• Fibers and Polymers
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• 제2권2호
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• pp.81-85
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• 2001

The effects of rate of phase separation to ester interchange reactions and the repulsive pair interaction energy on the phase behavior in a phase-separated immiscible polyester blend are investigated using a Monte Carlo simulation method. The time evolution of structure factor and the degree of randomness are monitored as a function of homogenization time. When the phase separation is dominant over ester interchange reactions, the domain size slowly increases with homogenization time. However, when the pair interaction becomes less repulsive, the domain size does not significantly change with homogenization time. On the other hand, when ester interchange reactions are dominant over the phase separation, the homogenization proceeds without a change in the domain size. The higher the extent of phase separation, the lower the increasing rate of the DR. However, when the phase separation is sufficiently dominant, the effect of the extent of phase separation on the increasing rate of the degree of randomness become less significant.

• Fibers and Polymers
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• 제2권2호
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• pp.86-91
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• 2001

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) [copoly(ET/CPT)] was prepared using poly(ethylene terephthalate) (PET) as a flexible spacer, terephthalic acid (TPA), and chlorohydroquinone diacetate (CHQDA). All reactions involved in the copolymerization were investigated using some model compounds: TAP was used for acidolysis, diphenylethyl terephthalate (DPET) for interchange reaction between PET chains, and 야-o-chlorophenyl terephthalate (DOCT) and di-m-chlorophenyl terephthalate (DMCT) for interchange reaction between PET and rigid rodlike segments. Activation energies obtained for the acidolysis of PET with TPA and for interchange reaction of PET with DPET, DOCT, and DMCT were 19.8 kcal/mol, 26.5 kcal/mole, and 45.9 kcal/mole, respectively. This result supports that the copolymerization proceeds through the acidolysis of PET with TPA first and subsequent polycondensation between carboxyl end group and CHQDA or acetyl end group, which is formed from the reaction of CHQDA and TPA. Also, it was found that ester-interchange reaction can be influenced by the steric hindrance. Copoly(ET/CPT)s obtained has ethylene acetate end groups formed from acetic acid hydroxy ethylene end groups and showed almost the random sequence distribution for all compositions.

• 대한가정학회지
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• 제36권8호
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• pp.95-104
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• 1998

PET microfiber fabric dissociation reactions by ethylene glycol (EG) catalayzed by the corresponding EG anions were examined to provide an empirical basis for the improvement of a PET microfiber fabrics. The alkoxide ions, monosodium ethylene glycolate in ethylene glycol solution(MSEG-EG) are prepared by the reaction between NaH and the EG respectively. The dissociation reactions were carried out until the sample PET microfiber fabrics dissociate up to 80%. Temperature used ranged 100~$160^{\circ}C$. The kinetic behaviors of the dissociated PET microfiber fabrics were examined. The results are as follows : 1. In all cases, it was found that the PET-alkoxide dissociation rate constants increased exponentially with increasing temperature. The activation energies (Ea) of the reactions were 23.31kcal/mol in PET-EG system respectively. The calculated enthalpies of the activated [PET-EG] complexes from the corresponding Ea values were 22.53 ~ 22.61 kcal/mol, and the entropies were -19.03 ~ -19.24 kcal/mol/k respectively. 2. The kinetic behavior of the PET-alkoxide dissociation reactions examined was explained by the transition state theory. PET-alkoxide transition state is believed to be formed during the ester interchange mechanism between PET and MSEG-EG in the course of the PET dissociation reactions.

• 한국염색가공학회지
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• 제2권3호
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• pp.26-35
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• 1990

This study was carried out with the view of fundamental investigating to improve the tactile and the hygroscopicity of Poly(ethylene Terephthalate) (PET)fibers. Mono-sodium ethylene glycolate in ethylene glycol (MSEG-EG) solution was prepared and PET films were treated with it. The following conclusions were obtained. When PET films were decomposed in MSEG-EG solution, decomposition rate constant showed an exponential relationship with treating temperature; activition energy was 23.30 Kcal/mol, activation enthalpy was 22.52~22.60 Kcal/mol and activation entropy was -29.20~ -29.41 e.u. On the basis of the results obtained above and structure identification of decomposition products, it was found that the decomposition reaction proceeded through ester interchange reaction.