Wang Yi-min

Effect of hot drawing on the structure and properties of novel polyamide 5,6 fibers

Polyamide 5,6 (PA 5,6) fibers were prepared using the melt-spinning method. The effects of draw ratio and temperature on the structure and properties of PA 5,6 fibers were investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction, sonic velocity and tensile test measurements. DSC results revealed that the melting temperature showed no considerable variation, while the heat of fusion increased with increments with draw ratio and temperature. It was found that the crystallinity and crystal size of PA 5,6 fibers were directly proportional to the draw ratio and temperature and the orientation factor increases as expected upon drawing. The tenacity and Youngs modulus were found to be increased, while the elongation at break decreased with the draw ratio and temperature. The improvement in mechanical properties may be attributed to the increase of orientation along the fiber axis and the crystallinity.

Parameters characterizing the kinetics of the non-isothermal crystallization of polyamide 5,6 determined by differential scanning calorimetry

Abstract The non-isothermal crystallization behavior of polyamide 5,6 (PA56) was investigated by differential scanning calorimeter (DSC), and the non-isothermal crystallization kinetics were analyzed using the modified Avrami equation, the Ozawa model, and the method combining the Avrami and Ozawa equations. It was found that the Avrami method modified by Jeziorny could only describe the primary stage of non-isothermal crystallization kinetics of PA56, the Ozawa model failed to describe the non-isothermal crystallization of PA56, while the combined approach could successfully describe the non-isothermal crystallization process much more effectively. Kinetic parameters, such as the Avrami exponent, kinetic crystallization rate constant, relative degree of crystallinity, the crystallization enthalpy, and activation energy, were also determined for PA56.

Mechanical properties, moisture absorption, and dyeability of polyamide 5,6 fibers

Polyamide 5,6 (PA56) and polyamide 6 (PA6) fibers were spun by melt spinning process and drawn by a thermal drawing in order to improve their mechanical properties. The effects of drawing conditions on mechanical properties, moisture absorption, and dyeing behavior were investigated by means of tensile testing measurements, moisture absorption test, as well as color strength measurements. It was found that the tenacity and Young’s modulus were significantly increased, while the elongation at break decreased as the draw ratio (DR) and temperature increased due to the increase in molecular orientation along the fiber axis and the crystallinity. PA56 fibers showed a little lower mechanical properties and much higher moisture regain than PA6 fibers at different DRs. This can be attributed to the amide group content in the polymer backbone, which yields higher moisture regain in PA56 fibers than PA6 fibers. The dyeing behaviors of PA56 fiber, in terms of dyebath exhaustion, color strength, and wash fastness are similar as those of PA6. Those results indicated that PA56 is a competitive novel fiber for textile material.

Properties of recycled poly (ethylene terephthalate) (PET)/hyperbranched polyester (HBPET) composite fibers

Hyperbranched polyester (HBPET) with aliphatic–aromatic structure was synthesized and extruded with recycled poly (ethylene terephthalate) (RPET) chips obtained from used water bottles, with ratio of 0.5% and 1 wt% of HBPET. Filament fibers from pure recycled PET (RPET-0) and (RPET-0.5 and RPET-1) composite were spun using a melt spinning process and drawn by a thermal drawing process to improve their mechanical properties. The effects of addition of HBPET on the properties of produced fibers as well as draw ratio are investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD), universal tensile analysis, and sonic velocity. It was found that mechanical properties of the (RPET-0.5 and RPET-1) fibers were improved with respect to pure recycled PET (PET-0) fibers. Moreover, the crystallinity of composites fibers was also increased with an increasing of HBPET content. The improvement in mechanical properties may be due to the increase of orientation of fiber molecules along the fiber axis. Moreover, addition of HBPET serves as lubricant within recycled PET matrix which increased its mechanical properties.

Study on Jute Fiber Reinforced Polypropylene (PP)Composite

Jute fiber reinforced PP composites are studied in this article. The composites are made of jute fiber as reinforcement for thermoplastic polypropylene. The effect of different fiber content and different fiber length on composite properties, such as the tensile strength, the flexural strength and impact strength are studied. The process conditions for making the composite and the invalidation theory of the composite are also discussed. The results indicate that the comprehensive properties of the composites with 12mm fiber length and 10% fiber weight content are improved obviously.