竹原纤维增强复合材料的研究

竹原纤维与低熔点聚酯纤维及聚丙烯纤维的混合纤维集合体加工成非织造物,再经热压成型后,制成竹原纤维增强聚酯、聚丙烯热塑性树脂复合材料板材,并与竹原/亚麻纤维增强聚酯、聚丙烯热塑性树脂复合材料进行性能对比,进一步探讨这种复合材料板材的最佳制作工艺。鉴于这种材料可以被用于汽车和建筑等领域,通过对材料力学性能测试结果的模糊综合评判,选出性能最优的复合材料为竹原纤维/LMPET(40/60),在模压温度、时间、压力分别为165℃,30min和30MPa的条件下,所压制复合材料的纵向拉伸强度为136MPa,横向为87·58MPa;纵向弯曲强度为534MPa,横向为470MPa。     

成型工艺对玄武岩纤维增强PPS夹芯结构材料力学性能影响

夹芯结构材料具备质量轻、刚性高、功能综合型等优点,广泛应用于航天航空、交通运输、功能材料等领域。为研究成型工艺对夹芯结构材料性能的影响,以玄武岩纤维增强聚苯硫醚复合材料、连续玻璃纤维增强聚丙烯单向预浸带为原材料,探究了模压成型工艺中贴合压力、热压温度、热压时间以及芯层材料密度等因素对夹芯结构材料性能的影响。结果表明,模压成型工艺中热压温度和热压时间的最优条件为220℃,15 min;芯层材料的密度减小时,其弯曲性能、冲击强度呈先增大后下降的趋势,弯曲强度和弯曲弹性模量最大为271.53 MPa,18 672.72 MPa,冲击强度最大为119.21 kJ/m2。芯层材料的密度减小时,其弯曲刚度呈上升趋势,最大弯曲刚度可达15 441.16 N·mm。     

蒸汽爆破预处理对LDPE／棉皮纤维复合材料力学性能的影响

采用蒸汽爆破预处理过的棉皮作为增强纤维,通过模压成型制备LDPE/棉皮纤维复合材料,研究了爆破压力、棉皮纤维质量分数对LDPE/棉皮纤维复合材料力学性能的影响.实验结果表明,该复合材料的力学性能得到了改善,当压力为1.8 MPa、棉皮纤维质量分数为35%时,所获得的拉伸强度和弯曲强度为最佳.     

干纤维铺放真空辅助成型复合材料的性能

模拟干纤维铺放原理,将连续热塑性纤维作为定型材料铺放在碳纤维无皱褶织物中间,在热压条件下制备复合材料预成型体,并采用真空辅助工艺制备复合材料试样。测定了采用不同预成型压力、预成型温度以及热塑性纤维含量等预成型条件下制备的复合材料试样的纤维体积含量、力学性能以及微观结构等。结果表明,预成型压力越大,纤维体积含量越高,当预成型压力达到1 MPa以后,纤维体积含量趋于稳定,最高可达65%;在相同预成型压力下,随着定型材料用量的增加,纤维体积含量降低,力学性能随之降低;预成型温度对复合材料的性能影响主要取决于定型材料本身是否发生熔融,若发生熔融,定型材料会对复合材料性能产生不利影响。     

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。     

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。     

PP/甘蔗皮纤维复合材料的拉伸性能

采用热压工艺制造聚丙烯(PP)/甘蔗皮纤维复合材料,并研究其拉伸性能。研究热压温度为175℃、压力为2 MPa、时间15 min工艺条件下纤维粒径大小和质量分数对复合材料拉伸强度和拉伸弹性模量的影响。结果表明:在甘蔗皮纤维质量分数为40%条件下,复合材料拉伸性能随着粒径减小呈现先增加后减少的趋势,当纤维粒径为40~60目(0.45~0.3 mm)时材料拉伸强度最大,为8.58 MPa,此时弹性模量为2.44 GPa;在相同纤维粒径40~60目条件下,纤维质量分数为40%时PP复合材料拉伸强度最大,纤维质量分数为50%时PP复合材料拉伸弹性模量最大,达到2.65 GPa。根据实验结果,甘蔗皮纤维增强PP复合材料在纤维粒径为40~60目、质量分数在40%时综合拉伸性能最佳。     

工艺间隙对气囊法成型复合材料圆管性能影响

设计并加工了气囊法成型复合材料圆管的不锈钢模具,并利用硅橡胶圆管作为加压气囊,制备了不同工艺间隙条件下的碳纤维复合材料圆管。利用金相显微镜观察了圆管横截面的微观形貌,对圆管的压缩性能进行了测试,并与同种材料和固化制度条件下热压罐成型平板的压缩强度进行了比较。结果表明,工艺间隙与圆管设计壁厚比值为34%时,圆管的成型质量最好,管壁的单层厚度相对较小且比较均匀,管壁内部缺陷较少,压缩强度为634MPa,与热压罐成型平板的压缩强度647MPa相当;工艺间隙增大后,成型质量逐步变差,压缩强度逐步下降,工艺间隙比值为86.7%时,出现了明显的分层和孔隙缺陷,且单层厚度明显偏大且不均匀,圆管的压缩强度下降到427MPa,相比最高值下降34%左右;工艺间隙减小后,成型质量和压缩强度也出现减小的趋势,但减小幅度相对不大。     

热压成型工艺对PE-LLD/CFBFA复合材料性能影响全文替换

将循环流化床粉煤灰（CFBFA）和线型低密度聚乙烯（PE-LLD）通过热压成型法制备成PE-LLD/CFBFA复合材料板材,在CFBFA质量分数为60%时,探讨了成型压力、热压温度、热压时间对PE-LLD/CFBFA复合材料力学性能的影响,并在优化的实验条件下探讨了CFBFA添加量对复合材料力学性能的影响。结果表明,复合材料的弯曲性能随成型压力、热压温度和热压时间的增加基本呈现先上升后下降的变化规律,冲击性能则大致呈现相反的变化趋势,过高的CFBFA添加量会导致复合材料力学性能严重下降。在成型压力6 MPa、热压温度180℃和热压时间45 min条件下,CFBFA质量分数为60%时制得的复合材料邵氏硬度为66.2,弯曲强度为17.69 MPa,弯曲弹性模量为2092 MPa,冲击强度为2.91 J/m²,该实验条件属优化参数,可用于指导工业生产。     

国内文摘

80 014 用于涤/棉混纺织物的活性分散染料大连工学院侯毓汾潘鑫宋东明本文综合分析了含β-羟乙基砜硫酸酯活性染料的染棉机理和涤纶纤维用微溶性非离子型分散染料的结构特点,提出了一类用于涤/棉混纺织物的活性分散染料。这类染料可经热熔法印染涤/棉混纺织物,并介绍了这类染料的分子结构特点以及与涤/棉混纺织物两种不同纤维的结合。     

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。