A new potential polymeric cladding material for polycarbonate fibre optic core for high temperature use

The selection of a suitable cladding material for a fibre optic is crucial, and the application of polymeric material in high temperature conditions is garnering much attention from many researchers. However, polymer suffers from a weak thermal resistance, limiting its use in high temperature conditions. Therefore, this study aims to develop a new potential cladding material that has a good balance between optical and thermal properties. Two sets of cladding materials are proposed, namely the blend of polycarbonate/polymethyl methacrylate (PC/PMMA) and polymethylpentene (PMP). The cladding materials were dissolved in different solvents, followed by the casting on a glass plate to form a flat sheet cladding layer. PC/PMMA blend showed a miscible blending with a single Tg value and physical blending. Both PC/PMMA blend and PMP claddings demonstrated more than 90% of luminous transparency. The materials also showed high thermal stability with the onset degradation temperature of ∼ 300 °C. The optimum ratio for PC/PMMA was 80/20. Next, the cladding layer was fabricated by coating the core in 80/20 PC/PMMA and PMP. The scanning electron microscopy (SEM) image reveals that core–clad ratio for the PC fibre is 1.02 for both materials. The maximum tensile strength for the PC with PMP cladding was higher than that of the PC with PC/PMMA cladding. PMP-clad fibre has higher power output, which was a 60% increment from bare PC fibre output compared to PC/PMMA-clad fibre, with only 28.8% power output increment. Though both materials have huge potential to be used as the cladding for PC core, PMP cladding showed superior performance compared to PC/PMMA cladding.