Browsing by Author "OU, CF"

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BLENDS OF POLY(ETHYLENE-TEREPHTHALATE) WITH CO[POLY(ETHYLENE TEREPHTHALATE-P-OXYBENZOATE)] .2. COMPOSITION EFFECT ON THE RATE OF CRYSTALLIZATION
(1995-05-31)
OU, CF
;
LIN, CC
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材料科學與工程學系
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Department of Materials Science and Engineering
Poly(ethylene terephthalate) (PET) was blended with four different kinds of eo[poly(ethylene terephthalate-p-oxybenzoate)] copolyesters, designated P28, P46, P64, and P82, with the level of copolyester varing from 1 to 15 wt%. All samples were prepared by melt-mixing in a Brabender Plasticorder for 8 min. The crystallization behavior of samples were then studied via DSC. The results indicate that these four copolyesters accelerate the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of the PET crystallization rate was most pronounced in the PET/P28 blends with a maximum level at 10 wt% of P28, and in the PET/P82 blends, at 5 wt% of P82. The melting endotherm onset temperatures and the melting peak widths for the blends are comparable with those of neat PET. These results imply that the stability of PET crystalline phase in the blends does not change by blending. The observed changes in crystallization behavior, however, are explained by the effect of the physical state of the copolyester during PET crystallization as well as the content of the p-oxybenzoate (POB) moiety incorporated into the blends. (C) 1995 John Wiley and Sons, Inc.
BLENDS OF POLYETHYLENE TEREPHTHALATE WITH CO[POLY(ETHYLENE TEREPHTHALATE-P-OXYBENZOATE)] .1. CRYSTALLIZATION KINETICS BY DSC STUDY
(1994-11-28)
OU, CF
;
LIN, CC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The dynamic and isothermal crystallization behaviors of polyethylene terephthalate (PET) blended with two types of co[poly(ethylene terephthalate-p-oxybenzoate){ copolyesters with different compositions, i.e., POB/PET = 20/80 (P28) and POB/PET = 80/20 (P82), has been studied by using differential scanning calorimetry (DSC). Both of these copolyesters in 10 wt % increase crystallization rate of PET in a manner similar to that of a nucleating agent. It is found that sample P28, which is an isotropic copolyester, accelerates the crystallization rate more significantly than that of P82, which is a thermotropic copolyester. The Avrami exponents n and rate constants k of these samples based on DSC studies were obtained in order to discuss the crystallization kinetics of PET accelerated by these copolyesters. The crystallization rate of the blends is also increased by 8 min blending due to the increased uniformity of the copolyester dispersed in the PET matrix. (C) 1994 John Wiley & Sons, Inc.
DEPOLYMERIZATION OF POLY(ETHYLENE-TEREPHTHALATE) RESIN UNDER PRESSURE
(1991-03-20)
CHEN, JY
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OU, CF
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HU, YC
;
LIN, CC
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應用化學系
The process of depolymerization of PET resin by EG glycolysis under pressure is investigated. The kinetics of this pressurized depolymerization of PET resin is discussed. It was found that the rate of deploymerization is dependent of temperature, pressure, and concentration ratio of EG to PET. The rate of depolymerization is proportional to the square of EG concentration and faster than that under atmospheric pressure. Glycolyzed products under pressure consist of the PET monomer, BHET, and oligomers, mostly dimer and trimer. An equilibrium between BHET and oligomers is attained quickly soon after the deploymerization step is completed in the case of a higher ratio of EG/PET used. In the case of lower ratio of EG/PET, the final product now consists of molecular weight of oligomers rather than monomer, dimer, and trimer.