Thermal investigation of the phase composition of poly(ethylene terephthalate). Analysis of different methods of determination of the degree of crystallinity of partially crystalline substances

1982 ◽  
Vol 23 (1-2) ◽  
pp. 111-121 ◽  
Author(s):  
M. Sh. Yagpharov
Keyword(s):  
Phase Composition ◽  
Ethylene Terephthalate ◽  
Degree Of Crystallinity ◽  
Thermal Investigation ◽  
Methods Of Determination ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
The Degree Of Crystallinity

Structure-Properties Relationships in Processed Poly(ethylene terephthalate)

2013 ◽  
Vol 554-557 ◽  
pp. 1757-1762
Author(s):  
Júlio C. Viana ◽  
Lyudmil Todorov
Keyword(s):  
Molecular Orientation ◽  
Ethylene Terephthalate ◽  
Degree Of Crystallinity ◽  
Thickness Variation ◽  
Pet Bottles ◽  
Poly Ethylene Terephthalate ◽  
Initial Modulus ◽  
Poly Ethylene ◽  
The Degree Of Crystallinity ◽  
Structure Properties

Abstract. Upon processing, polymeric products feature a complex microstructure. Besides evolving over the molded component, a through-the-thickness variation is also developed. This is the result of the thermo-mechanical environment (combined thermal and mechanical fields) applied during processing, which varies with the molding technique, the selected molding conditions and polymer properties (rheological, thermal, constitution). This complex microstructure makes rather intricate the establishment of structure-properties relationships in processed polymers. In fact, the basic identification of most relevant morphological parameters determining the behavior of the moldings is been revealed a difficult endeavor, further complicated by the multi-scale morphology presented by polymeric materials. This work follows an inductive approach for establishing the relationships between the structure and the properties (mechanical and barrier) of molded poly(ethylene terephthalate), PET. These relationships are investigated for specimens prepared by different methods, from “simple” to more “complex” stretching modes. Initially, PET specimens were prepared by stretching thin films at different high temperatures and strain rates, followed by quick cooling in a universal testing machine equipped with a thermal camera (uniaxial stretched specimens). More closely to processing, PET injection molded preforms were free blown without a mold with distinct conditions (free blown specimens). Finally, PET bottles were produced from the preforms also under different blown conditions. The morphology of all specimens was assessed by bi- and tri-refringence and DSC. The mechanical properties were evaluated by tensile tests at room temperature. Also, the oxygen transmission rate, OTR, was assessed for the PET bottles. For this low crystallinity and slowly crystallizable polymer, the initial modulus is mainly related to the amorphous phase (i.e., molecular mobility and orientation level). The yield stress appears to be determined by the degree of crystallinity and level of molecular orientation. In the case of free blown specimens (bi-axially stretched) the anisotropy of the initial modulus depends upon the induced anisotropy of the molecular orientation. OTR is influenced by the molecular orientation and the degree of crystallinity of the polymer. An attempt to interpret these types of relationships by molecular dynamics simulations is made.

scholarly journals Addition of Graphite Filler to Enhance Electrical, Morphological, Thermal, and Mechanical Properties in Poly (Ethylene Terephthalate): Experimental Characterization and Material Modeling

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1411 ◽  
Author(s):  
Basheer A. Alshammari ◽  
Fahad S. Al-Mubaddel ◽  
Mohammad Rezaul Karim ◽  
Mokarram Hossain ◽  
Abdullah S. Al-Mutairi ◽  
...  
Keyword(s):  
Percolation Threshold ◽  
Ethylene Terephthalate ◽  
Material Behavior ◽  
Degree Of Crystallinity ◽  
Experimental Characterization ◽  
Threshold Values ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Carbon Fillers ◽  
The Degree Of Crystallinity

Poly(ethylene terephthalate)/graphite (PET/G) micro-composites were fabricated by the melt compounding method using a minilab extruder. The carbon fillers were found to act as nucleating agents for the PET matrix and hence accelerated crystallization and increased the degree of crystallinity. TGA showed that carbon fillers improved the resistance to thermal and thermo-oxidative degradation under both air and nitrogen atmospheres. However, a poor agreement was observed at higher loadings of the filler where the composites displayed reduced reinforcement efficiency. The results demonstrate that the addition of graphite at loading >14.5 wt.% made electrically conductive composites. It was calculated that the electric conductivities of PET/graphite micro-composites were enhanced, above the percolation threshold values by two orders of magnitudes compared to the PET matrix. The minimum value of conductivity required to avoid electrostatic charge application of an insulating polymer was achieved, just above the threshold values. The addition of graphite also improved thermal stability of PET, accelerated its crystallization process and increased the degree of crystallinity. Microscopic results exhibit no indication of aggregations at 2 wt.% graphite, whereas more agglomeration and rolling up could be seen as the graphite content was increased in the PET matrix (in particular, above the percolation threshold value). Furthermore, based on the mechanical experimental characterization of the PET/graphite micro-composites, a large deformation-based mathematical model is proposed for material behavior predictions. The model fits well the experimental data and predicts other mechanical data that are not included in the parameter identification.

Supercritical fluid extraction and chromatography for the determination of oligomers in poly(ethylene terephthalate) films

1991 ◽  
Vol 63 (20) ◽  
pp. 2371-2377 ◽  
Author(s):  
Keith D. Bartle ◽  
Terry. Boddington ◽  
Anthony A. Clifford ◽  
Nicholas J. Cotton ◽  
Christopher J. Dowle
Keyword(s):  
Supercritical Fluid Extraction ◽  
Supercritical Fluid ◽  
Ethylene Terephthalate ◽  
Fluid Extraction ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Determination of local mechanical stresses in dyed poly(ethylene terephthalate) by IR spectroscopy

1979 ◽  
Vol 30 (5) ◽  
pp. 686-688
Author(s):  
D. Saidov ◽  
Kh. Khabibulloev ◽  
R. M. Marupov ◽  
V. I. Dasturi ◽  
M. S. Umarova
Keyword(s):  
Ir Spectroscopy ◽  
Ethylene Terephthalate ◽  
Mechanical Stresses ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

scholarly journals Determination of the degree of randomness in condensation copolymers containing both symmetrical and unsymmetrical monomer units: a theoretical study

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Martine Tessier ◽  
Alain Fradet
Keyword(s):  
Nmr Spectroscopy ◽  
Ethylene Terephthalate ◽  
Functional Group ◽  
Theoretical Study ◽  
Rational Functions ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Average Block

Abstract Expressions for the degree of randomness, B, and for the number- and weight-average block lengths of condensation copolymers containing both symmetrical (AA + BB) and unsymmetrical (AB) monomer units are established through an approach based on functional group probabilities. Several parameters introduced in literature to characterize randomness in AA + BB condensation copolymers are also calculated using this approach and compared to B, showing that they are simple linear or rational functions of B. A method for calculating functional group probabilities from the dyad and triad number-fractions determined by NMR spectroscopy is described for poly(ethylene terephthalate)-poly(ε-caprolactone) copolyesters. This method obviously applies to any AA + BB + AB polycondensation and is easily generalizable to other types of condensation copolymers.

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