兼具导电及抗原子氧性能的复合薄膜制备及性能

聚酰亚胺薄膜因其良好的耐热性和绝缘性在航空航天应用广泛,但其容易在低地球轨道受到原子氧的侵蚀,使其各项优异性能退化至丧失。首先采用原位自金属化法对聚酰亚胺薄膜进行开环刻蚀、离子交换和热还原后,制备出PI/Ag的复合薄膜,基于PI/Ag的复合薄膜结合刮涂的方式在表面引入抵抗原子氧侵蚀的含硅聚酰亚胺,从而制备出两种浓度的PI/Ag/Si-PI复合薄膜。并对其进行XPS,SEM和抗原子氧辐照测试等表征,结果发现PI/Ag/Si-PI复合薄膜具有优良的抗原子氧性能,且较高浓度的效果更佳。表层Si-PI在原子氧辐照过程中形成致密的SiO_2来进一步抵抗原子氧的侵蚀,从而保护与其紧挨着的下层及导电银层,从而保证了兼具导电及抗原子氧性能的复合薄膜。     

聚酰亚胺薄膜表面无钯活化化学镀铜

为了增加聚酰亚胺薄膜表面与化学镀铜层的结合力,采用NaOH溶液对其表面进行化学改性,然后在其表面制备出具有催化活性的银微粒,进而化学镀铜。使用傅里叶变换衰减全反射红外光谱仪(FTIR-ATR)和能谱分析仪(EDS)对聚酰亚胺的表面结构和组成进行了表征和分析,利用X射线衍射(XRD)及扫描电子显微镜(SEM)表征铜镀层的结构及表面微观形貌。结果表明,聚酰亚胺表面在NaOH溶液中发生水解,在AgNO3溶液中实现Ag+与Na+间的离子交换,Ag+通过化学吸附附着在聚酰亚胺表面。在镀铜液中,Ag+先被甲醛还原成银微粒,从而引发化学镀铜反应的发生,并可获得结合力良好的化学镀铜层。     

高导电纳米银/聚酰亚胺复合薄膜的制备及其性能研究

通过对聚酰亚胺(PI)薄膜进行碱溶液水解、离子交换和热处理制备出具有表面导电性的聚酰亚胺银复合薄膜,并研究了影响聚酰亚胺银复合薄膜导电性的因素。结果表明,一定的薄膜厚度、碱溶液处理时间、合适的固化时间和固化温度都有利于制备出高导电性的复合薄膜。该复合薄膜保持了聚酰亚胺薄膜的基本力学性能,并且银原子与聚合物之间有良好的黏附性能。该制备方法简单,成本低,易于大规模生产。     

聚酰亚胺/滑石粉/碳纤维复合薄膜的界面性能研究

根据碳纤维表面性质和稀土元素独特的物理化学特性,采用稀土溶液(RES)表面改性方法对碳纤维进行表面改性处理,以改善聚酰亚胺/滑石粉/碳纤维(PI/talc/CF)复合材料的界面结合性能,从而有效地提高PI/talc/CF复合材料的力学性能。采用RES改性方法对碳纤维进行表面改性处理,制备出具有不同界面的PI/talc/CF复合材料。以PMDA-ODA型聚酰亚胺为研究对象,在制备的聚酰胺酸中加入不同量的滑石粉和不同RES浓度处理过的碳纤维这两者的混合物,通过5℃/min匀速升温工艺得到聚酰亚胺/滑石粉碳纤维复合薄膜。对制备的复合薄膜进行各种性能测试和结构表征。研究发现,经过RES处理过的碳纤维和滑石粉可以诱导聚酰亚胺分子围绕其结晶,碳纤维和聚酰亚胺之间界面结合良好。RES表面处理提高碳纤维与PI基体之间的界面结合性能,其中RES浓度为0.3wt%的改性处理方法最有效,拉伸强度提高了9.5%。     

原位一步法制备表面银化的聚酰亚胺纳米复合薄膜

介绍了原位一步自金属化制备银/聚酰亚胺(PI)纳米复合薄膜的方法。以银盐为线索,评述了各种银盐/二酐/二胺体系所制得的复合薄膜的性能。采用该法可制得具有较高的表面反射率和电导率,优异的界面粘结性,并保持母体PI大部分优异性能的复合薄膜;其反射性和导电性与银含量,银的配位体或者反离子,二酐、二胺的种类及热处理工艺等因素相关。使用三氟乙酰丙酮银盐(AgTFA),银的质量分数为12％以上,进行适当的热处理,则某些体系所制薄膜的表面反射性和导电性可以达到纯银的水平,而其他的银盐体系制备的薄膜只能达到中等反射性而无导电性,但对薄膜表面进行轻微抛光可以提高反射性和导电性。     

多壁碳纳米管/聚酰亚胺复合薄膜的制备与性能研究

采用两种方法(混酸法和酰氯化法)处理多壁碳纳米管制得羧酸化多壁碳纳米管(MWNTs-COOH)和酰氯化多壁碳纳米管(MWNTs-COCl),并以4,4'-二氨基二苯醚(ODA)和均苯四甲酸二酐(PMDA)为原料,原位聚合制备多壁碳纳米管/聚酰亚胺复合薄膜。通过偏光显微镜(PLM)、傅里叶红外光谱测试仪(FT-IR)、热重分析仪(TGA)以及万能拉伸试验机对复合薄膜进行表征及测试。结果表明:随着多壁碳纳米管含量的增加,复合薄膜的拉伸强度呈现先增加后减小的趋势,酰氯化多壁碳纳米管/聚酰亚胺(MWNTsCOCl/PI)复合薄膜的拉伸强度较羧酸化多壁碳纳米管/聚酰亚胺(MWNTs-COOH/PI)复合薄膜提高了13.3%,导电性提高约103倍;且MWNTs-COCl含量在3%时,MWNTs-COCl/PI复合薄膜的综合性能达到最佳。     

硝酸银在聚酰亚胺薄膜表面化学镀铜中作用

硝酸银在化学镀的过程中常作为催化剂,实验研究发现,硝酸银在聚酰亚胺薄膜表面化学镀铜时,不仅起到催化剂的作用,还有增加聚酰亚胺薄膜和化学镀铜层结合力的作用。实验采用Na OH溶液对聚酰亚胺表面进行改性,利用不同浓度的硝酸银溶液进行活化,将吸附在聚酰亚胺薄膜表面Ag+还原,进行化学镀铜。使用红外光谱仪对聚酰亚胺的表面结构进行表征和分析,利用3M胶带粘贴法测试镀铜层与聚酰亚胺薄膜的结合力,利用X-射线衍射、扫描电子显微镜表征铜镀层结构及表面微观形貌。结果表明,当硝酸银在一定浓度范围内变化时,硝酸银浓度对化学镀铜层质量和化学镀铜沉积速度无明显影响,但对镀铜层与聚酰亚胺薄膜的结合力影响很大。     

SiO2表面包覆改性钛酸钡/聚酰亚胺复合薄膜的制备

通过溶胶凝胶法在BaTiO3纳米粉体表面包覆了一层SiO2壳层,在此基础上利用原位聚合法成功制备了SiO2包覆的钛酸钡(BT)/聚酰亚胺(PI)复合薄膜.SiO2通过范德华力等物理作用在BaTiO3表面形成了4 nm左右的SiO2壳层.SEM测试和介电性能测试表明,10％ SiO2@BT/PI具有较好的界面相容性和介电性能.在1 kHz下,复合薄膜介电常数为4.50,介电损耗达到0.148.热学性能测试表明,复合薄膜在500℃下具有良好的热稳定性.     

银复合激光刻蚀FTO薄膜的光电性能

在掺氟二氧化锡(FTO)薄膜基底表面用激光刻蚀凹槽后以磁控溅射法复合金属Ag层,然后进行炉内退火处理,制得Ag复合激光刻蚀FTO薄膜。研究了Ag层厚度对样品表面形貌、晶体结构及光电性能的影响。结果表明,当Ag层厚度为5 nm时,大部分银纳米颗粒均匀密集地分布在凹槽内表面而不是凹槽外表面。复合银纳米颗粒及炉内退火有效地提升了FTO薄膜的光电性能。Ag层厚度为5 nm的薄膜在400～800 nm波段的透光率为78.40%,方块电阻为8.21Ω,品质因子达到1.069×10~(-2) Ω~(-1)。     

离子交换法制备ZnO-聚酰亚胺复合薄膜及光催化性能研究

采用离子交换法制备Zn O-聚酰亚胺(Zn O-PI)复合薄膜,用扫描电镜、场发射扫描电子显微镜、X射线衍射仪、傅立叶红外光谱仪等手段对其形貌、结构进行表征。结果表明,复合薄膜表面负载的纳米颗粒为六方晶系纤锌结构,无团聚现象,复合薄膜保留了原有PI的结构与性能。考察了制备条件对复合薄膜光催化性能的影响,当PI薄膜经2 mol/L的KOH溶液刻蚀90 min,于0.5 mol/L的乙酸锌溶液中离子交换3 h,之后阶段升温到410℃并保温5 h的复合薄膜,以甲基橙模拟废水为目标产物进行光催化性能实验,4 h后降解率可达到99.5%,具有较高的催化活性。     

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.