Analysis of the Rotating Drum Polycondensation Reactior for PET Synthesis

Polyethylene terephthalate(PET) 중합반응은 기본적으로 평형반응으로서 부산물 제거 없이는 높은 분자량을 얻기가 힘들고, 특히 마지막 단계에서는 반응이 진행됨에 따라 반응 혼합물의 점도가 급격히 증가하여 부산물의 제거가 더욱 어려워지고 결국 우리가 얻고자하는 높은 분자량을 얻기가 힘들어진다. 본 연구에서는 이러한 문제를 해결하기 위해서 rotating drum 반응기를 개발하였고 그 효율을 알아 보았다. Bis-2-hydroxy ethylterephthalate(BHET)단량체가 온도 280℃로 유지되고 있는 반응기로 주입되고 반응기 압력이 조절되면서 생성된 부산물이 반응 혼합물로부터 연속적으로 제거된다. 촉매로는 Sb2O3를 사용하였고 안정제는 사용하지 않았다. 휘발성 부산물을 제거하는데 가장 유효한 인자로 알려진 film 재생성을 반응기 겉통을 적절히 회전시킴으로서 얻을 수가 있었고 기대했던 대로 film 재생성 주기를 줄임으로서 반응기 효율의 증가를 보였다. 또 반응기 효율에 진공도가 주는 영향을 알아보았다

Analysis of the rotating drum type polycondensation reactor for PET synthesis

학위논문(석사) - 한국과학기술원 : 화학공학과, 1988.2, [ vii, 61 p. ]한국과학기술원 : 화학공학과

표면 재생을 갖는 폴리에스터 중합반응기의 해석

학위논문(박사) - 한국과학기술원 : 화학공학과, 1992.2, [ xv, 150 p. ]For high efficiency polymerization of polyethylene terephthalate (PET), the development of polymerization catalysts, the elevation of monomer``s (bis-2-hydroxyethyl terephthalate, BHET) reactivity and the modeling of polymerization process have been continuously studied. In order to increase the molecular weight of PET, it has been reported that the removal of volatile byproduct in a final stage reactor is one of the most important factors to obtain the degree of polymerization wanted and the film renewal action is most important for the removal of volatile byproducts. Hence a reactor with film renewal was designed as a laboratory scale and tested as a batch reactor. At the same time comprehensive mathematical model was developed and compared with the experimental results to show a clear analysis of the influence of pertinent operating variables. The diffusivity of ethylene glycol (EG) in PET melt has a very important role to determine the overall polymerization profiles, which was separately obtained from desorption experiment. Reactants (BHET monomer, oligomer, prepolymer) were fed into the reactor at room temperature. After the reaction temperature reaching 255℃ by heating the silicone oil in the jacket with electric wire, the polymerization reaction was started by rotating the cylindrical screw within the reactor to generate the film continuously with the film exposure time 1.0 sec or others and pressure was gradually reduced. When reaction temperature reaches 285℃ (or specified levels) and the reduced pressure was set to be 2.5 torr (or a specified pressure level) and these were maintained throughout the experiment. Catalysts used were $Sb_2O_3$, Sn-Sb complex, KR41B and titanium tetrabutoxide. By comparing the modeling with experimental results, polycondensation reaction rate constant $k_1(=k_8)$ and diester group degradation reaction rate constant $k_7$ for $Sb_2O_3$ were obtained as follows: $k_1(=k_8) = 3.4\times 10^9 exp(-18500/RT)$, ㎤/mol-min a...한국과학기술원 : 화학공학과

Rheological anomalies of the poly(ethylene 2, 6-naphthalate) and poly(ethylene terephthalate) blends depending on the compositions

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