PAN基高模碳纤维阳极氧化的表面处理

采用阳极氧化法对PAN基高模碳纤维进行连续表面处理,重点研究了氧化电流密度对碳纤维宏观力学性能、表面形貌、表面酸性官能团以及碳纤维增强树脂基复合材料(CFRP)层间剪切强度(ILSS)的影响。结果表明,电流密度对纤维力学性能、表面形貌影响不大;氧化后纤维表面总的酸性官能团显著提高,最大增幅达13倍左右;适当的处理条件可使CFRP的ILSS从28.4 MPa提高到80 MPa以上。     

微波诱导碳纤维表面氧化处理的研究

以微波为能量源,双氧水溶液为氧化剂对碳纤维进行表面氧化处理,用X射线光电子能谱仪(XPS)、扫描电镜(SEM)以及热机械分析仪(TMA)对碳纤维的表面处理效果进行分析表征。研究结果表明,经微波氧化处理后,碳纤维表面的羟基含量增加47%,活性碳原子数增加了32%,显著提高了碳纤维的表面活性。由SEM可以观察到,经过表面氧化处理后的碳纤维增强树脂基复合材料(CFRP)具有较好的界面结合性。此外,处理后的CFRP玻璃化转变温度(T_g)较未处理的提高5.6℃,介电损耗角正切降低11.3%,平均热膨胀系数分别是未处理CFRP及纯环氧树脂的2/5和1/10。     

碳纤维增强树脂复合材料界面效应的研究

在一立方厘米的碳纤维增强树脂复合材料(CFRP)中,碳纤维(CF)与树脂的接触界面高达4000平方厘米左右。两相界面间的粘结程度是决定层问剪切强度(ILSS)的主要因素。CF经表面处理后,可改善两相间的粘接,从而使ILSS得到显著提高。用扫描电镜研究剪切断面已证实了这点。     

用SEM研究CFRP的界面效应

用气相氧化法对碳纤维进行表面处理,可使层间剪切强度(ILSS)提高40～76％。这归因于增加了碳纤维的表面积和表面化学官能团的浓度。同时,碳纤维增强塑料(CFRP)的剪切断裂形态也由未处理的多剪断裂变为处理后的抗剪断裂。用扫描电子显微镜(SEM)观察剪切断面已证实了这个问题。     

粗糙度对碳纤维/聚芳基乙炔复合材料界面性能的影响

采用二氧化碳超临界(scCO2)处理碳纤维(CF)表面的方法,研究了粗糙度对碳纤维/聚芳基乙炔(PAA)树脂复合材料界面性能的影响.处理前后的碳纤维通过XPS,AFM和表面能测量进行了表征.CF/PAA复合材料的界面力学性能通过层间剪切强度测试(ILSS)与断口形貌分析进行了评价.结果表明,scCO2处理前后碳纤维表面的化学组成基本上没有变化.随着碳纤维表面粗糙度的增加,CF/PAA复合材料的界面力学性能先增加后减小.其中粗糙度范围为30～45 nm的样品有最高的ILSS值,43.36MPa,比未处理的样品提高了44%.对复合材料的ILSS提高起主要作用的因素是碳纤维与PAA树脂的界面齿合作用.而齿合作用程度的不同主要是由于不同粗糙度而引起的碳纤维表面物理状态的不同.     

臭氧处理对碳纤维表面及其复合材料性能的影响

利用X射线光电子能谱(XPS)研究了碳纤维经臭氧(O3)氧化处理后表面元素组成及表面官能团的变化，结果发现，O3表面处理主要增加了碳纤维表面上的羟基或醚基官能团；研究了表面O3氧化处理对复合材料力学性能的影响，结果表明，碳纤维经O3氧化处理后明显改善了碳纤维与环氧树脂间的界面粘结，其复合材料的层间剪切强度明显提高。     

碳纤维表面处理对层间剪切断裂形貌的影响

用气相氧化法对碳纤维进行表面处理，可使碳纤维复合材料（CFRP）的层间剪切强度（ILSS）提高40％－76％，这归因于纤维表面增加了化学官能团和比表面积，同时，由于碳纤维（CF）与基体之间粘接得到改善，使单向（UD）－CFRP的剪切断裂形貌变为拉剪，这可用扫描电子显微镜（SEM）观察剪断形貌得到证实。     

臭氧改性碳纤维/聚酰亚胺复合材料的制备与性能研究

采用臭氧氧化的方法对碳纤维进行表面改性,并用作热塑性聚酰亚胺树脂的增强体。采用单丝拉伸试验、XPS研究臭氧处理时间对碳纤维单丝拉伸强度和表面官能团的影响。结果表明,臭氧处理时间越长,碳纤维力学性能的下降程度越大,而表面含氧官能团含量越多。优选单丝拉伸强度保留率较高、含氧官能团含量较丰富的碳纤维与热塑性聚酰亚胺制成复合材料,并评价其层间剪切强度(ILSS)。结果表明,臭氧处理5 min就可使碳纤维/聚酰亚胺复合材料的ILSS提升43%,说明臭氧处理可显著提升碳纤维/热塑性聚酰亚胺的界面性能。     

氨气处理碳纤维 第II报 碳纤维表面和复合材料的性能

常压下,使碳纤维通过以氨气为气体介质的600℃热反应炉,反应停留时间为30s。采用三点短梁法和界面评价装置研究处理前后复合材料的层间剪切强度(ILSS)和界面剪切强度(IFSS),经氨气处理后二者分别提高了13.2%和32.1%。接触角测试结果表明:处理后碳纤维与水和环氧树脂的浸润性得到很大改善。采用扫描电子显微镜(SEM)研究处理前后碳纤维表面和复合材料断裂面形貌的变化,发现氨气处理对碳纤维表面形貌没有影响。力学性能测试数据表明,氨气处理不影响碳纤维的强度。     

中间相沥青基碳纤维电化学氧化表面处理的正交优化设计

利用正交法研究了电化学氧化法对中间相沥青基碳纤维表面处理过程中各因素对表面处理效果的影响,获得了优化的表面处理条件。利用傅里叶变换红外光谱扫描、X射线光电子能谱分析等手段,对优化的最佳条件下的表面处理效果进行表征。实验结果表明：采用浓硝酸预处理后,再进行电化学氧化表面处理可使碳纤维复合材料的层间剪切强度（ILSS）进一步提高,可达45.324 MPa,较未经硝酸预处理而直接进行电化学氧化表面处理的碳纤维提高了24.1%,较未表面处理碳纤维提高了49.4%     

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。