New alginate foams: Box-Behnken design of their manufacturing; fire retardant and thermal insulating properties.

ABSTRACT A new method for preparing alginate foams with progressive release of copper in the presence of sodium lauryl sulfate (SLS, foaming agent) has been designed. Copper acts as the ionotropic gelling agent through the reaction of copper carbonate with gluconolactone. The process does not require freeze-drying contrarily to the conventional method used for preparing macroporous alginate foams. The new materials investigated in this study have remarkable thermal properties, including thermal conductivity lower than 0.041 W m⁻¹ K⁻¹ and low heat release (below 2 kJ g⁻¹), which allows labeling these foams self-extinguishing materials. An experimental design methodology, based on a Box-Behnken plan with three parameters and three levels, is successfully used for evaluating the impact of the amounts of alginate, SLS, and copper carbonate on the productivity, apparent density, and shrinking at air-drying. It yielded an optimization of the process for the manufacturing of light, and stable/rigid insulating and thermally stable materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45868. [ABSTRACT FROM AUTHOR]