Catalytic Synthesis of Poly(ethylene terephthalate-co-oxybenzoate) systems via the Melt Polyesterification Route: Copolyesterification Kinetics

Mathew, Johnson; Ghadage, R. S.; Ponrathnam, S.; Prasad, S.

doi:10.1021/ma00093a001

Cited by 30 publications

(32 citation statements)

References 12 publications

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“…Similar results were found for the polyesterification of 4-acetoxybenzoic acid, 288 yielding nonmeltable poly(4-hydroxybenzoic acid), or for its copolyesterification in PET, forming poly(ethylene terephthalate-co-4-oxybenzoyl), through ester interchange reactions. 289 …”

Section: Scheme 225mentioning

confidence: 99%

Polyesters

Fradet

Tessier

2003

Synthetic Methods in Step‐Growth Polymers

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Section: Scheme 225mentioning

confidence: 99%

Polyesters

Fradet

Tessier

2003

Synthetic Methods in Step‐Growth Polymers

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“…The aliphatic-aromatic TLCP was synthesized from poly(ethylene terephthalate) (PET) (70 mol % ) and 4-acetoxybenzoic acid (30 mol % ). 13 The intrinsic viscosity of the PET used in the synthesis was 0.6 dL g-1 . TLCP exhibited birefringence when it was heated up to 300°C and then cooled down.…”

Section: Methodsmentioning

confidence: 99%

In situ Fibre Composites from Poly(phenylene sulphide)/Thermotropic Liquid Crystalline Polymer Blends. Melting, Crystallization, and Phase Behavior

Gopakumar

Ponrathnam

Rajan

et al. 1997

Polym J

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ABSTRACT:Melting, crystallization and phase behavior of the blends of poly(phenylene sulphide) (PPS) and an aliphatic-aromatic thermotropic liquid crystalline polymer (TLCP), were investigated using differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). The equilibrium melting temperature (T~) and the crystal lamellar thickness of PPS phase decreases with an increase in TLCP concentration. This phenomenon can be ascribable to the nucleating effect of TLCP on the spherulite growth of PPS phase. Phase diagram shows that the PPS/TLCP blend crystallizes in well separated temperature regimes and that the PPS component will always be solidified before the crystallization of TLCP begins. The crystallization temperature of PPS increases with the addition of TLCP. The PPS/TLCP blends exists as phase separated in the melt state. The reduction in the spherulite size of PPS phase, as revealed by PLOM, indicates that the spherulitic growth rate as well as the overall crystallization rate of PPS is influenced by the presence of TLCP.KEY WORDS Poly(phenylene sulphide) / Thermotropic Liquid Crystalline Polymer / Polymer Blends / Melting Behavior / Crystallization Behavior / Phase Behavior / Poly(phenylene sulphide) (PPS) and thermotropic liquid crystalline polymers (TLCP) are high strength/high temperature specialty polymers which find applications in the electrical and electronic industries. 1 Blends of PPS with TLCPs are of interest for several reasons. 2 -12 The motivation was first to use the high-tensile modulus of the TLCPs in the solid state to reinforce the PPS matrix. Secondly, the low viscosity of the TLCPs can reduce the overall melt viscosity of the blend and thus act as a good processing aid. The thermotropic liquid crystalline polymer, which is initially dispersed as spheres or droplets, can be elongated to form fibrils in adequate flow fields to give an in situ reinforcement. Elongated fine fibrils can effectively reinforce the matrix polymer. Moreover, the TLCP phase has been shown to influence the crystallizability of the PPS matrix. 7 -10 Several studies 3 -7 have been published on the blends of PPS with wholly aromatic commercially available TLCPs such as Vectra-A950 (copolyester of 25 mol¾ of 2-hydroxy-6-naphthoic acid (HNA) and 75mol% 4-hydroxy benzoic acid (HBA)) and Vectra-B950 (copolyester of 60mol% 2-hydroxy-6-naphthoic acid, 20mol% terephthalic acid and 20mol% 4-aminophenol). Subramanian and Isayev 3 found that for effective reinforcement and betterment of mechanical properties, the melt viscosity of TLCP must be lower than that of the PPS at the processing temperature. The mechanical properties estimated for PPS/Vectra-A950 were lower than that of TLCP and no fibrillation of the TLCP phase in the matrix was found. Previous studies 4 -7 lead to the conclusion that maximum fibrillation occurs when the melt viscosity ratio of the original components is close to unity. The presence of fibres seems to be a necessary attribute for improving the mechanical properties. Thus...

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“…Instrument calibrations made were as described previously. 7,15 The block copolymers were observed by a hot stage coupled Leitz microscope under crossed polarizers in the temperature range over which transitions were observed by DSC. X-ray diffraction study of copolymer samples were performed with Philips PW 1730 X-ray diffractometer using Cu K␣ radiation.…”

Section: Measurementsmentioning

confidence: 99%

“…This decrease in glass transition temperature of PET/OB (T g of PET is 80°C) with OB mol % has been attributed to an enhanced randomization which increases the segmental mobility within PET/OB. 15 The nematic liquid crystalline transition ascribable to PET/OB occurs approximately at 193°C. The endotherm at 270°C correspond to PPS melting.…”

Section: Effect Of Oxybenzoate (Ob) Contentmentioning

confidence: 99%

“…length (n ϭ 6, 9, 12) and poly(ethylene terephthalate-co-oxybenzoate) (PET/OB), an aliphaticaromatic thermotropic liquid crystalline polymer (TLCP) with oxybenzoate content of 30, 45, and 60 mol %, were synthesized by procedures described in the literature. 15,16 Block copolymers of DCTPPS (n ϭ 12) and TLCP (75/25, 50/50, and 25/75 wt %) were synthesized by melt-transesterification at 300°C under reduced nitrogen pressure for varied times in the range 60, 90, 120, and 180 min. 17 The reactor set up was described previously.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Block copolymers of telechelic poly(phenylene sulfide) and semiaromatic thermotropic liquid crystalline polyester segments

Gopakumar

Ponrathnam

Rajan

et al. 1998

J. Polym. Sci. A Polym. Chem.

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We report the synthesis and characterization of copolymers comprising poly(phenyl sulfide) (PPS) blocks and semiaromatic thermotropic liquid crystalline polymer (TLCP) blocks. The copolymers, synthesized by melt‐transesterification of dicarboxy‐terminated poly(phenylene sulfide) with poly(ethylene terephthalate‐co‐oxybenzoate) (PET/OB), were characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and polarized light optical microscopy (PLOM). The crystallizability and liquid crystalline properties of the copolymers are greatly influenced by the extent of interchange reactions, the mole percent of oxybenzoate with respect to the PET, the PPS : PET/OB weight ratio, and the reaction time. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2707–2713, 1998

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Catalytic Synthesis of Poly(ethylene terephthalate-co-oxybenzoate) systems via the Melt Polyesterification Route: Copolyesterification Kinetics

Cited by 30 publications

References 12 publications

Polyesters

Polyesters

In situ Fibre Composites from Poly(phenylene sulphide)/Thermotropic Liquid Crystalline Polymer Blends. Melting, Crystallization, and Phase Behavior

Block copolymers of telechelic poly(phenylene sulfide) and semiaromatic thermotropic liquid crystalline polyester segments

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