Characterization of Recovered Polyvinylchloride by Size Exclusion Chromatography and Triple Detectors Technique

摘要

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 multidetector 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 of the PVC-R was dependent on a function of the excluded volume, z, where the z~2 coefficient was not zero. The obtained value of the 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.