Fabrication of High‐Performance Sustainable Packaging Composites via Blending of Recycled Polypropylene With Surface‐Functionalized Rice Husk‐Derived Nanosilica and Phthalate‐Modified Starch

ABSTRACT Polypropylene is extensively used as a packaging material, creating a huge amount of waste after use. This work highlights the use of recycled polypropylene (rPP), starch phthalate, and modified nanosilica to produce sustainable packaging material. Both starch and nanosilica are functionalized to improve overall compatibility by increasing dispersion within the rPP matrix. Among the formulations, the optimal composition was 8:0.6:32 (starch/starch phthalate:nanosilica:rPP:PMS3). Characterization through FTIR, SEM, XRD, and TGA confirmed structural and morphological improvements. SEM analysis reveals a more uniform and refined surface upon replacing starch with starch phthalate, reducing mechanical vulnerability and phase separation due to enhanced interfacial adhesion. XRD results indicated crystallinity in the modified blend. The starch phthalate‐based composite shows superior degradability and improved tensile (38.12 MPa) and tear strength (88.24 N/mm) compared to the starch‐based system, showing a higher Young's modulus (1707 N/mm 2 ). Loss in mechanical properties under soil burial conditions for a period of 12 months reveals a decrease in tensile strength, tear strength, and Young's modulus to 25.9216 MPa, 59.1208 N/mm, and 829.6 N/mm 2 , respectively. PMS3 exhibited statistically significant, reproducible, and highly predictable degradation behavior in tensile strength, Young's modulus, and tear strength over 12 months ( R 2 ≥ 0.977, p < 0.05). Kinetic analysis showed that starch modification increased the apparent degradation rate by approximately 86.5%. Thus, the synergistic blend presents a promising sustainable alternative for packaging applications.