Compatibilization Effect of Poly(ε-caprolactone)-b-poly(ethylene glycol) Block Copolymers and Phase Morphology Analysis in Immiscible Poly(lactide)/Poly(ε-caprolactone) Blends

Abstract

The miscibility and phase behavior of two stereoisomer forms of poly(lactide) (PLA: poly (L-lactide) (PLLA) and poly(DL-lactide) (PDLLA)) blends with poly(epsilon-caprolactone)-b-poly(ethylene glycol) (PCL-b-PEG) and PCL-b-monomethoxy-PEG (PCL-b-MPEG) block copolymers have been investigated by differential scanning calorimetry (DSC). The DSC thermal behavior of both the blend systems revealed that PLA is miscible with the PEG segment phase of PCL-b-(M)PEG but is still immiscible with its PCL segment phase although PCL was block-copolymerized with PEG. On the basis of these results, PCL-b-PEG was added as a compatibilizer to PLA/PCL binary blends. The improvement in mechanical properties of PLA/PCL blends was achieved as anticipated upon the addition of PCL-b-PEG. In addition, atomic force microscopy (AFM) measurements have been performed in order to study the compositional synergism to be observed in mechanical tests. AFM observations of the morphological dependency on blend composition indicate that PLA/PCL blends are immiscible but compatible to some extent and that synergism of compatibilizing may be maximized in the compositional blend ratio before apparent phase separation and coarsening.

Crystallization and morphological transition of poly(l-lactide)–poly(ε-caprolactone) diblock copolymers with different block length ratios

“…5 In contrast, PCL has high exibility and a relatively low T g and is easier to process than PLLA but its strength and melting point are relatively low for various applications. 6,7 Therefore, the copolymerization of PLLA with PCL is known to be an effective route to improve properties in comparison with each individual component. 8,9 In a copolymer, when one block can crystallize, the physical properties and degradability of other blocks will be affected since the morphology can also be dramatically altered at the microscale level.…”

Effect of halloysite on structure and properties of melt-drawn PCL/PLA microfibrillar composites

“…The mostly applied PLLA containing 2-4% D-isomer has low compatibility with PCL [5]; therefore, various compatibilizing techniques [6,7] must be applied. In this area, application of various nanofillers (NF) leading to simultaneous reinforcement, compatibilization, and improvement of other material parameters may also be beneficial [8][9][10][11][12].…”

Biodegradable Blend Nanoparticles of Amphiphilic Diblock Copolymers Prepared by Nano-Precipitation Method

“…Their thermal, biodegradation and drug release properties can be controlled through several approaches including block length adjustment [7][8][9][10] and copolymerization [11]. The physical blending is an alternative method that has been widely used to adjust the properties of polymers such as crystallinity, mechanical properties and biodegradation properties [12][13][14][15]. These properties strongly affected the drug release behaviors.…”

“…In addition, the MPEG segments attached to polyester segments can improve miscibility between PDLL and PCL blends to reduce the phase separation [12]. Thus, unique properties of polymer blends quite different from their origin polymers were obtained.…”