Department of Forest Biomaterials, North Carolina State University, Raleigh, North Carolina, USA.
Biopolymers. 2021 May;112(5):e23425. doi: 10.1002/bip.23425. Epub 2021 Apr 1.
Replacing synthetic polymers with renewable alternatives is a critical challenge for the packaging industry. This research investigated the use of leaf-based proteins as a sustainable co-binder in the coating formulations for paper-based packaging and other applications. Protein isolates from tobacco leaf and alfalfa concentrates were characterized using the Pierce protein assay, Kjeldahl nitrogen, and gel electrophoresis. The proteins were tested as co-binders in a typical latex-based paper coating formulation. The rheology and water retention properties of the wet coating and the surface, optical, structural, and strength properties of coated papers were measured. The coating performance was affected by the purity, solubility, and molecular weight of the tobacco protein and exhibited a shear-thinning behavior with lower water retention than soy protein. Analysis by scanning electron microscopy and time of flight secondary ion mass spectroscopy on the dried coating layer containing tobacco protein showed enhanced porosity (advantageous for package glueability) relative to the control latex coating. The tobacco protein offers adequate coverage and coating pigment distribution, indicating that this protein can be a suitable option in coatings for packaging applications.
用可再生替代品替代合成聚合物是包装行业面临的一项重大挑战。本研究探讨了将叶基蛋白用作基于纸张的包装和其他应用的涂层配方中的可持续共粘合剂。使用 Pierce 蛋白分析、凯氏氮和凝胶电泳对来自烟草叶和紫花苜蓿浓缩物的蛋白分离物进行了表征。将蛋白质作为典型的基于乳胶的纸张涂层配方中的共粘合剂进行了测试。测量了湿涂层的流变性和保水性以及涂层纸的表面、光学、结构和强度性能。涂层性能受到烟草蛋白的纯度、溶解度和分子量的影响，表现出剪切稀化行为，保水性低于大豆蛋白。对含有烟草蛋白的干燥涂层层进行扫描电子显微镜和飞行时间二次离子质谱分析表明，与对照乳胶涂层相比，其具有更高的孔隙率（有利于包装胶粘性）。烟草蛋白提供了足够的覆盖和涂层颜料分布，表明该蛋白质可以成为包装应用涂料的合适选择。
