Sustainable, Tree-Free, PLA Coated, Biodegradable, Barrier Papers from Kendir (Turkish Hemp)

In this study, hemp-based barrier papers were produced by a facile film coating route. The hemp plant was mechanically separated by crushing and breaking down the stalks. The woody hurd and fibers were separated manually. Then, cellulosic pulp was prepared by the Kraft method. Alkali treated hemp fibers were used for the paper preparation, and papers were coated with poly(lactic acid) (PLA) films. Physical, morphological, structural, wetting, mechanical properties, thermal dimensional stability, and water vapor permeability (WVP) properties were analyzed. Average hemp fiber diameter decreased by around 50% after alkali treatment. It was also found that dry and wet tensile strength values for PLA-coated hemp papers increased 3- and 2-orders of magnitudes, respectively. Also, PLA-coated hemp papers showed 0% shrinkage in the temperature range from 100°C to 200°C. WVP of PLA-coated hemp papers decreased by around 50% compared to hemp paper at the end of 300 h.

本研究采用简易薄膜涂覆工艺制备了大麻基阻隔纸。首先通过粉碎、拆解茎秆对大麻植株进行机械分离，人工分离出木质髓芯与纤维。随后采用硫酸盐法（Kraft）制备纤维素浆粕。使用碱处理后的大麻纤维制备纸张，并以聚乳酸（poly(lactic acid), PLA）薄膜对纸张进行涂覆。对样品的物理性能、形貌结构、表面润湿性、力学性能、热尺寸稳定性以及水蒸气透过率（water vapor permeability, WVP）进行了表征分析。经碱处理后，大麻纤维的平均直径降低约50%。研究同时发现，经PLA涂覆的大麻纸的干拉伸强度与湿拉伸强度分别提升了3个和2个数量级。此外，在100℃至200℃的温度区间内，PLA涂覆大麻纸的收缩率为0%。经300h测试后，PLA涂覆大麻纸的水蒸气透过率相较未涂覆大麻纸降低约50%。