空气介质阻挡放电等离子体对国产芳纶ⅢA表面改性的研究

采用空气介质阻挡放电等离子体对国产芳纶ⅢA进行表面处理,优化了其处理工艺。用SEM、XPS等方法研究了处理前后纤维表面形态和化学状态的变化,通过短梁剪切试验评价了芳纶ⅢA/环氧复合材料的抗层间剪切强度。结果表明:经空气等离子体处理后芳纶ⅢA表面粗糙度增加,极性增强,纤维力学性能无明显变化,芳纶ⅢA/环氧复合材料的抗层间剪切强度提高了18%。     

洋麻纤维的表面改性及其在聚丙烯基复合材料中的应用

采用碱处理、偶联剂处理以及碱–偶联剂复合处理对洋麻纤维进行表面改性,然后将其与聚丙烯(PP)纤维复合,采用非织造–模压工艺制备了PP/洋麻纤维复合材料。研究了上述3种表面改性方法对洋麻纤维强度及其复合材料弯曲与剪切性能的影响,并采用扫描电子显微镜(SEM)研究了洋麻纤维表面改性前后的形貌变化及其与PP基体之间的界面结合状况。结果表明,表面改性后洋麻纤维的拉伸强度均降低,但复合材料的弯曲强度及层间剪切强度均提高,表明这3种改性方法均提高了洋麻纤维与PP之间的界面结合强度;碱处理可去除纤维表面的果胶成分,使纤维束变得松散,使复合材料的弯曲强度及层间剪切强度分别较未表面改性时提高了21%和169%,但弯曲弹性模量降低了21%;偶联剂处理则使复合材料的弯曲强度,弯曲弹性模量和层间剪切强度较未表面改性时提高了23%,7%和160%;碱–偶联剂复合处理兼顾了碱处理和偶联剂处理的优点,使复合材料弯曲强度、弯曲弹性模量和层间剪切强度分别较未表面改性时提高了26%,18%和572%,综合性能最佳。SEM结果表明,碱–偶联剂复合处理后,复合材料中纤维与树脂之间的界面结合较好。     

芳纶纤维/AFR树脂复合材料界面粘结性能的研究

为了改善芳纶纤维复合材料的界面粘结性能,合成了一种新型树脂(AFR)作为基体,以未经任何表面处理的芳纶纤维作增强材料,制备了芳纶纤维/AFR复合材料。采用测定表面能、接触角、层间剪切强度、横向拉伸性能和扫描电镜观察形貌等方法,从宏观和微观等方面研究了芳纶纤维/AFR复合材料的界面粘结性能。结果表明,AFR树脂与芳纶纤维有相近的表面能,AFR树脂溶液与芳纶纤维的接触角为42.8°,而环氧树脂(EP)与芳纶纤维的接触角为68°,说明AFR树脂对芳纶纤维的润湿性优于EP树脂;芳纶/AFR复合材料的层间剪切强度、横向拉伸强度和纵向拉伸强度分别为74.64MPa、25.34MPa和2256MPa,比芳纶/EP复合材料的相应强度分别提高了28.7%、32.5%和13.4%,其复合材料破坏面的形貌也说明芳纶纤维与AFR树脂之间的界面粘结性能较好。     

黄麻纤维接枝聚醚增强UP复合材料研究

采用经过氢氧化钠和甲苯二异氰酸酯-聚醚二元醇(TDI-PPG)表面处理的黄麻纤维织物作为增强体,以191#通用不饱和聚酯树脂(UP)作为基体,通过模压成型的方法制备了黄麻纤维增强UP复合材料。傅立叶变换红外光谱及X射线光电子能谱分析表明,TDI-PPG接枝于黄麻纤维上;通过热分析确定了复合材料的加工温度为160℃,根据生产经验确定成型压力为2 MPa;用短梁弯曲法测试了黄麻纤维接枝前、后UP复合材料的层间剪切强度,后者大于前者;随着黄麻纤维体积分数的增加,接枝黄麻纤维增强UP复合材料的力学性能得到提高,当黄麻纤维体积分数为54.44%时,接枝黄麻纤维增强UP复合材料的拉伸强度、弯曲强度和冲击强度分别为112.31 MPa,109.32 MPa和14.85 k J/m2。     

芳纶纤维的热氧化处理及对环氧树脂界面黏结的影响

采用红外光谱(FTIR)、热重(TG)、差示扫描量热(DSC)对芳纶纤维在N_2和空气气氛下的热行为进行了研究,并以透射电镜(TEM)、界面剪切强度(IFSS)研究了芳纶纤维的空气热氧化处理及对其环氧树脂界面黏结的影响。结果表明:芳纶纤维在空气条件下,150～200℃温度范围内,仅仅是纤维表层上浆剂的挥发。250℃以上会出现分子链的氧化,同时纤维表层分子链能够重排使得氢键增强。高温过程中芳纶纤维的分子链苯环C—H被氧化成—C—OH、—COOH,从而使纤维表面极性增强。极性的结构有利于与环氧树脂的界面反应,使纤维与环氧树脂间形成40～50 nm的界面层。热处理后,芳纶纤维与环氧树脂微滴间界面剪切强度值增至18.05 MPa,与原丝相比增加了11.9%。同时,高温氧化后的芳纶纤维/环氧树脂界面黏合增强,复合材料的层间剪切强度为76.2 MPa,与原丝相比提高16.16%。     

PE⁃UHMW/海泡石纤维复合材料的力学性能与摩擦学性能研究

采用硅烷偶联剂KH550对海泡石纤维（Sep）进行了改性,采用平板硫化机通过热压成型法制备了超高分子量聚乙烯（PE?UHMW）/Sep和PE?UHMW/改性海泡石纤维（O?Sep）复合材料,并通过红外光谱仪（FTIR）、电子万能试验机、扫描电子显微镜（SEM）等对Sep 及O?Sep的表面结构和复合材料的力学性能、摩擦学性能及磨痕形貌进行了表征和测试。结果表明,O?Sep表面存在KH550分子,其在复合材料中分布比Sep更为均匀;当O?Sep含量达到6 %（质量分数,下同）时,复合材料力学性能和摩擦学性能表现最佳,其拉伸强度、弯曲强度、弯曲模量和冲击强度分别为32.1 MPa,171.2 MPa、138.3 GPa和17.62 kJ/mm²,比纯PE?UHMW分别提高了41.4 %、40.0 %、95.6 %和36.9 %;其摩擦因数和磨损量分别为0.124和 0.1 mg,比纯PE?UHMW分别提高了77.1 %和80 %。     

改性芳纶纬编增强体复合材料力学性能的研究

为探讨芳纶纬编增强体复合材料的力学性能,以对位芳纶为原料,采用LiCl/无水乙醇溶液对芳纶表面进行改性处理,设计并编织1+1满针罗纹和罗纹空气层2种组织织物增强体,以E-51环氧树脂为基体,应用手糊成型技术制备芳纶纬编增强体平板复合材料。采用YG026D型电子织物强力机对制备的芳纶纬编增强体复合平板材料的经纬向拉伸、弯曲、压缩以及层间剪切性能进行测定。结果显示:经LiCl/无水乙醇络合溶液处理的芳纶纬编增强体复合材料的各项力学性能均有所提高,且经向的各项力学性能优于纬向。在拉伸、弯曲性能方面,罗纹空气层芳纶纬编增强体平板复合材料优于1+1满针罗纹芳纶纬编增强体复合材料。     

γ射线辐照处理对芳纶纤维F-3A结构和性能的影响

为采用γ射线对芳纶纤维进行辐照处理,研究辐照对纤维表面形貌、拉伸性能、比浓黏度,表面能以及芳纶纤维复合材料机械性能的影响。实验结果显示,经过辐照处理后,纤维表面粗糙度,纤维的拉伸强度和比浓黏度发生明显变化,纤维在溶液中的浸润性能提高,表面能增大。当辐照强度为600k Gy时,纤维增强环氧树脂的层间剪切强度达到51.86MPa,提高了23.09%。     

高导热炭纤维复合材料的制备及其性能研究

以聚苯硫醚为基体,中间相沥青基炭纤维为增强材料,采用热压成型工艺制备高导热炭纤维复合材料。研究了不同炭纤维含量对聚苯硫醚基复合材料结构和性能的影响。通过XRD、SEM、TEM等手段对材料微观结构进行观察分析,并测试复合材料的力学性能和导热性能。结果表明:不同炭纤维含量对复合材料性能影响不同。随着炭纤维含量的增加,力学性能随之降低,导热率随之升高。纤维含量为5%时,复合材料拉伸强度最高为45.17 MPa,弯曲强度最高为82.24 MPa,导热率最低为0.82W/m·K;纤维含量为20%时,复合材料拉伸强度最低为30.57 MPa,弯曲强度最低为69.36 MPa,导热率最高为1.88 W/m·K。通过微观形貌分析得出炭纤维结合能低,惰性高,与基体结合不够紧密。     

原位聚合法制备PA6/KF复合材料

采用原位聚合法制备了尼龙6/芳纶纤维(PA6/KF)复合材料。测试结果显示复合材料的拉伸强度从50.4 MPa提高到75.3 MPa,弯曲强度从41.1 MPa提高到72.1 MPa,热变形温度从44.5℃提高到83.1℃,而其冲击强度略有下降。SEM和DMA结果表明:尼龙6与芳纶纤维的界面粘结性好,复合材料的刚性得到提高。     

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。