超音波檢測生物可分解性高分子之性質

An Ultrasonic Technique for Charcterization of Biodegradable Polymers

生物可分解性高分子除了應用於藥物控制釋放及骨科復健植入也是一種具有環保特性的被印體材料，本研究應用超音波檢測技術來量測生物可分解性高分子浸置於水中不同時間後的裂解特性，二千萬周率之縱波由超音波轉換器產生後穿透過高分子材料並由感測器接收及數位化，快速傅立葉轉換及交錯相關係數法等數位訊號處理技術將數位化的波形轉換，並計算超音波在高分子中的波速及衰減係數，結果顯示超音波的波速在高分子裂解過程中降低三分之一而衰減係數則增加四倍，故超音波檢測技術是有用的工具來量測與鑑定生物可分解性高分子材料的裂解特性。

An ultrasonic technique was used to measure material property change during hydrolytic degradation of a biodegradable copolymer, 50/50 poly(D,L-lactide-co-glycolide). Six groups of 3 copolymer buttons were immersed in 60°C distilled water for 0, 1.5, 3.0, 6.0, 10.0 and 24.0 hours. A longitudinal wave generated by a 20 MHz transducer and a pulser/receiver card was directed per-pendicularly to the copolymer disk at 20°C. The reflected signals coming back to transducer were recorded and saved through a data acquisition board. The longitudinal wave speeds and attenuation coefficients of the disks undergoing various exposures to a water bath were calculated by the cross-correlation method and fast Fourier transformation (FFT) of the digitized waveform data. The wave speed decreased by a factor of one third and the attenuation coefficient increased up to four times within 24 hours in the 60°C water bath. The results suggest that the ultrasonic technique provides a useful method for the study of hydrolytic degradation of poly(D, L-lactide-co-glycolide) in a non-destructive manner.