Investigation on the Thermo-Oxidative Degradation of Polyethylene, Poly(vinyl chloride), and Polystyrene Using NiPIm1.5 and NiPIm2 Nanocomposites

Rudrarapu Aravind; Akash Kumar Sahu; Gouri Sankhar Brahma; Trilochan Swain

doi:10.1021/acsomega.1c04358

Investigation on the Thermo-Oxidative Degradation of Polyethylene, Poly(vinyl chloride), and Polystyrene Using NiPIm_1.5 and NiPIm₂ Nanocomposites

ACS Omega. 2021 Oct 28;6(44):29869-29881. doi: 10.1021/acsomega.1c04358. eCollection 2021 Nov 9.

Authors

Rudrarapu Aravind¹, Akash Kumar Sahu¹, Gouri Sankhar Brahma¹, Trilochan Swain²

Affiliations

¹ Department of Chemistry, IcfaiTech (Faculty of Science and Technology), IFHE, Hyderabad, Telangana 501203, India.
² P.G. Department of Chemistry, Fakir Mohan University, Nuapadhi, Balasore, Odisha 756089, India.

Abstract

In this work, we report the synthesis of two nanoscale composites of nickel, NiPIm_1.5 and NiPIm₂ (NiPIm_1.5 = [Ni(C₃H₄N₂)(H₂O)₅](HPO₄)(H₂O)·0.3(C₃H₄N₂) and NiPIm₂ = [Ni(C₃H₄N₂)(H₂O)₅](HPO₄)(H₂O)·0.4(C₃H₄N₂)·H₂O), characterization by various instrumental methods and the investigation of the thermo-oxidative degradation of polyethylene (PE), poly(vinyl chloride) (PVC), and polystyrene (PS) in the presence of both nanocomposites. All of these polymers are subjected to thermal treatment with and without composites at 353 K for 120 min. The rate of degradation is maximum with NiPIm₂ for all three polymers, PE-13.1522%, PS-13.6152%, and PVC-8.04%, whereas with NiPIm_1.5, PE-7.3128%, PS-11.9837%, and PVC-4.9106%. The percentage of degradation in the presence of composites is much greater than the percentage of degradation without composites. The specific heat capacities of NiPIm_1.5 and NiPIm₂ are -148.42 and -348.64 J kg^-1 K^-1, respectively. The degradation process takes place by free radical mechanism. Thermogravimetric and differential thermal analyses revealed that the temperatures corresponding to the formation of composite materials with NiPIm₂ are 338.76, 331.78, and 354.30 K for PE, PVC, and PS, respectively. The temperatures of formation of the above composites are found to be less than that of NiPIm_1.5. The degraded residues of polymers indicate that ester is formed in each case along with other byproducts containing imidazole. Infrared studies revealed the thermal oxidation of hydroperoxides and the formation of ketone.