Synthesis and characterization of poly(methyl methacrylate) functional microspheres

Abstract

Microspheres based on synthetic polymers such as poly(methyl methacrylate) (PMMA) and PMMA derivatives are known for their medical applications, particularly for hard tissue repair and regeneration. In the present work, attempts were made to prepare low molecular weight functional poly(methyl methacrylate) (PMMA-F) using a chain-terminating agent such as thioglycolic acid (PMMA-F). It was found that the molecular weight of PMMA-F was very low compared with PMMA prepared without thioglycolic acid. Microspheres were prepared using PMMA-F by the solvent evaporation technique and PMMA (PMMA without the chain-terminating agent thioglycolic acid) microspheres were also prepared for comparison and both microspheres were fully characterized. The presence of characteristic groups in the PMMA (ester) and PMMA-F (ester and carboxylic) microspheres was confirmed using 13C- and 1H-FT-NMR spectroscopy. The molecular weight of both microsphere systems was determined using gel permeation chromatography. The FT-IR spectra clearly indicated the presence of carboxylic functional groups in PMMA-F microspheres. Quantitative carboxylic group estimation was carried out using the titrimetric method. Scanning electron micrographs indicated that the microspheres are spherical and porous in nature. The thermal behavior of PMMA and PMMA-F microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis.