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Everyone who drinks bottled water contributes at least 17 kg to the post‐consumer poly(ethylene terephthalate) (W‐PET) accelerating the accumulation of the waste plastics (WP) that already have an annual rate of increase of ~4.5%. Disposals of W‐PET mimics a pseudo‐renewable resource of WP, that creates many recycling and economic opportunities. This work presents a recycling method that reduces the burden of W‐PET on the environment while saves energy and creates new economic opportunities. The recovered purified PET (PET‐R) that its thermal properties are reported here was obtained by solvent extraction method. Five samples of PET‐R were analyzed by thermogravimetry to study its kinetics properties assuming that the degradation process followed a pseudo‐single component model. The isoconversional Ea,α values obtained from the f(α) functions were comparable to each other by the average and standard deviation of 200 ± 5 kJ mol−1; which is very close to the value of Ea of pure PET. The results were consistent with kinetics data reported in the literature for pure PET. [ABSTRACT FROM AUTHOR]

The production and utilization of disposal merchandise made of poly(ethylene terephthalate) (PET) continue to increase with an annual rate of ∼2%. The post-consumer PET (PC-PET), accumulated as waste, creates a pseudo-renewable resource which generates opportunities for reusing and recycling. The recycling of PC-PET saves energy and reduces the burden that the waste plastics in landfills and storage facilities impose on the environment. The polymer of this study (PET-R) was purified from PC-PET by a solvent extraction method and was characterized by thermogravimetric analysis (TGA) via five different linear temperature programs. The TGA curves of PET-R showed three distinct regions: the vaporization of the adsorbed volatile organic chemicals (VOCs) at temperatures 60–220 °C, the fast decomposition of the purified PET (PET-R) 350–500 °C, and the slow pyrolysis of the remains at temperatures >500 °C. The values of decomposition energy barrier (Ea), preexponential of the Arrhenius equation (lnA) and the mechanism of decomposition expressed by f(α), for both VOCs and PC-PET, were evaluated by isoconversional methods according to the Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall methods; the results of the two methods were very close to each other for each of the factors in each of the stages. The values of Ea, and lnA of the VOCs decreased with the increase of the extent of the reaction since they were related to the availability of the VOCs. The values of Ea, and A of PET-R were relatively constant with standard deviations of ±4 kJ/mol. The thermal properties of PET-R were close to the properties reported for the pure PET samples. This proves that pure PET can be extracted and purified from PC-PET by solvent extraction for industrial applications and upcycling wastes. [ABSTRACT FROM AUTHOR]

Thermal stability and kinetics of thermolysis of postconsumer milk containers made of high-density polyethylene (PC-HDPE) and filament rods extruded from them (HDPE-F) were examined by thermogravimetric analysis (TGA) with six linear temperature programs under a stream of nitrogen. The total weightloss of each sample took place in a one-step decomposition to volatiles at the heating rates, β = 1, 10, 25, 50, 70, and 100 Kmin-1. The values of initial decomposition temperature, the temperature at the maximum thermal degradation rate, and the maximum rate of decomposition were increased by increasing the heating rate as was the expectation. The isoconversional method was used to evaluate the fundamental kinetic parameters, the activation energy barrier (Ea), the Arrhenius pre-exponential factor (A), and the mechanism of the reaction, f(α). The values of Ea were independent of the model and heating rate, as was expected. However, the values of A depended on the model and the extent of reaction (α). The values of the Ea of PC-HDPE initiated at 171 kJ/mol at α = 0.05 and it increased to 207 kJ/mole at α = 0.95. The values of Ea of the HDPE-F rod were relatively constant for all α values, being 227 ± 3 kJ/mol. It was justified by the absence of easily volatilized substances in the HDPE-F. Knowledge of the thermal stability and decomposition kinetics of the starting materials (PC-HDPE) and the product (HDPE-F) is important in the context of thermochemical conversion processes aimed at the use of PC-HDPE as raw materials for recycling, upcycling, and down-cycling for objects used under room conditions. [ABSTRACT FROM AUTHOR]

A sample of cobaltocenium copolymer (Copolym) obtained by a controlled polymerization method was characterized by a multi-detector size exclusion chromatography (MD-SEC) method eluted by various pure and mixed mobile phases. The value of number average molecular weight ( M ¯ n ), estimated by MD-SEC using the above elutes, was comparable with the ones obtained from the SEC standard calibration curve and estimation by the monomer conversion method. The solution properties of the Copolym were studied based on the Mark-Houwink-Kuhn-Sakurada (MH) relationship where the values of the MH exponent of the Copolym in the above solutions were within the values corresponding to a flexible random coil system. The unperturbed end-to-end dimensions of the Copolym were obtained based on the Stockmayer-Fixman extrapolation method. It was found that the degree of flexibility of the Copolym was higher than that of C-C backbone polymers such as atactic polypropylene, and in the range of poly(acrylic acid), which is suggested to be due to the short-range interference effect of the ionic side chains and solvent molecules on the degree of free rotation of the copolymer. [ABSTRACT FROM AUTHOR]

Polyvinyl chloride (PVC) is an indispensable compound that accounts for 66% of the water distribution infrastructure and 75% of sanitary sewer pipe applications in the U.S.A. In this study PVC resin was recovered by solvent extraction from a postconsumer PVC pipe. The recovered PVC (PVC-R) was characterized by a multi-detector size exclusion chromatography system eluted with tetrahydrofuran (THF) at 30 °C. The values of the Mark-Houwink-Kuhn-Sakurada (MH) parameters of the PVC-R were obtained by averaging three replicable experiments and the results were comparable with the reported values of pure PVC. The Stockmayer-Fixman plot of the PVC-R in THF had a curved shape which is due to the notorious tendency of the PVC molecules to remain partly associated in supermolecular aggregates even if the PVC is dissolved in a good solvent. As a results, the unperturbed molecular dimension, R ¯ 0 2 / M ¯ w 1/2 , of the PVC-R was dependent on a function of the excluded volume, z, where the z2 coefficient was not zero. The obtained value of the R ¯ 0 2 / M ¯ w 1/2 of PVC-R, having a M ¯ w = 87 kDa and M ¯ w / M ¯ n = 1.41, was 8.19 × 10−9 (cgs), comparable with the reported value for pure industrial PVCs in THF, 6.4 kDa < M ¯ w < 650 kDa at 25 °C, 8.17 × 10−9 (cgs) and in benzyl alcohol, an ideal solvent, at 155.4 °C, 40 kDa < M ¯ w < 350 kDa, 8.20 × 10−9 (cgs). The comparison of the results showed that the PVC-R had similar characteristics to the industrial PVC reported in the published literature, and hence can be reused as a resin for the manufacturing of PVC commodities. [ABSTRACT FROM AUTHOR]

Both preferential adsorption coefficient λ and intrinsic viscosity [η] for poly (di-o-alkylphenyl methacrylates) /Tetrahydrofuran (THF)/water have been determined. The results are discussed in relation to the steric effect of the ortho-substituent groups on the aromatic ring. [ABSTRACT FROM AUTHOR]