石墨／碳纤维／聚丙烯高强导热材料的研究

采用聚丙烯、石墨、碳纤维 (CF)制备出满足实际应用要求的高导热、高强度复合材料。实验结果表明 ,石墨和碳纤维在基体中的合理分布能显著提高复合材料的导热性能和力学性能。当聚丙烯和石墨的质量比为 5 0 /5 0时 ,添加 3 .3 3 %的碳纤维 ,其热导率为 2 .1W /(m·K) ,拉伸强度达到 5 1.49MPa。     

聚四氟乙烯基纳米复合材料滑动轴承的研制

以聚四氟乙烯(PTFE)、石墨、MoS_2、玻璃纤维、碳纤维和纳米Al_2O_3为原料制备了PTFE基纳米复合材料,研究了复合材料的力学性能,并用PTFE基复合材料制备了机械用滑动轴承,阐述了其设计要点、成型工艺。该复合材料轴承 PV值可达1.42～1.49 MPa·m/s,使用温度可达 230℃以上,实际应用效果良好。     

碳纤维/膨胀石墨协同复合对天然橡胶导热性能的影响

以片层状膨胀石墨和纤维状碳纤维为导热填料、天然橡胶(NR)为基体,制备了导热填料/NR复合材料,并对其导热性能进行了探讨。研究结果表明:随着膨胀石墨或碳纤维掺量的不断增加,相应复合材料的导热系数增大,但由于碳纤维在NR基体内部没有实现定向排布,故碳纤维/NR复合材料的导热系数增幅不大;碳纤维/膨胀石墨的协同复合,使得相应复合材料的导热系数[0.413 7 W/(m·K)]比纯NR提高了96.6%;碳纤维与NR基体的界面结合力较弱,故对碳纤维表面进行改性,可有效增强碳纤维/NR基体的界面结合力,从而能进一步改善相应复合材料的导热性能。     

密封用PTFE复合材料的压缩蠕变性能

采用碳粉/石墨、青铜粉、玻璃纤维(GF)、碳纤维(CF)、聚苯酯(POB)等改性材料改性聚四氟乙烯(PTFE),通过冷压、烧结的方式制得改性PTFE复合材料,研究了载荷、温度等环境条件对不同改性PTFE复合材料压缩蠕变的影响,通过退火进一步改善复合材料的抗蠕变性能,研究了退火温度对复合材料压缩蠕变及力学和摩擦磨损性能的影响。结果表明,各改性材料均能降低PTFE的压缩蠕变量,其中碳粉/石墨改性的PTFE复合材料压缩蠕变量最小,其次为青铜粉改性的复合材料,其余依次为GF,POB和CF改性的复合材料;改性PTFE复合材料的压缩蠕变量随着载荷和温度的增加明显增大,碳粉/石墨改性的PTFE复合材料蠕变受载荷增加的影响最小,且高温(150℃)下的压缩蠕变量最小。在150～300℃下对改性PTFE复合材料进行退火处理,可使其压缩蠕变量减少20%～40%,最佳的退火温度为300℃,在此温度下进行退火对复合材料力学和摩擦磨损性能影响不大。     

氟醚橡胶摩擦磨损性能研究

研究了石墨、碳纤维和聚四氟乙烯不同用量和三者并用对氟醚橡胶摩擦磨损性能的影响,并用SEM对橡胶磨损表面形貌进行了分析。结果表明,石墨和聚四氟乙烯填充的氟醚橡胶以粘着磨损为主,磨损严重,而碳纤维填充的橡胶磨损主要是疲劳磨损,可显著提高氟醚橡胶的摩擦磨损性能。石墨和碳纤维并用可产生协同效应,两者用量均为15份时橡胶摩擦磨损性能较好,此时摩擦系数为0.378,磨损率为5.590×10-8mm3/Nm。     

PA6/CF/EG导电复合材料的制备与性能

采用熔融共混法制备了不同碳纤维/热膨胀石墨(CF/EG)比例的尼龙6/碳纤维/热膨胀石墨(PA6/CF/EG)导电复合材料并研究其性能。结果表明,CF的加入能显著提高复合材料的力学性能;而随着EG含量的提高,复合材料的导电性能和导热性能显著提高,但力学性能在一定程度上得到降低。当CF质量分数为20%时,复合材料具有最优的力学性能,当EG质量分数为20%时,复合材料体积电导率可显著提高至0.262 S/m,热导率可达1.3379W/(m·K)。     

新型网球球拍用碳纤维复合材料的制备与性能研究

采用浸涂法制备了新型网球球拍用S-E-碳纤维布/环氧树脂复合材料,对比分析了原始碳纤维布、E-碳纤维布和S-E碳纤维布的化学组成和表面形貌,研究了可溶性聚四氟乙烯含量对新型网球球拍用S-E-碳纤维布/环氧树脂复合材料表面接触角和耐磨性能的影响,并对新型网球球拍用S-E-碳纤维布/环氧树脂复合材料的耐酸碱性能进行了研究。结果表明,随着可溶性聚四氟乙烯含量的增加,原始碳纤维布/环氧树脂复合材料和新型网球球拍用S-E碳纤维布/环氧树脂复合材料的表面接触角都呈现出先增加而后减小的特征,在可溶性聚四氟乙烯含量为45%时取得表面接触角最大值;随着摩擦磨损周次的增加,新型网球球拍用S-E碳纤维布/环氧树脂复合材料的磨损量和表面接触角都呈现逐渐减小的趋势;新型网球球拍用S-E碳纤维布/环氧树脂复合材料在不同pH值溶液中都具有良好的耐化学腐蚀性能。     

碳／锡青铜／聚苯酯／二硫化钼填充聚四氟乙烯的摩擦磨损性能

介绍了几种含碳材料一石墨、碳、碳纤维,锡青铜粉ZQSn6—6—3,聚苯酯、二硫化钼对其填充聚四氟乙烯复合材料在干摩擦、油润滑、水润滑条件下的摩擦磨损性能的影响,简要介绍了复合材料在液压气动密封等方面的应用。     

不同填料对PTFE复合材料力学性能和摩擦学性能的影响

为探索不同填料及其含量对往复压缩机密封件用聚四氟乙烯(PTFE)复合材料力学性能和摩擦学性能的影响,采用微机控制电子万能试验机和立式万能摩擦磨损试验机检测不同玻璃纤维、石墨和碳纤维含量的PTFE复合材料力学性能和磨损性能。并采用扫描电子显微镜(SEM)对摩擦磨损试样表面的微观形貌进行分析。结果表明:添加石墨以及一定含量以上的玻纤和碳纤,会降低PTFE复合材料的拉伸强度和断裂伸长率。复合材料的磨损量随着玻纤含量的增加而提高,石墨和一定含量内的碳纤使复合材料的磨损量下降。在摩擦过程中,磨粒磨损与黏着磨损并存,不添加碳纤,只含石墨和玻纤的复合材料以磨粒磨损为主,而添加碳纤维,同时含玻璃纤维和石墨的复合材料以黏着磨损为主。随着玻纤和碳纤的增加,复合材料的硬度逐渐增加,而石墨的加入会降低复合材料的硬度。     

体育器械用碳纤维复合新材料的制备与性能研究

将多巴胺改性的碳纳米管接枝到碳纤维表面并进入到含聚四氟乙烯的环氧树脂溶液中,固化成型后形成碳纤维/环氧树脂复合材料,研究了体育器械用CNT-PDA-碳纤维布/环氧树脂复合材料的表面形貌和耐磨性能。结果表明,CNT-PDA-碳纤维布的红外光谱图中除含有比原始碳纤维布相同的3418cm~(-1)处的更强邻苯二酚的-OH伸缩振动峰、1608cm~(-1)处更强的C=C吸收峰外,CNT-PDA-碳纤维布在1265cm~(-1)和1046cm~(-1)处还分别发现了苯基弯曲振动峰和C-N伸缩振动峰;聚四氟乙烯含量为30%的CNT-PDA-碳纤维布/环氧树脂复合材料具有最佳的疏水特性,且随着在氨基硅油中浸泡时间的增加,CNT-PDA-碳纤维布/环氧树脂复合材料的表面接触角呈现先增加而后减小的趋势,在浸泡时间为30min时取得最大值153.7°±1.8°,此时,CNT-PDA-碳纤维布/环氧树脂复合材料具有良好的耐磨性能,并且摩擦磨损后仍然具有较好的疏水性能。     

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.     

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。