纳米二氧化硅接枝黄麻纤维可降解复合材料制备

利用高活性甲苯二异氰酸酯将纳米二氧化硅接枝到黄麻纤维上,以接枝后的黄麻纤维为增强体,聚乳酸为基体注塑成型制备复合材料并测试了力学性能,通过红外光谱(IR)、热重(TG)、扫描电镜(SEM)等手段对材料的化学接枝、结构形态进行研究。结果表明,纳米二氧化硅修饰率为20%,黄麻纤维的接枝率为25%时,复合材料拉伸强度最大为82.15 MPa,缺口冲击强度最大为10.30 k J/m~2;热重分析表明,20%的纳米二氧化硅接枝黄麻纤维复合材料的热分解温度提高至300℃;扫描电镜显示复合材料制备过程会损伤增强体结构。     

麻纤维增强完全可降解复合材料的制备及性能研究

以亚麻落麻纤维、聚乳酸纤维为原料,采用非织造结合模压成型工艺制备了完全可降解复合材料.研究了增强纤维体积分数及纤维长度对复合材料弯曲、冲击性能的影响,采用扫描电镜(SEM)研究了复合材料中纤维与树脂之间的界面结合状况.结果表明:材料的弯曲、冲击强度均随纤维长度的增加而增大,当纤维长度为72mm时,体积分数为40%的材料具有最好的弯曲性能,纵横向弯曲强度分别为55.15、42.02MPa;体积分数为50%的材料具有最好的冲击性能,纵横向冲击强度分别为19.714、14.012kJ/m2;裁切断口处的SEM表明增强纤维与基体树脂之间存有一定数量的空隙,两相之间的界面结合强度有待进一步改善.     

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。     

腰果酚接枝黄麻纤维不饱和聚酯复合材料的力学性能及界面调控

用甲苯二异氰酸酯与腰果酚(CNSL)合成大分子偶联剂接枝黄麻纤维。以接枝的黄麻纤维为增强体,通用的不饱和聚酯树脂为基体,采用热压方式制备复合材料。比较了纯饱和聚酯树脂、5 %CNSL增韧的不饱和聚酯树脂、25 %碱处理的黄麻纤维不饱和聚酯树脂复合材料和25 %的CNSL接枝黄麻纤维不饱和聚酯树脂复合材料的拉伸强度和冲击强度。结果表明,CNSL接枝于黄麻纤维上;CNSL的加入能提高材料的韧性,黄麻纤维能提高材料的拉伸强度而不能提高材料韧性;25 %CNSL接枝的黄麻纤维不饱和聚酯树脂能提高材料的拉伸强度和韧性,25 %CNSL接枝的黄麻纤维增强含5 %CNSL的不饱和聚酯复合材料,其冲击强度为12.10 kJ/m^2。     

苯乙烯对植物纤维渗透性及UP复合材料成型质量影响

为提高真空辅助树脂注射成型工艺制备植物纤维增强复合材料的生产效率和成型质量,以苯乙烯为稀释剂,以不同黏度不饱和聚酯树脂(UP)和苎麻织物制备苎麻织物增强UP复合材料.基于达西定律研究UP黏度对苎麻增强体渗透率的影响,结合复合材料纤维体积分数、力学性能以及内部缺陷对复合材料成型质量进行分析.结果表明,随着UP黏度降低,增...     

废弃混纺纤维/聚乳酸复合材料的制备及力学性能研究

以废弃涤/棉(65/35)混纺纤维作为增强材料,聚乳酸颗粒作为基体材料制备复合材料,并且采用正交及单因素试验对其成型工艺进行优化。结果表明:最优成型工艺条件为涤/棉混纺纤维质量分数40%、热压温度180℃、热压压力12 MPa,该条件下的复合材料的拉伸强度和弯曲强度分别是59.56 MPa和48.75 MPa。     

连续碳纤维增强PPBES基复合材料的力学性能

以共聚型二氮杂萘联苯结构聚醚砜(PPBES)树脂为基体、连续碳纤维(CF)为增强体,通过溶液预浸、热压成型工艺制备单向复合材料.通过对树脂溶液黏度、复合材料纤维体积含量测试,复合材料样条三点弯曲、层间剪切试验,研究了纤维体积含量对复合材料力学性能的影响,并借助SEM断面形貌分析了复合材料受力破坏模式.结果表明:CF/PPBES复合材料的弯曲强度随纤维体积含量的增加呈现先增大后减小的趋势,极值出现在CF体积分数60％时;弯曲模量和层间剪切强度随纤维体积含量的增加呈现逐渐增大的趋势;复合材料受力破坏模式以树脂基体内部破坏为主.     

汽车内饰用纤维素纤维增强聚丙烯复合材料的制备及性能研究

以纤维素纤维母粒和聚丙烯(PP)为主要原料,利用挤出成型工艺制备纤维素纤维增强PP复合材料,研究了不同纤维含量以及马来酸酐接枝聚丙烯(PP-g-MAH)质量分数对材料力学性能、散发特性以及其他性能的影响。研究表明,当纤维含量为15%且PP-g-MAH浓度为3%时,相比滑石粉填充PP复合材料,材料密度下降8%左右,其拉伸强度、弯曲模量和缺口冲击强度分别达到45.2 MPa、2 607 MPa和4.39 kJ/m~2,可满足汽车内饰材料性能要求;纤维素纤维只改变材料味型,同时增加材料甲醛含量,而PP-g-MAH对材料气味等级和味型有着较大的影响;纤维素材料可提高材料的维卡软化点和吸湿率,但通过PP-g-MAH的改性可改善材料吸湿性。     

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.     

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。     

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。