Impact of Antifreeze Protectant Addition on the Pore Structure Formation and Air Filtration‐Related Properties of Konjac Glucomannan/Starch Aerogel

Abstract

ABSTRACT Both pore size and size distribution evenness are of great importance to achieve the desirable performance of aerogels. For aerogels prepared by freeze‐drying techniques, the pore formation is directly related to the control of ice crystal formation during the freezing process. This study aimed to compare the impacts of the addition of three kinds of antifreeze protectants (trehalose, L‐Lysine monohydrochloride, and hydroxypropyl methylcellulose [HPMC]) on the ice crystal formation of the frozen konjac glucomannan/starch sol, and the pore characteristics of the corresponding aerogels. Results showed that HPMC addition caused bubbles in the sol and led to small holes in the aerogel pore walls, which weakened the air filtration property. Both trehalose and L‐lysine additions contributed to the smaller ice crystal sizes in the frozen sol and the corresponding aerogel pore size became smaller and more even. However, stronger molecular interactions were observed between trehalose and aerogel components, favoring the strongest compressive strength. Also, trehalose addition showed an overall better air filtration performance. Therefore, trehalose might be a promising choice to improve the pore size distribution of air filtration polysaccharide‐based aerogels.