聚氨酯改性中温快速固化环氧粘合剂的制备与应用

以聚四氢呋喃醚、异佛尔酮二异氰酸酯、2-乙基咪唑为原料,合成了以2-乙基咪唑封端的聚氨酯,并用于改性环氧树脂E-44.利用傅立叶红外分析仪、示差扫描量热仪、拉伸试验机等手段对其与环氧树脂混合物的凝胶时间、固化温度、解封情况、拉伸剪切强度等性能进行了研究.结果表明,咪唑封端的聚氨酯可以在130℃下较好地解封,每10份E-...     

2-甲基咪唑的改性及性能研究

以2-甲基咪唑为原料,通过与丙烯酸甲酯反应制备了丙烯酸甲酯改性的2-甲基基咪唑衍生物。将其作为环氧树脂的固化剂。研究表明,改性后的2-甲基咪唑其性能优于咪唑和2-甲基咪唑。     

HPM/St/MA三元共聚物固化E-44环氧树脂的研究

制备了N-(4-羟基苯基)马来酰亚胺/苯乙烯/马来酸酐三元共聚物,并将其用做固化剂对E-44环氧树脂进行耐热改性。对固化物的耐溶剂性进行了测定,结果表明HPM/St/MA固化后的E-44环氧树脂具有很好的的耐溶剂性能;采用TG热分析技术研究了E-44环氧树脂固化物的耐热性能,结果表明加入相同比例活性含量的改性剂时HPM/St/MA比其它常见的固化剂固化效果更好,耐热性更高。     

改性2-乙基咪唑环氧树脂潜伏型固化剂的制备

通过2-乙基咪唑(2EI)分别与N-(4-羟基苯基)马来酰亚胺(HPM)和三聚氯氰反应,成功地合成了两种改性2-乙基咪唑衍生物,分别采用红外光谱、核磁共振对其分子结构进行表征。将制备的改性咪唑类固化剂与环氧树脂混合,研究了树脂体系的固化特性和潜伏性。研究表明:相比EP/2EI体系,改性固化体系的固化放热区间均向高温区域移动;此外,改性固化体系在室温下具有更长的储存期。具有强吸电子效应的马来酰亚胺基团和三嗪环降低了咪唑环的亲核性,抑制了固化剂的室温固化活性。此外,在升温条件下,改性固化剂可以克服固化反应能量势垒,恢复快速固化能力。     

提升输油管道防腐效果的环氧粉末涂料材料制备

目前环境污染已经成为人们关注的重点问题,传统涂料中包含一定的环境污染因素,因此需要对其进行有效控制。采用线型酚醛环氧树脂(ENR)、环氧树脂E-12、固化剂JECP-02B制备了输油管线用熔结环氧粉末涂料。考察了线型酚醛环氧树脂与环氧树脂E-12质量比对涂料性能的影响,以及固化剂JECP-02B、流平剂GLP588和固化促进剂2-甲基咪唑对固化行为的影响,用红外光谱分析了固化前后树脂的变化,m(ENR)/m(E-12)=(70/20)～(20/80)、m(固化剂)/m(环氧树脂)=1/4、m(流平剂)/m(环氧树脂)=2/100、m(2-甲基咪唑)/m(环氧树脂)=(0.1～0.18)/100时,涂层性能达到输油管线防腐指标(SY/T0315-97)。     

环氧粉末涂料的固化动力学和固化工艺的研究

采用非等温示差扫描量热法(DSC)研究了E-12/双氰胺(固化剂)和E-12/双氰胺/2-甲基咪唑(促进剂)体系的固化反应动力学。采用Kissinger法和Crane公式对DSC数据进行处理,获得了固化反应动力学参数,应用热重分析(TGA)研究了固化产物的热稳定性。结果表明:双氰胺、2-甲基咪唑的最佳用量分别为环氧树脂质量的4%和0.4%,最佳固化条件为160℃/15min。E-12/双氰胺体系和E-12/双氰胺/2-甲基咪唑体系的表观活化能分别为105.12kJ/mol和70.62kJ/mol,固化反应级数n=0.92。起始分解温度约为410℃,促进剂2-甲基咪唑的加入对体系热稳定性没有影响。     

环氧片状模塑料用微胶囊固化剂的制备

以2-乙基-4-甲基咪唑(2E4MI)为芯材、聚乙二醇(PEG-6000)为壁材,采用熔融喷雾法制备了一种环氧片状模塑料用微胶囊固化剂。对微胶囊进行了表征,对环氧树脂的固化行为进行了研究。研究表明,该胶囊固化剂中囊芯材料2E4MI的质量分数约为l3.7%。ESMC的最佳固化工艺确定为:101℃/10min+111℃/10min+150℃/10min+180℃/10min。微胶囊化固化剂中的PEG-6000壁膜在常温下可以阻止环氧树脂的固化,使ESMC树脂糊体系具有更好的室温贮存稳定性。固化剂的微胶囊化不会引起固化机理的变化。环氧树脂的固化度α可达0.93。     

利用外推法研究JEh-031型环氧树脂复合材料的固化工艺

以JEh-031环氧树脂为基体材料、改性甲基四氢苯酐为固化剂制备而成的碳纤维复合材料具有良好的耐热性能,然而其固化过程需要较长的时间。咪唑及其衍生物可作为促进剂显著改善固化体系的性能,为缩短JEh-031环氧树脂基碳纤维复合材料的固化时间,本文选用2-乙基-4-甲基咪唑作为固化过程中的促进剂,按照树脂、固化剂、促进剂质量比为100︰110︰0.5与100︰110︰0的比例试验得到DSC曲线,活化能拟合图,反应级数n的拟合图以及等固化线,然后利用外推法从理论上研究促进剂对固化工艺的影响。结果表明,2-乙基-4-甲基咪唑在高温下释放出游离的咪唑与环氧树脂体系反应可以促进反应固化,明显缩短固化时间。     

羧基丁腈橡胶增韧改性环氧树脂复合材料的性能研究

采用反应性羧基丁腈橡胶(CTBN)对环氧树脂E-51(EP)进行了增韧改性,并制备了CTBN/EP复合材料,研究了不同用量CTBN增韧改性环氧树脂复合材料的性能。结果表明,采用15份CTBN对EP进行增韧改性,并以2-乙基-4-甲基咪唑作固化剂在100℃下制备的CTBN/EP复合材料综合性能满足要求。     

输油管线用熔结环氧粉末涂料的制备

采用线型酚醛环氧树脂(ENR)、环氧树脂E-12、固化剂JECP-02B制备了输油管线用熔结环氧粉末涂料。考察了线型酚醛环氧树脂与环氧树脂E-12质量比对涂料性能的影响,以及固化剂JECP-02B、流平剂GLP588和固化促进剂2-甲基咪唑对固化行为的影响,用红外光谱分析了固化前后树脂的变化,m(ENR)/m(E-12)=(75/25)~(25/75)、m(固化剂)/m(环氧树脂)=1/4、m(流平剂)/m(环氧树脂)=2/100、m(2-甲基咪唑)/m(环氧树脂)=(0.1~0.15)/100时,涂层性能达到输油管线防腐指标(SY/T 0315-97)。长庆化工有限责任公司用该技术扩大生产约10 t环氧粉末涂料,用于长庆油田输油管线的防腐,产品满足了1.5 m in/230℃快速固化的施工要求。     

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.     

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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.