IDENTFICATION OF MAXIMUM MELT BLEND RATIO FOR POLYLACTIDE/POLYBUTYLENE SUCCINATE BASED ON RHEOLOGICAL MODEL
Keywords:
Polylactide (PLA), Polybutylene succinate (PBS), Rheological modelAbstract
Rheological model of the polylactide (PLA)/polybutylene succinate (PBS) blend as a function of shear rate, temperature and PBS content was proposed for predicting the shear viscosity of PLA/PBS blends. Melt blending of PLA/PBS with various ratios was prepared by using a single screw extruder and a disk shape sample required for rheological measurement was obtained by a compression molding process. Effect of PBS content on the compatibility of the blend was thoroughly investigated via rheological behavior. The results of rheological properties indicated that below 35% of PBS, the PLA/PBS blends showed an acceptable miscibility level. With the addition of PBS, the shear viscosity was greatly reduced and more liquid-like of the PLA/PBS melt flow was noticeable. The steady shear rate testing of the blends over the shear rate of 0 – 1000 s-1 exhibited the shear-thinning non-Newtonian behavior. The shear viscosity of the PLA/PBS blends as a function of shear rate, softening temperature and %PBS content was able to predict from the modified Cross model. Moreover, each blending ratio contained individual set of zero shear viscosity and infinite shear viscosity indicating a profound impact of PBS on the flow behavior of the blend and partial miscibility of the melt blend process.
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