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Polybutylene Terephthalate Synthesis Essay

School of Chemical Engineering, Chungbuk National University, Cheongju, Chungbuk, 361-763 South Korea, Saehan Industry Inc., Gumi, Kyungbook, 730-707 South Korea, and Polymer Branch, Materials & Manufacturing Directorate, AFRL/MLBP, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433

Synopsis

Multiwalled carbon nanotubes (MWNTs) were functionalized with 4-alkyloxybenzoic acids. In situ polymerizations of ethylene glycol containing functionalized MWNTs and terephthalic acid were carried out to afford MWNT/PET nanocomposites. Due to structural similarity, ethoxybenzoyl-functionalized MWNT/PET system showed homogeneous dispersion and the interfacial boundary between EtO-MWNT and PET matrix was practically indiscernable.

Chem. Mater., 2005, 17 (20), pp 5057–5064

DOI: 10.1021/cm051218t

Publication Date (Web): September 3, 2005

Copyright © 2005 American Chemical Society

Using biomass-derived ethylene glycol (bio-EG) to synthesize poly(ethylene terephthalate) (PET) is of notable significance for alleviating the dependence on fossil energy resources. Bio-EG readily contains a small amount of miscellaneous diols, which derive from the side reactions in the catalytic conversion of biomass. To disclose the effects of miscellaneous diols on the synthesis and properties of PET, EG feedstock containing four 1,2-diols, i.e., 1,2-propylene glycol, 1,2-butanediol, 1,2-pentanediol, and 1,2-hexanediol at 0–10% concentrations was used for the synthesis of PET. The molecular weights, intrinsic viscosities, and thermal and mechanical properties of obtained PET materials were measured. It was found that when the overall content of miscellaneous diols in EG was lower than 5%, the molecular weights and thermal properties of the prepared PET materials were very similar to that of PET synthesized from pure EG. The miscellaneous diols were less likely to be incorporated into PET resin because of the steric hindrance of the alkyl group in diols to the esterification and polycondensation reactions. Instead, they preferred to undergo dehydration reactions to form low-boiling-point aldehydes and hemiacetals, which could be removed from the reaction system during the reactions. Three bio-EG samples at purities of 99.9, 98.5, and 95.8 wt % were used for the bio-PET synthesis. Transparent and colorless bio-PET samples were obtained, demonstrating that the presence of miscellaneous diols does not have negative effects on the color quality of PET. The physical properties of bio-PET prepared with bio-EG at a purity of higher than 98 wt % were nearly the same as those of PET derived from pure EG. At a lower bio-EG purity of 95.8 wt %, the tensile strength of the obtained bio-PET sample was slightly decreased. The comprehensive results of property characterization show that bio-PET materials prepared with bio-EG at purity higher than 95 wt % could be used as widely as the conventional petro-PET resin without notable deterioration in their performance.

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