Development of porous biodegradable polymer materials for biological applications

Details

Supervisors

Demoustier-Champagne, Sophie ; Jonas, Alain M.

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

Porous biodegradable organic materials are ideal scaffolds for cell colonization. The ability to 3D print them into any shape offers even more opportunities for tissue engineering and organ rehabilitation. However, one challenge is to provide easy access to 3D printable materials that result in pores with well-controlled sizes, using only biocompatible and sustainable processes. In this work, a method for the preparation of porous PLLA was described, starting from miscible mixtures of PLLA and a water-soluble polymer (PEG). The composition of the mixture, the molar mass of PEG, the isothermal crystallization temperature, and the crystallization time were the four parameters studied. During its crystallization, PLA repels PEG outside its crystals, leading to the formation of aggregates of PEG within and between PLLA spherulites, from which pores can be formed by dissolving PEG in water. The crystallization and morphology of the semi-crystalline mixture were studied, as well as the evaluation of porosity after dissolution of PEG. All parameters were found to affect both crystalline morphology and porosity. PEG diffuses out of the spherulites more rapidly and accumulates at their interface at lower molar mass, higher PEG content and higher crystallization temperature; at which the viscosity is higher. However, if the PEG content is too high, the resulting porosity makes the film brittle. The pore size at the surface did not vary much, but the porosity at depth still needs to be investigated. In addition, it remains difficult to establish a protocol with the various parameters that must be chosen to obtain a very accurate porosity. This work succeed in showing the effect of PEG and important processing parameters on PLA crystallization and porosity. However, the mechanical properties still need to be studied for future perspectives.