Hydrolyzable poly(ester‐urethane) networks from L‐lysine diisocyanate and D,L‐lactide/ϵ‐caprolactone homo‐ and copolyester triols

Abstract

SYNOPSISBioabsorbable poly (ester-urethane) networks were synthesized from ethyl 2,6-diisocyanatohexanoate (L-lysine diisocyanate) (LDI) and a series of polyester triols. LDI was synthesized by refluxing L-lysine monohydrochloride with ethanol to form the ester, which was subsequently refluxed with 1,1,1,3,3,3-hexamethyldisilazane to yield a silazane-protected intermediate. This product was then phosgenated using triphosgene. Polyester triols were synthesized from D,L-lactide, c-caprolactone, or comonomer mixtures thereof, using glycerol as initiator and stannous octoate as catalyst. Polyurethane networks were cured using[ NCO] / [ OH] = 1.05 and stannous octoate (0.05 wt % ) for 24 h at room temperature and pressure and 24 h at 5OoC and 0.1 mm Hg. LDI-based polyurethane networks were totally amorphous and possessed very low sol contents. Networks based on poly (D,L-lactide) triols were rigid ( Tg E 60°C) with ultimate tensile strengths of -40-70 MPa, tensile moduli of -1.2-2.0 GPa, and ultimate elongations of -4-10%. Networks based on c-caprolactone triols were low-modulus elastomers with tensile strengths and moduli of -1-4 MPa and -3-6 GPa, respectively, and ultimate elongations of -50-300%. Networks based on copolymers displayed physical properties consistent with monomer composition and were tougher than the networks based on the homopolymers. Tensile strengths for the copolymers were -3-25 MPa with ultimate elongations up to 600%. Hydrolytic degradation under simulated physiological conditions showed that D,L-lactide homopolymer networks were the most resistant to degradation, undergoing virtually no change in mass or physical properties for 60 days. e-Caprolactone-based networks were resistant to degradation for 40 days, and high-lactide copolymer-based networks suffered substantial losses in physical properties after only 3 days.

Isohexide and Sorbitol-Derived, Enzymatically Synthesized Renewable Polyesters with Enhanced Tg

“…While the first curing agent is a cyclic trifunctional isocyanate, the latter is an aliphatic difunctional isocyanate. Although the synthetic route for the preparation of the isocyanate functionality still requires a petroleum-based compound, namely phosgene, 36 the carbon mass of the L-lysine amino acid-based EELDI is 75% renewable, which combined with fully bio-based polyesters provides cured coatings with a large renewable content.…”

Enzymatic synthesis and preliminary evaluation as coating of sorbitol-based, hydroxy-functional polyesters with controlled molecular weights

“…EELDI and DDI have been selected to study their applicability as renewable diisocyanates in PU synthesis. DDI is a vegetable oil-based product from BASF while EELDI is derived from the amino acid lysine [43]. The best conditions to prepare a good coating and the corresponding curing procedure were evaluated.…”

Stereocomplexation, Thermal and Mechanical Properties of Conetworks Composed of Star-Shaped l-Lactide, d-Lactide and ε-Caprolactone Oligomers Utilizing Sugar Alcohols as Core Molecules

“…Recently, network polymers derived from terminal functionalized star-shaped biodegradable polyesters have gathered considerable attention since the curing reaction of their at least three functional groups easily generates crosslinked structures and the crosslinking density can be controlled by changing the arm length [3,13,[29][30][31][32][33][34][35][36][37][38]. For example, Storey et al reported the networks prepared by the crosslinking reaction of hydroxy-terminated 3-armed random copolymers of D,L-LA and CL with L-lysine diisocyanate [30]. Amsden et al reported biodegradable elastomeric networks prepared by the photo-crosslinking reaction of acrylate-terminated GC-based 3-armed random copolymers of LA and CL [31].…”

“…Jahandideh et al reported the thermomechanical properties of cured products of methacrylate-functionalized star-shaped lactide oligomers with a XL core and their biocomposites with jute fibers [36]. Also, we reported pentaerythritol-based polymer networks (PEPN-4scLAO/2CLOs) prepared by reactions of methylenediphenyl 4,4′-diisocyanate (MDI), hydroxy-terminated two enantiomeric 4-armed star-shaped lactide oligomers bearing a pentaerythritol core (PE4LLAO and PE4DLAO) and a diethylene glycol-based hydroxy-terminated 2-armed ε-caprolactone oligomer (H2CLO) [37], and glycerol (GC)-based polymer networks (GCPN-3scLAO/2CLOs) by reactions of hexamethylene diisocyanate (HDI), hydroxy-terminated Recently, network polymers derived from terminal functionalized star-shaped biodegradable polyesters have gathered considerable attention since the curing reaction of their at least three functional groups easily generates crosslinked structures and the crosslinking density can be controlled by changing the arm length [3,13,[29][30][31][32][33][34][35][36][37][38]. For example, Storey et al reported the networks prepared by the crosslinking reaction of hydroxy-terminated 3-armed random copolymers of D,L-LA and CL with L-lysine diisocyanate [30].…”