No 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

Polymerization of itaconic acid Summary-Poly(itaconic acid) (PIA) has been prepared by various methods namely in radical polymerization in the presence of various initiators and using water or dioxane as reaction medium, or by poly(itaconic anhydride) hydrolysis. The main purpose was to investigate the effect of method of synthesis on the chemical structure of the product. Possibilities of the structures described by Formula (II) or (III) occurring have been considered. The following methods were used for PIA characterization: FT-IR, 1 H NMR, 13 C NMR, elemental analysis, size exclusion chromatography and conductometric titration as well as potentiometric titration. The reasons of known phenomenon of limited availability of PIA carboxylic groups in titration conditions were discussed. Significant effect of drying conditions on the results obtained suggests the importance of keeping the drying conditions constant. Two types of neighborhood of methylene or carboxylic groups in PIA have been found.