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研究了一种应用微波技术在常压下对废PET催化降解以实现化学回收的方法。考察了在微波作用下,醇解温度、物料配比、催化剂含量及醇解剂官能度对废PET降解程度及降解产物的影响,并利用红外光谱仪对降解产物的化学结构进行了分析。结果表明:综合考虑废PET的醇解程度、醇解产物的性能以及经济成本因素,选定的最佳工艺条件是微波功率500W时,醇解时间15min、反应温度220℃、二甘醇与废PET的质量比为1.25、醋酸锌用量0.2%;其他反应条件不变,将醇解剂改为甘油和二甘醇的混合醇,混合醇与废PET的质量比为1.5,当二甘醇与甘油质量比为1:1时,醇解产物羟值最高,可以达到477mg/g;实验所得的废PET的二甘醇醇解产物是羟基封端分子链含有醚键的聚酯多元醇。 相似文献
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聚四氢呋喃学名聚四亚甲基醚二醇、四氢呋喃均聚醚,简称PTMEG,常温下为白色蜡状固体,熔化后为无色透明液体,是由四氢呋喃开环聚合而成。 相似文献
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通过高温高压醇解法对废聚对苯二甲酸乙二醇酯(PET)在催化剂金属醋酸盐作用下,进行乙二醇醇解得到对苯二甲酸乙二醇酯(BHET),研究了废PET高温醇解的影响因素及工艺条件。结果表明:在高温醇解反应中,乙二醇与废PET的质量比和反应压力为主要影响因素,反应温度和解聚时间为次要影响因素;BHET收率随反应时间的延长、温度与压力的升高、乙二醇与废PET的质量比加大、催化剂的用量增大而增加,而二甘醇含量(除质量比因素)及醇解产物的熔点则随其相应降低;最佳醇解反应条件为压力0.4 MPa、乙二醇与废PET质量比0.5∶1.0、反应温度250℃、反应时间4 h,BHET收率达82%。 相似文献
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《煤炭转化》2016,(3)
以新疆阜康西沟煤为研究对象,考察了甲醇(MET)和洗油(WO)混合溶剂下的醇解条件,醇-碱体系下的醇解行为及醇解残渣的液化性能,并与煤样直接液化结果进行对比.结果表明:θ=320℃,t=60min,m(solvent)∶m(coal)=10∶1,mMET∶mWO=8∶2为适宜的醇解条件,此条件下,醇解率为21.8%.进一步加入NaOH或CaO作为醇解催化剂,当碱煤比=0.8∶1时,醇解率分别为51.3%和27.4%.以洗油为供氢溶剂,对醇解残渣进行直接液化,并与原煤样直接液化的结果进行对比,煤样直接液化的总液体产率为62.3%,而无碱醇解、CaO醇解和NaOH醇解产物的总液体产率依次为71.0%,72.7%,83.2%,分别提高了8.7%,10.4%和20.9%.同时,对醇解产物进行了FTIR,TG-DTG和SEM表征,对催化醇解与煤样直接液化的气体产物进行了GC分析. 相似文献
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甲基丙烯酸二元醇酯的合成及分析 总被引:1,自引:0,他引:1
以对甲苯磺酸为催化剂,对苯二酚为阻聚剂,采用酸醇直接酯化新方法合成了二(甲基丙烯酸)乙二醇酯,二(甲基丙烯酸)二甘醇酯,二(甲基丙烯酸)聚乙二醇-200酯。所得产物颜色浅,纯度及收率高。并对产物进行了GC、IR、1HNMR、MS分析 相似文献
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分别采用等离子喷涂两层和三层梯度隔热涂层的方法研究了梯度隔热涂层对高炉风口寿命的影响,并分别进行了工业试验。试验采用的两层结构即金属型粘结底层(Ni-Cr-Al-Y)和ZrO2陶瓷工作层;三层结构即在工作层的ZrO2涂层中配入3%~6%的CaO作为稳定剂来抑制ZrO2相变膨胀,在金属型粘结底层(Ni-Cr-Al-Y)上涂附25%Ni-Cr-Al-Y和75%ZrO2的复合粉作为中间过渡层以消除膨胀应力。两种涂层的厚度均为0.1mm。结果表明:这两种涂层结构设计都能够有效延长金属风口的寿命,使风口的寿命分别提高了1倍和3倍;但理想的涂层厚度应为0.3~0.5mm。 相似文献
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A lattice model of catalyst layer in proton exchange membrane fuel cells (PEMFCs), consisting of randomly distributed catalyst phase (C phase) and mixed ionomer-pore phase (IP phase), was established by means of Monte Carlo method. Transport and electrochemical reactions in the model catalyst layer were calculated. The newly proposed C-IP model was compared with previously established pore-solid two phase model. The variation of oxygen level and reaction rate along the thickness of catalyst layer with cell current was discussed. The effect of ionomer distribution across catalyst layer was studied by comparing profiles of oxygen level, reaction rate and overpotential, as well as corresponding polarization curves. 相似文献
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Yoshiaki Morisada Yoshinari Miyamoto Hideki Moriguchi Katsunori Tsuduki Akihiko Ikegaya 《Journal of the American Ceramic Society》2004,87(5):809-813
Diamond particles were coated with a thin SiC layer by the reaction of SiO vapor with diamond, and the growth mechanism of SiC as well as the oxidation resistance of the SiC-coated diamond were studied. The growth process of the SiC layer can be separated into two steps. In the first step, a thin layer of SiC with a thickness of about 15 nm is formed due to the reaction between SiO vapor and diamond. In the second step, nanometer-sized SiC granules are deposited on the SiC layer by the reaction between SiO vapor and CO. The apparent activation energy for the formation of SiC layer on diamond was found to be 100 kJ/mol. This value suggests that the SiC coating process occurred mainly by vapor-phase reaction. The oxidation resistance of the SiC-coated diamond was improved depending on the thickness of the SiC layer. Oxidation of the SiC-coated diamond particles began at 950°C, which was 400°C higher than that of uncoated diamond. 相似文献
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Mitsugi Senda 《Electrochimica acta》1995,40(18):2993-2997
Effect of the electric double-layer structure on the rate equations of charge (ion or electron) transfer across an electrolyte/electrolyte solution interface is discussed. The electric double layer is considered as composed of the inner layer sandwiched by two diffuse layers in both side. The charge transfer reaction is considered as taking place between two chemical species at the planes of contact of the inner layer with the two respective diffuse layers. A steady-state ionic transport in the diffuse layers (Levich correction) is assumed. Two ideal processes; inner layer rate-determining process and diffuse layer rate-determining process are addressed. 相似文献
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将酶与带相反电荷的聚电解质在单分散疏水多孔St/DVB共聚微球表面交替吸附静电自组装多层脂肪酶膜. 确定了静电自组装单层酶膜的最佳条件为酶与载体的质量比3:1,吸附时间0.5 h, pH 5.5. 在上述条件下静电自组装3层脂肪酶膜,结果表明,当最外层为酶层时,组装2层酶的活性比单层酶提高24%,组装3层酶的活性比2层酶的活性稍有增加. 在酶液pH 7.5的条件下,考察了聚电解质中的离子强度对静电自组装各层酶活力的影响,结果表明,当最外层为酶层或聚电解质层时,酶的活力随层数增加而下降. 相似文献
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在1400℃下,将平均尺寸φ15 mm?10 mm的石灰块投入CaO?SiO2?FeO及CaO?SiO2?FeO?P2O5两组渣系中,研究了静态条件下石灰在两组渣系中的溶解行为。结果表明,两组渣系在反应界面周围形成四个区域,即基体渣层、C2S渗透层、铁酸钙渗透层和石灰层。渗透层为石灰中的Ca2+与液渣中的Fe2+相互渗透所形成的一个多相共存区域,存在致密固相层影响石灰的溶解。渗透层中的铁酸钙层逐渐被C2S层取代,C2S层厚度不断增加最终溶解于液相渣中。5~60 s两组渣系石灰溶解速度相近,60~80 s含磷渣系石灰溶解速度显著加快。当渣中加入P2O5时,磷会固溶于C2S中形成C2S?C3P固溶体层,该层的形成会排挤FeO进入渣中,提高渣的渗透能力,加速石灰溶解。 相似文献
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Micro Four‐Layer SiC Coating on Matrix Graphite Spheres of HTR Fuel Elements by Two‐Step Pack Cementation 下载免费PDF全文
Ping Zhou Xiaoxue Liu Hongsheng Zhao Ziqiang Li Zujie Zheng Kaihong Zhang Bing Liu 《Journal of the American Ceramic Society》2016,99(11):3525-3532
A micro four‐layer SiC coating, which includes inner transition layer, fine‐grained layer, dense bulk layer, and outer loose layer, was fabricated on the matrix graphite spheres of high‐temperature gas‐cooled reactor fuel elements to improve the oxidation‐resistant property by a two‐step pack cementation process. According to the experiment results, the micro four‐layer can be differentiated by SiC grain size and microstructure variation. The oxidation tests at 1773 K for 200 h reveal that the coating structure could effectively improve the oxidation resistance of matrix graphite spheres with a weight gain of 0.52 wt%, and the fine‐grained and dense bulk layers are evidenced as two main antioxidation layers. Although the thermal expansion coefficients of SiC and matrix graphite do not match each other so well, no obvious stress cracking was observed after thermal shocking tests from 1773 K to room temperature for 100 times. 相似文献
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介绍芳纶材料在轮胎胎圈上的应用与制造技术,重点以折叠胎为例介绍层叠法芳纶胎圈骨架生产工艺。采用以天然橡胶为基体的粘合体系,用热敏剂控制不同流程中所需要的粘合体系的形态,对芳纶纤维进行浸浆处理。以2股芳纶并行缠绕层叠形成宽4mm、高3mm的芳纶胎圈骨架,其有效利用率可达78%。 相似文献
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Methylene diphenyl isocyanate (MDI)-based polyurethane flexible foams were decomposed by alkanolamines without a catalyst at 150°C. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, and the lower liquid layer was methylene diphenyl amine (MDA) and alkanolamine derivatives. These layers were analyzed using gel permeation chromatography (GPC) and 13C-NMR. The upper layer was obtained as a relatively pure polyether. The lower layer was observed to be MDA and 2-hydroxyethyl carbamic acid ester prepared from alcoholysis products during the decomposition reaction. It was thought that the decomposition process of polyurethane foam by alkanolamines was not aminolysis but alcoholysis. © 1994 John Wiley & Sons, Inc. 相似文献
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《Ceramics International》2020,46(3):2915-2922
The growth of thermally grown oxide (TGO) is a significant factor affecting the failure mechanism of thermal barrier coatings (TBCs) during cyclic high temperature service. In this work, a complicated finite element model with two semicircles reflecting the undulation of TGO interfaces was proposed, and four representative shapes of TGO interfaces were selected. There are mainly two methods to simulate TGO growth under high temperature, and each method was achieved by implementation of user subroutines in finite element method. A total of 100 thermal cycle loads were applied to the TBCs continuously. The stress evolution in the layers of Top Ceramic Coating (TC) and Bond Coating (BC) at the end of each thermal cycle load was obtained, the influence of TGO growth on stress evolution was analyzed, the differences between two methods of TGO growth were discussed. The results show that under TGO growth simulated by the first method, the stress distribution in the y direction does not change in both TC and BC layer, and the maximum stress decreases a lot in TC layer but nearly remains the same in BC. When the growth of TGO was simulated by the second method, stress evolution is complex and undergoes up to five stages with a small undulation or convex of TGO interfaces. Stress evolution in BC layer remains as the same as in the first method. Moreover, the maximum stress increases continually in BC layer. The comparison of these two simulation method would help to study the failure of TBCs caused by TGO growth. 相似文献