卡拉胶/金属氧化物协同聚磷酸铵制备阻燃天然橡胶

将卡拉胶（KC）、聚磷酸铵（APP）分别和Fe2O3、CuO、Al2O3、MnO2 4种金属氧化物（MO）三者复配构成的协同阻燃剂（KC/MO/APP）加入到天然橡胶（NR）中,制备NR/KC/MO/APP复合材料。通过极限氧指数（LOI）、垂直燃烧（UL-94）、锥形量热（CCT）测试了复合材料阻燃性能。结果表明,NR/KC/MO/APP复合材料的UL-94均达到V-0等级,LOI在26.5%~27.3%之间,具有较好的阻燃性。与NR相比,NR/KC/CuO/APP复合材料的热释放速率峰值（pHRR）和总热释放量（THR）分别下降了63.7%和42.0%。同时KC/MO/APP还有抑烟作用,NR/KC/Fe2O3/APP复合材料总烟释放量（TSP）比NR下降了35%,处于最低水平。TGA结果显示,NR/KC/CuO/APP复合材料W800达到34.85%,比NR/APP提高了28.7%。SEM分析表明,NR/KC/MO/APP复合材料体系炭层更致密,表明KC/MO与APP的协同作用对形成稳定炭层起着重要作用。DMA和力学性能测试发现,NR/KC/MnO2/APP复合材料力学性能最优,其拉伸强度和断裂伸长率比NR/APP分别提高32.6%和20.9%,表明MnO2的加入可弥补阻燃剂对NR造成的力学性能损失。     

卡拉胶包覆APP/MnO2增强水性环氧树脂阻燃抑烟性能

用反相乳液法，以卡拉胶（KC）为壳材，聚磷酸铵（APP）和二氧化锰（MnO2）为芯材，制备了KC包覆APP/MnO2阻燃剂（KC-FR）。通过FTIR、 XRD、 SEM和 EDS对KC-FR进行了表征。结果表明：卡拉胶已成功包覆APP和MnO2，合成的样品具有微胶囊结构。将KC-FR应用于水性环氧树脂（EP）中，考察KC、APP、MnO2 三者质量比对EP阻燃、抑烟性能的影响。用极限氧指数（LOI）、垂直燃烧（UL-94）和锥形量热（CCT）测试了涂层的阻燃、抑烟性能。结果发现，当KC/APP/MnO2的质量比为2∶1∶1，并且在EP中添加量为20%时，制备的阻燃涂层EP2的LOI达到29.1%，UL-94达到V-0级，表现出较好的阻燃性能。EP2相比于其它涂层热释放峰值（pHRR）、热释放总量（THR）和烟释放总量（TSP）最低，相比于EP0分别下降了42%、37%和46%，表现出较好的抑烟性能。另外，热重分析（TGA）测试结果显示EP2在800℃残炭量（W800）为33%，表明KC-FR具有促进EP成炭的功能。通过SEM对残炭表面分析发现，EP2表面炭层更加致密，这表明KC-FR对促进形成稳定并且致密的炭层起到至关重要的作用。     

CONE法研究聚磷酸铵和硼酸对环氧树脂复合材料的阻燃作用

采用锥形量热法研究了聚磷酸铵(APP)、硼酸及由这两者组成的复配阻燃剂对环氧树脂(EP)复合材料燃烧性能的影响.结果表明:APP可使EP复合材料燃烧时的热释放量和烟释放量大大降低,到495s时累积热释放量为27.3MJ/m2,烟产生速率为2243m2/m2,与未阻燃EP复合材料相比分别下降了37%和49%,阻燃抑烟效果显著;硼酸推迟EP复合材料热解时间,延缓了烟尘和有毒气体的释放;APP与硼酸之间存在着协同阻燃作用,APP在燃烧前期催化EP成炭,硼酸降低燃烧后期的累积热释放量.     

磷钨酸在膨胀阻燃聚乳酸中的协效作用研究

利用磷钨酸(PWA)与膨胀阻燃剂(IFR)复配得到复合阻燃剂,并与聚乳酸(PLA)熔融共混制备阻燃复合材料PLA/IFR/PWA。通过氧指数测试(LOI)、垂直燃烧(UL-94)、扫描电子显微镜(SEM)、锥形量热测试(CONE)和热失重分析(TGA)对该复合材料的阻燃性能和热稳定性能进行研究。结果表明:PLA/IFR/PWA复合材料表现出优异的阻燃效果和明显的抑烟作用。当添加总质量分数为20%(IFR为18%,PWA为2%)时,复合材料的LOI达到41.7%,UL-94等级为V-0等级,高温残炭量显著提高,燃烧过程中烟释放量明显降低。     

APP/ADP体系阻燃木塑复合材料研究

选用聚磷酸铵(APP)与二乙基次膦酸铝(ADP)复配用于木塑复合材料(WPC)的阻燃并研究了材料的阻燃性能。结果表明,纯WPC的氧指数(LOI)值为23.5%,当单独添加19%(wt)的APP时,材料通过了垂直燃烧测试UL-94 V-0级,LOI值为28.9%。当APP与ADP以质量比为6∶1复配,阻燃剂总添加量仅为15%(wt)时,材料通过了UL-94 V-0级,LOI值达到了28.7%,表明ADP/APP体系对WPC具有很好的协同阻燃效应。力学性能测试表明,APP/ADP体系的加入对材料的力学性能影响较小。热重分析测试表明,APP/ADP体系促进了材料的初期热降解,但提高了材料的成炭性能。锥形量热测试及扫描电镜对残炭的测试表明,APP/ADP体系的加入使得材料在燃烧过程中形成了膨胀、连续的炭层,很好地抑制了材料的燃烧,使得材料的热释放速率、总热释放量显著降低。     

三嗪成炭剂对EVA阻燃性能的影响

三嗪成炭剂(CNCH-DA)与多聚磷酸铵(APP)复配成膨胀型阻燃剂(IFR)应用于EVA的阻燃改性,采用氧指数测定仪(LOI)、垂直燃烧测定仪(UL-94)分析了EVA/IFR复合材料的阻燃性能,采用微型量热仪(MCC)分析了其燃烧行为,并采用热重分析仪(TGA)和扫描电子显微镜(SEM)研究了其阻燃机理。结果表明,当APP与CNCH-DA的质量比为2∶1时,EVA/IFR复合材料的LOI值达到27. 7%,并且通过了UL-94 V-0级测试; MCC分析结果表明,添加了IFR后,EVA的燃烧性能下降; TGA分析结果表明,当添加IFR后,EVA/IFR复合材料的热降解推迟,残炭量增加;SEM分析表明,EVA/IFR在燃烧后能形成致密且蓬松的炭层,起到良好的阻燃效果,而EVA/CNCH-DA燃烧后,形成众多不致密的微球。     

卡拉胶-纳米氢氧化铝协同阻燃天然橡胶

将BaCl2分级的k型卡拉胶(KC)和纳米氢氧化铝〔Al(OH)3〕构成的协同阻燃体系添加到天然橡胶(NR)中制备KC-Al(OH)3/NR复合材料。通过TG、极限氧指数(LOI)、锥形量热(CCT)以及SEM考察了不同质量比的KC和Al(OH)3对复合材料力学性能和阻燃性能的影响。结果表明,当KC与Al(OH)3以1∶1的质量比加入到NR时,KC-Al(OH)3/NR复合材料的热稳定性、阻燃性能最优,复合材料的LOI达到25%。与纯天然橡胶相比,复合材料总热释放量(THR)、热释放速率峰值(pHRR)、总烟释放量(TSP)和平均质量损失率(AMLR)分别降低了12%、65%、23%和62%。相比于单独添加Al(OH)3体系,复合材料拉伸强度和断裂伸长率分别增加了11%和17%。     

新型阻燃木塑复合材料的制备及其性能研究

应用有机硅阻燃剂(FRX-210)及FRX-210与聚磷酸铵(APP)或有机磷氮阻燃剂(PNP)的复合阻燃剂制备了阻燃木塑复合材料,研究了阻燃剂对PE基木塑复合材料的阻燃性能及力学性能的影响。结果表明,FRX-210使木塑复合材料的极限氧指数(LOI)提高,且随FRX-210添加量的增加而增加,添加40份FRX-210,使木塑材料的LOI提高了34%。FRX-210使木塑复合材料的热、烟、CO、CO_2释放量显著降低,火灾性能指数提高,且对材料的力学性能的影响较小。FRX-210与APP及PNP对PE基木塑复合材料具有阻燃协效作用,且FRX-210与APP复配后的阻燃效果明显优于与PNP复配的效果。     

ATH和APP对聚乳酸/竹粉复合材料阻燃抑烟性能的影响

利用竹粉和聚乳酸为原料复合制备聚乳酸/竹粉复合材料,分别采用氢氧化铝(ATH)和聚磷酸铵(APP)阻燃剂对聚乳酸/竹粉复合材料进行阻燃抑烟处理并对阻燃处理后的复合材料进行性能测试。结果表明,两种阻燃剂的加入均使复合材料高温下的成炭率提高了约2倍,分别达到了24.7%和25.6%;ATH和APP的加入均有效提高了聚乳酸/竹粉复合材料的阻燃性能;其中,APP对复合材料燃烧过程中热量释放的抑制明显,其热释放速率在燃烧100s以后下降了近2倍,约为150kW/m2,但生烟量大;而ATH对复合材料的抑热效果不及APP,但抑烟效果显著,平均烟释放速率只有约0.02m2/s。     

硬质聚氨酯泡沫/聚磷酸铵复合材料的制备及阻燃性能研究

以聚磷酸铵(APP)为阻燃剂,采用一步法全水发泡制备一系列硬质聚氨酯泡沫/聚磷酸铵复合材料(RPUF/APP),通过扫描电镜(SEM)、热重分析(TG)、极限氧指数(LOI)、UL94垂直燃烧以及烟密度测试来研究聚磷酸铵对硬质聚氨酯泡沫(RPUF)泡孔结构、热稳定性、阻燃性能以及燃烧烟密度的影响。研究表明,聚磷酸铵可以明显提高RPUF/APP复合材料的阻燃性能,30份的聚磷酸铵使得RPUF/APP达到UL94 V-0级别,LOI达到23. 6%。同时发现,APP的加入会降低RPUF/APP泡沫复合材料的热分解温度,提高其成炭率和炭层的高温稳定性,并降低复合材料的燃烧烟密度,有效提高复合材料火灾安全性能。     

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.