HDPE/麦秸粉微孔发泡复合材料挤出工艺的研究

研究了麦秸粉、AC发泡剂、挤出温度等对高密度聚乙烯(HDPE)/麦秸粉微孔发泡复合材料性能的影响。结果表明,麦秸粉用量为30份时,材料的综合性能较好;AC发泡剂用量为2份时,材料的密度较小,力学性能较好,且随着AC发泡剂用量的增加,材料的微观结构由闭孔到开孔直到泡孔破裂;口模温度为165℃时,材料的挤出性能较好,且随着口模温度的增加,材料的挤出性能由差变好,但泡孔由小到大,甚至泡孔破裂。     

聚乙烯/氮化铝纳米复合材料的制备与性能研究

制备了聚乙烯/氮化铝纳米复合材料,研究了氮化铝对聚乙烯纳米复合材料力学性能、导热性能和热性能的影响。研究结果表明,氮化铝可以显著提高聚乙烯纳米复合材料的力学性能和导热性能。随着氮化铝用量的增加纳米复合材料的力学性能先增加后降低,当添加质量分数为9%的氮化铝时,聚乙烯纳米复合材料的拉伸强度、弯曲强度和冲击强度比纯聚乙烯分别提高了47.16%、31.48%和51.68%。聚乙烯纳米复合材料的导热系数和热稳定性能随着氮化铝用量的增加而提高。利用SEM对复合材料增强机理进行了探讨。     

界面改性剂对PE基木塑复合材料性能的影响

以高密度聚乙烯(HDPE)和木粉为主要原料、马来酸酐接枝聚乙烯(MAPE)和硅烷偶联剂(KH570)为界面改性剂,采用压制成型法制备了PE基木塑复合材料.研究了界面改性剂MAPE和KH570用量对复合材料力学性能的影响,并采用FT-IR和SEM对复合材料的微观结构进行了表征.结果表明:界面改性剂MAPE和KH570可以显著改善木塑复合材料的拉伸强度、冲击强度和弯曲强度,当木粉、HDPE、MAPE、KH570质量比为40∶36∶24∶5时,木塑复合材料的综合力学性能最佳;FT-IR和SEM表明:在界面改性剂MAPE和KH570的作用下,木粉在塑料基体中的分散均匀,相容性提高,并发生了一定程度的化学键合.     

油茶果壳对PE-HD力学性能的影响

以废弃油茶果壳和高密度聚乙烯(PE-HD)为原料,采用挤出成型工艺制备了PE-HD/油茶果壳复合材料。采用热重法测试了油茶果壳的热稳定性,研究了油茶果壳平均粒径、添加量及相容剂马来酸酐接枝聚乙烯(MAPE)添加量对复合材料力学性能的影响。结果表明,油茶果壳初始热解温度为211℃,热解残炭率达31.35%。随着油茶果壳平均粒径减小、油茶果壳和MAPE添加量增加,复合材料的拉伸、弯曲和缺口冲击强度均呈现先增大后减小的趋势。当油茶果壳平均粒径为380μm,添加量为40份,MAPE添加量为3份时,复合材料的力学性能最佳。     

界面相容剂对HDPE/黄麻纤维复合材料性能的影响

研究了马来酸酐接枝聚乙烯(MAPE)、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)及γ-甲基丙烯酰氧基丙基三甲氧基硅烷接枝聚乙烯(KH-g-PE)三种界面相容剂对高密度聚乙烯(HDPE)/黄麻纤维复合材料的力学性能和耐水性的影响;考察了MAPE的用量对复合材料拉伸性能的影响;并用扫描电子显微镜对拉伸断口形貌进行了观察.结果表明:添加界面相容剂后,复合材料的拉伸性能和耐水性均有不同程度的提高.其中,大分子偶联剂MAPE和KH-g-PE的加入使复合材料的拉伸强度提高更为明显.     

麦秸纤维增强聚乙烯复合材料的制备及性能

以麦秸纤维和聚乙烯为原料,通过模压成型制备了麦秸纤维增强聚乙烯复合材料,研究了改性剂（NaOH）浓度、麦秸纤维含量以及热压温度对复合材料力学性能的影响。结果表明,5 %NaOH处理可以溶解麦秸纤维中半纤维素、果胶等,使纤维更细化,比表面积增大,有效改善了复合材料力学性能;麦秸纤维含量为30 %（质量分数,下同）时,麦秸纤维与聚乙烯混合均匀性较好,复合材料的拉伸强度和冲击强度得到改善;热压温度为170 ℃时聚乙烯的流动性有助于改善麦秸纤维在聚乙烯中分散的均匀性,且不会使聚乙烯降解,复合材料拉伸强度和冲击强度分别达到了最大值46.1 MPa和13.8 MJ/m2。     

离子聚合物改性木塑复合材料的研究

研究了钠离子聚合物(Surlyn 8940)对杨木粉/高密度聚乙烯(HDPE)木塑复合材料的增容和增韧改性效果,并与马来酸酐接枝聚乙烯(MAPE)改性杨木粉/HDPE木塑复合材料相比较。通过万能力学试验机和悬臂梁冲击试验机测试了不同用量的钠离子聚合物或MAPE改性HDPE复合材料的力学性能,以及使用场发射扫描电镜观察钠离子聚合物改性HDPE复合材料的表面和断面形貌。结果表明,当木粉质量分数为40%时,添加4%钠离子聚合物的复合材料的拉伸强度(25.8 MPa)比添加4%MAPE时提高了78.6%;随着钠离子聚合物含量的增加,复合材料的弯曲弹性模量呈现出明显的降低趋势,而添加钠离子聚合物的复合材料的弯曲强度要高于添加MAPE复合材料的弯曲强度,并且发现钠离子聚合物对复合材料有突出的增韧效果,表明钠离子聚合物对于木塑复合材料是较好的增容增韧剂;SEM分析表明添加离子聚合物后,塑料基体对木粉有很好的包覆效果,没有明显的界面缝隙。     

废纸／再生高密度聚乙烯复合材料的力学性能研究

以废纸和再生HDPE为原料制备废纸/再生HDPE复合材料.采用红外光谱分析和差示扫描量热法分析手段研究了废纸和再生HDPE的基本特性,同时探讨了废纸用量、增容剂(硅烷偶联剂KH550和马来酸酐接枝聚乙烯MAPE)对复合材料力学性能的影响,并借助扫描电镜观察复合材料的拉伸断面形貌.结果表明:废纸能作为再生HDPE的增强体,且废纸质量分数为15%时,拉伸强度和弯曲强度分别为23.68 MPa、28.78 MPa;增容剂能改善复合材料的界面性质,提高复合材料的力学性能,KH550和MAPE最佳用量分别为1%和4%～6%.     

塑料基体中MAPE/HDPE比例对木塑复合材料力学性能的影响

以高密度聚乙烯(HDPE)和马来酸酐接枝聚乙烯(MAPE)共混物为塑料基体,以木粉为填料,用注塑成型法制备木塑复合材料,研究MAPE/HDPE质量比变化对塑料基体和木塑复合材料力学性能的影响.结果表明:MAPE/HDPE比变化对MAPE/HDPE共混形成的塑料基体强度基本没有影响,但对由该共混物所制得的木塑复合材料的强度影响显著;在相同的木粉含量下,保持配方中MAPE和HDPE的总含量不变,木塑复合材料的拉伸强度随MAPE/HDPE比率增大先迅速增加,然后趋于平缓.冲击强度随MAPE/HDPE比增大逐渐减小.     

废白土/核桃壳粉/低密度聚乙烯复合材料的制备

用钛酸酯偶联剂改性核桃壳粉,与废白土、低密度聚乙烯制备复合材料,研究废白土用量对复合材料力学性能及加工流动性能的影响,并用扫描电镜观察核桃壳粉及复合材料表面微观形态.结果表明:随着废白土用量的增加,复合材料的力学性能、熔体指数呈先升后降趋势;核桃壳粉、废白土与低密度聚乙烯树脂的界面结合情况会影响复合材料的力学性能.     

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。