Flexible dielectric materials with environmental-friendly, low-cost and high-energy density characteristics are in increasing demand as the world steps into the new Industrial 4.0 era. In this work, an elastomeric nanocomposite was developed by incorporating two components: cellulose nanofibrils (CNFs) and recycled alum sludge, as the reinforcement phase and to improve the dielectric properties, in a bio-elastomer matrix. CNF and alum sludge were produced by processing waste materials that would otherwise be disposed to landfills. A biodegradable elastomer polydimethylsiloxane was used as the matrix and the nanocomposites were processed by casting the materials in Petri dishes. Nanocellulose extraction and heat treatment of alum sludge were conducted and characterized using various techniques including scanning electron microscopy (SEM), thermogravimetric analysis/derivative thermogravimetric (TGA/DTG) and X-ray diffraction (XRD) analysis. When preparing the nanocomposite samples, various amount of alum sludge was added to examine their impact on the mechanical, thermal and electrical properties. Results have shown that it could be a sustainable practice of reusing such wastes in preparing flexible, lightweight and miniature dielectric materials that can be used for energy storage applications.Flexible dielectric materials with environmental-friendly, low-cost and high-energy density characteristics are in increasing demand as the world steps into the new Industrial 4.0 era. In this work, an elastomeric nanocomposite was developed by incorporating two components: cellulose nanofibrils (CNFs) and recycled alum sludge, as the reinforcement phase and to improve the dielectric properties, in a bio-elastomer matrix. CNF and alum sludge were produced by processing waste materials that would otherwise be disposed to landfills. A biodegradable elastomer polydimethylsiloxane was used as the matrix and the nanocomposites were processed by casting the materials in Petri dishes. Nanocellulose extraction and heat treatment of alum sludge were conducted and characterized using various techniques including scanning electron microscopy (SEM), thermogravimetric analysis/derivative thermogravimetric (TGA/DTG) and X-ray diffraction (XRD) analysis. When preparing the nanocomposite samples, various amount of alum sludge was added to examine their impact on the mechanical, thermal and electrical properties. Results have shown that it could be a sustainable practice of reusing such wastes in preparing flexible, lightweight and miniature dielectric materials that can be used for energy storage applications.

明矾是一种可以改良粉条粉丝易断粗糙特性的违法添加剂, 明矾的含量过高进入人体后会直接影响身体健康。 结合太赫兹光谱技术探索红薯淀粉中明矾含量快速检测方法。 采用太赫兹时域光谱系统(Terahertz time domain spectroscopy, THz-TDS)于常温下获取0.5～7 THz范围内红薯淀粉、 明矾及其混合物的光谱数据。 因0～0.5 THz测得的频谱均为噪声, 高频段区域的吸收系数大、 信噪比低, 故选取0.5～2 THz波段的吸收系数谱和折射率谱进行分析。 发现明矾在该波段存在明显的特征吸收峰, 可作为指纹特征用于物质识别。 分别采用Savitzky-Golay卷积平滑（SG Smoothing, SG 平滑）、 基线校正（Baseline）、 归一化（Normalization）等方法进行光谱预处理, 再结合偏最小二乘(partial least squares, PLS)对红薯淀粉中明矾含量建立预测模型。 结果表明, 采用原始光谱、 SG 平滑、 Baseline、 Normalization等光谱数据建立PLS模型的最佳因子数（principal component factors）分别为3, 3, 3和2; 校正集相关系数（ｒc）分别为0.982, 0.980, 0.982和0.984; 预测集相关系数（rp）分别为0.982, 0.979, 0.982和0.987; 校正集均方根误差（root mean square error of calibration, RMSEC）分别为0.011, 0.012, 0.012和0.011; 预测集均方根误差（root mean square error of prediction, RMSEP）分别为0.013, 0.014, 0.013和0.012; 可知归一化预处理后建立PLS模型效果最佳。 为对比分析线性（PLS）与非线性（LS-SVM）两种定量模型方法的预测精度, 采用相同预处理方法后的红薯淀粉中明矾含量光谱数据建立最小二乘支持向量机（least squares support vector machine, LS-SVM）预测模型, 选用径向基函数（RBF）作为核函数。 结果表明, 归一化预处理后建立LS-SVM模型效果最佳, 其预测集均方根误差（RMSEP）为0.0047, 预测集相关系数（rp）为0.997 2。 发现对红薯淀粉中明矾含量建立LS-SVM预测模型的稳定性更好、 精确度更高。 采用太赫兹时域光谱结合LS-SVM和PLS对红薯淀粉中明矾含量进行定量分析。 结果表明, 采用归一化预处理后的LS-SVM比PLS模型的预测效果更优, 可能是红薯淀粉与明矾混合物中含有更多的非线性信息。 研究表明, 太赫兹时域光谱结合化学计量学方法可为红薯淀粉中明矾含量的定量分析提供快速精确的分析方法。

胶矾水是中国传统书画修复和装裱材料, 但过量使用明矾会引起宣纸不同程度的酸化。 为了解胶矾水中明矾对宣纸中不同成分的影响, 明确传统胶矾水中明矾用量范围, 减少其对宣纸的危害, 采用傅里叶变换衰减全反射红外光谱(ATR-FTIR)和X射线衍射(XRD)研究了明矾对宣纸中纤维素和碳酸钙的影响, 并将傅里叶退卷积和二阶导曲线拟合的方法引入研究明矾对宣纸中明胶蛋白质二级结构的影响。 XRD和ATR-FTIR结果表明明矾会不同程度溶解纸张中的结晶纤维素、 非结晶纤维素和CaCO3(生成CaSO4), 在明矾浓度超过5 Wt%后成分变化最剧烈。 傅里叶退卷积和二阶导曲线拟合结果表明明矾会使宣纸中明胶蛋白质二级结构改变, 使α-螺旋结构、 β-转向结构和γ-随机结构向β-折叠结构转变。 在明矾浓度超过5 Wt%后, 蛋白质二级结构发生剧烈变化。 研究得出了明矾对宣纸中不同成分的影响, 在最小干预的文物保护原则基础上给出了明矾用量范围, 为纸质文物中蛋白质二级结构研究引入了一种新方法, 扩大了ATR-FTIR在纸质文物中的研究和应用范围。

应用太赫兹时域光谱(THz-TDS)技术对红薯淀粉中的添加剂明矾进行了实验研究, 获得了红薯淀粉和明矾的太赫兹时域光谱和频域光谱, 通过计算得到二者的吸收系数谱和折射率谱, 吸收系数谱显示明矾在太赫兹波段有明显的特征吸收峰, 可以用THz-TDS技术对淀粉中的明矾进行特征识别。 实验获得了红薯淀粉中掺杂不同百分比(质量分数)明矾的太赫兹时域光谱, 计算得到吸收系数谱和折射率谱, 发现随着明矾含量的增加吸收峰的幅度下降, 折射率逐渐下降, 说明THz-TDS技术可以用于淀粉中明矾的定性识别和定量检测。