Formulation and Characterization of Fully Bio‐Based Plastisol From Poly(3‐Hydroxybutyrate)

ABSTRACT Plastisol is defined as a liquid dispersion of fine polymeric powders in a plasticizer that remains fluid at ambient temperature yet solidifies upon heating. Plastisol is highly versatile and widely used across various sectors, particularly in industrial and consumer applications. The current research aims to develop a bioplastisol using biobased and biodegradable poly(3‐hydroxybutyrate) (PHB) as the polymer and tributyl citrate as the plasticizer. A comprehensive evaluation was conducted on the dynamic rheological behavior, thermal properties, crystallographic features, and mechanical characteristics of both PHB bioplastisol and plasticized PHB. The study observed remarkable compatibility of tributyl citrate with PHB, along with significant gelation and fusion properties. Notable changes in the thermal properties of PHB were identified, indicating altered characteristics, as shown by the increase in interplanar spacing in the X‐ray diffraction peaks. Additionally, the developed bioplastisol demonstrated essential features comparable to traditional plastisols, including efficient plasticizer absorption, particle swelling, and the formation of uniform and flexible films. The Young's modulus and tensile strength were within the range of conventional plastisol films; however, the plasticized PHB films initially showed limited elongation at break, which increased significantly through high‐temperature annealing. Nonetheless, this process also caused substantial leaching of the plasticizer.