Test-tube model for rapid and accelerated biodegradation of poly(lactic acid)/poly(butylene succinate) blended bioplastic obtained from solution casting

Abstract

Developing an alternative accelerated biodegradation test to the standard tests is crucial for the swift assessment of bioplastics to reduce the time duration and cost. Designing a blended bioplastic with an acceptable extent of miscibility in the polymeric phase and its rapid and accelerated real-time degradation is a persistent challenge because of its different chemical and crystalline properties. Hereby, we developed miscible blended bioplastic films of biopolymers poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) with varied ratios by a simple solution casting method. The as prepared bioplastic blends of PLA/PBS (50/50 and 20/80) showed high miscibility with fascinating morphology as confirmed by optical and electron microscopy. Furthermore, the PLA/PBS films were validated by physicochemical methods including infrared spectroscopy, powder X-ray diffraction, thermogravimetric analyses and wettability by the contact angle measurements. All the results confirmed the successful preparation of blended bioplastics of PLA/PBS. Next, we developed a test-tube model for rapid and accelerated biodegradation (RAB) of the developed bioplastic blends of PLA/PBS in the form of films and powder (microparticles) using mobilised enzymes such as proteinase K and lipase in the aqueous buffer. The extent of degradation of the blends was followed using the physicochemical methods, along with the weight loss measurements. All the RAB results suggested that changes in surface area (from films to microparticle powder) affected the extent of enzymatic degradation of the bioplastic films and powder.