Open Access4-Carboalkoxylated Polyvalerolactones from Malic Acid: Tough and Degradable Polyesters
Author(s) -
Grant W. Fahnhorst,
Guilhem X. De Hoe,
Marc A. Hillmyer,
Thomas R. Hoye
Publication year - 2020
Publication title -
macromolecules
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.994
H-Index - 313
eISSN - 1520-5835
pISSN - 0024-9297
DOI - 10.1021/acs.macromol.0c00212
Subject(s) - molar mass , polyester , malic acid , alkyl , polymer chemistry , chemistry , hydrolysis , condensation polymer , polymerization , adipate , branching (polymer chemistry) , ring opening polymerization , transesterification , ultimate tensile strength , organic chemistry , materials science , catalysis , polymer , citric acid , composite material
Eight 4-carboalkoxyvalerolactones ( CRVL s), varying in the composition of their alkyl ( R ) side chains, were synthesized from malic acid and subjected to ring-opening transesterification polymerization (ROTEP) using diphenyl phosphate [DPP, (PhO) 2 PO 2 H] as a catalyst. Each CRVL produced a semicrystalline poly(4-carboalkoxyvalerolactone) ( PCRVL ), and the nature of the R group impacted the thermal transitions of these polyesters. Bulk polymerizations at 70 °C allowed for preparation of high molar mass samples that contained small amounts of branching, as evidenced by 1 H NMR spectroscopy, MALDI spectrometry, size-exclusion chromatography, and eliminative degradation. Tensile testing of these lightly branched, high molar mass samples revealed that these polyesters are tough (tensile toughness values up to 88 ± 33 MJ•m -3 ) and have Young's moduli ( E ) up to 186 ± 13 MPa. The acid- and base-catalyzed hydrolytic degradation of the PCRVL s was quantitatively monitored using total organic carbon analysis, and effect of the alkyl chain length on PCRVL hydrolysis rate was determined. Finally, the methyl ester variant of these malic acid-derived thermoplastics is known to be chemically recyclable.