低温等离子体对PBO纤维表面的改性

采用硅烷偶联剂处理聚对苯撑苯并双噁唑(PBO)纤维,利用常压射频低温等离子体对PBO纤维进行了表面处理,通过扫描电镜、红外光谱、光学显微镜等研究了处理时间对PBO纤维表面官能团和表面形貌的影响规律,通过单丝拔出实验测定PBO纤维基复合材料的界面剪切强度。结果表明:经过常压射频低温等离子体处理后,PBO纤维的表面形成了大量的极性基团,表面产生明显的凹坑,PBO纤维与树脂的粘接性能提高50%,纤维的拉伸强度下降5%。     

PBO纤维及其改性的研究进展

简述了聚对苯撑苯并双噁唑(PBO)纤维的结构与性能;详述了PBO纤维的改性研究进展。PBO纤维的改性主要是改善其抗压性能和表面粘结性能。提高微纤间相互作用或交联等方法可提高PBO纤维的压缩强度;通过酸处理、偶联剂处理、等离子体处理及电晕处理等方法可提高PBO纤维的表面粘结性能。指出表面改性仍将是PBO纤维改性研究的重点。     

多聚磷酸改性PBO纤维的研究

采用多聚磷酸及其乙醇溶液(体积比1:1)对聚对苯二撑苯并二噁唑(PBO)纤维进行表面处理。通过单丝拔出剪切强度的测试来表征纤维／树脂的界面粘结性能,并通过液滴形态法来表征纤维的表面润湿性能,利用扫描电镜和X射线衍射分析探讨了表面形态及结晶结构在改性前后的变化。结果表明:PBO纤维经两种溶液分别处理1 min,5 min后,纤维／树脂的界面粘结强度分别提高24％,55％,但单丝强度均下降;纤维与水的接触角由大于90°均降低至45°左右;结晶度从原丝的56.4％分别降低至52.9％,52.3％。     

PBO纤维表面改性的研究进展

聚对苯撑苯并双噁唑(PBO)由于其特殊的表层结构,与聚合物树脂基体复合时存在严重的界面不相容性。简要介绍了PBO纤维的结构与性能,综述了化学刻蚀、偶联剂处理、等离子体处理、电晕处理、辐射处理、酶处理、热处理、化学涂层和超临界液体处理等PBO纤维表面改性方法。     

PBO纤维表面改性的研究进展

简要介绍了PBO纤维的结构、性能以及制备方法,综述了PBO纤维的表面改性方法,包括酸处理、碱处理、酶处理、偶联剂处理、辐射处理和等离子体处理等。     

PBO纤维表面改性与热处理研究

运用扫描电镜对自制的聚对苯撑苯并二噁唑(PBO)纤维表面进行观察,发现未经烘干的PBO纤维表面有许多的裂纹和沟槽,而烘干的纤维表面则较光滑。通过单丝拔出实验研究了偶联剂对不同表面形态纤维的表面处理情况,结果表明:用偶联剂表面处理后,纤维与树脂间的界面剪切强度得到提高,偶联剂对未经烘干纤维表面处理比对烘干纤维处理的效果要好,与原丝相比,提高率可达69.4%。对自制的PBO纤维进行了热处理,发现未烘干的PBO纤维比经烘干而干燥致密化的纤维的热处理效果要好,模量有很大提高,强度也有一定的增加。     

PBO纤维表面改性技术的研究进展

介绍了聚对苯基苯并二噁唑(PBO)纤维的合成、结构与性能;同时,综述了目前常见的对PBO纤维表面改性方法的研究进展,如以等离子体处理、辐射处理和电晕处理等为代表的物理方法,以酸处理、偶联剂改性、共聚改性和酶处理等为代表的化学方法。     

PBO纤维表面改性方法的研究

对PBO纤维表面性能的改善进行了研究,考察了混杂芳纶纤维、电晕处理、偶联剂处理及强酸处理等多种方法对PBO纤维与环氧树脂表面粘接强度及其复合材料层间剪切性能的影响程度,比较了各种方法的改性效果及各自优缺点。     

低温等离子体处理对PBO纤维润湿性的影响

为改善PBO纤维的润湿性,拓宽其应用领域,探究了空气低温等离子体处理对PBO纤维润湿性的影响。通过芯吸效应和接触角表征处理前后PBO纤维润湿性,并采用扫描电子显微镜SEM观察处理前后PBO纤维表面形貌,用X射线光电子能谱仪(XPS)对处理前后PBO纤维表面化学组成进行定性分析。实验结果表明,改性后PBO纤维芯吸高度大幅上升,接触角明显降低,并且在其表面产生明显刻痕,局部有剥离现象,改性后PBO纤维O、N元素含量均有所提高,PBO纤维润湿性明显增强。()     

偶联剂改性UHMWPE纤维表面性能的研究

选用硅烷偶联剂KH-550,KH-560和钛酸酯偶联剂NDZ-201作为表面改性剂,对超高相对分子质量聚乙烯(UHMWPE)冻胶纤维在萃取阶段进行表面处理,经干燥、超拉伸制得表面改性UHMWPE纤维。采用红外光谱仪、接触角测量仪测定了纤维的表面化学结构和表面润湿性能,采用单纤维树脂包埋-拔出法测定了纤维与树脂基体的界面剪切强度,比较了改性前后纤维的力学性能变化。结果表明:改性后纤维表面引入了极性基团,硅烷偶联剂KH-550对UHMWPE纤维的表面改性效果最好。采用质量分数为1%的硅烷偶联剂KH-550溶液处理后,纤维与环氧树脂间的界面剪切强度提高了87.8%,纤维的断裂强度和模量分别提高了6.9%和32.6%。     

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。