Synthesis and characterization of biodegradable poly(ϵ‐caprolactone urethane)s. I. Effect of the polyol molecular weight, catalyst, and chain extender on the molecular and physical characteristics

Abstract

Biodegradable polyurethanes with potential for applications in medical implants were synthesized in bulk with aliphatic hexamethylene diisocyanate, isophorone diisocyanate, poly(ϵ‐caprolactone) diols of various molecular weights, 1,4‐butane diol, 2‐amino‐1‐butanol, thiodiethylene diol, and 2‐mercaptoethyl ether chain extenders. The catalysts used were stannous octoate, dibutyltin dilaurate, ferric acetyl acetonate, magnesium methoxide, zinc octoate, and manganese 2‐ethyl hexanoate. The synthesis reactions were second‐order. All the materials had narrow, unimodal molecular weight distributions and polydispersity indices of 1.5–1.9. The chemical structures of the polyurethanes, as assessed from 1H NMR and 13C NMR spectra, were in good agreement with the monomer stoichiometric ratios. The glass‐transition temperatures of the materials ranged from −38 to −57 °C and were higher for polymers based on isophorone diisocyanate and with higher hard‐segment contents. For polyurethanes with the same hard‐segment content, there was no effect of the material molecular weight on the thermal properties. The tensile strengths of the materials were 12–63 MPa, and the tensile moduli were 8–107 MPa. These increased with an increasing hard‐segment content. The least effective catalyst was magnesium methoxide, and the most effective was ferric acetyl acetonate. Stannous octoate and manganese 2‐ethyl hexanoate were less effective than dibutyltin dilaurate and zinc octoate. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 156–170, 2002

Injectable Biodegradable Polyurethane Scaffolds with Release of Platelet-derived Growth Factor for Tissue Repair and Regeneration

“…However, the compressive strength (i.e., the compressive stress measured at 50% strain) of the HDIt and LTI materials (5-15 kPa) was higher than that of the LDI materials (2-4 kPa). HDI-prepolymer foams of comparable density (80-107 kg m −3 ) from a previous study were generally stronger than the one-shot HDIt and LTI foams of the present study, with compressive strengths of 30-85 kPa (at 40% strain) versus 5-15 kPa (at 50% strain) for the HDIt and LTI foams (44,45). However, the Young's moduli of the HDI-prepolymer foams are lower, at 9-21 kPa, compared to 26-202 kPa for the one-shot foams.…”

“…Furthermore, enzymatic cleavage of the lysine residues likely contributes to accelerated degradation of the LTI scaffolds in vivo (48). Previous studies have shown that the addition of PEG increases the hydrolytic degradation rate, presumably due to the increased hydrophilicity with PEG (38,(44)(45)(46). The addition of PEG 600 to HDIt foams increased the initial degradation rate (1-8 weeks), which is attributed to increased bulk hydrophilicity resulting from higher PEG content.…”

“…Polyether and polyester polyols have been mixed in previous studies to produce foams via prepolymers and chain extension, but not for one-shot foams prepared directly from polyisocyanates without the prepolymer step (37,38,(43)(44)(45)(46). Polyethers are generally immiscible with polyesters and are typically stabilized with water-soluble polyethersiloxanes (32).…”

Transparent sulfur-containing thermoplastic polyurethanes with polyether and polycarbonate soft segments

“…However, the SPURs derived from PHCD, which were plasticized in slightly higher temperatures, exhibited somewhat higher molar-mass dispersity compared with those from PTMO (see pressing temperature in Table 6). Polymers with similar molar-mass dispersity were also obtained by other authors [18,28,29]. Table 1 Designations, g red , GPC, transmittance, and refractive index data of the SPURs The chemical structures of all the SPURs were examined by elemental analysis and ATR-FTIR spectroscopy.…”

New thermoplastic poly(thiourethane-urethane) elastomers based on hexane-1,6-diyl diisocyanate (HDI)

“…In the last decade only a few articles containing comprehensive studies on thermoplastic poly(thiourethane) elastomers [10] and poly(thiourethane-urethane) elastomers (EPTURs) [11][12][13][14], as well as crosslinked ones [15], have been published.…”