促进剂含量对真空导入成型用环氧树脂的影响

应用流变仪和DSC分析技术,系统研究了促进剂含量对一种用于大型碳纤维复合材料结构件真空导入成型的环氧树脂体系的影响.对促进剂含量分别为0.5％、1.0％和1.5％的环氧树脂体系,分别进行了粘度特性、工艺窗口、固化特性和基本力学性能的分析.该树脂体系的最佳灌注温度并未随促进剂含量增加而变化,适用期、完全固化所需的温度和时间均随促进剂含量的增加而降低.增加促进剂含量可以降低固化温度,并保证浇铸体的力学性能基本不受影响,从而可以在普通模具中应用该环氧树脂体系.     

热固性丙烯酸树脂罩光清漆的合成研究

合成了一种热固性丙烯酸树脂,用其配制的热固性金属罩光漆在120℃下,30 min即可完全固化,具有附着力强、硬度高、光泽好以及耐盐水性优异等特点;试验中发现,引发剂的用量、反应温度对热固性树脂的黏度有明显影响。     

悬浮接枝法AAS树脂的合成研究

用悬浮接枝法,以丙烯腑、苯乙烯、丙烯酸丁酯为原料,偶氮二异丁腈为引发荆,羟丙基纤维素为分散剂,在一定的水油比下合成AAS三元接枝共聚物。讨论了反应时间、温度、引发剂用量、分散剂浓度及丙烯酸丁醇含量对合成反应及产品颗粒形态、玻璃化转变温度(Tg)的影响。结果表明,反应8小时后转化率增大的趋势较缓慢;随反应温度的提高及引发剂用量、丙烯酸丁酯含量的增加,产品的相对粘度(η)下降;分散剂用量在0.5%时,可得到良好颗粒形态的产品;当丙烯酸丁酯的含量为30%时,AAS树脂的Tg达最大值;由红外光谱表明,所合成的产物为苯乙烯—丙烯腑—丙烯酸丁酯的接枝共聚物。     

改性环保装饰型胶粘剂粘接性能的研究

以苯乙烯/丁二烯/苯乙烯嵌段共聚物(SBS)为基体树脂、增黏树脂为改性剂、溶剂汽油和丙酮为溶剂制备环保型SBS装饰胶粘剂,研究了胶粘剂的固化行为对其力学性能和玻璃化转变温度(Tg)的影响,考察了不同的热老化时间对其力学性能、Tg、表面微观形貌和表面碳元素含量的影响。研究结果表明,当固化时间低于120h时力学性能和Tg随着固化时间的延长而增加,当固化时间超过120h时力学性能和Tg基本不变;当热老化时间超过160h时胶粘剂老化开始加剧,当热老化时间超过300h时胶粘剂发生热分解。     

复合材料气瓶用环氧树脂固化性能研究

为了制造复合材料气瓶,采用红外光谱、动态模量分析(DMA)等方法研究了按不同升温制度固化的复合材料气瓶用环氧树脂基体的反应固化度、玻璃化转变温度(Tg)以及其力学性能,以考察固化温度对树脂基体性能的影响,并对2种固化制度各自优缺点进行了对比分析。结果表明:加上促进剂可有效降低固化反应温度,80℃固化8 h固化度可达95%以上。同130℃固化4 h结果相似。试验证明该基体配方可以作为高性能湿法缠绕复合材料气瓶用树脂基体配方。     

中温固化氰酸酯树脂基体动态热机械分析研究

采用动态热机械分析法详细考察了中温(125℃)固化氰酸酯树脂基体的温度-模量谱,研究了连续温度变化情况下促进剂用量、固化温度、环氧树脂、多官能氰酸酯对树脂基体的模量、损耗、玻璃化转变温度等使用性能的影响。促进剂的加入有效地提高了CE树脂中温固化反应程度和固化物的Tg,加入量在1.5phr时,改性CE树脂的弹性模量在150℃处显现出GPa量级波动,但仍呈玻璃态特征,表观Tg达238℃。提高固化温度,可使DMA曲线上的弹性模量波动消失,180℃固化后的Tg与中温固化的表观Tg相近。采用E-51环氧改性CE树脂,会显著降低树脂的耐热性。E-51用量在10份,Tg在233.5℃,用量到20份以上时,CE树脂的Tg急剧降低。酚醛型氰酸酯CY-5能有效地提高树脂的Tg,用量在20份时,Tg可达289℃。     

PGMA/PMMA树脂制备与性能研究

采用氧化-还原体系制备了一种丙烯酸树脂——PGMA/PMMA树脂,用于金相试样镶嵌料。主要考察不同引发剂/促进剂配比和不同溶剂单体配比对固化树脂热性能、固化时间、体积收缩率和拉伸强度的影响。测试结果表明,两种溶剂单体发生了共聚合反应,当引发剂/促进剂=5,GMA/MMA=1∶3时,树脂固化时间29 min,玻璃化转变温度为112.99℃,体积收缩率小于8%,力学性能优异,适用于金相检测镶嵌料。     

聚三唑酯树脂的合成及其性能

通过酯化反应合成丁二酸二炔丙醇酯(DPS)、间苯二甲酸二炔丙醇酯(DPIP)、对苯二甲酸二炔丙醇酯(DPP),与三官能团叠氮化合物(TAMTMB)反应,制备了3种热固性聚三唑酯(PTAE)树脂,研究了树脂的加工特性、固化行为、树脂固化物的力学性能,制备和表征了T700单向碳纤维增强PTAE树脂复合材料。结果表明,PTAE树脂具有良好的加工性能,可在较低温度(80℃)下固化;固化后的PTAE树脂的玻璃化转变温度(Tg)受主链结构影响,3种树脂的Tg均高于140℃,浇铸体弯曲强度高于170 MPa,T700单向纤维增强PTAE树脂复合材料的常温弯曲强度高于1500 MPa。     

新型咪唑衍生物固化促进剂对环氧/酸酐体系的催化活性

采用自制的一种新型含羟基咪唑衍生物固化促进剂(HPID),通过非等温差示扫描量热(DSC)法研究了该固化促进剂对环氧树脂(EP)/酸酐体系固化反应的催化活性,对比分析了无促进剂时及分别加入HPID和常用固化促进剂DMP–30时EP/酸酐体系的固化特征温度,并应用Kissinger和Crane方程对3种体系固化动力学进行了分析,同时研究了HPID用量对体系浇铸体玻璃化转变温度(Tg)的影响,并与DMP–30进行了对比。结果表明,HPID明显降低了无促进剂体系的固化反应表观活化能和固化特征温度,其对EP/酸酐体系固化反应的促进作用与DMP–30相近,随HPID用量增加,浇铸体的Tg下降。当HPID用量为1.5份时,体系固化反应的表观活化能为76.821 kJ/mol,反应级数为0.913 4,反应较为复杂,相应浇铸体的Tg达到181.01℃,比加入DMP–30的浇铸体提高了31.48℃,耐热性得到明显提高。     

辅助材料

一种粉末涂料组合物含有由两种成分构成的热固性树脂。第一种组分包括聚环氧化物或介轻基酸胺化合物的酸活性材料;第二种组分为可与第一科,成分反应的酸封端的树脂。所用固化剂包含官能度)3的聚梭酸以及叔N母体,用以与过量的第一种成分反应而使该热固性树脂固化。由该组合物形成的涂膜具有优异的外观,通过改变组分间的比例可降低涂膜光泽。0103487可共聚的光引发剂[刊,英]IDavies,W.D.等// Surf.Coat.Int一2000,83(2)一72一78 如今,根据各类光引发剂引发聚合反应的机理,可以很容易地确定UV固化工业用的光引发剂类型。近来,未反应的光引…     

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.     

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.     

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。