Correlating side-chain and backbone dynamics of modified polysaccharide to glass-transition temperatures

Arabinoxylan (AX) is an abundant polysaccharide present in cereals. The AX can be valorized as thermoplastic material by chemical modifications, which supposedly increase polymer mobility of the originally rigid chains. Recently, we developed a strategy that enables the production of highly processible modified AX through a ring-opening reaction, followed by grafting of ether chains (melt extrusion at 150°C and compression molding from 70 °C). The molar ratio of ether to AX required is 1:1 in this process; lower than those for non-ring opened ether/esters which are between 2:1 and 3:1. The mechanical and processing properties of the ring-opened ether AX were also found to be improved when compared to only etherified AX. The material has multiple relaxation behaviors and are also plasticized by water at 50% RH. Our goal is to use QENS to obtain a more refined description of the mechanisms at play in the resulting melt processability. A more complete understanding of the dynamics involved can help evaluate and guide the development of modification reactions for thermoplastic polysaccharide materials in the future.