Biodegradable Poly(ester–urethane–amide)s Based on Poly(ε-caprolactone) and Diamide–Diol Chain Extenders with Crystalline Hard Segments. Synthesis and Characterization

Abstract

Twenty seven poly(ester−urethane−amide)s (PEUAs) were synthesized from the reaction of α,ω-telechelic poly(ε-caprolactone) diols, 1,6-hexamethylene diisocyanate, and three different diamide−diol chain extenders derived from ε-caprolactone and three aliphatic diamines with increasing length (n = 2, 4, and 6). The hard segment (HS) was designed to be crystalline and to introduce amide groups, more susceptible to hydrolysis than urethane or urea groups. Crystallization of the HS was achieved even at very low HS content, leading to a phase-separated material. Furthermore, HS crystallinity recovered from the material homogeneous melt on cooling. Thermal degradation was well above HS melting point, allowing for melt processing of these materials. HS melting point was affected by HS content, poly(ε-caprolactone) diol length, and chain extender length. The length scale of the phase-separated morphology lied in between 11 and 13 nm up to ∼60% HS content and decreased at higher HS content values. HS content was the main parameter affecting the mechanical properties. The prepared PEUAs degraded hydrolytically at very long times by surface erosion.

Amide-containing segmented copolymers

“…Applications for these types of PA segmented copolymers include electrical insulating materials, circuit board materials, chiral phases for enantiomeric separations, protective coatings, and slowly biodegrading materials. [136,[138][139][140] Some of these segmented copolymers also find applications as biomedical devices. For example, PUUA segmented copolymers composed of a polyether SS showed promising properties for antithrombogenic applications due to favorable surface properties of the copolymer and the ability to tune the surface properties through structural variation.…”

Catalyst‐Free Ring Opening Synthesis of Biodegradable Poly(ester‐urethane)s Using Isosorbide Bio‐Based Initiator

“…This observation confirmed the microphase separation due to the hard‐block/soft‐block nature of the polymer. It has been proven that the hydroxyl number value of the starting PCL, tends to affect its crystalline property …”

“…In the case of F2, the enzymatic degradation consisted of two steps: first, the enzyme was adsorbed on the surface of the polymer matrix through its binding domain; second, the ester bonds were cleaved due to the effect of the catalytic domain of the enzyme …”

Synthesis and structure-property relationships of biodegradable polyurethanes

“…Baez et al [120] have reported the synthesis and characterization of segmented poly(ester−urethane−amide)s (PEUAs) based on PCL and diamide−diol chain extenders (DCEs) of different length (n = 2, 4, 6). PEUAs based on HDI or 1,4-diisocyanatobutane were highly crystalline with high melting points.…”