Utilization of cyclocarbonated lignin as a bio-based cross-linker for the preparation of poly(hydroxy urethane)s

Abstract

In this work, cyclocarbonated modified lignin, the most abundant reservoir of aromatic moieties in nature, was used as a green bio-based cross-linker on polyhydroxy urethane formulations. As a preliminary study, a complete 13 C NMR characterization of the aminolysis products of cyclocarbonated lignin with 1,12diaminododecane was provided. The best reaction conditions found for the aminolysis reaction were applied for the preparation of thermoset resins. Cyclocarbonated lignin was then reacted with 1,12diaminododecane, acting as a chain extender, in the presence of poly(ethylene glycol) bis cyclic carbonate, a soft segment used to tune the resin properties. Different (total cyclocarbonates)/(total amines) equivalent ratios and diverse poly(ethylene glycol)/lignin stoichiometry were tested. The evolution in time of the molecular weight distribution of a selected composition was followed by gel permeation chromatography until the solubility in THF was appreciable. Moreover, some significant resin samples were subjected to DSC analysis to evaluate favourable changes in the glass transition temperature and compared to blank experiments that did not include lignin in the composition.

From the Synthesis of Biobased Cyclic Carbonate to Polyhydroxyurethanes: A Promising Route towards Renewable Non‐Isocyanate Polyurethanes

“…Then, carbonated lignin was obtained through CO 2 carbonation . Cross‐linked materials were thereafter reported with the use of carbonated lignin with diaminododecane and polyethylene glycol (PEG)‐CC as a chain extender . By tuning the ratio between PEG‐C5 and lignin‐based CC, polymers with tailored properties were obtained, ranging from soft elastomers to rigid thermoset resins.…”

“…For example, vegetable oils are mainly soft with functional compounds, but they possess internal CCs on aliphatic chains, which have a low reactivity . On the other hand, thanks to their aromatic structures, wood derivatives, such as lignins or tannins, bring stiffness and thermal stability . Finally, sugar‐based CCs are generally short, stiff, and reactive monomers .…”

“…[119] Crosslinked materials weret hereafter reported with the use of carbonated lignin with diaminododecane and polyethylene glycol (PEG)-CCa sachain extender. [120] By tuning the ratio between PEG-C5a nd lignin-based CC, polymers with tailoredp roperties were obtained, ranging from soft elastomers to rigid thermoset resins. The curing process at 80 8Cf or 20 hi nT HF has led to materials with T g values from À35 to À15 8C.…”

“…[60b] On the other hand, thanks to their aromatic structures, wood derivatives, such as lignins or tannins, bring stiffness and thermal stability. [120,122] Finally,s ugar-based CCs are generally short, stiff, and reactive monomers. [35,115,116] The nature of the functional sites will also determine the synthetic routes.…”

Stimuli‐Responsive Polyurethane Dispersions – Aqueous Auto‐Dispersion

“…[13] Glass transition temperatures and mechanical properties such as hardness and flexibility can be tailored by incorporation of soft and hard segments and through careful selection of polyols. [14,15] These segments also affect amounts of crystalline and amorphous structures developed and provide both abrasion and solvent resistance.…”