聚醚醚酮复合材料的改性研究及应用进展

分别从化学改性、填充改性及纤维增强、混合型改性及表面改性等方面综述了聚醚醚酮(PEEK)及其复合材料的改性方法,尤其是对摩擦学性能的改性方法,阐述了PEEK复合材料在各个领域的应用情况,指出了PEEK复合材料摩擦学改性研究的未来发展方向。     

聚醚醚酮共混改性研究进展

综述了聚醚醚酮（PEEK）、聚醚酰亚胺（PEI）、聚四氟乙烯（PTFE）、热致液晶（TLCP）和聚醚砜（PES）等高性能工程塑料的共混改性研究进展,详细探讨了各种PEEK共混物的相容性、结晶行为、微观结构、热行为和力学性能等性能特征。PEEK与PEI在熔融和无定形状态下完全相容,常用于PEEK的结晶行为和微观结构的基础研究;与PTFE、TLCP、PES共混分别是提高PEEK的摩擦磨损性能、加工性能和热稳定性的有效手段。各种共混物的相容性好坏对其结晶行为和微观结构有重要影响,从而影响了共混物的力学性能。在此基础上,对PEEK共混改性领域进一步的研究方向和内容进行了讨论。     

聚醚醚酮复合材料改性研究进展

总结了聚醚醚酮(PEEK)及其复合材料的力学性能、导电性能、耐摩擦性能、耐高温性能及其它性能的改进方法.着重评述了碳纳米材料、纤维、晶须等填料对PEEK复合材料性能的研究,介绍了近年来改性PEEK复合材料的研究进展,并在一定程度上总结了发展态势和规律.最后展望了PEEK复合材料未来的发展趋势.指出碳纳米材料、纤维、多种...     

SiO2改进PVC材料性能的研究进展

对SiO_2的表面改性方法及其对PVC材料力学性能、热学性能、光学性能的影响研究现状进行了总结。结果表明:SiO_2/PVC复合材料综合性能优于纯PVC材料,具有良好发展前景,其中表面改性的纳米SiO_2可以提高PVC力学性能及热性能,表面改性的微米SiO_2可以改进PVC消光性能。     

高生物活性聚醚醚酮化学改性研究进展

由于聚醚醚酮（PEEK）表面疏水及生物惰性，用作骨科材料难以与周围细胞、骨组织结合。通过化学改性在PEEK分子链中引入具有生物活性的功能化基团是提高其表面细胞黏附、增殖和成骨分化能力最有效的方式。基于功能化基团引入位置的不同，本文将PEEK化学改性分为苯环位改性、酮基位改性和共聚改性等三种，并且重点综述了这些不同化学改性方法的原理和特性及其对PEEK材料生物活性的影响。苯环位改性主要是通过强酸处理引入羧基等官能团，但会残留含硫或含硝化合物，对细胞有一定的毒害作用；酮基位改性是通过胺类、硼氢化钠等试剂与酮基反应，进一步接枝引入功能化基团，但是会破坏PEEK主链上的醚酮比，影响物理性能和热性能。通过亲电、亲核及卤代改性等共聚方式在PEEK侧链引入功能化基团，能保持聚合物主链醚酮比基本不变，同时提升材料生物活性，具有良好的应用前景。在化学改性的基础上，研究多种功能基团的协同作用，进一步引入物理改性，优化面向不同场景的综合性能，是拓宽其在医疗领域应用的发展趋势。     

改性聚醚醚酮复合材料在齿轮上的应用

用液晶聚合物（TLCP）、碳纤维（CF）、铜粉、MoS2等添加剂对聚醚醚酮（PEEK)进行改性，制备了改性PEEK复合材料，讨论了各添加剂对改性PEEK性能的影响，并用来制造发动机机油泵齿轮。结果表明，用TLCP、CF等改性的PEEK可提高PEEK的强度和耐磨性，并改善加工性，该复合材料能满足机油泵类齿轮的使用要求。     

聚醚醚酮/多壁碳纳米管复合材料力学及阻燃性能研究

通过熔融共混法将聚醚醚酮（PEEK）与多壁碳纳米管(MWCNT)混合,利用模压法制备了MWCNT增强型PEEK复合材料,研究了MWCNT对PEEK性能的影响。结果表明,添加一定比例的MWCNT能够提高PEEK的力学和阻燃性能;当MWCNT含量为5%（质量分数,下同）时,PEEK的弯曲强度提高了53%;当MWCNT含量为1%时,锥形量热法测得的热释放速率峰值最低,燃烧性能指数值最大,热重分析显示初始分解温度较纯PEEK提高了13℃,表明MWCNT有效地提高了PEEK的阻燃和热稳定性能。     

聚丁二酸丁二酯(PBS)/蛭石复合材料的热性能研究

以有机插层改性后的膨胀蛭石与PBS制备复合材料,研究偶联剂对蛭石/PBS复合材料热学性能的影响。运用差示扫描量热(DSC对比膨胀蛭石/PBS与改性蛭石/PBS复合材料之间的异同。结果表明,有机插层改性蛭石能够使PBS的结晶更加完善。     

聚醚醚酮/碳纤维复合粉末的制备及性能

将热处理改性的聚醚醚酮(PEEK)粉末和碳纤维(CF)共混制备了PEEK/CF复合粉末。采用表观密度测试、扫描电子显微镜、电子万能试验机、热重分析、差示扫描量热法等对复合粉末材料的微观形貌、力学性能和热性能进行分析。结果表明,热处理后的PEEK粉末表观密度最高可达0.286 g/cm3。与纯PEEK相比,复合粉末的玻璃化转变温度、熔融温度和分解温度都有较大的提高;随着CF质量分数逐渐增加,复合粉末材料的拉伸强度、弯曲强度、弯曲弹性模量、热变形温度和维卡软化温度逐渐增大,冲击强度逐渐减小。改性PEEK/CF复合粉末材料为选择性激光烧结技术提供了高强度、高耐热性能的粉末材料,从而应用于汽车工业、电器工业、医疗器械和航空航天等领域。     

改性聚碳酸亚丙酯研究进展

对可降解塑料聚碳酸亚丙酯(PPC)进行改性是改善其力学性能和热学性能的有效方法.综述了近年来改性PPC的研究机理,介绍了PPC的合成机理和热降解机理,主要阐述了PPC物理改性和化学改性方法.物理方法主要包括碳纤维、碳酸钙、改性纳米二氧化硅、纳米粘土、纤维素、有机蒙脱土(OMMT)等材料与PPC进行共混改性,化学方法主要...     

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。