Ghazi Faisal Najmuldeen

Dissolution/reprecipitation technique for waste polyolefin recycling using new pure and blend organic solvents

Abstract Restoration of waste polymer based on low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) is studied using the dissolution/reprecipitation method. In this technique, pure turpentine, turpentine/petroleum ether (PetE) and turpentine/benzene as solvents with different fractions and PetE and n-hexane as non-solvents were examined. Commercial polymer products (packaging food, bags, laboratory plastic materials, detergent containers) used as raw materials were optimized with model polymers. Polymer recoveries in every case were <94%. Fourier transform infrared (FTIR) spectra and tensile mechanical properties of the samples before and after recycling were measured. Potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity), before and after recycling, using differential scanning calorimetry (DSC). The blend solvents were seen as good solvents for all polyolefins used and the dissolution temperature was less than the pure solvent at the same time. High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

Potential solvent for reconditioning polyolefin waste materials

Abstract Waste polymer reconditioning was examined by a method of dissolution/reprecipitation on low- and high-density polyethylene (PE) and polypropylene (PP). Toluene and petroleum ether, in different proportions, were used as solvents, and n-hexane was used as a non-solvent. Commercial polymer products used on an everyday basis were used with a virgin polymer, to optimize the qualities of the final product, and 98% polymer was recovered in each case. Fourier transform infrared spectroscopy (FTIR) images and tensile mechanical properties of the samples, before and after recycling, were analyzed. The potential recycling-based degradation of the polymer was further investigated by measuring the thermal properties (melting point and crystallinity) before and after recycling, using differential scanning calorimetry (DSC). High reconditioning was observed in most recycled samples, with no significant difference from the virgin materials. The studied technique seems to be viable for waste polyolefin polymer recycling.

Prediction of Experimental Measurement Data for High Density Polyethylene and Polypropylene Solubility in Organic Solvents

Abstract High density polyethylene (HDPE) and polypropylene (PP) solubility in several pure and blend non-polar organic solvents was measured at 365–430 K temperature at atmospheric pressure, with polymer concentration of 0.5–25 g in 100 ml of solvent. The activity coefficients were estimated depending on the experimental solubility results for all the polymer-solvent systems. A non-ideal equation combined with activity coefficient was developed based on the crystallinity. A new correlation equation was attained, which is based on the melting temperature and heat of fusion using SSPS software. These two equations were used to predict the solid-liquid experimental data for the binary system polymer-solvent. The distinction between the experimental and model data was assessed by using mean absolute deviation percentage (MAD %). The non-ideal equation based on crystallinity and the new correlations showed low MAD %, displaying a close match with the experimental data.