碳纳米管增强固体浮力材料性能研究

采用超声分散和模具浇注成型法制备环氧树脂/多壁碳纳米管/空心玻璃微珠固体浮力材料。研究了碳纳米管用量对固体浮力材料密度、压缩性能及吸水性的影响。结果表明:当空心玻璃微珠体积分数为60%时,随着碳纳米管用量的增加,复合材料的压缩强度先提高后降低;当碳纳米管用量为0.1%时,复合材料的压缩强度最高(44.03 MPa),密度为0.572 g/cm3,吸水率低于1.0%;随着碳纳米管用量的增加,固体浮力材料的压缩强度和密度降低,吸水率提高。     

凝胶-注模成型技术制备碳纤维/HA复合材料的研究

本文研究了pH值、分散剂、有机单体和碳纤维含量对碳纤维/HA陶瓷浆料粘度的影响,观察了复相陶瓷浆料的凝胶固化过程,研究了烧结温度和碳纤维含量对复合材料烧结密度、抗弯强度和断裂韧性的影响.研究结果表明:当pH =9、有机单体含量为10wt％、分散剂含量为5wt％、固相含量为50wt％的碳纤维/HA陶瓷浆料具有良好的分散性.随引发剂、催化剂含量的增加,复相陶瓷浆料的凝胶固化时间缩短.复合材料的烧结密度、抗弯强度和断裂韧性均随烧结温度的升高而升高.复合材料的抗弯强度和断裂韧性均随着碳纤维含量的增加呈现先增加而后降低趋势.当碳纤维含量为2wt％和2.5wt％时,凝胶注模成型所制备的复合材料的抗弯强度和断裂韧性分别为80.6 MPa和1.87 MPa·m1/2,较干压成型样品提高了24.9％和19.8％.     

碳纤维增强PE-UHMW/木粉复合材料的力学性能

为了改善超高分子量聚乙烯(PE-UHMW)的加工性能,提高其力学性能,以木粉和碳纤维为填料,制备了高填充量碳纤维增强PE-UHMW/木粉复合材料。研究了碳纤维含量对PE-UHMW/木粉复合材料弯曲性能、拉伸性能及动态热机械性能的影响。研究结果表明,加入碳纤维可提高PE-UHMW/木粉复合材料的弯曲强度及拉伸强度。拉伸强度和弯曲强度都随着碳纤维的含量的增加呈现出先增加后减小的趋势。当碳纤维质量分数为3%时,弯曲强度达到最大值,为25.2 MPa,比未加碳纤维时提高了46.5%。当碳纤维质量分数为2%时,弯曲强度达到最大值,为38.4 MPa,比未加碳纤维时提高了27.1%。随着碳纤维含量的增加,复合材料的储能模量显著提高。碳纤维的加入使复合材料的损耗因子峰值增大。     

空心玻璃微珠种类及加入量对无机非金属固体浮力材料性能的影响

以偏高岭土、钠水玻璃与空心玻璃微珠(HGB)为主要原料制备无机非金属固体浮力材料.研究了四种不同型号HGB对材料密度和抗压强度的影响,以及HGB加入量对材料成型性、密度、孔隙率、抗压强度、吸水性和冲击断面微观形貌的影响,并对材料的耐高温性能进行了测试.研究结果表明:综合考虑不同型号HGB的自身参数及对材料密度和抗压强度的影响,型号为S38HS的微珠效果最佳;随着HGB-S38HS加入量的增加,材料密度和抗压强度逐渐降低,而孔隙率和吸水率逐渐增大;当HGB-S38HS加入量为30％ ～ 35％时,制得的无机非金属固体浮力材料具有相对较低的密度和相对较高的抗压强度,分别为0.82 ～0.90 g/cm3和8.4 ～9.2 MPa,且耐高温性能较好,可达到550℃.     

氧化石墨烯增强环氧树脂复合材料的制备与性能

利用二乙烯三胺在氧化石墨烯(GO)表面引入氨基基团得到改性GO,然后与环氧树脂(EP)复合,制备出GO增强EP复合材料。性能测试结果表明,该复合材料具有良好的疏水性及力学性能。复合材料的吸水率随着改性GO含量增加先降低后提高,当改性GO含量为0.2%时,吸水率最低,浸泡12 d后吸水率为0.125%,与纯EP相比降低了81.48%,当改性GO含量继续增加,由于复合材料界面局部空隙的增加,吸水率反而大幅上升。复合材料的拉伸强度、冲击强度随着改性GO含量增加先提高后降低,当改性GO含量为0.05%时,拉伸强度、冲击强度最高,分别为50.94 MPa,5.78 k J/m2,相比纯EP增加了104%和90%。综合考虑,当改性GO含量为0.05%时,复合材料的分散性能、疏水性及力学性能较优。     

高性能复合泡沫材料的制备与性能研究

以环氧树脂、氰酸酯树脂和中空玻璃微珠为原料制备了高性能复合泡沫材料,通过示差扫描量热分析和热重分析以及弯曲性能和吸水率测试研究了玻璃微珠含量对复合泡沫材料性能的影响。结果表明,玻璃微珠的加入促进了环氧与氰酸酯间的固化反应。加入玻璃微珠后,复合材料的最大热分解温度和玻璃化转变温度变化不大,但初始热分解温度略有下降。与纯树脂基体相比,复合材料的弯曲模量基本保持不变,但在玻璃微珠质量分数从5%增至10%时,弯曲强度急剧下降。此外,随着空心玻璃微珠含量的增加,复合泡沫材料的密度逐渐降低,吸水率逐渐增加。     

空心玻璃微珠/PA66复合材料的性能研究

采用空心玻璃微珠(HGM)填充聚酰胺66(PA66),经挤出注塑制得改性PA66复合材料,通过一系列测试方法研究了HGM用量和表面处理方式对复合材料的力学性能、密度和吸水率的影响。结果表明,随着HGM含量的增加,复合材料的拉伸强度、弯曲强度和硬度均增加,在HGM质量分数为10%时达到最大值;密度和吸水率则减少,缺口冲击强度也有所下降。     

粉煤灰空心微珠多孔陶瓷的结构与性能

以粉煤灰和矿粉为原料,制备空心微珠坯体,坯体中粉煤灰含量分别为12.5%(质量分数)、25.0%、37.5%、50.0%,将空心微珠坯体进行堆烧,制备多孔陶瓷。用扫描电子显微镜、X射线衍射仪、X射线荧光光谱仪及电子探针分析仪分析样品的微观形貌和物相组成。结果表明:随着粉煤灰含量的增加,多孔陶瓷体积密度增大。多孔陶瓷的主晶相为硅灰石相,同时含有少量的辉石相。当粉煤灰含量为25.0%、空心微珠坯体在1 000℃烧结时,多孔陶瓷样品体积密度为1.94 g/cm3,抗压强度为163.20 MPa。     

木质素基燃料电池双极板的制备及性能研究

为了充分利用木质素,扩大其在复合材料的应用范围,采用木质素、苯酚和甲醛合成了木质素基酚醛树脂。以天然石墨和碳纤维做导电填料,采用模压工艺制备燃料电池用双极板材料。对复合材料的密度、弯曲性能、动态力学性能和电导率进行表征分析。结果表明,当天然石墨逐步被碳纤维取代后,木质素基复合材料的密度随着碳纤维含量的增加而逐渐下降;弯曲强度则一直增加,但是弯曲模量在碳纤维达到30%时达到最大值,之后开始下降。动态力学性能实验表明,材料的储能模量和玻璃化转变温度随着碳纤含量增加而增加,并在30%碳纤维时达到最高值。复合材料的电导率随着碳纤维含量增加而增加,最大达到500 S/cm,之后复合材料的电导率开始下降。研究结果证明,含有30%碳纤维和30%天然石墨的木质素基复合材料具有较好的综合性能:密度为1.16 g/cm~3,弯曲强度和弯曲模量分别为52.7 MPa和10.7 GPa,电导率500 S/cm。     

玻璃纤维对PTFE/SiO2复合基板材料性能的影响

采用表面改性、物料混合、压延成型、高温真空热压烧结工艺,得到了不同含量玻璃纤维(GF)增强聚四氟乙烯(PTFE)/二氧化硅(SiO2)复合基板材料,考察分析了GF含量对复合材料微观形貌、密度、吸水率、拉伸性能、压缩性能以及微波介电性能的影响情况。结果表明,随着GF含量的增加,PTFE/SiO2复合材料的密度逐渐减小,吸水率和损耗因子逐渐增大,拉伸模量、压缩模量和相对介电常数呈现出先增大后减小的趋势。当PTFE/SiO2复合材料中加入2%的GF时,复合材料具有良好的综合性能,密度为2.085 g/cm3,吸水率为0.094%,拉伸模量为1351 MPa,压缩模量为1643 MPa,相对介电常数为2.93,损耗因子为1.04×10–3。     

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。