Natural Organic UV-Absorbent Coatings Based on Cellulose and Lignin: Designed Effects on Spectroscopic Properties
Natural Organic UV-Absorbent Coatings Based on Cellulose and Lignin: Designed Effects on Spectroscopic Properties
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DOI：
10.1021/bm301373b
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发表时间：
2012-12-01
影响因子：
6.2
通讯作者：
Aguie-Beghin, Veronique
中科院分区：
文献类型：
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作者：
Hambardzumyan, Arayik;Foulon, Laurence;Aguie-Beghin, Veronique
新型纳米复合材料涂层组成的纤维素纳米晶体（CNCs）和木质素（无论是合成或分馏云杉和玉米秸秆）的制备没有化学改性或功能化（通过共价连接）的两种生物聚合物之一。采用紫外-可见分光光度法和椭圆偏振光谱法研究了薄膜的光谱特性。当使用适当重量比的CNC/木质素（R）时，这些纳米复合材料体系表现出高性能的光学性质、在可见光谱中的高透射率和在UV光谱中的高阻挡。原子力显微镜分析表明，这些涂层是光滑和均匀的，在纤维素基质中具有可见的分散的木质素结节。还证明了将纳米颗粒引入介质中增加了重量比和CNC比表面积，这允许木质素分子在整个固体膜中更好地分散。因此，纤维素纳米颗粒表面上的这些芳族聚合物的较大分子膨胀使π-π芳族聚集体移位，这增加了消光系数并降低了UV区域中的透射率。这些纳米复合涂层在可见光波长下是光学透明的。
Novel nanocomposite coatings composed of cellulose nanocrystals (CNCs) and lignin (either synthetic or fractionated from spruce and corn stalks) were prepared without chemical modification or functionalization (via covalent attachment) of one of the two biopolymers. The spectroscopic properties of these coatings were investigated by UV-visible spectrophotometry and spectroscopic ellipsometry. When using the appropriate weight ratio of CNC/lignin (R), these nanocomposite systems exhibited high-performance optical properties, high transmittance in the visible spectrum, and high blocking in the UV spectrum. Atomic force microscopy analysis demonstrated that these coatings were smooth and homogeneous, with visible dispersed lignin nodules in a cellulosic matrix. It was also demonstrated that the introduction of nanoparticles into the medium increases the weight ratio and the CNC-specific surface area, which allows better dispersion of the lignin molecules throughout the solid film. Consequently, the larger molecular expansion of these aromatic polymers on the surface of the cellulosic nanoparticles dislocates the pi-pi aromatic aggregates, which increases the extinction coefficient and decreases the transmittance in the UV region. These nanocomposite coatings were optically transparent at visible wavelengths.