An eco-friendly way to fire retardant flexible polyurethane foam: layer-by-layer assembly of fully bio-based substances

The objective of the present study is to develop fully renewable and environmentally benign techniques for improving the fire safety of flexible polyurethane foams (PUFs). A multilayered coating made from cationic chitosan (CS) and anionic alginate (AL) was deposited on PUFs through layer-by-layer assembly. This coating system exhibits a slight influence on the thermal stability of PUF, but significantly improves the char formation during combustion. Cone calorimetry reveals that 10 CS-AL bilayers (only 5.7% of the foams weight) lead to a 66% and 11% reduction in peak heat release rate and total heat release, respectively, compared with those of the uncoated control. The notable decreased fire hazards of PUF are attributed to the CS-AL coatings being beneficial to form an insulating protective layer on the surface of burning materials that inhibits the oxygen and heat permeation and slows down the flammable gases in the vapor phase, and thereby improves the flame resistance. This water-based, environmentally benign natural coating will stimulate further efforts in improving fire safety for a variety of polymer substrates.

La belleza del Shan shui en la arquitectura. Reflexiones sobre la interpretación de la teoría estética del Shan shui a la arquitectura de Wang Shu

El Shan shui como la línea principal de investigación de Wang Shu, todavía está estimulando la exploración de la arquitectura de Wang shu. La filosofía y la visión universal del Shan shui se basan en la naturaleza, que es una manifestación específica de los valores culturales tradicionales chinos. Wang Shu sigue esta visión de valor observando el mundo y pensando la arquitectura china ideal. Vuelvo a analizar la presentación y la teoría del Shan shui para buscar más posibilidades de la aplicación de la estética tradicional a la arquitectura contemporánea. ABSTRACT. The Shan shui, as the main line of Wang Shu's research, is constantly stimulating his exploration of the architecture. The philosophy and the universal vision of Shan shui are based on nature, which is a specific manifestation of the traditional Chinese cultural values. And Wang Shu still values the world and thinks about the ideal Chinese architecture through this vision. This text aims at returning to the presentation and Shan shui theory in order to search for more possibilities of applying traditional aesthetics to contemporary architecture.