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1.
刘贵熊 《当代化工》2012,41(7):684-686,694
通过γ-缩水甘油醚氧丙基三甲氧基硅(KH-560)对壳聚糖进行交联改性制备乙醇脱水渗透蒸发杂化膜.实验结果表明偶联剂的加入能有效提高壳聚糖膜的分离效果,随着偶联剂含量的增加,杂化膜的对水的选择性先增加后下降,在2%(质量分数)时有最好的选择性.膜的分离因子随着进料温度的增大而降低,随着乙醇浓度的增大而增大;通量随着进料温度的增大而增大,随着乙醇浓度增大而减小.硅烷偶联剂/壳聚糖杂化膜呈现出良好的渗透蒸发分离性能,当进料乙醇浓度为95%(质量分数),温度为35℃时,通量和分离因子分别为134g/(h·m2)和97214.  相似文献   

2.
制备了以聚乙烯醇(PVA)填充纳米SiO2改性膜为活性层,聚丙烯腈(PAN)超滤膜为底膜的PVA-SiO2/PAN杂化复合膜,并用于己内酰胺(CPL)脱水。用FTIR,SEM,XRD,TGA分别对膜进行了表征,并考察了膜中纳米SiO2粒子的质量分数、进料组分质量分数和温度对复合膜分离性能的影响。结果表明,引入纳米SiO2后,杂化膜的热稳定性明显提高。当膜中纳米SiO2质量分数为1.0%时,复合膜渗透蒸发分离性能最佳。60℃下此复合膜用于分离质量分数为40%的CPL溶液时,其总通量和分离因子分别达到2 177 g/(m2.h)和349。  相似文献   

3.
将氧化石墨烯(GO)与白炭黑(SiO_2)在液相中实现纳米杂化,并通过3-氨基丙基三乙氧基硅烷(KH 550)构建化学键合,然后经喷雾干燥制备GO-SiO_2纳米杂化填料,进一步与溶聚丁苯(SSBR)-顺丁橡胶(BR)共混制备了GO-SiO_2/SSBR-BR纳米复合材料。通过X射线衍射和电子显微镜表征了GO-SiO_2杂化填料的内部结构,结果证实GO实现了纳米剥离,并与白炭黑在纳米尺度上相互穿插隔离。性能研究结果表明,GO-SiO_2纳米杂化填料与橡胶基质的相容性大幅改善,二者具有更强的界面相互作用;在GO填充量为3份(质量)时,相比于未填充GO的试样,复合材料的拉伸强度、100%定伸应力和撕裂强度分别提高了23%、55%和18%,滚阻温升降低了13%,耐磨性能提高了31%。GO-SiO_2纳米杂化填料有望应用于绿色节能轮胎胎面中,而喷雾干燥技术也有望实现GO在橡胶纳米复合材料中的规模化应用。  相似文献   

4.
溶胶-凝胶法制备纳米SiO2/环氧树脂杂化材料   总被引:6,自引:1,他引:5  
采用溶胶凝胶(Sol-Gel)法,以正硅酸乙酯(TEOS)为无机先驱体,γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)为偶联剂,氨水为催化剂,制备了纳米SiO2/环氧树脂杂化材料以有效控制纳米粒子在基体树脂中的分散。考察了共溶剂乙醇对溶胶-凝胶过程的影响,通过力学性能测试研究了TEOS和KH-570用量对杂化材料性能的影响并通过扫描电镜(SEM)对杂化材料的微观结构进行了表征。结果表明:TEOS质量分数为3%,KH-570质量分数为2%时杂化材料拉伸强度和弯曲强度分别提高9%和10%。杂化材料断口形貌有明显的波纹状,表现为韧性断裂。该方法能够实现无机成分和有机环氧树脂在分子级别上的复合,制备出高性能杂化材料。  相似文献   

5.
聚丙烯酸酯/TiO2-SiO2纳米杂化材料性能的研究   总被引:1,自引:0,他引:1  
采用具有核-壳结构的纳米TiO2-SjO2与热固性聚丙烯酸酯原位复合,通过溶胶-凝胶法制得了有机-无机纳米杂化材料,并对材料的结构和性能进行了表征。结果表明:聚丙烯酸酯基纳米SiO2包覆TiO2的有机-无机纳米杂化材料在无机组分质量分数低于8%时是透明的;随着TiO2-SiO2用量的增加,纳米杂化材料的附着力是先增后降,而热稳定性则是逐渐增加;拉伸强度和冲击强度随TiO2-SiO2用量的增加都是先增后降,当TiO2-SiO2质量分数为5.10%时,拉伸强度达到最大值,提高了25%;当TiO2-SiO2质量分数为3.45%时,无缺口冲击强度达到最大值,提高了27%。  相似文献   

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利用2,2'-偶氮(2-脒基丙烷)二氯化氢(AIBA)引发剂与纳米氧化硅粒子的静电作用而使AIBA吸附在纳米氧化硅表面,进而引发丙烯腈-甲基丙烯酸甲酯(AN-MMA)原位乳液聚合.考察了AIBA浓度和反应温度对AN-MMA原位乳液聚合动力学的影响以及氧化硅含量对AN-MMA共聚物/纳米氧化硅复合乳胶粒径分布和形态的影响.结果表明:聚合速率随AIBA浓度和聚合温度的升高而增大; AIBA浓度相同时,原位乳液聚合速率小于普通乳液聚合;AN-MMA共聚物/纳米氧化硅复合粒子粒径随纳米氧化硅含量增加而增大;原位乳液聚合得到的复合胶粒表面粗糙,当纳米氧化硅质量分数为10%时,纳米氧化硅与聚合物乳胶粒子复合良好;当纳米氧化硅质量分数为20%和30%时,有部分纳米氧化硅粒子与乳胶粒子分离而分散在连续相中.  相似文献   

7.
通过纳米TiO2粒子填充改性制备了新型TiO2/PVA杂化膜。红外光谱表明纳米TiO2表面的羟基与聚乙烯醇(PVA)链上的羟基存在较强的氢键作用。扫描电镜显示当TiO2的质量分数低于1.5%时,在PVA中分散均匀。X射线衍射显示纳米TiO2的加入降低了膜的结晶度。通过对含水质量分数低于20%的水/乙醇体系的脱水研究了该杂化膜的渗透性能,考察了TiO2粒子填充量、料液质量分数和温度与膜分离性能之间的关系。渗透通量J随着TiO2、水质量分数和温度的升高而增加,分离因子随着温度和水质量分数的升高而下降,在TiO2质量分数为1.5%时分离因子达到最佳值。40℃下分离质量分数85%的乙醇水溶液,分离因子可达1 590,渗透通量为0.049kg/(m2.h)。  相似文献   

8.
为了解决造纸废液污染、有效利用废弃资源,以造纸废液为原料,采用喷雾干燥法制备木质素超细粉,在小试的基础上,对工业化制备条件及影响因素进行了讨论。确定出制备木质素超细粉的最佳工艺条件为:喷雾进料温度50—60℃、进料质量分数20%—25%、进风温度190℃、出风温度70℃、进料流量150 mL/m in、雾化压力2.3 MPa、喷嘴孔径0.8 mm,制得的木质素超细粉粒径为20—100 nm,比表面积37.8—455.6 m2/g。结果表明,采用喷雾干燥法处理造纸废液可得到木质素超细粉。  相似文献   

9.
以自制的端异氰酸酯基聚丁二烯(ITPB)为基体,纳米二氧化硅(SiO2)为交联固化剂,采用预聚体法制备了一系列不同纳米SiO2含量的有机-无机杂化材料。阐述了其制备机理,研究了不同固化条件对有ITPB/SiO2杂化材料力学性能的影响,并对其进行了动态力学分析和X射线衍射分析。结果表明:室温固化14 d后,110℃固化24 h,杂化材料的综合力学性能最佳。纳米SiO2的添加量越多,杂化材料的储能模量越大。添加质量分数12%的纳米SiO2杂化材料的抗湿滑性能和操控性能最好,纳米SiO2添加质量分数为8%时,杂化材料的滚动阻力最小。  相似文献   

10.
《工程塑料应用》2007,35(11):81-82
本发明涉及一种全生物降解聚乳酸纳米复合材料的制备方法。其制备工艺步骤为:①按质量比1:500~3:2选取天然纳米高分子材料与聚乳酸,增塑剂的质量为天然纳米高分子材料和聚乳酸的1%-30%,所述的天然纳米高分子材料为淀粉纳米晶或甲壳素晶须;初步混合均匀;②进行密炼或混合;③在进料速度60~300g/min下将物料加入到双螺杆挤出机(多段温度控制,温度区间为90—210℃)中在挤出温度150—205℃、  相似文献   

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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.  相似文献   

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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.  相似文献   

15.
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.  相似文献   

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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.  相似文献   

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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.  相似文献   

20.
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。  相似文献   

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