聚苯胺-碳纤维导电纸的制备

：区别于常用的液相原位聚合法，采用改良的分步液相原位聚合法使得聚苯胺均匀生长在碳纤维纸基体上。探究了碳纤维与芳纶浆粕配比、引发剂与苯胺用量，以及浸渍时间和反应时间对聚苯胺-碳纤维导电纸的导电性能的影响。采用扫描电子显微镜（SEM）观察导电纸的微观形貌，利用傅里叶变换红外光谱（FT-IR）与电镜能谱图分析（EDS）分别表征其表面结构与元素变化。结果表明：当碳纤维与芳纶浆粕的配比为2:8；引发剂用量为0.375 mol/l；苯胺与盐酸摩尔比为2:1；反应时间为12 h，浸渍时间为1 min时效果最佳，相对于碳纤维原纸（CP），分步液相原位聚合法制备的导电纸（PANI-CP）体积电阻率为0.184 Ω?cm，导电性能提高71.4%，抗张指数为22.993 N?m/g，物理强度提高14.1%；且相对于液相原位聚合法制备的导电纸（L-PANI-CP），导电性能提高46.2%，总色差值DE下降66.0%。     

聚苯胺/改性胶粉导电材料的制备及其性能研究

将废旧轮胎胶粉用硅烷偶联剂(KH-560)处理得到改性胶粉,然后以过硫酸铵为引发剂,采用化学原位聚合法制备了聚苯胺/改性胶粉导电材料。采用傅里叶变换红外光谱仪(FTIR)、扫描电子显微镜(SEM)、能谱仪(EDS)、四探针测试仪及电化学工作站等仪器,研究了原料配比、反应温度、反应时间对聚苯胺/改性胶粉导电材料导电性能的影响,并分析了胶粉改性及复合材料导电机理。结果表明,通过改性能明显提高胶粉分散性能;当温度为10 ℃,过硫酸铵与苯胺摩尔比为1∶1,盐酸浓度为1.0 mol/L,反应时间10 h时,制得的聚苯胺/改性胶粉导电材料的电导率为4.79 S/cm。     

聚苯胺/nano-ATO导电复合材料的原位聚合与表征

用原位聚合法,以十二烷基苯磺酸(DBSA)/HC l混酸为掺杂剂,过硫酸胺(APS)为氧化剂,制备了聚苯胺/掺锑二氧化锡(ATO)导电复合材料。探讨了ATO用量对导电复合材料电导率的影响。在n(苯胺)∶n(APS)∶n(DBSA)=1∶1∶0.7,m(ATO)∶m(苯胺)=0.1∶1时,复合材料室温25℃的电导率最高可达8.35 S/cm,比通常方法合成的聚苯胺和nano-ATO的电导率分别提高约1至2个数量级。通过FTIR、XRD、SEM和TEM对目标物进行了表征,结果表明,苯胺优先在ATO纳米粒子表面聚合,形成聚苯胺包覆ATO的导电复合材料。     

聚3,4-乙烯二氧噻吩/聚苯胺复合材料的制备与性能

以过硫酸铵(APS)和FeCl3为复合氧化剂,采用原位化学氧化聚合法合成了导电聚3,4-乙烯二氧噻吩/聚苯胺(PEDOT/PANI)复合材料,研究了苯胺浓度及加入时间、复合氧化剂配比和复合乳化剂配比对复合材料性能的影响,并对复合材料进行了分析. 结果表明,PEDOT/PANI复合材料合成的较佳工艺条件为：3,4-乙烯二氧噻(EDOT) 0.6 mol/L、复合氧化剂 0.6 mol/L(FeCl3:APS=1:2, mol)、复合乳化剂 0.4 mol/L(SDBS:CTAB=2:3, mol)、复合掺杂剂1.2 mol/L(H2SO4:SSA=4:1, mol)及苯胺0.8 mol/L, EDOT聚合2 h后加入苯胺溶液继续反应8 h. 复合材料的导电性、结晶性和热稳定性比纯导电聚合物好.     

原位吸附聚合法制备聚苯胺/废弃丁羟黏合剂复合导电材料

采用原位吸附聚合法制备了聚苯胺/废弃丁羟黏合剂导电复合材料,考察了苯胺单体质量分数、掺杂质子酸浓度、氧化剂浓度、反应时间和反应温度对复合产物导电性的影响,并用红外光谱仪对复合物的结构进行了表征。结果表明,较佳反应条件为苯胺单体质量分数为20%,掺杂质子酸对甲苯磺酸浓度为0.1 mol/L,氧化剂浓度为0.16 mol/L,反应时间为2 h,反应温度为10℃。在此条件下处理废弃丁羟黏合剂可使体积电阻率由原来的1011Ω·m降低到105Ω·m。     

聚苯胺的制备及其导电性能

以苯胺为单体,过硫酸铵为氧化剂,盐酸为掺杂酸,采用化学氧化法制备出盐酸掺杂聚苯胺(PANI-HA),研究了过硫酸铵与苯胺单体摩尔比(n APS:n An)、HCl浓度、反应温度和反应时间对PANI-HA电导率的影响;采用正交分析法研究了各影响因素对PANI-HA电导率的主次关系。结果表明:影响PANI-HA电导率的主次关系为反应温度n APS:n An反应时间HCl浓度;制备PANI-HA的最佳工艺为nAPS:n An=1.0,HCl浓度1.0 mol/L,反应温度10℃,反应时间8 h。     

聚苯胺/PE复合材料的制备探究

采用原位化学氧化聚合法制备苯胺/PE导电复合材料,使苯胺在基体高分子PE的水溶液中进行聚合,研究反应体系中聚苯胺的含量、反应时间、温度对复合材料电导率的影响,确定了较佳的聚合反应条件,并且通过红外对光谱复合材料的结构、光电性能和稳定性进行了表征和分析。     

掺杂引发剂对聚苯胺和煤基聚苯胺导电性影响

以盐酸为掺杂剂、过渡金属盐为引发剂,制备了煤基聚苯胺(CPANI)和聚苯胺(PANI),探讨了掺杂引发剂及力化学作用对CPANI和PANI导电性能的影响,并研究了CPANI,PANI的红外光谱图.结果表明,在过渡金属盐的作用下,制备的CPANI,PANI具有一定导电性能,这表明过渡金属盐在一定程度上起到了引发苯胺单体聚合的作用,但相对过硫酸铵作为引发剂引发聚合的CPANI,PANI而言,导电性能有一定程度的下降.     

原位化学氧化聚合制备PANI/PMMA导电复合膜

采用原位化学氧化聚合的方法制备了聚苯胺(PANI)/聚甲基丙烯酸甲酯(PMMA)复合膜,电导率达到1.2×10-2S/cm.考察了苯胺单体含量、聚合温度以及聚合时间对复合膜电导率的影响;通过红外光谱分析了PANI/PMMA导电复合膜的分子结构;应用热重分析仪测试了复合膜的热性能.结果表明,原位化学氧化聚合制备PANI/PMMA复合膜的工艺是可行的,苯胺的最佳用量为35%,聚合反应时间6 h左右,聚合反应温度不宜高于40℃;复合膜的热稳定性较盐酸掺杂聚苯胺有所提高.     

聚苯胺/涤纶导电织物的制备

将导电聚合物聚苯胺采用现场吸附聚合法吸附到涤纶织物表面上制备复合导电织物,通过单因素分析得出第一次聚合并掺杂的较优工艺条件为:苯胺浓度0.25mol/L,氧化剂过硫酸铵质量浓度0.02g/mL,掺杂剂盐酸浓度2.5mol/L,反应时间2h,反应温度20℃。若将经第一次聚合掺杂处理的织物在相同工艺参数条件下再经过第二次掺杂,则能显著提高导电织物的电学性能。从光学显微镜里可以看到聚苯胺沉积在纤维表面上,形成致密且均匀分布的连续导电膜。     

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.