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Jain, Anjana; Vijayan, Kalyani

doi:10.1023/a:1015837312634

Cited by 27 publications

(16 citation statements)

References 5 publications

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“…This fact adversely influences the yarn quality 20. As stated before by other authors, the temperature influence on yarn tensile characteristics is very important 21. Our results on tensile properties (Table 1 and 2) show that increase in draw ratio causes mostly an increase in yarn strength, while a temperature increase induces slight decrease in yarn strength.…”

Section: Resultssupporting

confidence: 80%

Structural Changes in the Fabrication and Ageing of PA66 Textured Yarn

Popovic¹,

Jovanović

Džunuzović

et al. 2005

Macro Materials & Eng

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Summary: The characterization of textured yarn is of great significance for both producers and final users. The influence of the texturing parameters (draw ratio and heater temperature) on the characteristics of the textured polyamide yarn has been investigated in this study. Textured yarn was characterized by the degree of orientation, degree of crystallinity, breaking characteristics, shrinkage, elasticity characteristics, the contents of the end groups and degree of whiteness. It was observed that the mentioned characteristics changed as a function of time. The influence of yarn ageing on its characteristics was assessed. The parameters of polyamide textured yarn structure were determined by DSC.Reflectance curve changes after ageing of PA 66 yarn.imageReflectance curve changes after ageing of PA 66 yarn.

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Section: Resultssupporting

confidence: 80%

Structural Changes in the Fabrication and Ageing of PA66 Textured Yarn

Popovic¹,

Jovanović

Džunuzović

et al. 2005

Macro Materials & Eng

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“…The WAXS diffractograms for these tensile specimens are shown in Figure 2(b). The crystal structures usually observed at room temperature in PA66 are the ␣ and ␤ form, 26 the ␣ form being the most commonly occurring phase. The nonoccurrence of peak intensities at 2 values of about 12 and 19°confirmed the absence of the ␤ form in the injection-molded specimens.…”

Section: Waxs Resultsmentioning

confidence: 99%

Effect of ambient‐temperature and high‐temperature electron‐beam radiation on the structural, thermal, mechanical, and dynamic mechanical properties of injection‐molded polyamide‐6,6

Sengupta

Sabharwal

Tikku³

et al. 2005

J of Applied Polymer Sci

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Electron-beam irradiation of injection-molded specimens of polyiminohexamethyleneiminoadipoyl (better known as polyamide-6,6) was carried out in air at ambient temperature (303 K) and a high temperature (393 K). Most of the irradiated specimens were tensile dumbbells, although a few were cylinders for compressive stress relaxation testing. A few representative samples were dipped in triallyl cyanurate (TAC) solution before ambient-temperature irradiation. The gel content of the specimens increased with radiation dose and the temperature of irradiation. Moreover, the TAC-treated specimens showed an increase in gel content over the neat specimens irradiated at the same dose levels. Wide-angle X-ray scattering and differential scanning calorimetry studies revealed that the crystallinity decreased with increasing radiation dose. Irradiation at the high temperature and treatment with TAC further decreased the crystallinity compared to irradiation at ambient temperature. As determined from compressive stress relaxation and mechanical and dynamic mechanical properties, the optimized radiation dose for ambient-temperature radiation was 200 kGy. The gels had a stiffening effect, and the rate of relaxation decreased significantly. The water-uptake characteristics of the tensile specimens were investigated; this revealed a decrease in the water absorption tendency with increasing gel content.

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“…This may be related to thermal annealing of the polymer, which improves the degree of perfection of the crystals and favors crystalline phase aggregation. 19 However, crystallization due to thermal oxidation may be even more important: chain scission results from the oxidation reactions as prolonged thermal irradiation is carried out in the presence of oxygen, and the oxidative degradation preferentially occurs in the amorphous region since this phase has higher oxygen permeability. The entangled tie-molecules are released as a result of chain scission and their rearrangement increases the overall crystallinity.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Thermal oxidative stability and effect of water on gas transport and mechanical properties in PA6‐EVOH films

Cerruti

Laurienzo

Malinconico

et al. 2007

J Polym Sci B Polym Phys

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The thermal oxidative stability and the effect of water on gas transport and mechanical properties of blends of polyamide 6 (PA6) with ethylene-co-vinyl alcohol (EVOH) and EVOH modified with carboxyl groups (EVOH-COOH) have been investigated. The presence of EVOH reduces water vapor and oxygen gas permeability of polyamide, as well as small amounts of EVOH-COOH further improve barrier properties, especially to oxygen. This has been explained in terms of improved interactions of the blend constituents in the amorphous phase, due to ionic linkages between the polyamide amino groups and the carboxyls of modified EVOH. The permeation to gases was found to increase with the amount of sorbed water. The morphology of the samples was found to have an effect on barrier properties, as the presence of EVOH causes the PA6 a crystalline form to increase, lowering the permeability to oxygen and water vapor. Mechanical properties are strongly affected by water sorption, as tensile modulus and strength decrease with increasing water content. Chemiluminescence (CL), infrared spectroscopy (FTIR), and tensile test were employed in order to assess the correlation between chemical composition and the thermal oxidative stability of the films aged at 110 8C in air. CL experiments suggest that the presence of EVOH and EVOH-COOH efficiently inhibits the formation of peroxidized species during the processing, and increases the thermal oxidative stability of the films. Infrared spectroscopy showed a build-up of carbonyl absorption in the range 1700-1780 cm À1 , due to the formation of oxidation products, which is greater in the case of the pure polymer. Tensile tests on films revealed a reduction in ductility as a result of ageing for neat PA6, whereas in comparison the blends exhibit a far better long-term stability. V V C 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 840-849, 2007

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Cited by 27 publications

References 5 publications

Structural Changes in the Fabrication and Ageing of PA66 Textured Yarn

Structural Changes in the Fabrication and Ageing of PA66 Textured Yarn

Effect of ambient‐temperature and high‐temperature electron‐beam radiation on the structural, thermal, mechanical, and dynamic mechanical properties of injection‐molded polyamide‐6,6

Thermal oxidative stability and effect of water on gas transport and mechanical properties in PA6‐EVOH films

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