Synthesis and Characterization of Three-Arm Poly(ε-caprolactone)-Based Poly(ester−urethanes) with Shape-Memory Effect at Body Temperature

Abstract

Novel biodegradable star poly(ester-urethanes) containing three-arm poly(ε-caprolactone) (PCL) as switching segment were prepared as shape-memory polymers (SMPs) with switching temperature (T s ) around body temperature. PCL-triols with molecular weight (M n ) of 2700-4200 g/mol and T m of 45-47 °C were synthesized in 55-67% yield by Novozym 435-catalyzed ring-opening polymerization of ε-caprolactone with glycerol as initiator, and their three-arm structures were confirmed by 1 H and 13 C NMR analysis. Reaction of the PCL-triols with methylene diphenyl 4,4′-diisocyanate isocynate and 1,6-hexanediol gave three-arm PCL-based poly(ester-urethane)s (tPCL-PUs) in 83-92% yield, with 65-75% soft segment. The structure of tPCL-PUs was confirmed by 1 H NMR analysis, and the thermal properties were analyzed by DSC with T s of 36-39 °C. tPCL-PUs showed excellent shape-memory effects at 38 °C during cyclic thermomechanical tensile tests: shape recovery within 10 s, shape fixity rate of 92%, and shape recovery rate of 99%. The novel biodegradable star SMPs are potentially useful in biomedical applications.

Design of Triple-Shape Memory Polyurethane with Photo-cross-linking of Cinnamon Groups

“…30 SMPU contains the hard segments and the soft segments, the soft segments mostly including crystalline polyethers or polyesters whose melting temperature (T m ) is used as the shape recovery temperature. 31 In this study, we designed a new triple shape memory system which contains both a T m -type segment and a T g -type segment, differing from the previously reported triple shape memory polymers which have either two T m -type segments or two T gtype segments. Firstly, shape memory polyurethane based on PCL with pendant cinnamon groups was synthesized.…”

Design of Cross‐Linked Semicrystalline Poly(ε‐caprolactone)‐Based Networks with One‐Way and Two‐Way Shape‐Memory Properties through Diels–Alder Reactions

“…[1][2][3][4][5] SMPs are polymeric materials capable of mechanically deforming from a temporary shape to a permanent shape under the influence of an external stimulus such as temperature, light, and so on. [6][7][8][9][10][11] The most widely studied SMPs are thermally responsive, combining a permanent domain (i.e., a chemically or physically cross-linked structure) and a switching domain (T fix ) associated with a transition temperature (glass transition temperature or melting point). The shape-memory behavior is obtained after deforming SMPs at temperatures higher than T fix , followed by a cooling process to a temperature below T fix under a constant stress to maintain the temporary shape.…”

Review on the Functional Determinants and Durability of Shape Memory Polymers

“…Biodegradable SMPs with controllable degradation behavior provide interesting advantages over other implant materials, because much of today's follow-on surgery in removing the implants can thus be avoided. With this concept in mind, biodegradable SMPs based on poly(DL-lactide) and PCL [78,148,[244][245][246][247][248][249], blends based on poly(L-lactide-co-ε-caprolactone) and poly(L-lactide-co-glycolide) [250], SMPs based on bile acids [251,252] and many others [253][254][255][256][257] have been synthesized. Recent research trends regarding medical applications of SMPs have been summarized by Sokolowski et al [149], Mather et al [13], Small et al [258] and Lendlein et al [259].…”