Polyethylene oxide-hydroxyapatite composite and microporous polyethylene oxide-polymethacrylic acid polymer complex preparation and characterization

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2002
Banat, Raid M I
The first part of this study covers the crosslinking of polyethylene oxide (PEO) and its composite with calcium hydroxyapatite (HA) and their mechanical, swelling and morphological properties. Sheets of neat PEO (two different molecular weights) and composites of PEO-HA were prepared by compression molding. The composites and PEO thick sheets were crosslinked with exposure of UV- irradiation in presence of acetophenone (AP) for different periods of time. This simple method of crosslinking, UV-irradiation induced crosslinking in the presence of acetophenone, yielded PEO with gel content up to 90%. Gel content, equilibrium swelling ratio, mechanical and morphological properties of the low molecular weight polyethylene oxide LMPEO-HA composites of crosslinked and uncrosslinked were evaluated. Although the inclusion of HA into LMPEO inhibited the extent of crosslinking, LMPEO- III(20%)HA composite showed the highest gel content with appreciable equilibrium swelling and mechanical strength. The growth of HA from simulated body fluid solutions on fractured surfaces of LMPEO and LMPEO-HA was found to be very favourable in short times. The dimensional stability of these samples is found to be good enough after swelling and deposition experiments. Good compatibility between the hydroxyapatite and PEO can be regarded to be useful tissue-adhesive material. In the second part of this study a microporous polymer complex of polymethacrylic acid (PMAA)-polyethylene oxide was prepared and characterized. Microporous polymer complex of PMAA-PEO was obtained by solution polymerization using benzoyl peroxide as the initiator. PEO (Mv; 200,000) and methacrylic acid monomer mixture produced a microporous polymer complex with a scaffold strength. The polymer complex of PMAA- PEO was partially water soluble. To overcome the solubility of the water- soluble microporous polymer complex; chemical crosslinking was carried out by using ethlyleneglycol dimethacrylate monomer (EGDMA) as the crosslinking agent. Depending upon the extent of crosslinking process PMAA-PEO became water insoluble but it could swell in aqueous solution without any rupture. Thermal stability of the prepared crosslinked and uncrosslinked microporous polymer complex of PMAA-PEO was examined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Compressive mechanical properties were also examined.

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Citation Formats
R. M. I. Banat, “Polyethylene oxide-hydroxyapatite composite and microporous polyethylene oxide-polymethacrylic acid polymer complex preparation and characterization,” Ph.D. - Doctoral Program, Middle East Technical University, 2002.