Multifunctional PVC/PMMA/MgO Nanocomposites: A Study of Free Volume, Optical Behavior, and Radiation Shielding Performance

• Published in: Polymers for advanced technologies Vol. 36; no. 7
• Main Authors: Mohammed, M. I., Ashry, A., Ismail, A. M., Ibrahim, Magii M., Abdel‐Hady, Esam E., Awad, Somia
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.07.2025; Wiley Subscription Services, Inc
• Subjects: Attenuation coefficients; Fourier transforms; free volume; Functional groups; Functional materials; Infrared spectroscopy; Magnesium oxide; Nanocomposites; Nanoparticles; Optical measurement; optical properties; Optoelectronic devices; polymer nanocomposites; Polymethyl methacrylate; Polyvinyl chloride; Positron annihilation; positron annihilation lifetime; Positronium; Radiation; Radiation shielding; Refractivity; Spectrum analysis; Superconductors (materials); Surface roughness; γ‐rays attenuation
• ISSN: 1042-7147; 1099-1581
• DOI: 10.1002/pat.70270

ABSTRACT Using the solution casting method, polymeric nanocomposite films were created using a 1:1 weight ratio of polyvinyl chloride and polymethyl methacrylate, reinforced with different amounts of magnesium oxide (MgO) nanoparticles (0, 3, 6, 9, 12, and 15 wt%). X‐ray diffraction examination verified that the produced nanocomposites had an amorphous structure. Despite noticeable aggregation and surface roughness, the MgO nanoparticles' primarily spherical morphology and well‐ordered nanocrystalline domains were revealed by scanning electron microscopy. Fourier transform infrared spectroscopy showed that the MgO nanofillers and the polymer matrix interacted effectively. Positron annihilation lifetime spectroscopy showed that as the MgO content increased, the free volume (Vf) and ortho‐positronium pick‐off lifetime (τ3) decreased. This was explained by void filling caused by nanoparticles, a decrease in the local free volume due to particle size, and the impact of polar functional groups in the matrix. As the concentration of nanoparticles increased, optical measurements showed that the optical band gap (Egap) decreased from 4.09 to 3.40 eV for direct transitions and from 3.69 to 3.00 eV for indirect transitions. Furthermore, at 15 wt% MgO, the Urbach energy (Eu) rose significantly from 0.23 eV (unfilled blend) to 1.04 eV, along with a rise in the refractive index. Higher MgO loading resulted in a considerable improvement in gamma shielding performance, as evidenced by better mass attenuation coefficients, linear attenuation coefficients, and lower half‐value layer values. Urbach energy and free volume characteristics were found to be correlated. Overall, the PVC/PMMA/MgO nanocomposites exhibit favorable characteristics for potential applications in radiation shielding, optoelectronic devices, and other advanced functional materials.