Imai Y, Fukuzawa A, Watanabe M
Institute for Medical and Dental Engineering, Tokyo Medical and Dental University, Japan.
J Biomater Sci Polym Ed. 1999;10(7):773-86. doi: 10.1163/156856299x00630.
The effect of blending tricalcium phosphate (TCP) on hydrolytic degradation of a new type of poly(L-lactic acid)/poly(ethylene:hexamethylene/sebacate) block polyester (60: 40 wt%) was studied. 100- and 250-microm film specimens blended with 0, 10, and 30 wt% TCP were immersed in phosphate buffered saline (pH 7.4) at 37 degrees C for up to 80-104 weeks. At appropriate intervals, water absorption, dry and wet tensile strength, molecular weight, and thermal properties of the specimens were measured by weighing, tensile strength testing, size exclusion chromatography, and differential scanning calorimetry, respectively. Some samples were characterized by 1H NMR spectroscopy. Blending of TCP with the block polyester was effective in retarding degradation. The blended TCP was thought to retard degradation for the most part by neutralizing the lactic acid oligomers produced by hydrolysis of the poly(lactic acid) part during the initial stage of degradation.
