石墨烯/聚丙烯复合材料制备及性能研究

以石墨烯(GNPs)为填料对聚丙烯(PP)进行改性,通过球磨和熔融挤出共混的方法制备了一系列不同GNPs含量的GNPs/PP复合材料。用X射线衍射、扫描电子显微镜、电导率测试及拉伸测试等手段对复合材料的结构和性能进行表征分析,研究GNPs含量对复合材料性能的影响。结果表明:随着GNPs含量的增加,复合材料的电导率逐渐增大;当GNPs质量分数为15%时,复合材料的电导率达到0. 127 S/cm;复合材料的电阻逾渗阈值在GNPs质量分数为5%～8%之间。在力学性能方面,随着GNPs含量的增加,复合材料的拉伸强度呈现出先增加后降低的趋势;当GNPs质量分数为3%时,复合材料的拉伸强度达到最大,为35. 658 MPa,比纯PP提高了21. 04%;复合材料的弹性模量随着GNPs含量的增加而增加,在GNPs质量分数为15%时,复合材料的弹性模量比纯PP提高了89. 6%,达到2 068. 54 MPa。本文对制备高导电和高强度的导电聚合物或者导电纤维母粒可以提供一定的参考价值。     

具有隔离结构的聚苯硫醚/石墨烯纳米片 复合材料的制备及电磁屏蔽性能研究

导电填料石墨烯纳米片（GNPs）通过高速混合包覆于聚苯硫醚（PPS）树脂基体颗粒表面,再通过热压成型制备出具有完善隔离结构的PPS/GNPs复合材料。采用光学显微镜、扫描电子显微镜、电导率测试、电磁屏蔽性能测试对复合材料导电网络形貌、电性能和电磁屏蔽性能进行表征。结果表明,复合材料具有完善的隔离结构导电网络;隔离结构复合材料具备优异的电导率和电磁屏蔽效能（EMI SE）,当GNPs含量为3.0 %（质量分数,下同）时,复合材料的电导率和EMI SE分别为25.6 S/m和41.0 dB。     

PE-UHMW/GNPs导电复合材料的制备和表征

采用超声溶液分散法制备出超高分子量聚乙烯/石墨烯(PE-UHMW/GNPs)导电复合材料,研究了该材料的导电渗流行为和阻-温特性。研究发现,PE-UHMW/GNPs导电复合材料的导电渗流阈值为3.8%,即当导电填料在体系中的质量分数达到3.8%时,材料内部逐渐形成较为完善的导电网络,从而实现其导电特性。研究和探讨了PE-UHMW/GNPs导电复合材料的正温度系数(PTC)效应和负温度系数(NTC)效应。研究发现,PE-UHMW/GNPs导电复合材料的PTC效应会随着GNPs含量的增加逐渐增强,当导电填料GNPs的添加量达到3.8%时,通过阻-温曲线可以观察到,PE-UHMW/GNPs导电复合材料具有最大的PTC强度和相对较低的室温体积电阻率。场发射扫描电子显微镜分析结果表明,GNPs和PE-UHMW之间的相互作用会随着热循环次数的不同而发生变化,最终会影响到材料的PTC效应。     

聚偏氟乙烯/石墨烯发泡复合材料制备及电磁屏蔽性能

使用熔融共混的方法制备不同含量石墨烯纳米片(GNPs)的聚偏氟乙烯(PVDF)复合材料,并采用超临界二氧化碳作为发泡剂对其进行釜压发泡,制备PVDF复合材料泡沫.研究了PVDF复合材料的断面结构、结晶行为、熔融行为、流变行为和发泡行为,并研究了PVDF复合材料及其泡沫的电导率和电磁屏蔽性能.结果表明,GNPs质量分数为...     

PA6/ODOPB/GNPs阻燃复合材料及纤维的制备与性能表征

将磷系阻燃剂10-(2,5-二羟基苯基)-10-氢-9-氧杂-10-磷杂菲-10-氧化物(ODOPB)与纳米石墨片(GNPs)复配加入到聚酰胺6(PA 6)聚合体系中,通过原位聚合的方式制备了PA 6/ODOPB/GNPs复合材料,再经熔融纺丝得到PA 6/ODOPB/GNPs复合纤维,并对复合材料及纤维的阻燃性能进行了研究。结果表明:ODOPB的加入导致复合材料的相对黏度下降,GNPs的添加对复合材料的相对黏度无明显影响;ODOPB与GNPs的复配协同作用提升了复合材料及纤维的阻燃抗熔滴性能,表现为凝聚相阻燃作用,ODOPB对PA 6具有优异的阻燃效果,GNPs具有优异的抗熔滴和抑烟效果;当添加ODOPB质量分数为5%、GNPs质量分数为2%时,复合材料的极限氧指数(LOI)可达31.8%,垂直燃烧达到V-0等级,复合纤维的LOI达29.8%;加入ODOPB及GNPs均会导致复合纤维的力学性能下降,当ODOPB质量分数为5%、GNPs质量分数为2%时,所得复合纤维的断裂强度从纯PA 6纤维的3.3 cN/dtex下降至1.5 cN/dtex。     

超声辅助真空作用下石墨烯/PBS复合材料的制备及热性能

以石墨烯纳米片(GNPs)和聚丁二酸丁二醇酯(PBS)为原料,利用自制的超声辅助真空实验装置进行熔融混合,通过调控超声振荡-真空灌注工艺制备了一系列GNPs/PBS复合材料。分别采用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、热重分析仪(TG)、维卡软化温度(VST)和Hot disk导热仪研究了PBS基复合材料的界面形态、结晶性能、热稳定性能、抗热变形性能和导热性能。结果表明:与纯PBS相比,当GNPs添加量达到0.5%、超声功率300 W时,GNPs/PBS复合材料的玻璃化转变温度、最大热分解温度、维卡软化点与导热系数分别提高了5.4℃、5.3℃、12.7℃与1 107.8%,而结晶度出现轻微降低。同时,对比超声功率研究结果发现,提高超声功率可以明显改善GNPs/PBS复合材料的热稳定性、抗热变形性和热导率,这是因为高功率的超声振荡提高了GNPs在PBS基体中的分散性。     

GNPs/PEG对聚乳酸材料结晶及力学性能的影响

采用超声辅助真空装置制备石墨烯纳米片(GNPs)/聚乙二醇(PEG)复配改性剂,通过熔融共混法制备了一系列聚乳酸(PLA)/GNPs、PLA/GNPs/PEG复合材料,利用扫描电子显微镜(SEM)、X-射线衍射仪(XRD)、差示扫描量热仪(DSC)、偏光显微镜(POM)和万能试验机对其断面形貌、结晶行为和力学性能进行研究。结果表明,添加复配改性剂GNPs/PEG后,PLA基复合材料的断面出现明显的PLA纤维,呈现韧性断裂; GNPs或GNPs/PEG的添加未改变PLA的晶型,当GNPs/PEG为0. 1%时,PLA基复合材料的结晶度达到38. 50%,比纯PLA提高了27. 99%; GNPs/PEG的添加也有效地改善了PLA的拉伸强度和缺口冲击强度,分别比纯PLA的提高了13. 32%和51. 9%。     

拉伸力场对聚丙烯/石墨烯微片纳米复合材料形态和性能的影响

设计了2种挤出机头以产生不同加工力场,研究了聚丙烯（PP）/石墨烯微片（GNPs）纳米复合材料的微观形态、导电及导热性能,分析GNPs在PP基体中的分布形态对复合材料的性能影响。结果表明,收敛流道产生的拉伸力场对GNPs有剥离分散作用,减少GNPs团聚;加入静态混合器后产生的混沌混炼力场能进一步提高GNPs在PP中的分散均匀性,有利于构建导电导热网络,从而提高复合材料的导电导热性能;当GNPs含量为6 %(质量分数,下同)时,相比于无静态混合器的拉伸机头,在带静态混合器的拉伸机头挤出下,电导率增大了5个数量级,热导率提高了24.1 %。     

PP/多层石墨烯纳米复合材料性能研究

利用双螺杆挤出机制备了聚丙烯/多层石墨烯(GNPs)纳米复合材料并研究了其性能。结果表明,GNPs具有明显的异相成核作用,使PP的结晶过程可在较高温度下进行。GNPs对PP具有增强增韧作用,在GNPs质量分数为1.5%时,拉伸强度增加了15%,弹性模量增加了33%。GNPs能有效地提高聚丙烯的耐热性能,在GNPs质量分数为2%时,维卡软化点提高了10℃以上。     

PI 介电复合材料的研制及其应用研究

以2,2-二(3,4-邻苯二甲酸酐)-1,1,1,3,3,3-六氟丙烷和2,2′-双(三氟甲基)联苯胺和纳米SiC为主要原料制备了聚酰亚胺(PI)及其不同纳米SiC含量的PI/纳米SiC复合材料,利用阻抗分析仪、傅立叶变换红外光谱仪、透射电子显微镜等对其进行了性能测试及表征。研究表明,当纳米SiC的质量分数为20%时,PI/纳米SiC复合材料的介电常数最低可达2.0,较目前常用介电材料的介电性能显著提高,可用于陶瓷电容器等的制备。     

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。