吸水膨胀聚合物PAA/AM的研究

以N,N-亚甲基双丙烯酰胺为交联剂、过硫酸钾为引发剂,以丙烯酸、丙烯酰胺为反应单体,水溶液聚合法合成了适用于淡水和盐水的吸水膨胀聚合物PAA/AM。采用正交实验法对最佳聚合反应条件进行了优选:单体用量[M]0=30%;单体中和度N=75%;引发剂用量[I]=0.15%;交联剂用量[C]=0.011%;反应温度为75℃及反应时间3 h。对PAA/AM的吸液速率进行了测定,并讨论了它的反复吸液能力。     

聚丙烯酸钠高吸水剂的合成和性能评价

以丙烯酸（从）共聚单体,分别以过硫酸钾（KPS）和N,N-亚甲基双丙烯酰胺（NMBA）为引发剂和交联剂,采用水溶液聚合法合成聚丙烯酸钠高吸水性树脂。评价了SAP在蒸馏水的吸水速率及SAP在水中的保水能力。探讨了单体浓度（M）、引发剂浓度（I）、交联剂浓度（C）、聚合温度（℃）对SAP在自来水中吸水倍率的影响。结果表明：在AA浓度为40％：交联剂N,N′-亚甲基双丙烯酰胺质量分数为单体总量的0．035％;引发剂质量分数为0．10％;聚合温度为80℃;合成得到的高吸水性树脂吸蒸馏水率达到1050g／g。     

耐盐性树脂PAA的合成及应用研究

以丙烯酸-丙烯酰胺为单体，过硫酸钾为引发剂，N，N-亚甲基双丙烯酰胺为交联剂。水浴阶梯升温共聚合成耐盐性树脂，采用正交试验通过分析，研究了主要因素对产物性能的影响，确定较佳反应条件：T=50℃(2h)～65℃(3h)，单体配比nAM：nAA=1：11，单体中和度[N]=90％～95％。引发剂浓度[I]=0．3％，单体浓度[M]=30％～35％，交联剂浓度[C]=0．025％～0．03％，并将此树脂作为缓释剂应用于固载二氧化氯中，取得了良好的效果。     

吸水膨胀型聚合物堵漏剂的合成与评价

本实验研制了一种吸水膨胀聚合物堵漏剂,该堵剂由丙烯酸（AA）、丙烯酰胺（AM）、膨润土、N,N-亚甲基双丙烯酰胺通过溶液自由基聚合法合成。并通过实验探讨了交联剂用量、引发剂用量等因素对此聚合物堵漏剂的性能的影响,获得了适宜的制备条件为：引发剂用量0.35%;AA/AM=3：1;单体浓度30%;膨润土加入量15%;交联剂用量0.06%;体系pH值7.0;反应温度50℃。再采用正交实验法对聚合物配方进行了优选。并将优选出的几组配方进行堵漏评价,实验结果表明,该吸水膨胀聚合物具有堵漏性能,且该聚合物具有吸液倍数大、耐盐性好、吸水后凝胶强度较好的等特点。     

水溶液聚合法合成高吸水性树脂的研究

以N,N-亚甲基双丙烯酰胺为交联剂,过硫酸钾-亚硫酸氢钠为引发剂,以丙烯酸和丙烯酰胺为单体,采用水溶液聚合法合成了丙烯酸-丙烯酰胺共聚的吸水树脂,并探讨了单体浓度、单体质量比、丙烯酸中和度、交联剂用量、引发剂用量对吸水树脂吸水量的影响,最大吸水率为799.3 g/g。     

吸水膨胀型聚合物堵漏剂的合成与评价

研制了一种吸水膨胀聚合物堵漏剂,该堵剂由丙烯酸（AA）、丙烯酰胺（AM）、膨润土、N,N-亚甲基双丙烯酰胺通过溶液自由基聚合法合成。并通过实验探讨了交联剂用量、引发剂用量等因素对此聚合物堵漏剂的性能的影响,获得了适宜的制备条件为：引发剂用量0.35%;m（AA）：m（AM）=3：1;单体浓度30%;膨润土加入量15%;交联剂用量0.06%;体系pH值7.0;反应温度50℃。再采用正交实验法对聚合物配方进行了优选。并将优选出的几组配方进行堵漏评价,实验结果表明,该吸水膨胀聚合物具有堵漏性能,且该聚合物具有吸液倍数大、耐盐性好、吸水后凝胶强度较好的等特点。     

甘露醇交联的聚丙烯酸钠类高吸水性树脂的制备及性能研究

以多元醇甘露醇为交联剂、丙烯酸为单体、过硫酸铵为引发剂,采用溶液聚合法合成聚丙烯酸钠超强吸水剂.实验结果表明：单体浓度（单体在水中的质量百分比）为40%,中和度为75%,引发剂和交联剂用量分别占单体质量的0.5%和6%,反应温度为70℃时得到的产物吸水（蒸馏水）性1750 mL/g,吸盐水（生理盐水）性130 mL/g,探讨了产物的吸水动力学、保水率及热稳定性,并研究了不同pH值溶液、不同离子强度的盐溶液对产物吸液性能的影响.     

魔芋超强吸水剂的合成及吸液性能研究

以过硫酸钾为引发剂,N,N＇-亚甲基双丙烯酰胺为交联剂,采用水溶液自由基聚合法,合成了魔芋粉-丙烯酸（钠）-丙烯酰胺超强吸水剂。采用均匀试验设计法对该合成工艺进行优化,最佳工艺条件为单体总用量（单体/魔芋粉）8.79 g·g-1、引发剂量（引发剂/魔芋粉）4.50%、反应温度66.7℃、交联剂量（交联剂/魔芋粉）1.42%、反应时间2.55 h、丙烯酸中和度81.74%、单体比例51.7%。产物吸水率为751.3 g·g-1,吸盐水率为128.6 g·g-1。     

喷雾干燥制备吸水树脂的研究

以喷雾干燥制备为主要工艺手段，探究单体浓度、中和度、引发剂、交联剂以及反应温度对吸水树脂产品性能的影响，主要考察对去离子水及生理盐水的吸收倍率，确定了丙烯酸单体占反应体系质量65%,中和度70%,引发剂过硫酸钾占反应体系质量0.45%,内交联剂N,N-亚甲基双丙烯酰胺占反应体系质量0.035%,反应温度140℃的最佳工艺参数，去离子水吸水倍率到达713g/g,生理盐水吸水倍率达到35g/g。     

两性共聚高吸水树脂的合成与性能研究

以AA、AMPS、DMDAAC为单体,N,N′-亚甲基双丙烯酰胺为交联剂,在K_2S_2O_8引发下,利用反相悬浮聚合法合成基于两性共聚高吸水树脂(SAR)。讨论了AA、AMPS、引发剂用量、交联剂用量以及反应温度对吸水速率的影响,并通过红外光谱、热失重等进行表征。结果表明,AMPS 5 g,交联剂为单体量的0.05%,引发剂为单体量的0.7%,反应温度为70℃条件下合成的吸水树脂具有优异的性能,吸水倍率达420 g/g,吸水树脂完全分解温度为450℃,较普通吸水树脂热稳定性提高。     

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.