Oxidation Level and Glycidyl Ether Structure Determine Thermal Processability and Thermomechanical Properties of Arabinoxylan-Derived Thermoplastics

Herein we present arabinoxylan (AX)-based thermoplastics obtained by ring opening oxidation and subsequent reduction (dA-AX) combined with hydrophobization with three different glycidyl ethers [n-butyl (BuGE), isopropyl (iPrGE) and 2-ethylhexyl (EtHGE) glycidyl ether]. We also present the relationship of structural composition, thermal processing and thermomechanical properties. The BuGE and iPrGE etherified dA-AXs showed glass transition temperatures (T_g) far below their degradation temperatures and gave thermoplastic materials when compression-molded at 140˚C. The BuGE (3 mole) etherified dA-AX films at 19 and 31 % oxidation levels exclusively exhibit 244 % (±42) and 267 % (±72) elongation. In contrast, iPrGE-dA-AX samples with shorter and branched terminals in the side chains had maximum 60 % (±19) elongation. The dramatic difference in elongation is assumed to be due to the presence of longer alkoxide chains, higher molar substitution and dual T_g for the BuGE samples. Such superior elongation of AX thermoplastic films and its relationship with molar substitution and T_g has not been reported before.