Macromolecular Design of Aliphatic Polyesters with Maintained Mechanical Properties and a Rapid, Customized Degradation Profile

Abstract

An innovative type of triblock copolymer that maintains and even increases the mechanical properties of poly(l-lactide) (PLLA) and poly(ε-caprolactone) (PCL) with a controlled, predictable, and rapid degradation profile has been synthesized. Elastic triblock copolymers were formed from the hydrophobic and crystalline PLLA and PCL with an amorphous and hydrophilic middle block of poly(but-2-ene-1,4-diyl malonate) (PBM). The polymers were subjected to degradation in PBS at 37 °C for up to 91 days. Prior to degradation, ductility of the PLLA-PBM-PLLA was approximately 4 times greater than that of the homopolymer of PLLA, whereas the modulus and tensile stress at break were unchanged. A rapid initial hydrolysis in the amorphous PBM middle block changed the microstructure from triblock to diblock with a significant reduction in ductility and molecular weight. The macromolecular structure of the triblock copolymer of PLLA and PBM generates a more flexible and easier material to handle during implant, with the advantage of a customized degradation profile, demonstrating its potential use in future biomedical applications.

Assessing the Degradation Profile of Functional Aliphatic Polyesters with Precise Control of the Degradation Products

“…We have in previous work shown that the triblock copolymer of PBM and PLLA degrades by a rapid initial hydrolysis in the amorphous PBM middle block forming two diblock copolymers, where after the degradation profile follows that of the homopolymer of PLLA with similar molecular weight. [20] This was also accompanied with a significant reduction in ductility and molecular weight. The molecular weight of the homopolymer of PBM decreased much more slowly and 90% remained after 28 d of degradation.…”

“…The triblock copolymer retained its mechanical properties for a specific time period and then degraded via a rapid initial hydrolysis. [20] We have The pre-polymer poly(but-2-ene-1,4-diyl malonate) (PBM) and a series of PBM-based materials are shown to be degradable under physiological conditions in vitro and they are therefore presented as potential materials for biomedical applications. Four different PBM-based materials are synthesized: a PBM homopolymer, crosslinked PBM with and without spacer, and a triblock copolymer of PBM and PLLA with the PBM as an amorphous middle block.…”

A comparative study on Poly(ε-caprolactone) film degradation at extreme pH values

“…Besides, when the polymer chains are short enough, the increased mobility of the chains makes it possible for them to reorganize and crystallize [40,45]. The melting temperature for films degraded at pH 1 decreased (from 66 to 64 C) as a result of the formation of smaller crystals of shorter polymer chains [46].…”

Forecasting linear aliphatic copolyester degradation through modular block design

“…Some of the explored systems include central blocks of 1,5-dioxepan-2-one (DXO), ε-caprolactone (CL), poly(but-2-ene-1,4-diyl malonate) (PBM) and ε-decalactone (DL) [13,17e20]. Specifically, fast hydrolyzable block modules of either poly(1,5-dioxepan-2-one) (PDXO) [13] or poly(-but-2-ene-1,4-diyl malonate) (PBM) [20] have shown gradual or rapid hydrolysis profiles, respectively. In contrast, slow degrading blocks of either poly(ε-caprolactone) (PCL) or poly(ε-decalactone) (PDL) have been demonstrated to severely reduce the hydrolysis rates of the triblock materials [19].…”