Tensile Response of Plasticized Polyvinyl Chloride Containing Thermally Modified Rice Starch and Commercial Glycerol Monostearate

Abstract

Background: Incorporating starch into plasticised polyvinyl chloride (PVC) can increase the renewable constituent fraction but may reduce tensile strength, deformability, and stiffness. Commercial glycerol monostearate may influence these properties through formulation-related effects. However, the tensile response of plasticised PVC containing thermally modified rice starch with and without glycerol monostearate remains insufficiently characterised. Aims: To compare tensile properties of plasticised polyvinyl chloride containing thermally modified rice starch, with and without commercial glycerol monostearate. Study Design: A laboratory formulation study with one unfilled control, fourteen starch-containing formulations and five tensile specimens per formulation. Place and Duration of Study: Navoi State University of Mining and Technologies, Navoi, Uzbekistan, 2023–2025. Methodology: Formulations with 5–30 wt% starch without the additive and 5–55 wt% starch with 5 wt% commercial glycerol monostearate (GMS-40) were extruded and compression moulded. Mean stress at break, elongation and reported Young’s modulus were compared descriptively. The additive replaced an equal mass of the plasticised matrix. Results: At matched starch contents, additive-containing formulations showed mean stress at break, elongation and modulus values 12.4–18.8%, 19.0–26.6% and 9.8–16.5% higher, respectively. At 30 wt% starch, stress at break increased from 1.76 to 2.09 MPa and elongation from 52.39% to 66.32%. Replicate dispersion is not reported, precluding significance testing. Conclusion: GMS-40 was associated with partial recovery of the reported tensile properties at matched starch loading. The comparison describes a combined formulation effect and does not establish an optimum additive concentration or an interfacial mechanism.