The effects of polymerization conditions were evaluated on the production of polyethylene by silica-supported (n-BuCp) 2 ZrCl 2 grafted under optimized conditions and cocatalyzed by methylaluminoxane (MAO). The Al : Zr molar ratio, reaction temperature, monomer pressure, and the age and concentratio
Effect of ring-opening polymerization condition on the characteristic and mechanical properties of hydroxyapatite/poly(ethylene glutarate) biomaterials
β Scribed by Pathavuth Monvisade; Punnama Siriphannon; Walailak Tapcharoen
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 509 KB
- Volume
- 90A
- Category
- Article
- ISSN
- 1549-3296
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β¦ Synopsis
Abstract
Preparation of hydroxyapatite/poly(ethylene glutarate) (HAp/PEG) composites was carried out by ringβopening polymerization (ROP) of cyclic oligo(ethylene glutarate) in porous HAp scaffolds using various reaction temperatures and times. The content of ROPβPEG interpenetrated into the porous HAp scaffold was about 13β18 wt % with the values of number average molecular weight ($ \overline {M_{\rm n} } $) and weight average molecular weight ($ \overline {M_{\rm W} } $) of 2120β3630 and 2760β5250 g/mol, respectively. The increase in polymerization time and temperature brought about increase in molecular weight of ROPβPEG, but decrease in its content. Compressive strength and compressive modulus of the HAp/PEG composites were about 5.8β20.1 and 105β208 MPa, respectively. These mechanical properties depend upon the effects of distribution, content, and molecular weight of ROPβPEG in the composites. In vitro bioactivity of the HAp/PEG composites was studied by soaking them in simulated body fluid (SBF) for 28 days. The formation of HAp nanocrystal on the composite surfaces through the consumption of calcium and phosphorus from the SBF solution was observed after soaking, indicating the bioactivity of these HAp/PEG composites. Β© 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
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