Influence of mass ratio between MTMS and solvent on the synthesis of monolithic flexible hydrophobic aerogels at normal air pressure

english

2020

Narodna in univerzitetna knjižnica
(Obvezni izvod spletne publikacije)

With the pressing issues of climate change and Coronavirus, effective thermal insulation and the prevention of aerosol infections have become two important developmental challenges. The need for new types of thermal insulation materials, which combine low thermal conductivity and flexibility has led to the development of aerogels, the widespread use of which is limited by the high cost of their synthesis. Flexible xerogels and aerogels based on silicon dioxide were synthesized with the help of sol-gel technology. As a precursor we used methyltrimethoxysi- lane (MTMS). The process used was catalysed by an acid catalyst followed by drying the product at a normal air pressure and temperatures of up to 140 °C. The synthesis of monolithic alcohols was successful only in cases where we had a mass ratio ranging between precursor (MTMS) and solvent with a value between 0.11 and 0.25. We assumed that these ratios allow the right level of crosslinking of the product, thus a stable structure and still very low density. The most favourable ratio of precursor, solvent and water was found to be 1 : 8 : 16. We succeeded in obtaining a mixture of aerogels, which also showed xerogel properties (brittleness and low elas- ticity). The obtained materials showed promising properties, such as low density (0.011 g / cm3), high absorption capacity for halogenated organic solvents, super hydrophobicity and high temperature resistance (of up to 350 °C). Also, the obtained products are affordable. Due to their nano size internal web structure and highly hydrophobic properties, they repre- sent a material that could also be used as filters in face protection masks.

10.10.2024