Ion conductivities and interfacial characteristics of the plasticized polymer electrolytes based on poly(methyl methacrylate-co-Li maleate)

The plasticized polymer electrolytes composed of poly(methyl methacrylate-co-Li maleate), lithium perchlorate, and ethylene carbonate as a plasticizer, were newly prepared. The ion conductivities of the plasticized polymer electrolytes based on the poly(methyl methacrylate-co-Li maleate) were found to be dependent on the ion content of the ionomer, poly(methyl methacrylate-co-Li maleate), in the polymer electrolyte, and the polymer electrolyte based on the ionomer with 8.5 mol% ion content showed the maximum ion conductivity.The interfacial resistance at the polymer electrolyte/lithium interface and the cationic transference number were also investigated as a function of the ion content of the ionomer in the polymer electrolyte. The interfacial resistances as well as the cationic transference numbers of the polymer electrolytes were found to be also dependent on the ion content of the ionomer in the polymer electrolyte. Ion aggregations in the ionomer seemed to significantly influence the electrochemical behavior of the polymer electrolytes based on the ionomer.     

Effect of acidic pretreatment on the chemistry and distribution of lignin in aspen wood and wheat straw substrates

In this work, aspen and wheat straw substrates were pretreated using aqueous dilute acid (DA) and chemimechanical (CM) pretreatment, and the impact of these pretreatments on biomass lignin was investigated. Here DA pretreatment refers to the acidic treatment of biomass powders and CM pretreatment refers to the acidic treatments of chips or stalks followed by disc refining. The resulting substrates were observed using advanced microscopy techniques to determine changes in lignin distribution throughout the fiber cell wall due to the acid treatments. Following acid treatment, lignin within the cell wall was divided into spherical or elongated bundles. The surface of DA and CM pretreated substrates were shown to differ, with CM pretreated aspen exhibited a more cellulose-rich surface. X-ray Photoelectron Spectroscopy data indicated reduced surface lignin on CM pretreated aspen and increased surface lignin on CM pretreated wheat straw. Fourier transform infrared spectroscopy (FT-IR) spectra illustrated changes in bands related to hemicellulose lignin, and surface hydroxyl content suggesting possible differences in lignin chemistry. It was hypothesized that differences in lignin distribution based on biomass type and pretreatment method were due to interactions between the chemical treatment and the mechanical size reductions steps. Particle size prior to chemical treatment could impact the movement of lignin onto sample surface, and chemical treatment prior to size reduction could impact the fracture plane during the downsizing process. It is expected that both these effects could impact lignin distribution within the sample and on the sample surface.     

麦渣与制浆废液共混制备成型颗粒燃料及其燃烧特性分析

为研究麦渣与制浆废液共混制备的成型颗粒燃料的燃烧特性, 通过热重分析法对其燃烧热力学及燃烧动力学进行了研究。结果表明: 制浆废液的添加使颗粒燃料出现固定碳的二次燃烧阶段, 有利于降低成型颗粒燃料的挥发分、固定碳燃烧阶段的点火温度及最大燃烧速率温度, 对颗粒燃料的燃烧有正向协同作用; 制备的颗粒燃料的一阶动力学模型拟合曲线的相关系数在0.95以上, 颗粒燃料在挥发分燃烧和固定碳燃烧阶段的活化能和指前因子均随制浆废液的添加而降低。当废液固形物质量分数为53%时制备的成型颗粒燃料, 其挥发分燃烧阶段和固定碳燃烧阶段的活化能为72.85和83.52kJ/mol, 指前因子为2.82×10⁶和3.73×10⁵min^-1。制浆废液的添加使颗粒燃料更易燃烧, 且燃烧过程稳定不易爆燃。     

微晶纤维素基复合材料的制备及其对亚甲基蓝的催化降解性能

以微晶纤维素(MCC)为原料,通过在其表面负载纳米氧化铜颗粒(CuO NPs),添加3-氯丙基三甲氧基硅烷(CPTES)与二乙醇胺(DEA)进行接枝反应制备CuO NPs@MCC–Si–N(OH)₂复合材料。探讨了DEA添加量对CuO NPs@MCC–Si–N(OH)₂性能的影响,表征并分析了改性微晶纤维素红外光谱、晶体结构、表面形貌和热稳定性。结果表明,CuO NPs可成功负载在MCC表面,硅烷偶联剂可提高复合材料的分散性与接枝胺基的能力,进而增强其催化活性,使硼氢化钠(NaBH₄)与亚甲基蓝(MB)氧化还原反应效率增加,快速降解MB染色剂。通过优化发现DEA用量为20wt%时制得的CuO NPs@MCC–Si–N(OH)₂催化效果最佳,CuO NPs@MCC–Si–N(OH)₂和NaBH₄的用量分别为30 mg和10 mg,处理30 mL 3 mmol/L MB溶液5 min后,MB去除率可达99.71%,五次循环性测试后,去除率为93.24%。      

Effect of oxygen on the surface conductance of porous silicon: towards room temperature sensor applications

The surface conductance of an aluminum/p-type porous silicon device is reversibly changed on exposure to gaseous oxygen. The aluminum electrode gap has been found to cause a four-fold increase in initial rate of change of conductance on doubling the electrode separation on exposure to oxygen. Potential use of such devices in room temperature oxygen sensing is described.