双马来酰亚胺改性芳香胺固化环氧树脂的研究

针对环氧树脂(EP)耐湿热性差和韧性不足的缺点,用双马来酰亚胺(BMI)对常用的芳香族二元胺(DA)固化剂进行扩链改性。研究了改性4,4′-二氨基二苯砜(DDS)固化剂对7种环氧树脂固化物的力学性能、热性能和工艺性能的影响,优化出一种BMI改性环氧树脂基体。改性树脂浇铸体韧性好、耐热性高,断裂韧性GIC195J/m2,断裂延伸率3.37%,Tg218℃,135℃弯曲强度保持率72.2%,沸水饱和吸湿率3.3%;其碳纤维复合材料综合性能良好、断裂韧性高、耐湿热性好,横向拉伸强度75.5MPa,层间断裂韧性GIC267J/m2,135℃湿态弯曲强度保持率70.5%,132℃湿态层间剪切强度保持率49.5%。     

MDPES/EP/PBI树脂碳纤维复合材料的性能

将甲基二笨乙炔基硅烷(MDPES)、环氧树脂(EP)、聚苯并咪唑(PBI)共混改性制得碳纤维复合材料,结果表明:合适的共混比例能使MDPES/EP/PBI树脂碳纤维复合材料具有较好的界面粘结性能,同时具有良好的力学性能及耐热性能.当MDPES∶EP∶PBI=5∶5∶1时,层间剪切强度为49.2 MPa,常温下的拉伸强度1263.7 MPa,弯曲强度为1191.9 MPa,200 ℃弯曲强度保留率达到78.9%.     

弹性固化环氧树脂体系及其复合材料研究

制备了一种体育用品用弹性固化EP(环氧树脂)体系,并着重探讨了其与碳纤维制成的复合材料的相关性能。研究结果表明:弹性固化EP体系的相对最佳固化温度为113.5~147.0℃,95~110℃时固化度超过90%;复合材料的横向拉伸强度60.00 MPa、拉伸弹性模量≥8.20 GPa、弯曲强度≥1.50 GPa、弯曲弹性模量110.00 GPa和层间剪切强度82.00 MPa,经98℃水煮48 h后,复合材料的弯曲性能和层间剪切强度与国内外同类产品(150℃固化40 min)的性能相当;纤维表面有树脂附着,并且有部分树脂浸润纤维,说明该弹性固化EP体系与碳纤维之间的浸润效果良好。     

中温固化热熔胶膜法制备环氧树脂预浸料及其复合材料

以双酚A型环氧树脂为基体,3,3'-二乙基-4,4'-二氨基二苯甲烷(DEDDM)为固化剂,热塑性树脂为增韧剂,采用中温固化热熔胶膜法制备环氧树脂预浸料,并以玻璃纤维为增强体制备玻璃纤维/环氧树脂复合材料。结果表明,环氧树脂固化物及其复合材料的力学性能和热性能均随增韧剂的加入呈上升趋势。当增韧剂质量分数为20%时,环氧固化物的弯曲和冲击强度分别为122.4MPa和23.8 kJ/m~2,较纯环氧树脂分别提高50%和154%;玻璃化转变温度(T_g)从102℃提升到123℃;增韧剂/玻璃纤维/环氧树脂复合材料的弯曲强度和层间剪切强度为636.5 MPa和54.9 MPa,T_g为130℃。扫描电子显微镜(SEM)分析表明,玻璃纤维和环氧树脂具有较好的界面粘接性能。     

连续CF增强PEEK复合材料层压板的制备工艺

采用熔融浸渍法制备了连续碳纤维(CF)增强聚醚醚酮(PEEK)复合材料预浸带,并层压成型制备复合材料层压板。研究了成型温度、成型压力、成型时间、纤维含量等因素对复合材料层压板力学性能的影响。结果表明,在成型温度为370℃、成型压力为12 MPa、成型时间为70 min、纤维含量为61%的工艺条件下,连续CF增强PEEK复合材料层压板的力学性能达到最优值,弯曲强度和弯曲弹性模量分别达到(1 750.76±49.13)MPa和(107.54±6.35)GPa,层间剪切强度达到(100.04±6.88)MPa,缺口冲击强度为(84.44±1.54)k J/m2。随着冷却速率的增大,复合材料层压板的弯曲性能和层间剪切强度下降,而缺口冲击强度提高。SEM分析表明,复合材料层压板的界面粘结良好。     

湿法缠绕成型T700碳纤维/氰酸酯树脂复合材料力学性能研究

研究了湿法缠绕成型的T700碳纤维/氰酸酯树脂复合材料NOL环及单向板力学性能。测试了树脂配方的粘度-温度特性,T700碳纤维/氰酸酯树脂复合材料NOL环的拉伸及剪切性能,采用SEM对NOL环拉伸试样破坏形貌进行了观察。测试了T700碳纤维/氰酸酯树脂单向板复合材料的常温拉伸性能、弯曲性能、层间剪切性能和高温弯曲性能。结果表明,树脂配方在25℃下的粘度为800 cps,可以直接在室温条件下用于复合材料湿法缠绕成型,并具有充分的使用期。NOL环的拉伸强度为2220 MPa,剪切强度为56. 8 MPa,树脂基体对碳纤维具有良好的浸润性,能够较好地发挥出碳纤维的高强度特性。T700碳纤维氰酸酯树脂单向板复合材料的高温力学性能优异,200℃下弯曲强度保留率高达60. 4%,250℃下弯曲强度保留率高达45. 0%。     

玻璃纤维增强环氧树脂复合材料的力学性能研究

本文以环氧树脂为基体,经改性过的短切玻璃纤维为增强材料,制备了玻璃纤维增强环氧树脂(GF/EP)复合材料。探究了玻璃纤维与环氧树脂配比、固化条件对GF/EP复合材料力学性能的影响。结果表明:当玻纤用量为20%、固化温度为120℃、固化时间为3.0 h时制备的GF/EP复合材料拉伸强度约为38.52 MPa、冲击强度约为6.46k J/m2;GF/EP复合材料经60℃、5%的食盐水浸泡48 h后力学性能下降,SEM显示纤维与树脂的粘结界面经腐蚀后被破坏。     

短纤维层间增强碳纤维复合材料层板的力学研究

以斜纹3k T300碳纤维布、环氧树脂和0.3~0.5 mm短切碳纤维为主要实验原料,使用短切纤维铺放装置将短切碳纤维定量铺放在碳纤维布表面,并铺层得到5块层间短切纤维增强的预制体,每块预制体含8层碳纤维布且每块预制体层间短切碳纤维铺放面密度分别为5,10,20,30,40 g/m2,并增设一块层数为8层、层间不含短切纤维增强的预制体作为对照组。采用真空辅助树脂灌注成型方式浸渍预制体后高温固化,得到层间含不同面密度短切纤维的碳纤维复合材料层合板,研究了不同面密度短切纤维含量对碳纤维复合材料层合板拉伸、弯曲以及层间剪切强度的影响。研究结果表明,当短切碳纤维铺放面密度为5 g/m2时,复合材料层板的拉伸、弯曲强度最好,在5~40 g/m2范围内,复合材料层板的层间剪切强度随短切碳纤维铺放面密度的增大而增大。     

硼酸铝晶须改性双酚A二氰酸酯树脂性能研究

对硼酸铝(Al18B4O33)晶须改性双酚A二氰酸酯(BADCy)树脂基体的力学性能及热性能进行了研究。经硅烷偶联剂处理后,5％(质量含量,下同)Al18B4O33晶须改性体系的弯曲强度和冲击强度分别提高了14．3％和5．9％;当晶须含量为8％时,体系的弯曲强度和冲击强度分别由原来的112．4MPa和9．17kJ／m2提高到了121．7MPa和10．36kJ／m2,热变形温度提高8℃;经24h水煮后力学性能保持率都在70％以上。     

碳纤维增强聚甲醛复合材料的制备及性能研究

以碳纤维为增强体,用双螺杆挤出机共混制备了碳纤维增强聚甲醛复合材料,研究了碳纤维含量对复合材料的力学性能、热性能、熔体流动性能的影响。结果表明,碳纤维的加入大幅提高了复合材料的力学性能,改善了热稳定性能,但熔体流动速率减小;当碳纤维质量分数为25%时,复合材料的弯曲弹性模量、弯曲强度、拉伸强度、缺口冲击强度、断裂伸长率分别为19.8 GPa,187 MPa,153 MPa,16.2 kJ/m2,0.52%,综合力学性能最佳。     

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.