果糖缩二脲树脂胶粘剂的合成

以果糖代替甲醛,在酸性条件下合成了果糖缩二脲树脂胶粘剂,并通过正交实验法获得了该树脂合成的最佳反应条件:n(果糖)∶n(缩二脲)=6∶1,催化剂用量为0.4%,反应温度为100℃,反应时间为2.5 h;同时对树脂的固化条件也进行了优选,最佳固化温度为120℃,固化剂用量为8%,固化时间为2 h。     

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.     

微波辐射法合成葡萄糖对苯二酚树脂胶粘剂

以葡萄糖代替甲醛,在碱性条件下用微波加热法合成了葡萄糖对苯二酚树脂胶粘剂。并通过正交实验获得了合成的最佳反应条件:n(葡萄糖)∶n(对苯二酚)=8∶1;pH=11;催化剂用量:1.5%;反应时间:6 min。同时对树脂的固化条件进行了研究。     

葡萄糖对苯二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对苯二酚树脂胶粘剂。利用红外光谱(IR)及热重分析(TGA)对树脂的结构及热稳定性进行了分析,并通过正交实验获得了该树脂合成的最佳反应条件:pH=13,n(葡萄糖)n∶(对苯二酚)=101,∶反应温度110℃,催化剂用量2.0%,反应时间7h;同时对树脂的固化条件进行了系统研究。     

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.     

乳糖缩二脲树脂胶黏剂的合成

以乳糖代替甲醛,在酸性条件下和缩二脲合成了一种新型环保型树脂胶粘剂。以产物黏度为指标,在单因素实验的基础上采用响应面分析法对其实验条件进行了优化,通过对实验结果的分析比较,确定出最佳工艺条件为:n(乳糖)∶n(缩二脲)=6.03∶1,反应温度198.9℃,反应时间45.3 min和催化剂用量1.47%(即催化剂质量占乳糖质量的百分数,下同),在该条件下产物的理论黏度最大,为175.6 mPa.s,实测值为173.8 mPa.s。     

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。     

超声法合成D-葡萄糖酸-δ-内酯

研究了连续性超声反应条件下D-葡萄糖酸-δ-内酯合成的新方法。考察了反应时间、反应温度、葡萄糖与I2的摩尔比对反应的影响。经过正交试验确定了较佳的合成工艺条件为:n(葡萄糖)∶n(I2)=1∶2,40℃下连续超声反应40min,生成的葡萄糖酸钾收率为93%,将其水溶液经过强酸性苯乙烯系阳离子交换树脂柱,酸液在45℃下减压浓缩,20℃下静置过夜重结晶得到D-葡萄糖酸-δ-内酯,收率88%,产物通过IR,1 H NMR得到证实。结果表明,连续性超声反应合成D-葡萄糖酸-δ-内酯,操作简单,反应时间短,收率高。     

乙二醇葡萄糖苷的合成及性能研究

以大孔强酸性阳离子交换树脂为催化剂,以葡萄糖和乙二醇为原料合成了乙二醇葡萄糖苷。探讨了催化剂用量、醇糖摩尔比和反应温度对反应的影响,得到最优的反应条件为:n(乙二醇)∶n(葡萄糖)=7∶1,n(催化剂)∶n(葡萄糖)=0.25∶1,反应温度为100℃,产品收率可达90.58%,催化剂重复使用5次,产品收率基本不变,具有较好的回用性能。对乙二醇葡萄糖苷的保湿性能进行了研究,发现乙二醇葡萄糖苷的保湿性优良,可用于日化保湿剂行业中。     

乙二醇葡萄糖苷的合成及性能研究

以大孔强酸性阳离子交换树脂为催化剂,以葡萄糖和乙二醇为原料合成了乙二醇葡萄糖苷。探讨了催化剂用量、醇糖摩尔比和反应温度对反应的影响,得到最优的反应条件为:n(乙二醇)∶n(葡萄糖)=7∶1,n(催化剂)∶n(葡萄糖)=0.25∶1,反应温度为100℃,产品收率可达90.58%,催化剂重复使用5次,产品收率基本不变,具有较好的回用性能。对乙二醇葡萄糖苷的保湿性能进行了研究,发现乙二醇葡萄糖苷的保湿性优良,可用于日化保湿剂行业中。     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.