竹纤维增强聚丙烯复合材料的制备及其性能研究

以适当脱胶处理后的竹原纤维与聚丙烯纤维为原料，采用非织造工程的加工方法制作了混合纤维预制件，通过热压成型工艺制备了竹原纤维增强聚丙烯热塑性树脂复合材料。对复合材料的基本力学性能进行了测试与评价，探讨了预制件制作工艺、竹原纤维比例及热压成型工艺对复合材料力学性能的影响。利用扫描电镜（SEM）研究了复合材料拉伸断口的形貌。结果表明：竹原纤维与聚丙烯纤维的质量配比为50／50，模压温度、时间及压力分别为190℃，30min及30MPa时，制得的复合材料力学性能最好，其纵、横向拉伸强度分别为96．6MPa和82．3MPa；纵、横向弯曲强度分别为400．7MPa和367．3MPa。     

竹原纤维增强低熔点聚酯复合材料的制作及其性能研究

采用非织造加工工艺将经适当脱胶处理的竹原纤维与低熔点聚酯(LMPET)纤维制成混合纤维预成型件,经模压成型制成竹原纤维增强LMPET复合材料板材。研究表明,当模压温度、时间及压力分别为170℃、20 m in及30 MPa,竹原纤维的质量分数为40%时,制得的复合材料的纵、横向拉伸强度分别为136.0、87.6 MPa;纵、横向弯曲强度分别为534.0、470.0 MPa。竹原纤维增强LMPET复合材料初步确定可用于汽车、建材等领域。     

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。     

竹原纤维/聚乳酸纤维基复合材料的拉伸性能

本文采用竹纤维作为增强材料,聚乳酸作为基体,混合编织了两种衬经衬纬针织物,根据聚乳酸熔点较低的特点,利用热压复合制备形成竹原纤维/聚乳酸复合材料。此复合材料在自然环境下能够降解为绿色环保型复合材料。在复合材料的应用中,应用设计是必不可少的,而拉伸试验的目的恰是为此。在万能强力机上通过对复合材料的拉伸性能测试分析发现,复合材料板材的纵向拉伸性能好于横向和斜向,同时12根针织线圈捆绑纱形成的复合材料板材拉伸性能明显好于6根捆绑纱形成的板材,而且竹原纤维/聚乳酸复合材料板材的断裂为韧性断裂。     

亚麻非织造布的缝合加固及其复合材料成型性研究

亚麻纤维通过针刺工艺加工成非织造布,再经缝合加固后,作为复合材料的增强体,与不饱和聚酯树脂复合,制成亚麻/不饱和聚酯复合材料板材及异型件。利用真空辅助树脂传递模塑法制备出的板材,亚麻纤维和树脂结合较为均匀、充分。模压法形成的亚麻非织造布异型件成型良好,无褶皱与破洞。对板材及异型件拉伸、弯曲及压缩等性能的测试结果表明,板材拉伸强度最大值达58.59MPa,弯曲强度最大值为120.26MPa;采用平行缝合工艺的异型件最大破坏载荷为8.99kN。     

亚麻针织物增强聚丙烯基热塑性复合材料的制备

本文以天然亚麻纤维为增强纤维,聚丙烯为基体,编织形成不同纤维体积比、不同结构的亚麻/聚丙烯针织物预制件,并经过热压复合制备形成一定的亚麻/聚丙烯针织物增强热塑性绿色环保的民用纺织复合材料。通过对增强纤维及基体材料性能的分析,以及对预制件和复合材料板材结构参数和制备工艺的设计和分析,得到较优的产品结构和制备工艺,认为亚麻/聚丙烯针织结构预制件的编织工序简单且效率高,并可直接热压复合,降低了复合材料的制备成本。4层、6层预制件热压过程中施加的最大压力为10MPa时最优,8层预制件热压过程中施加的最大压力为15MPa时最优。     

基于麻纤维板材回收再利用的汽车内饰用短纤维增强复合材料性能的研究

采用汽车内饰的黄麻纤维板材回收破碎,通过侧喂料喂入进行共混加工,最佳加工温度为190℃,最终注塑成短纤维增强复合材料。当纤维含量为20%时,复合材料力学性能与滑石粉/聚丙烯材料的相互媲美,而且密度下降9%左右,满足汽车内饰聚丙烯材料轻量化和绿色化的要求。基于此,采用马来酸酐接枝聚丙烯(MAPP)来提高材料力学性能。当MAPP质量分数为3%时,复合材料拉伸强度、弯曲强度和冲击强度分别达最大值为35.5 MPa、58.3 MPa和2.9 J/m,而拉伸模量和弯曲模量最大值为3 452、2 797 MPa。     

芳纶纤维增强树脂基复合材料的界面粘结性能研究

为了改善芳纶纤维增强树脂基复合材料的界面粘结性能,从树脂基体入手,依据相似相容原理和芳纶的结构特点,合成出新型热固性树脂(AFR–T)用作芳纶复合材料的基体,以未经表面处理的芳纶作增强材料,采用热压成型法制备了AFR–T/芳纶纤维复合材料,并通过测定溶度参数、接触角、线膨胀系数、层间剪切强度(ILSS)和横向拉伸强度等方法研究了复合材料的界面粘结性能。结果表明,AFR–T树脂浇注体与芳纶的溶度参数相近,AFR–T树脂溶液在芳纶纸表面的接触角为36.9°,小于环氧树脂(EP)溶液与芳纶纸的接触角(53.2°),说明AFR–T树脂对芳纶的浸润性优于EP;AFR–T/芳纶纤维复合材料的ILSS和横向拉伸强度为73.0 MPa和25.3 MPa,分别比EP/芳纶纤维复合材料提高了25.9%和32.5%,这表明AFR–T树脂与芳纶纤维之间的浸润性和界面粘结性能较好。     

光引发原位聚合聚丙烯酸酯树脂/玻纤预浸料的制备与研究

热塑性复合材料具有较高的抗损性、抗冲击能力,因此得到了迅速发展,但是热塑性树脂基体与增强材料之间的浸渍问题严重阻碍了其推广。为了有效改善热塑性复合材料的界面性能,以甲基丙烯酸甲酯、丙烯酸丁酯、甲基丙烯酸缩水甘油酯为单体,以单向玻璃纤维为增强材料,采用紫外光引发为聚合条件进行原位聚合,制备了聚丙烯酸酯树脂/玻纤预浸料。通过热压法将预浸料制备成复合材料,对复合材料的热稳定性、树脂含量、力学性能和微观形貌进行了研究。实验结果表明:聚丙烯酸酯树脂的热分解温度随GMA含量的增加而增加;玻璃化转变温度随GMA含量的增加而降低;复合材料的弯曲强度和拉伸强度随GMA含量的增加呈现出先增加后降低的趋势,并在GMA含量为20%时达到最大值,分别为861.4 MPa和780.9MPa;通过复合材料微观形貌的观察表明树脂和纤维结合紧密,达到了良好的浸渍效果。     

连续碳纤维增强聚醚醚酮板材的研究

采用自行设计、组装的连续纤维增强热塑性树脂基复合材料粉末浸渍试验装置制备了连续碳纤维(CF)增强聚醚醚酮(PEEK)预浸带,再将浸渍带通过热压模塑成型制备出层合板材。通过万能材料试验机、悬臂梁冲击试验机研究了纤维含量和浸渍带铺放方式对板材力学性能的影响。结果表明,在一定范围内CF/PEEK板材弯曲、冲击强度随着纤维含量的增大而提高,拉伸强度达1 124. 89 MPa,约是PEEK纯料的11倍,浸渍带以0°铺放压制的纤维含量为60%的板材力学性能相对最优。扫描电子显微镜(SEM)结果表明,纤维被树脂基体紧密包覆,纤维分散均匀、排列紧密、界面黏结性较好。     

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。