Conductive polymer, polypyrrole (PPy), was synthesized by chemical oxidative polymerization technique for a period of four hours at room temperature using pyrrole monomer (mPPy) in aqueous solution. Different oxidants such as ferric chloride (FeCl₃) and ammonium persulphate (N₂H₈S₂O₈) and surfactant sodium dodecyl sulphate (C₁₂H₂₅NaO₄S) were used. The produced PPy samples were characterized by using different techniques such as the electrical resistivity by four probe technique, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The performance of the oxidants has been investigated and compared. It was found that both oxidants, FeCl₃ and N₂H₈S₂O₈, have decreased electrical resistivity as a function of temperature, which means increased conductivity. However, FeCl₃ has achieved better performance than N₂H₈S₂O₈, where it has achieved a lower resistivity of about 60 ohms at room temperature, which indicates higher conductivity of PPy samples with FeCl₃ as an oxidant. Similarly, further investigation of FeCl₃ oxidant has been conducted by varying its concentration, and its influence on the final properties was reported. It has been observed that the morphology of PPy samples has a significant influence on the conductivity. It was found that 0.1 M and 0.05 M concentrations of FeCl₃ oxidant and monomer, respectively, have achieved better thermal stability, which is FeCl₃/mPPy ratio of 2 as an optimum value. FTIR and XRD results confirmed the structural formation of polypyrrole from pyrrole monomer during the synthesizing process.

In this research work, graphene nanoplatelets (GNP) were selected as alternative reinforcing nanofillers to enhance the properties of polypropylene (PP) using different compatibilizers called polypropylene grafted maleic anhydride (PP-g-MA) and ethylene-octene elastomer grafted maleic anhydride (POE-g-MA). A twin screw extruder was used to compound PP, GNP, and either the PP-g-MA or POE-g-MA compatibilizer. The effect of GNP loading on mechanical and thermal properties of neat PP was investigated. Furthermore, the influence and performance of different compatibilizers on the final properties, such as mechanical and thermal, were discussed and reported. Tensile, flexural, impact, melting temperature, crystallization temperature, and thermal stability were evaluated by using a universal testing system, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). For mechanical properties, it was found that increasing GNP content from 1 wt.% to 5 wt.% increased tensile strength of the neat PP up to 4 MPa. The influence of compatibilizers on the mechanical properties had been discussed and reported. For instance, the addition of PP-g-MA compatibilizer improved tensile strength of neat PP with GNP loading. However, the addition of compatibilizer POE-g-MA slightly decreased the tensile strength of neat PP. A similar trend of behavior was observed for flexural strength. For thermal properties, it was found that both GNP loading and compatibilizers have no significant influence on both crystallization and melting temperature of neat PP. For thermal stability, however, it was found that increasing the GNP loading had a significant influence on improving the thermal behavior of neat PP. Furthermore, the addition of compatibilizers into the PP/GNP nanocomposite had slightly improved the thermal stability of neat PP.

This paper examines the effect of high-pressure carbon dioxide on the foaming process in polystyrene near the glass transition temperature and the foaming was studied using cylindrical high-pressure view cell with two optical windows. This technique has potential applications in the shape foaming of polymers at lower temperatures, dye impregnation, and the foaming of polystyrene. Three sets of experiments were carried out at operating temperatures of 50, 70, and 100°C, each over a range of pressures from 24 to 120 bar. Foaming was not observed when the polymer was initially at conditions below Tg but was observed above Tg. The nucleation appeared to occur randomly leading to subsequent bubble growth from these sites, with maximum radius of 0.02–0.83 mm. Three models were applied on the foaming experimental data. Variable diffusivity and viscosity model (Model C) was applied to assess the experimental data with the WLF equation. The model shows very good agreement by using realistic parameter values. The expansion occurs by diffusion of a dissolved gas from the supersaturated polymer envelope into the bubble.

High-density polyethylene (HDPE) was used in this study as a matrix for accommodating carbon nanofiber (CNF) along with ionic liquid, to investigate the effect of nanofibers loading on the morphological thermal and rheological properties of the composites. The nanocomposite materials were prepared via melt processing using dilakylimidazolium tetrafluoroborate (ionic liquid) as a compatibilizing agent. The samples blended with imidazolium ionic liquid exhibited higher thermal stability, while DSC analysis showed the clear miscibility of ionic liquid in the HDPE matrix with a single endothermic peak. The influence of CNF (ranging from 0, 0.5, 1, and 2 wt.%) and ionic liquid concentration on the viscoelastic parameters was investigated. The rheological analysis showed the shear-thinning behavior of the composites. An improvement in the viscoelastic properties was observed as the nanofiber concentration increased. Composites blended with ionic liquid (HDPE/CNF/IL) exhibited slightly lower values of complex viscosity and modulus over the corresponding HDPE/CNF nanocomposites. Therefore, it is also significant that the reduction in melt viscosity is an additional benefit for polymer composite processing as a result of the wetting effect by polymer-ionic liquid combinations.

The reliable interpretation of polymer plasticization under high-pressure CO₂ requires measurements that preserve the polymer–gas state while recording pressure, temperature, and response. This study presents a configuration-specific evaluation and validation evidence framework for in situ thermomechanical and optical polymer characterization. The three-point-bending platform used LVDT displacement monitoring; a separate optical cell provided morphological observation; and a patented compact analyzer screened PS/MMT formulations. A 15-point LVDT calibration gave R² = 0.9997 and RMSE = 0.073 mm; ambient comparison with corresponding DSC thermal events differed by 0–2 °C across four polymers. For polystyrene, the mechanical response shifted by approximately 45 K from 0 to 120 bar, and heating-rate changes shifted the operational criterion by up to 30 K. Optical observations provided mechanistic corroboration across the pressure-dependent softening boundary. Seven PS/MMT/MAH formulations showed 7.76–11.94 °C reductions at 50 bar. The framework links each result to its platform configuration and transition criterion while explicitly distinguishing demonstrated measurement capability from validation that remains incomplete for the fully integrated architecture.