Modification And Enzymatic Degradation Kinetics Of Fiber Based On Poly(β-hydroxybutyrate)

The use of biodegradable polyester as transplant bracket, which representation is poly(lactide), has rapidly become a fascinating field of research in tissue engineering. Poly(L-lactide) and poly(β-hydroxybutyrate) possess excellent properties, such as good biocompatibility, biodegradability and mechanical strength, which suggest strong application potentials in tissue engineering. In this paper, poly(L-lactide) and poly(β-hydroxybutyrate) were blended and spun, attempting to improve the hydrophilicity, high crystallization and slow degradation. The material's brittleness and degradability were improved by adjusting the rate of blending . In addition, the hydrophilicity of fiber was designed by blending biocompatible polymer, such as poly(ethylene oxide) and poly(L-lactide-co-aminophenol). The influence factors on degradable velocity and the fiber's enzyme degradation kinetics were also studied.The compatibility of blending was investigated by testing glass temperature, which accorded with the Fox equation. The top-quality fiber can be produced under the condition as: spinning fluid concentration 6% , apparent viscosity 740 mPas, spinning die temperature 25℃ , the heat air temperature 50℃~55℃, and winding speed 28.48 meter per minute, draw ratio 3, drawing temperature 110℃, tension- setting temperature 90℃ and thermal setting time 25 minute.The degradable properties of fiber were investigated by the weight loss, the difference of mechanical property, crystallization and appearance during the degradation. With degradable time increasing, the weight loss of fiber increased, but the strength and elongation at break both declined. The rupture intensity decreased sharp after 30 days degradation;the outcome were titrated by sodium hydroxide, which wastage was increased at first and then descended because of acidity of oligomer. The fiber's toughness and hydrophilicity was improved by blending poly(ethylene oxide). The addition of poly(L-lactide-co-aminophenol) improved fiber's mechanics property.The degradation behavior of fiber which the content of poly(ethylene oxide) was 5 %(wt ) were investigated in the phosphate solution and lysozyme solution by the weight loss and the difference of the appearance. The influences of substrate concentration and reaction time on degradable velocity were also studied. The Ghose-Walseth experience formula was validated, and the enzyme degradation kinetics ofpoly(ethylene oxide) (wt5%) fiber at 37.5 °C was concluded by means of the experiment data's non-linearity calculation. The equation was :P= [Ln(-5.395+92.779[E]o)]t0396P-degree of degradation, the quantity of sodium hydroxide titration, (umol/ml);t-degradable time (min);[Eo]~the original concentration of lysozyme, (mg/ml) The value of n which was forecasted in Freundlich equal temperature expression was validated by studying the relation between enzyme concentration and degradable velocity. The accuracy of formula V=Kki[E]n which was applied to enzyme degradation of non-dissolve substrate was testified.