活化时间等4个因素对产品亚甲基蓝吸附值的影响。在磷酸质量分数60%,料液质量比1:2.0,活化温度550℃,活化时间75 min的条件下,活性炭的亚甲基蓝吸附值可达226 mg/g,A法焦糖脱色率达100%以上,灰分为4.6%~5.2%。油茶果壳可用微波加热磷酸活化法制取液相脱色活性炭。     

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.