Effects of latex type and processed-mica waste loading on the structural and thermo-physical properties of natural rubber latex foam composites

Abstract

Mica waste, a type of commercial waste produced in bulk quantities by the mica mining industry, was processed and added to Natural Rubber Latex Foams (NRLF) made of centrifuged and creamed latex. Following the Dunlop method, NRLF composites with various Processed Mica Waste (PMW) loadings (0, 2, 4, 6, 8, and 10 Phr) were prepared, and the thermo-physical characteristics were compared. Thermal conductivity, electrical resistivity of NRLF against the latex type and mica loading were compared for the first time. NRLFs prepared using creamed latex exhibit 33 and 50 μm (width and height) cell diameter, 3 ibf hardness, 281 % swelling index improvements and 0.05 Wm⁻¹K⁻¹ thermal conductivity, and 1 °C glass transition temperature (T_g) reductions than centrifuged NRLF and indistinguishable electrical resistivity. With the addition of mica (0–10 Phr), both NRLF types showed a similar ascending trend in hardness (42 ibf), water absorption (16 %), T_g (7 °C), thermal conductivity (0.54 Wm⁻¹K⁻¹), electrical resistivity (69 × 10³ Ω m) with decreasing gel time (3 min) and swelling index (550 %). The key objective of this research was to prepare PMW-filled NRLF and compare structural, electrical and thermo-physical properties, for the first time, against mica content and latex type.