Thermal Characterization of “Comb‐Like” Block Copolymers Based on PCL Obtained by Combining ROP and RAFT Polymerizations

Abstract

Summary In this work we report the synthesis of poly(hydroxyethyl‐methacrylate‐graft‐polycaprolactone)‐block‐poly(caprolactone) copolymers, P(HEMA‐g‐PCL)‐b‐PCL, by combining ring‐opening polymerization (ROP) and reversible addition‐fragmentation chain‐transfer polymerization (RAFT). The successful synthesis of the targeted “comb‐like” block copolymers obtained was confirmed by 1H‐Nuclear Magnetic Resonance, Fourier Transform Infrared Spectroscopy and Size Exclusion Chromatography. Thermal behavior of the copolymers was studied by Differential Scanning Calorimetry, and their thermal stability was investigated by modulated thermogravimetric analysis. In this sense, the “comb‐like” block copolymers exhibited controlled molar masses between 6,000 g/mol and 45,000 g/mol, and polydispersity indexes lower than 1.3. Besides, thermal analysis evidenced a noticeable reduction in the melting temperature compared with linear PCL homopolymer, as well as, in the activation energy for the degradation process.

Tailor-Made, Linear, and “Comb-Like” Polyester-Based Copolymers: Synthesis, Characterization, and Thermal Behavior of Potential 3D-Printing/Electrospinning Candidates

“…Synthesis of P (HEMA-co-(HEMA-g-ε-CL)-b-ε-CL) Copolymers (HEMACL#). Copolymerizations were carried out in a one-pot procedure through a combination of simultaneous RAFT and ROP polymerizations, by following a methodology already published [28]. BSTSE, HEMA and ε-CL monomers, Vazo-88 radical initiator, dry toluene, and DMF were placed in a dry Schlenk flask equipped with a stirrer.…”

“…The conventional synthesis of PDMS is carried out by hydrolysis and condensation reactions of dimethyldichlorosilanes in alkaline or acid media, by producing cyclic and linear polymers without a good control of the homogeneity [26]. A better control of PDMS molecular parameters can be achieved by using anionic ROP of cyclic siloxanes [27][28][29]. Although PDMS and its derivatives are widely employed in technical applications, their use as 3D-printing materials has been proved challenging due to poor mechanical properties and need for supporting during the process [30,31].…”

“…In previous papers, we have reported the synthesis of PCL-based copolymers by employing controlled polymerization techniques [27,28,32]. In an effort to expand the understanding of their physicochemical characteristics, the aim of this work was focused on the thermal behavior (at moderate temperatures) of two block copolymers series based on ε-CL monomer.…”

Fabricación de recubrimientos compuestos de Bioglass®/poli(ɛ-capro-lactona) obtenidos por co-deposición electroforética sobre acero inoxidable

“…Con el fin de evaluar la influencia que producen las partículas de biovidrio durante el proceso de cristalización de la PCL C y PCL S , se evaluó el comportamiento térmico empleando DSC en ambos recubrimientos. Como se esperaba, ambos materiales (PCL C y PCL S ) mostraron una temperatura de fusión de ~ 56,6ºC, esperada para PCL lineales [28,30,40]. También se observó una reducción significativa de la cristalinidad de la PCL en cada recubrimiento (X C ), con valores de ~ 6,7 % para BG/PCL C y ~ 6,3 % para BG/PCL S , respectivamente.…”

“…Aunque en diversos trabajos se ha reportado el uso de PCL junto a silicatos bioactivos y nanopartículas de HA [2,3,8], su uso en la formulación de materiales compuestos a base de BG/PCL depositados sobre sustratos de acero inoxidable por aplicación de campo eléctrico, es un área de aplicación aún no explorada. Por otra parte, la PCL con estructura controlada puede obtenerse a partir de polimerización aniónica, técnica que permite obtener una amplia variedad de materiales con características específicas [28][29][30]. Por estas razones, el estudio de materiales basados en polímeros modificados estructuralmente o la combinación de diferentes polímeros con rellenos inorgánicos, se plantea como una alternativa poco explorada y promisoria que permitiría desarrollar materiales compuestos con propiedades híbridas cuyas características específicas los convertirían en potenciales candidatos para ser usados en medicina regenerativa [12,31,32].…”