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1.
环氧树脂/聚氨酯梯度聚合物的弯曲性能研究   总被引:1,自引:0,他引:1  
考察了不同层数的环氧树脂/聚氨酯(EP/PU)梯度聚合物弯曲性能,采用有限元法分析了材料在弯曲状态下的应力分布,从理论上解释了EP/PU梯度材料弯曲性能的试验结果,并与相同组成的均质材料进行了比较.研究发现:EP/PU梯度材料的弯曲强度和模量随梯度层数的增加而增加,当梯度层数超过5层以后,EP/PU梯度材料的弯曲强度高于相同组成的均质材料.有限元分析结果表明:在EP/PU梯度材料中,应力的分布与各层材料承受的强度相匹配,即应力大的部位材料的强度也越大.梯度层越多,各层之间强度变化越小,应力变化越为缓和,且应力分布与材料强度之间匹配越好,在受外力时,材料断裂强度越高.梯度材料中应力分布方式的理论计算结果很好的解释了实测的各种梯度材料强度变化规律.  相似文献   

2.
一种高性能环氧树脂固化体系的研究   总被引:2,自引:6,他引:2  
通过凝胶化测试和示差扫描量热分析(DSC),研究了CYD128/DMP-30体系固化反应性,20℃凝胶化时间为70min;测试了浇铸体力学性能和耐热性,其中拉伸强度为50.2MPa,拉伸模量为3.5GPa,弯曲强度为156.7MPa,冲击强度为15.0(kJ·m^-2,玻璃化温度(Tg)为96℃。研究了连续纤维增强CYD128/DMP-30体系复合材料的性能,其中连续玻璃纤维增强复合材料弯曲强度为954.8MPa,连续碳纤维增强复合材料弯曲强度为1057.4MPa。  相似文献   

3.
刘学清  刘继延  王源升 《塑料工业》2004,32(9):45-47,56
以二苯甲烷二胺(DDM)为交联剂,研究了环氧树脂/苯酚封端的聚氨酯(EP/PU)预聚体系在微波固化条件下的热膨胀行为;并通过热膨胀行为考察了体系热膨胀系数、玻璃化转变及其与微波功率、体系组成之间的关系。结果表明:当体系组成一定时,随着微波功率的增加,体系中富EP相和富PU相的玻璃化转变移向高温,过渡相的转变加宽,膨胀系数变小。在一定组成范围内,体系具有两个玻璃化转变,随着PU和EP含量的接近,富EP相和富PU相的玻璃化转变温度差值缩小。组成相同的体系,微波固化产品的热膨胀系数低于热固化。  相似文献   

4.
以兼具引发剂和稀释剂功能的自制BH-1为固化剂,通过引入低黏度活性稀释剂,制备室温固化EP(环氧树脂)胶粘剂;然后以EP/BH-1/活性稀释剂为基体、单向玻璃纤维为增强材料,制备相应的复合材料。研究结果表明:当w(BH-1)=4%时,EP浇铸体的室温(25℃)凝胶时间约为8.5 h和玻璃化转变温度(Tg)为130.9℃,并具有优异的力学性能,其冲击强度为50.0 kJ/m2、拉伸强度和模量分别为0.075 GPa和2.80 GPa、弯曲强度和模量分别为0.136 GPa和3.02 GPa;当m(EP)∶m(BH-1)∶m(活性稀释剂)=100∶4∶10时,复合材料的弯曲强度(0.984 GPa)和层间剪切强度(56.1 MPa)分别提高了26.4%和15.2%。  相似文献   

5.
穆中国  王源升 《塑料工业》2007,35(B06):171-173
设计了一种新的梯度组分分布数学模型,采用梯度因子和梯度层数控制梯度组分的分布,并采用逐层浇铸的方法制备了不同层数的EP/PU梯度互穿网络聚合物(IPN)材料;测试了材料的拉伸性能、弯曲性能以及冲击性能;研究了梯度层数变化对这些性能的影响,并同普通IPN的性能进行了对比。研究结果表明,在相同质量比和梯度因子情况下,梯度层数越多,拉伸强度和冲击强度越高,弯曲强度越低。梯度IPN的拉伸强度和冲击强度均高于普通IPN,弯曲强度低于普通IPN。  相似文献   

6.
利用填充混合法制备了环氧树脂(EP)/炭黑(CB)复合材料,研究了CB对体系反应及性能的影响。使用扫描电镜对拉伸断口形貌进行了观察;利用透射电镜观察了CB在EP中的分散状态。结果表明:CB的加入使体系固化时的最高放热温度从179℃降到169℃,凝胶化时间变短;适量CB的引入提高了材料的拉仲强度、断裂伸长率和冲击强度,CB用量在2%时材料的综合力学性能最佳;随着CB用量的增加,复合材料的玻璃化温度也随之提高。  相似文献   

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为研究不同用量(20%、30%、40%)聚氨酯(PU)对于环氧树脂(EP)改性沥青及其混合料性能的影响,通过拉伸试验、动态剪切流变和低温弯曲流变试验分析了PU/EP复合改性沥青性能,并利用车辙试验、低温弯曲试验和浸水马歇尔、冻融劈裂试验探讨了复合改性沥青混合料的高温稳定性、低温抗裂性和水稳定性,并以不掺PU的环氧沥青和4%SBS改性沥青混合料为对照组。试验结果表明,加入PU将会降低改性沥青的抗拉强度、车辙因子,但同时提高了沥青的柔韧性和低温性能;加入一定量的PU虽然降低了沥青混合料的高温抗车辙变形能力,但依然远大于4%SBS改性沥青混合料,此外PU加入后明显改善了沥青混合料的低温抗裂性和抗水损害性能。综合各方面性能,建议PU用量为30%~40%。  相似文献   

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采用聚甲基三乙氧基硅烷(PTS)化学改性双酚A型环氧树脂,制备出一系列高性能的PTS改性环氧树脂。对固化物的玻璃化转变温度(Tg)、拉伸强度及断裂伸长率、热稳定性进行了分析测定,探讨了改性方法、有机硅含量等对材料性能的影响。结果表明,双酚A型环氧树脂通过PTS(质量比为100/1B)化学反应改性后:拉伸强度达到56.61MPa,断裂伸长率达到10.40%,Tg达到168.07℃,50%的质量热损失温度达到484℃;比未改性的纯环氧树脂分别提高了7.67MPa、3.66%、15.44℃、36℃。  相似文献   

9.
采用不同表面宫能团的预氧化聚丙烯腈(PAN)纤维作为增强体,以酚醛树脂和煤沥青分别为基体材料制成的碳/碳复合材料已经开发出来了。树脂基复合材料的热解行为表现为:横截面收缩以及分别为18-24%和32-40%的重量损失,这取决于预氧化PAN纤维表面所含表面宫能团的数量。经1000℃热处理,树脂基复合材料的弹性强度和弹性模量分别在11.0-30MPa和30-50GPa范围内,而煤沥青基复合材料则在35-55MPa和30-50GPa范围内。经过石墨化(2700℃)处理后,树脂基复合材料的机械性能改变不大(复合物变脆),但煤沥青基复合材料的弱性强度则增加了4-6倍(200-250MPa),弹性模量增加2-3倍(100-120PGa)。因此,可利用预氧化PAN纤维作增强体来制备碳/碳复合材料,且与商业级碳纤维增强的碳/碳复合材料具有大致相同的机械性能(T-300,日本东丽制)。  相似文献   

10.
来育梅  程茹  章刚  王伟  黄培 《塑料工业》2006,34(6):40-42,45
在380℃下熔融挤出制得聚醚醚酮(PEEK)与聚醚酰亚胺(PEI)共混物。采用差示扫描量热仪(DSC)和广角X射线衍射仪(WAXD)研究了共混物的相容性和结晶行为。结果表明,PEEK/PEI共混物完全相容.所有共混物均呈现一个玻璃化转变温度(Tg),且与组分的关系符合Porch方程;随PEI含量的增加,共混体系的熔点、结晶度、整体结晶速率和结晶能力均降低:而PEEK的结晶度呈现先增加后减小的趋势,当PEI质量分数为50%时,达到最大。  相似文献   

11.
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.  相似文献   

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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.  相似文献   

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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。  相似文献   

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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.  相似文献   

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Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.  相似文献   

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Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.  相似文献   

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