Abstract This work aims to demonstrate the possibility of using laser technology to seal compostable coffee capsules in engineered, poly(lactic acid) (PLA) based, bioplastic material with thermoplastic starch (TPS) toplids. The welded joints were characterized by peel-off tests to evaluate the adhesion energy of the toplid to the capsule body as the laser process parameters vary, i.e. the power of the laser beam and scan speed. The results of the peel-off test made it possible to optimize the choice of laser process parameters for the various scenarios under investigation. 3D process maps were then constructed in which the adhesion index between toplid and capsule body was reported as the laser process parameters changed, allowing to identify the intervals of greatest practical relevance. In particular, the procedure allowed to define an adhesion index, a measure of the total adhesion energy between capsule body and toplid. Adhesion between conventional aluminum toplids and compostable capsules were also studied for comparative purposes. Based on the experimental findings, mechanisms of adhesion varying the material used for the toplid and capsule body were also discussed.

中文翻译：

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可堆肥包装解决方案的激光密封：实验方法和粘附机制

摘要 这项工作旨在证明使用激光技术将可堆肥咖啡胶囊密封在工程、聚乳酸 (PLA) 基、具有热塑性淀粉 (TPS) 顶盖的生物塑料材料中的可能性。焊接接头的特征是剥离试验，以评估随着激光工艺参数（即激光束功率和扫描速度）变化时顶盖与胶囊体的粘附能。剥离测试的结果使得针对所研究的各种场景优化激光工艺参数的选择成为可能。然后构建 3D 工艺图，其中随着激光工艺参数的变化报告顶盖体和胶囊体之间的粘附指数，从而确定具有最大实际相关性的间隔。特别是，该程序允许定义粘附指数，这是胶囊体和顶盖之间总粘附能的量度。出于比较目的，还研究了传统铝制顶盖和可堆肥胶囊之间的粘附性。根据实验结果，还讨论了不同用于顶盖和胶囊体的材料的粘附机制。