• Clean Technology
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• v.8 no.1
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• pp.39-44
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• 2002

In order to recycle poly(ethylene terephthalate), methanolysis has been investigated at elevated temperature and under high pressure without catalyst to afford dimethyl terephthalate and ethylene glycol. The reaction was carried out under 62 atm, $310^{\circ}C$ for 50min to obtain 98% dimethyl terephthalate. The method has been suggested as a simple and economical one to recycle the poly(ethylene terephthalate).

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.930-934
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• 1998

The modified poly(ethylene terephthalate) (PET) was synthesized by copolymerizing dimethyl terephthalate with ethylene glycol, polyethyleneglycol, and dodecylbenzene sulfonate as a surfactant. After characterization of viscosity, color, and contant angle, hydrophilic characteristics of the modified PET depending on additives was discussed.

• Applied Chemistry for Engineering
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• v.2 no.3
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• pp.246-252
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• 1991

Copolyesters (PEHT) of poly (ethylene terephthalate) (PET) and poly (1,4-phenylene terephthalate) (PHT) were synthesized by the solution polymerization with the PHT unit contents of less than 30 mol %, and their physical properties were studied. As the content of PHT unit in PEHT was increased, glass transition temperature, crystallization rate, thermal stability increased, whereas melting temperature decreased. When the PHT unit contents were 16.5 and 24.9 mol%, nematic mesophase was observed. Wide angle X-ray diffraction pattern showed the peaks originated from both PET unit and PHT unit.

• Polymer(Korea)
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• v.25 no.6
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• pp.848-854
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• 2001

The crystallization behavior of poly (ethylene terephthalate) (PET) /ethylene-methyl acrylate-glycidyl methacrylate copolymer (E-MeA-GMA) blend was studied. The extent of reaction and the reaction rate between PET and E-MeA-GMA were measured with torque rheometer, FT-IR and SEM. The effects of the grafting reaction on the crystallization behavior were investigated with DSC and time-resolved light scattering (TR-LS) techniques. The morphological change at the lamellar level was also examined by using a small angle X-ray scattering (SAXS) method.

• Fibers and Polymers
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• v.2 no.2
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• pp.75-80
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• 2001

The thermal degradation of poly(ethylene terephthalate-co-isophthalate)s (PETIs) is investigated by using isothermal thermogravimetric analysis at the temperature range of 280-31$0^{\circ}C$. The degradation rate of PETIs is increased as the mole ratio of ethylene isophthaloyl (EI) units in PETIs increases. The activation energies for the thermal degradation of poly(ethylene terephthalate), PETI(5/5), and poly(ethylene isophthalate) are 33.4, 16.6, and 8.9 kcal/mole, respectively. The degradation rate of PETIs is influenced by their volatile cyclic oligomer components formed during the polymerization and the thermal degradation. It is simulated by the rotational isomeric state model that the content of cyclic dimer in PETIs, which is the most volatile cyclic oligomer component, increases with the EI units in PETIs.

• Korea-Australia Rheology Journal
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• v.11 no.3
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• pp.219-223
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• 1999

The effects of the transreactions on the rheological properties have been found in the poly(ethylene 2, 6-naphthalate) (PEN) and poly (ethylene terephthalate) (PET) blends. The rheological properties were very much dependent on the blend compositions, which, in turn, were related to extent of the reactions. In particular, a blend with 50/50 wt% composition exhibits an unusual and remarkable decrease in complex viscosity and it may be related to the randomness of the copolymer structure through transreactions. It has been identified by investigating the extent of transreactions and block length of the copolymer from the (ethylene 2, 6-naphthalate) (EN) and (ethylene terephthalate) (ET) units from $^1{H}$ n.m.r. spectra.

• Textile Coloration and Finishing
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• v.6 no.3
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• pp.37-43
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• 1994

Commercial Poly(ethylene terephthalate) (PET) filaments were treated in solvents mixtures such as benzyl alcohol/perchloroethylene(BA/PER), benzyl alcohol/trichloroethylene(BA/TRI), benzyl alcohol/ethylene chloride(BA/EC), metha nol/perchloroethylene(ME/PER), and methanol/trichloroethyle(ME/TRI). Swelling of PET in solvent mixtures showed rapidly in the middle range of mixture ratio. Contribution of swelling of each component to total swelling of binary mixtures with increasing treated time was generally showed in proportion to the mixture ratio of the each component in dependence of the extend of swelling.

• Proceedings of the Korean Society of Rheology Conference
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• 2002.11a
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• pp.109-112
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• 2002

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.276-284
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• 1988

The crystallization behaviours of poly(ethylene terephthalate) modified by 1, 3-propane diol, 1, 5-pentane diol, 1, 6-hexane diol, or poly(ethylene glycol) of molecular weight 300 as a third component were studied by isothermal and nonisothermal crystallization. When the content of the third diol was about 4 mol %, the isothermal crystallization rate at the same supercooling below the melting temperature and the nonisothermal crystallization rate at the same overheating above the glass transition temperature were increased more by the shorter flexible diol unit. On the contrary the nonisothermal crystallization rate at the same supercooling below the melting temperature was increased more by the longer flexible diol unit.

• Polymer(Korea)
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• v.25 no.2
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• pp.226-232
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• 2001

The properties of poly(ethylene terephthalate) (PET)/maleic anhydride-grafted polypropylene (MAgPP)/poly(styrene-co-maleic anhydride)(PScMA) ternary blend were investigated. The ternary blend was immiscible based on the glass transition temperatures measured by dynamic mechanical analyzer (DMA). The degradation of MAgPP during melt mixing for 30 min at 280$^{\circ}C$ did not affect the properties of the ternary blend. The interaction among the components was confirmed from the rheological properties, which was increased with the PSCMA contents. In terms of the mechanical properties, it was observed to satisfy the mixture rule for a multiple system.