Recycled soda lime silica glass inclusion in polytetrafluoroethylene matrix as reinforcement for microwave substrate application

• Published in: Materialwissenschaft und Werkstofftechnik 2022-11, Vol.53 (11), p.1373-1385
• Main Authors: Alhaji, I. A., Abbas, Z., Zainuddin, N., Ibrahim, N.A., Khamis, A.M., Lakin, I.I.
• Format: Article
• Language: English
• Subjects: Composite materials; Dispersion; Fillers; Laufzeitverzögerung; Lime; microwave; Microwave frequencies; Mikrowelle; Moisture absorption; Moisture effects; permittivity; Permittivität; Photomicrographs; Polymer composites; Polymer-Verbundwerkstoff; Polytetrafluoroethylene; propagation delay; recycling; Silica glass; Solid phases; Substrates; Tensile strength; Thermal expansion; Thermodynamic properties
• ISSN: 0933-5137; 1521-4052
• DOI: 10.1002/mawe.202200126

Recycled soda lime silica glass‐filled polytetrafluoroethylene composites were prepared for substrate application at microwave frequencies. Various volume fractions (0.05–0.25) of the filler were dispersed in the polytetrafluoroethylene matrix. The composites’ dielectric, mechanical, and thermal properties were examined with respect to the filler content. X‐ray diffraction data established the phase structure of the polytetrafluoroethylene matrix and recycled soda lime silica glass. Scanning electron microscope micrographs revealed uniform filler distribution at lower recycled soda lime silica contents, while energy dispersive x‐ray analysis showed the purity of the composites. The tensile strength of the composites reduced from 13.5 MPa to 4.26 MPa, while the moisture absorption and density raised from 0.07 % and 2.195 g/cm3 to 0.19 % and 2.228 g/cm3 when the recycled soda lime silica filler volume fraction was adjusted from 0.05–0.25. The lowest coefficient of thermal expansion values was recorded at 0.25 % recycled soda lime silica volume fraction, which increased from 31.12 ppm/°C to 68.32 ppm/°C at 40 °C to 200 °C. At 0.05 filler volume fraction, the respective values of ϵ' ${\varepsilon{} { {^\prime}}}$ , tanδ ${tan\delta }$ and Td ${{T}_{d}}$ of the composites decreased from 2.20, 0.0017, and 29.69 ps to 2.15, 0.0015, and 29.35 ps in the 8.2 GHz–12.4 GHz range. Recycled soda lime silica glass‐filled polytetrafluoroethylene composites are promising candidates for microwave substrate application. They are cheap with the required performance for the mass production of substrates. Thus, we research the dielectric, mechanical and thermal properties of the polytetrafluoroethylene/recycled soda lime silica composites for substrate application.