Influence of stress-induced crystallization on the dimensional stability of monoaxially drawn poly(ethylene terephthalate)

Mascia, L.; Fekkai, Zakia

doi:10.1016/0032-3861(93)90854-4

Cited by 18 publications

(14 citation statements)

References 15 publications

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“…The reason for this is that crystallization can effectively stabilize the polymer. Mascia and Fekkai's work17 indicated that when the degree of crystalline of PET reached 43%, the shrinkage would be completely suppressed.…”

Section: Resultsmentioning

confidence: 97%

Tensile and dynamic mechanical properties of improved ultrathin polymeric films

Bhushan

Higashioji

2001

J of Applied Polymer Sci

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ABSTRACT:Tensile and dynamic mechanical properties of improved ultrathin polymeric films for magnetic tapes are presented. These films include poly(ethylene terephthalate) or PET, poly(ethylene naphthalate) or PEN, and aromatic polyamide (ARAMID). PET film is currently the standard substrate used for magnetic tapes; thinner tensilized-type PET, PEN, and ARAMID were recently used as alternate substrates with improved material properties. The thickness of the films ranges from 6.2 to 4.8 m.Young's modulus of elasticity, F5 value, strain-at-yield, breaking strength, and strainat-break were obtained at low strain rates by using a tensile machine. Storage (or elastic) modulus, EЈ, and the loss tangent, tan ␦, which is a measurement of viscous energy dissipation, are measured by using a dynamic mechanical analyzer at temperature ranges of Ϫ50 to 150°C (for PET), and Ϫ50 to 210°C (for PEN and ARAMID), and at a frequency range of 0.016 to 29 Hz. Frequency-temperature superposition was used to predict the dynamic mechanical behavior of the films over a 28 decade frequency range. Results show that ARAMID and tensilized films tend to have higher strength and moduli than standard PET and PEN. The rates of decrease of storage modulus as a function of temperature are lower for PET films than those for PEN and ARAMID films. Storage modulus for PEN films are higher than that for PET films at high frequencies, but this relationship reverses at low frequencies. ARAMID has the highest modulus and strength among the films in this study. The relationship between polymeric structure and mechanical properties are also discussed.

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Section: Resultsmentioning

confidence: 97%

Tensile and dynamic mechanical properties of improved ultrathin polymeric films

Bhushan

Higashioji

2001

J of Applied Polymer Sci

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“…Shrinkage behavior mainly depended on the fraction of the oriented amorphous regions at higher temperature range. Masia et al 34 reported that the crystallite formed during stress-induced crystallization in processing has lowered the value of shrinkage. At the temperature below T g , the values of thermal shrinkage for TLCP/PEN/PET ternary blend fibers little changed due to the restricted molecular motion.…”

Section: Resultsmentioning

confidence: 99%

Effects of annealing on structure and properties of TLCP/PEN/PET ternary blend fibers

et al. 2003

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Thermotropic liquid crystalline polymer (TLCP)/poly(ethylene 2,6-naphthalate) (PEN)/poly(ethylene terephthalate) (PET) ternary blends were prepared by melt blending, and were melt-spun to fibers at various spinning speeds in an effort to improve fiber performance and processability. Structure and property relationship of TLCP/ PEN/PET ternary blend fibers and effects of annealing on those were investigated. The mechanical properties of ternary blend fibers could be significantly improved by annealing, which were attributed to the development of more ordered crystallites and the formation of more perfect crystalline structures. TLCP/PEN/PET ternary blend fibers that annealed at 180 o C for 2 h, exhibited the highest values of tensile strength and modulus. The double melting behaviors observed in the annealed ternary blend fibers depended on annealing temperature and time, which might be caused by different lamellae thickness distribution as a result of the melting-reorganization process during the DSC scans.

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“…Cakmak and Wang29 suggested that the increase in crystallinity and orientation of chains in the amorphous region results in a reduction in creep strains for PET. Mascia and Fekkai30 indicated that when the degree of crystallinity of PET reached 43% the shrinkage would be completely suppressed. The network structure formed by the crystalline region significantly improves the stiffness and mechanical stability by anchoring polymeric chains in the high‐density and less mobile crystalline region.…”

Section: Resultsmentioning

confidence: 99%

Mechanical, hygroscopic, and thermal properties of ultrathin polymeric substrates for magnetic tapes

Bhushan

2003

J of Applied Polymer Sci

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Mechanical, hygroscopic, and thermal properties of improved ultrathin polymeric films for magnetic tapes are presented. These films include poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), and aromatic polyamide (ARAMID). PET films are currently the most commonly used polymeric substrate material for magnetic tapes, followed by PEN and ARAMID. The thickness of the films ranges from 6.2 to 4.8 m. Tensile tests were run to obtain the Young's modulus, F5 value, strain at yield, breaking strength, and strain at break. The storage modulus, EЈ, and the loss tangent, tan ␦, were measured using a dynamic mechanical analyzer (DMA) at temperature ranges of Ϫ50 to 150°C (for PET) and Ϫ50 to 210°C (for PEN and ARAMID) and at a frequency range of 0.016 -28 Hz. Frequency-temperature superposition was used to predict the dynamic mechanical behavior of the films over a 28-decade frequency range. Short-term longitudinal creep behavior of the films during 10, 30, 60, and 300 s, 7 MPa, were measured at 25 and 55°C. Long-term longitudinal creep measurements were performed at 25, 40, and 55°C for 100 h. The Poisson's ratio and 50-h long-term lateral creep were measured at 25°C/ 15% RH, 25°C/50% RH, 25°C/80% RH, and 40°C/50% RH. The in-plane coefficient of hygroscopic expansion (CHE) at 25°C/20 -80% RH and the coefficient of thermal expansion (CTE) at 30 -70°C were measured for all the samples. The properties for all films are summarized. The relationship between the polymeric structure and the mechanical and physical properties are discussed, based on the molecular structure, crystallinity, and molecular orientation.

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Influence of stress-induced crystallization on the dimensional stability of monoaxially drawn poly(ethylene terephthalate)

Cited by 18 publications

References 15 publications

Tensile and dynamic mechanical properties of improved ultrathin polymeric films

Tensile and dynamic mechanical properties of improved ultrathin polymeric films

Effects of annealing on structure and properties of TLCP/PEN/PET ternary blend fibers

Mechanical, hygroscopic, and thermal properties of ultrathin polymeric substrates for magnetic tapes

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