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Characterization of Novel Biodegradable Segmented Polyurethanes Prepared from Amino‐Acid Based Diisocyanate
Author(s) -
Takahara Atsushi,
Hadano Michiko,
Yamaguchi Tomohiro,
Otsuka Hideyuki,
Kidoaki Satoru,
Matsuda Takehisa
Publication year - 2005
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200550618
Subject(s) - polycaprolactone , differential scanning calorimetry , materials science , glass transition , small angle x ray scattering , dynamic mechanical analysis , composite material , polyurethane , prepolymer , polymer , mass fraction , polyester , polymer chemistry , chemical engineering , scattering , physics , optics , thermodynamics , engineering
Segmented polyurethanes (SPUs) which were expected to yield non‐toxic degradation products were synthesized from lysine‐based diisocyanate (LDI), 1,3‐propanediol (PDO), and polycaprolactone diol (PCL). SPUs were synthesized via a standard two‐step prepolymer method. The hard segment fraction was changed in order to tune the mechanical properties and the degradability. The aggregation structures of the SPUs were characterized by infrared spectroscopy and differential scanning calorimetry (DSC), temperature dependence of dynamic viscoelasticity, and small‐angle X‐ray scattering (SAXS). DSC and dynamic viscoelastic measurements revealed that the glass transition temperature ( T g ) of the soft segment increased with an increase in the hard segment fraction. SAXS of SPUs revealed the aggregation states of hard and soft segments. Furthermore, the degradation of SPUs was investigated by exposing the polymers to a buffer solution at 310 K (pH=7.6). The degradation rate of SPUs increased with an increase in the soft segment fraction. This is because the soft segment has the hydrolyzable ester linkages and the ester linkages are susceptible to hydrolysis compared with the urethane linkages. Finally, an electrospray deposition method was used to fabricate biodegradable SPU micro‐fibers. FE‐SEM images showed that higher concentration of solution favored the formation of uniform biodegradable micro‐fibers without beads‐like structure.