Glass chemical transition: An unknown thermal transition observed in cellulose acetate butyrate

Costas Tsioptsias

doi:10.1016/j.carbpol.2021.117754

Glass chemical transition: An unknown thermal transition observed in cellulose acetate butyrate

Carbohydr Polym. 2021 May 1:259:117754. doi: 10.1016/j.carbpol.2021.117754. Epub 2021 Feb 4.

Author

Costas Tsioptsias¹

Affiliation

¹ Laboratory of Physical Chemistry, Department of Chemical Engineering, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece. Electronic address: ktsiopts@auth.gr.

PMID: 33674008
DOI: 10.1016/j.carbpol.2021.117754

Abstract

Cellulose acetate butyrate (CAB) belongs to cellulose esters, an important category of polymers, that are derived from the most abundant organic substance on earth (cellulose). As most cellulose esters, CAB is believed to exhibit a melting point. In this study, carefully selected experiments were performed, in order to test if the endothermic peak, observed in the Differential Scanning Calorimetry (DSC) scan of CAB, is a melting point. It was found that it is not a melting peak but a chemically induced transition (appearing as glass transition) occurring simultaneously with mass loss (decomposition and vaporization). For this phenomenon, the term "glass chemical transition" is proposed. Various literature misinterpretations/confusions are clarified and the potential consequences of this discovery are shortly discussed. Based on literature data and the presented results, it seems almost certain that secondary cellulose esters exhibit this behavior. It is likely, that other polymers, also exhibit this peculiar thermal transition.

Keywords: Cellulose acetate butyrate; Decomposition; Glass transition; Simultaneous.