Phase behavior, crystallization, and morphology in thermosetting blends of a biodegradable poly(ethylene glycol)‐type epoxy resin and poly(ϵ‐caprolactone)

Abstract

Thermosetting blends of a biodegradable poly(ethylene glycol)-type epoxy resin (PEG-ER) and poly(⑀-caprolactone) (PCL) were prepared via an in situ curing reaction of poly(ethylene glycol) diglycidyl ether (PEGDGE) and maleic anhydride (MAH) in the presence of PCL. The miscibility, phase behavior, crystallization, and morphology of these blends were investigated. The uncured PCL/PEGDGE blends were miscible, mainly because of the entropic contribution, as the molecular weight of PEGDGE was very low. The crystallization and melting behavior of both PCL and the poly(ethylene glycol) (PEG) segment of PEGDGE were less affected in the uncured PCL/PEGDGE blends because of the very close glass-transition temperatures of PCL and PEGDGE. However, the cured PCL/PEG-ER blends were immiscible and exhibited two separate glass transitions, as revealed by differential scanning calorimetry and dynamic mechanical analysis. There existed two phases in the cured PCL/PEG-ER blends, that is, a PCL-rich phase and a PEG-ER crosslinked phase composed of an MAH-cured PEGDGE network. The crystallization of PCL was slightly enhanced in the cured blends because of the phase-separated nature; meanwhile, the PEG segment was highly restricted in the crosslinked network and was noncrystallizable in the cured blends. The phase structure and morphology of the cured PCL/PEG-ER blends were examined with scanning electron microscopy; a variety of phase morphologies were observed that depended on the blend composition.

Cu(II)‐incorporated, histidine‐containing, magnetic‐metal‐complexing beads as specific sorbents for the metal chelate affinity of albumin

“…The size of phase structure is on the order of about 100–500 nm. A similar morphology was previously reported in other epoxy/thermoplastic blends 37, 38. For the blend containing 40 wt % HBP [Fig.…”

Poly(ethyl glycol) assisting water sorption enhancement of poly(ε‐caprolactone) blend for drug delivery

“…The fusion of PEG has not been observed in the DSC thermograms due to its low content, so the peaks, stage or shoulder in the thermograms are attributed to the fusion of PCL in the blends. Double melting‐peaks of PCL in blends have been found in compatible and in partially compatible systems 34–37. Guo et al37 have prepared blends of low‐molecular‐weight uncured poly(ethylene glycol)‐type epoxy resin (PEG‐ER) and PCL to discover double melting peaks of PCL in the DSC thermograms.…”

Preparation and characterization of (PCL‐crosslinked‐PEG)/hydroxyapatite as bone tissue engineering scaffolds

“…At present, poly( ‐caprolactone) (PCL) has been considered for several biomedical applications such as scaffolds for supporting fibroblasts and osteoblasts growth . It is hydrophobic and insoluble in water but degradable through the hydrolytic attack of the ester bond . Because of its high crystallinity and hydrophilic/hydrophobic balance between ester and methylene groups, PCL has shown remarkably long in vivo degradation times .…”

“…It is hydrophobic and insoluble in water but degradable through the hydrolytic attack of the ester bond . Because of its high crystallinity and hydrophilic/hydrophobic balance between ester and methylene groups, PCL has shown remarkably long in vivo degradation times . Moreover, the lack of bioactive functional groups and intrinsic hydrophobicity result in a poor cell adhesion, which is a critical issue for successful in vitro 3D cell culture and the subsequent tissue formation .…”

“…Therefore, modification of PCL is of great necessity for a wider range of medical applications . Poly(ethyleneglycol) (PEG) has been an important type of hydrophilic polymers for biomedical applications because they have critical properties, such as good biocompatibility, hydrophilicity, lack of toxicity, and absence of antigenicity and immunogenicity . Hydroxyapatite (HA) is a ceramic material with a composition and structure similar to natural bone mineral and has been demonstrated to have good biocompatibility, and even osteoconductivity and osteoinductivity .…”