• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1071-1076
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• 2000

Temperature dependent data of 13C spin-lattice relaxation times and NOE factors for methylene carbons at 50.3MHz and 125.5 MHz have been used to probe the local chain dynamics of poly(butylene terephthalate) (PBT) in solution phase. The interpretation of the relaxation data for methylene chain carbons in PBT was attempted on the basis of several proposed motional models, among which the DLM model was found to be superior. Analysis based on the DLM model indicated that the motion of the $OCH_2groups$ was more restricted compared with the central methylene carbon, which is consistent with conclusions from solid state experiments reported by other investigators. Librational amplitudes of terminal and central carbon of PBT were estimated to be $29.84^{\circ}$ and $32.01^{\circ}respectively.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.213-214
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• 2003

1950년 Poly(ethylene terephthalate)(이하 PET)의 상업화 이후 Poly(trimethylene terephthalate)(이하 PTT)는 동종의 Poly(methylene terephthalate)계열의 고분자 중에서 Poly(butylene terephthalate) (이하 PBT)와 함께 최근 가장 주목받는 섬유 중의 하나이다. PTT 섬유는 얼마 전까지만 해도 주원료인 1,3-propanediol(이하 PDO)의 가격이 너무 높아 지난 60년 간 상업화 및 학문적 연구가 거의 이루어지지 않다가 최근 미국의 Shell사와 독일의 Degussa(미국의 Dupont)에 의해 PDO가 대량 생산되면서 상업화에 대한 연구가 활발히 이루어지고 있다. (중략)

• Korea-Australia Rheology Journal
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• v.13 no.4
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• pp.169-177
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• 2001

Morphological, thermal, rheological, and mechanical properties of reactive compatabilized blends of poly(butylene terephthalate) (PBT) and Polyamide-6 (PA) containing EGMA copolymer were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), advanced rheometric expansion system (ARES), and universal testing machine (UTM). From the results of thermal analysis by DSC, the melting point of the 30/70 PBT-PA blend was broadened after EGMA was added in the blends, since the enthalpy of melting of the PBT-PA somewhat decreased with the increase of EGMA content. From this result, it is suggested that the EGMA affected to the crystallization behavior and crystallinity of the PBT-PA blends. From SEM micrographs of the 70/30, 50/50, and 30/70 PBT-PA blends, the droplet size of the 30/70 PBT-PA blend was about 0.8 ${\mu}{\textrm}{m}$ which was smaller than that of the 50/50 and 70/30 PBT-PA blends. The complex viscosity of the 30/70 PBT-PA blend observed to be higher than that of the 50/50 and 70/30 PBT-PA blends. From the results of the morphology and rheological properties for the PBT-PA blends, it is suggested that the compatibility is increased in the 30/70 PBT-PA blend than the 50/50 and 70/30 PBT-PA blends. From the results of mechanical properties, it was found that the tensile strength of the 30/70 PBT-PA blend increased with the increase of EGMA up to 2 phr, while tensile strength of the blend in which EGMA content was higher than 2 phr decreased with the increase of EGMA content. From the results of morphological, thermal, rheological, and mechanical properties for the PBT-PA-EGMA blends, it is suggested that the EGMA could be used as a compatibilization role in the blends.

• Macromolecular Research
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• v.11 no.1
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• pp.25-35
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• 2003

A series of random poly(ethylene-co-1,4-butylene terephthalate)s (PEBTs), as well as poly(ethylene terephthalate) (PET) and poly(1,4-butylene terephthalate) (PBT), were synthesized by the bulk polycondensation. Their composition, molecular weight, and thermal properties were determined. All the copolymers are crystallizable, regardless of the compositions, which may originate from both even-atomic-numbered ethylene terephthalate and butylenes terephthalate units that undergo inherently crystallization. Non-isothermal crystallization exotherms were measured over the cooling rate of 2.5-20.0 K/min by calorimetry and then analyzed reasonably by the modified Avrami method rather than the Ozawa method. The results suggest that the primary crystallizations in the copolymers and the homopolymers follow a heterogeneous nucleation and spherulitic growth mechanism. However, when the cooling rate increases and the content of comonomer unit (ethylene glycol or 1,4-butylene glycol) increases, the crystallization behavior still becomes deviated slightly from the prediction of the modified Avrami analysis, which is due to the involvement of secondary crystallization and the formation of relatively low crystallinity. Overall, the crystallization rate is accelerated by increasing cooling rate but still depended on the composition. In addition, the activation energy in the non-isothermal crystallization was estimated.

• Polymer(Korea)
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• v.28 no.3
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• pp.239-244
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• 2004

Effect of lubricants on the rheological and thermal properties of poly(butylene terephthalate) [PBT] were investigated. Calcium stearate and adipic acid glycol polyester (AhGP) were used as processing lubricants for PBT. Decrease of melt viscosity was accomplished by the addition of 1 wt％ of lubricants. It was understood that melt viscosity was affected by the enhancement of chain mobility of PBT with AhGP as an internal lubricant as well as the lubricity on processing equipment developed by calcium stearate as an external lubricant. Lubricants also influenced chain scission of PBT which caused the viscosity drop as well. In addition, lubricant is resulted in the lowering of thermal stability, however, this might be minimized by adding less than 3 wt％ of calcium stearate as a lubricant. As a consequence, calcium stearate as an external lubricant is more effective to control the melt viscosity of PBT with minimizing of chain scission and thermal instability in PBT.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.163-166
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• 2002

PBT 섬유에 관한 연구[1-4]는 주로 섬유화 가능성에 관한 것을 타진하는 것으로써, 그 중 Spruiell[1]은 권취속도 1000-5600m/min에서 얻어진 PBT 필라멘트의 구조와 물성에 대하여 연구하였다. 그는 방사시 온라인상의 직경변화, 온도, 하중의 변화에 대해 연구하였으며, 방사선상에서 PET에 비해 결정화속도가 매우 빠르다고 보고하였다. 저자 등[2-3]은 권취속도 1-8km/min까지 변화시켜 얻은 PBT섬유의 구조에 관한 연구에서 6km/min 이상의 속도에서 얻은 경우 초기탄성률이 최고값을 가지며 그 이후 변화가 없음을 확인하였다. (중략)

• Elastomers and Composites
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• v.38 no.4
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• pp.295-302
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• 2003

The amount of shrinkage of injection molded parts is different from operational conditions of injection molding such as injection temperature, injection pressure and mold temperature, and mold design such as gate size. It also varies depending on the presence of crystalline structure in resins. In this study, part shrinkage was investigated for various operational conditions and resins. Poly(butylene terephthalate) (PBT) for crystalline polymer, and polycarbonate (PC) and poly(methyl methacrylate) (PMMA) for amorphous polymers were used. Crystall me polymer showed higher part shrinkage by about three times than that of amorphous polymers. Part shrinkage increased as melt and molt temperatures increased, and injection pressure decreased. Part shrinkage decreased as gate size increased since the pressure delivery is mush easier for larger gate sizes. Part shrinkage at the position close to the gate was larger than that or the position far from gate. This phenomenon might be occur by difference of residual stress.

• Polymer(Korea)
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• v.32 no.1
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• pp.13-18
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• 2008

For the evaluation of brominated flame retardants included in polymeric electronic devices, we investigated the extraction methods and solvent systems for four different types of polymers of PC (polycarbonate), PP (polyropylene), PET (poly(ethylene terephthalate)) and PBT (poly(butylene terephthalate)) using different solvent systems of hexane/acetone, THF, toluene, and THF/toluene. In order to compare the extraction efficiency of different methods and solvent systems, the deca-BDE (decabromo diphenyl ether) flame retardant was included in PC, PP, PET and PBT systems and subsequently extracted by soxhlet, ultrasonic, accelerated solvent, microwave and supercritical fluid extraction methods. The amount of the extracted flame retardant was monitored to evaluate the extraction efficiency. The ultrasonic extraction method was found not to be acceptable as an extraction method for the polymer systems mainly due to a low salvation efficiency of the organic solvents. Soxhlet, accelerated solvent and microwave extraction methods exhibited over 80% of extraction efficiency for toluene. The supercritical fluid extraction method, which has been used as an extraction method for flame retardants in polymers, showed the extraction efficiencies of ca. 100% for PC and PP in the optimal extraction conditions of $60^{\circ}C$ and 120 bar.

• Polymer(Korea)
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• v.31 no.5
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• pp.399-403
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• 2007

Trans-esterification behavior of polycarbonate/poly(butylene terephthalate) (PC/PBT) blends was investigated during the melt mixing process. Rheological and fracture behaviors, and fracture morphology were also investigated as a function of PC/PBT blend ratio. Based on FT-IR and $^1H-NMR$ results, a trans-esterification reaction was confirmed to occur between PC and PBT during the melt mixing process. The melt index(MI) decreased with increased PC content, indicating the higher flow resistance of PC. The storage and loss moduli were increased by increasing the PC loading, and the PC/PBT blends were rheologically incompatible based on the Cole-Cole plot. The tensile property increased linearly with the increased PC content. However, the impact strength increased until 50 wt% of PC loading, notably around $30{\sim}40wt%$, and then was levelled off at 50 wt%. Rough ridges were formed on the impact fracture surfaces above the 40 wt% of PC content, supporting the observed higher impact strength in this range.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.197-198
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• 2003

Poly(butylene terephthalate)(P5T) has long history as an engineering thermoplastic. PBT was first introduced commercially to the market place as an injection molding resin about 1969 by Celanese Plastics in the U.S.A. It is still widely used as a molding resin. Processing or forming methods for solid-phase deformation, such as stretching, hydrostatic extrusion. roller stretching, rolling, and so on can improve the mechanical properties effectively. (omitted)