Control of microstructure in poly-lactic acid and the effect on biodegradation

Owen, Kylie Leanne (2013). Control of microstructure in poly-lactic acid and the effect on biodegradation. University of Birmingham. M.Res.

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Abstract

Polylactic acid (PLA) is a biodegradable polymer with numerous applications in tissue regeneration and repair. The degree of crystallinity governs the rate of degradation in vitro and in vivo. In this project, the effect of the microstructure on the degradation of Polylactic Acid (PLA) is studied.

PLA samples were crystallised to 40% crystallinity at various temperatures between 90°C and 140°C and then subjected to enzymatic degradation using the enzyme Proteinase K. Hot stage microscopy showed that on increasing the crystallisation temperature an increase in the growth rate of spherulites and a decrease in spherulite nucleation was observed. Short-term (five day) and preliminary long-term (ten week) biodegradation studies were conducted on samples crystallised to 40% at 90°C, 108°C and 118°C. DSC and FT-IR analysis in short-term degradation studies showed little difference in samples before and after degradation. However, it is seen that as the crystallisation temperature increased there was a resulting increase in weight loss observed in samples after degradation. Preliminary long-term degradation studies found that weight loss increased after three weeks and also found weight loss to be higher in samples crystallised to 40% at 118°C than at 90°C. The results suggest that the microstructure of PLA does have an effect on the rate of biodegradation and further long term biodegradation studies must be conducted to explore this fully.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

Supervisor(s):