عبدالحميد نصر عبدالحميد القمي
عضو هيئة تدريس قار
المؤهل العلمي: دكتوراه
الدرجة العلمية: أستاذ مساعد
التخصص: كيمياء عضوية - كيمياء
الصيدلة - الصيدلة
المنشورات العلمية
Kinetic Analysis of Polyvinylpyrrolidone Pyrolysis Using Thermogravimetric Analysis
Journal ArticlePolyvinylpyrrolidone (PVP; poly(N-vinylpyrrolidone)) is a versatile water-soluble polymer widely used in pharmaceuticals, coatings, and nanocomposites due to its solubility, biocompatibility, and film-forming properties. Despite its extensive applications, systematic kinetic data describing its thermal degradation remain limited. In this study, non-isothermal thermogravimetric analysis (TGA) of PVP was performed under nitrogen and air atmospheres at heating rates of 5, 10, 20, and 40 °C min⁻¹. Thermal profiles revealed three degradation stages: moisture loss (30–150 °C), main-chain scission and depolymerization (150–450 °C), and carbonaceous residue formation (>450 °C), with the principal decomposition peak at 370–410 °C. Activation energies (Eₐ) determined using Kissinger, Flynn–Wall–Ozawa (FWO), and Kissinger–Akahira–Sunose (KAS) methods ranged from 179 to 186 kJ mol⁻¹ and were validated using the Coats–Redfern model-fitting approach. Reaction orders (n ≈ 1.1–1.3) indicate random chain scission as the dominant mechanism. The resulting kinetic dataset provides reliable insight into PVP thermal stability and supports optimization of processing, recycling, and composite fabrication.
Abdulhamid Nasr Abdulhamid Elghemi, (03-2026), Libya: AlQalam Journal of Medical and Applied Sciences, 9 (4), 833-837
Isothermal Kinetic Study of Polyvinylpyrrolidone Thermal Degradation Using Thermogravimetric Analysis
Journal ArticlePolyvinylpyrrolidone (PVP) is a widely used water-soluble polymer with applications in pharmaceuticals, cosmetics, adhesives, and medical devices. Despite its versatility, the thermal stability of PVP remains a concern during processing and high-temperature applications, where degradation can compromise performance and safety. This study aimed to investigate the kinetic parameters of PVP thermal degradation using isothermal thermogravimetric analysis (TGA) over a temperature range of 30–800 °C. PVP samples were analyzed under a nitrogen atmosphere, and weight loss was recorded over time. Kinetic parameters, including activation energy (Ea) and pre-exponential factor (A), were determined, and molecular weight changes were evaluated via gel permeation chromatography. Results indicated multi-stage degradation with increasing Ea at higher temperatures, consistent with backbone scission and pyrrolidone ring decomposition. Molecular weight decreased progressively, and polydispersity increased, reflecting chain fragmentation. The study provides accurate isothermal kinetic data, contributing to better prediction of PVP behavior under thermal stress and guiding the design of thermally stable formulations
Abdulhamid Nasr Abdulhamid Elghemi, (03-2026), Libya: Libyan Medical Journal, 18 (4), 178-183
Thermal Decomposition Using TG–FTIR Coupled Analysis
Journal ArticleThermal decomposition analysis is fundamental for evaluating the stability, degradation pathways, and safety profile of materials exposed to elevated temperatures. Thermogravimetric analysis (TG) provides quantitative information on mass loss, while Fourier-transform infrared spectroscopy (FTIR) identifies evolved gaseous products. The coupling of TG with FTIR (TG–FTIR) offers a comprehensive analytical platform capable of correlating weight-loss events with chemical species released during thermal degradation. This integrated technique has gained increasing importance in polymer science and pharmaceutical research. Selected polymeric and pharmaceutical samples were subjected to TG–FTIR analysis under a nitrogen atmosphere. Approximately 8–10 mg of each sample was heated from 25°C to 800°C at a constant heating rate of 10°C/min. The evolved gases were transferred through a heated interface to the FTIR gas cell to prevent condensation. TG and DTG curves were recorded and synchronized with FTIR spectra to identify volatile degradation products and correlate them with specific thermal events. Distinct multi-stage decomposition patterns were observed for all samples. Polymeric materials demonstrated higher onset degradation temperatures compared to pharmaceutical compounds. FTIR analysis revealed the evolution of CO₂, CO, H₂O, and volatile organic compounds at characteristic temperatures corresponding to dehydration, bond cleavage, and oxidative degradation phases. The integration of TG and FTIR data enabled accurate identification of decomposition pathways and estimation of kinetic parameters. TG–FTIR coupling provides a robust and informative technique for comprehensive thermal characterization. The method enhances mechanistic understanding of degradation behavior and supports the development of thermally stable materials in industrial and pharmaceutical applications.
Abdulhamid Nasr Abdulhamid Elghemi, (03-2026), Libya: Attahdi Medical Journal, 3 (2), 116-120
Spectroscopic and Mechanistic Investigation of Polyvinylpyrrolidone (PVP) Thermal Decomposition Using TG–FTIR Coupled Analysis
Journal ArticlePolyvinylpyrrolidone (PVP) is a widely utilized polymer in pharmaceutical formulations, nanocomposites, biomedical devices, and membrane fabrication. Despite numerous thermogravimetric studies, detailed mechanistic insight into its volatile degradation products remains limited. This study aims to investigate the thermal decomposition mechanism of PVP using thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy (TG–FTIR) under inert and oxidative atmospheres. Degradation stages, evolved gaseous species, and structural transformations were systematically analyzed between 30–800 °C. Results are expected to reveal multi-step degradation involving dehydration, pyrrolidone ring opening, backbone scission, and carbonaceous residue formation. Identification of CO₂, CO, amide fragments, vinylpyrrolidone monomers, and nitrogen-containing volatiles will clarify the degradation pathway. The study provides mechanistic confirmation complementary to kinetic models and enhances predictive understanding of PVP behavior during sterilization, extrusion, pyrolysis, and composite processing.
Abdulhamid Nasr Abdulhamid Elghemi, (03-2026), Libya: Razi Medical Journal, 2 (2), 192-197