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Ring-opening polymerization of lactones in the presence of hydroxyapatite

Paper ID Volume ID Publish Year Pages File Format Full-Text
13642 886 2001 8 PDF Available
Title
Ring-opening polymerization of lactones in the presence of hydroxyapatite
Abstract

The ring-opening polymerization of ε-caprolactone, δ-valerolactone (VL) and d,l-lactide, respectively, in the presence of different proportions of hydroxyapatite (HA) was catalyzed by stannous (II)octoate (SnOct2) at 130°C and resulted in composites. The lactones were almost completely converted to the polymers within a reaction time of 70 up to 240 min. The number-average molecular weights Mn as determined by size exclusion chromatography decreased with increasing content of HA. The initiating efficiency of HA as calculated from the difference of the polymerization degrees Pn obtained with and without HA turned out to be relatively low with ca. 11 to 0.5% for 1 to 80 wt% HA, respectively. For the polymerization of VL, the initiating efficiency of HA was on the average threefold higher. The quantitative proof of non-extractable polymer on HA by means of thermogravimetric analysis, fourier transform infrared spectroscopy with photoacoustic detection and differential scanning calorimetry confirmed the initiating efficiency of HA as mentioned above. This poly(lactone) can be debound from HA by treatment with aqueous HCl. Hence it is assumed to be ionically bound.

Keywords
Hydroxyapatite; Lactone polymerization; Initiating efficiency; Interfacial bonding
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 22, Issue 19, 1 October 2001, Pages 2695–2702
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
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Price was $35.95
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