35703-32-3Relevant articles and documents
Copolymerization of lactones and bioaromatics: Via concurrent ring-opening polymerization/polycondensation
Nguyen, Ha Thi Hoang,Short, Gabriel N.,Qi, Pengxu,Miller, Stephen A.
supporting information, p. 1877 - 1888 (2017/06/09)
The general and efficient copolymerization of lactones with hydroxy-acid bioaromatics was accomplished via a concurrent ring-opening polymerization (ROP) and polycondensation methodology. Suitable lactones were l-lactide or ε-caprolactone and four hydroxy-acid comonomers were prepared as hydroxyethyl variants of the bioaromatics syringic acid, vanillic acid, ferulic acid, and p-coumaric acid. Copolymerization conditions were optimized on a paradigm system with a 20 : 80 feed ratio of caprolactone : hydroxyethylsyringic acid. Among six investigated catalysts, polymer yield was optimized with 1 mol% of Sb2O3, affording eight copolymer series in good yields (32-95% for lactide; 80-95% for caprolactone). Half of the polymers were soluble in the GPC solvent hexafluoroisopropanol and analyzed to high molecular weight, with Mn = 10 500-60 700 Da. Mass spectrometry and 1H NMR analysis revealed an initial ring-opening formation of oligolactones, followed by polycondensation of these with the hydroxy-acid bioaromatic, followed by transesterification, yielding a random copolymer. By copolymerizing bioaromatics with l-lactide, the glass transition temperature (Tg) of polylactic acid (PLA, 50 °C) could be improved and tuned in the range of 62-107 °C; the thermal stability (T95%) of PLA (207 °C) could be substantially increased up to 323 °C. Similarly, bioaromatic incorporation into polycaprolactone (PCL, Tg = -60 °C) accessed an improved Tg range from -48 to 105 °C, while exchanging petroleum-based content with biobased content. Thus, this ROP/polycondensation methodology yields substantially or fully biobased polymers with thermal properties competitive with incumbent packaging thermoplastics such as polyethylene terephthalate (Tg = 67 °C) or polystyrene (Tg = 95 °C).
Purification, structural characterization, and modification of organosolv wheat straw lignin
Mbotchak, Laurie,Le Morvan, Clara,Duong, Khanh Linh,Rousseau, Brigitte,Tessier, Martine,Fradet, Alain
, p. 5178 - 5188 (2015/06/16)
Biolignin, a wheat straw lignin produced by acetic acid/formic acid/water hydrolysis, was characterized by 31P and 13C-1H 2D NMR spectroscopy and by size-exclusion chromatography. Biolignin is a mixture of low molar mass compounds (Mn = 1660 g/mol) made up of S, G, and H units and of coumaric and ferulic acid units. β-5 and β-O-4 interunit linkages are partially acylated in the γ-position by acetate and p-coumarate groups. Deacylated samples with a low content of contaminants were obtained by combining alkaline hydrolysis and solvent extraction. The high phenolic OH content found by 31P NMR reflects the presence of condensed aromatic units, such as 5-5 units. Reaction of purified lignin with ethanol and ethane-1,2-diol yielded esterified lignins much more soluble than Biolignin in common organic solvents. During this reaction, the secondary OH of β-O-4 linkages was simultaneously etherified. Phenol hydroxyethylation by 2-chloroethanol yielded samples containing only aliphatic hydroxyl groups.
Polyethylene ferulate (PEF) and congeners: polystyrene mimics derived from biorenewable aromatics
Nguyen, Ha Thi Hoang,Reis, Marcus H.,Qi, Pengxu,Miller, Stephen A.
supporting information, p. 4512 - 4517 (2015/09/15)
Ferulic acid and p-coumaric acid are abundant, biorenewable precursors for the synthesis of polyethylene ferulate (PEF) and polyethylene coumarate (PEC), as well as cognate copolymers with prescribed hydrogenation of the main-chain double bond. By controlling the comonomer feed ratios, copolymers with tunable thermal properties are obtained, including the thermal range occupied by polystyrene (PS).
