Thermal, surface and mechanical properties of PCL/PLA composites with coconut fibres as an alternative material to photopolymer printing plates

Abstract

In this paper, methods of thermal, mechanical and surface analyses of biodegradable PCL/PLA composites with the addition of different concentrations of coconut fibres were performed. The aim was to assess the potential of these composite materials for the relief-printing plates as an alternative to classical photopolymer materials. Differential scanning calorimetry, surface free energy calculations and hardness measurements were performed on the samples. Results have shown that most thermal transitions that are characteristic for PLA and PCL do not take place in the area of temperatures applicable in the printing process. Most thermal transitions were not affected by the addition of coconut fibres. Coconut fibres in the composite structure contributed to the increased hardness of the material. Moreover, the hardness range of the prepared PCL/PLA composites was within the range of some classic photopolymer printing plates. By adding coconut fibres in higher concentrations, surface free energy of the materials decreased, which enables a wider application of the material for the production of printing plates. From the obtained results it can be concluded that there is a potential for the use of PCL/PLA biodegradable composite materials in the manufacture of various relief-printing plates for different printing techniques (letterpress, embossing, label printing).

Keywords

• biodegradable material
• coconut fibres
• PCL
• PLA
• relief printing