• Steel and Composite Structures
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• v.45 no.1
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• pp.147-157
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• 2022

This study assessed the compressive and tensile strengths and modulus of elasticity of waste polyethylene terephthalate (PET) using the ASTM standard tests. In addition, short carbon and glass fibers were mixed with waste PET to examine the improvements in ductility and strength during compression. The bonding was examined via field-emission scanning electron microscopy. The strength degradation of the waste PET tested under UV was 40-50%. However, it had a compressive strength of 32.37 MPa (equivalent to that of concrete), tensile strength of 31.83 MPa (approximately ten times that of concrete), and a unit weight of 12-13 kN/m3 (approximately half that of concrete). A finite element analysis showed that, compared with concrete, a waste PET pile foundation can support approximately 1.3 times greater loads. Mixing reinforcing fibers with waste PET further mitigated this, thereby extending ductility. Waste PET holds excellent potential for use in foundation piles, especially while mitigating brittleness using short reinforcing fibers and avoiding UV degradation.

• Polymer(Korea)
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• v.31 no.6
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• pp.518-525
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• 2007

The thermomechanical properties and morphologies of nanocomposite fibers of poly(ethylene terephthalate)(PET) incorporating thermally stable organoclays are compared. Dodecyltriphenyl-phosphonium-mica($C_{12}PPh-Mica$) and 1-hexadecane benzimidazole-mica ($C_{16}BIMD-Mica$) were used as reinforcing fillers in the fabrication of PET hybrid fibers. Dispersions of organoclays with PET were studied by using the in-situ polymerization method at various organoclay contents to produce nano-scale composites. The thermo-mechanical properties and morphologies of the PET hybrid fibers were determined using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X-ray diffraction (XRD), electron microscopy (SEM and TEM), and a universal tensile machine (UTM). Transmission electron microscopy (TEM) micrographs show that some of the clay layers are dispersed homogeneously within the polymer matrix on the nano-scale, although some clay particles are agglomerated. We also found that the addition of only a small amount of organoclay is enough to improve the thermal stabilities and mechanical properties of the PET nanocomposite fibers. Even polymers with low organoclay content (<5 wt%) were found to exhibit much higher thermo-mechanical values than pure PET fibers.

• Textile Coloration and Finishing
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• v.18 no.3 s.88
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• pp.10-15
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• 2006

In this research, we studied the dyeing properties of PET fibers in terms of $TiO_2$ contents, fiber strength and spinning oil which may cause barre' effect. The effect of $TiO_2$ contents in the fibers had no influence on the dye uptake. However, the reflectance(%) behaviors showed the different visual properties as $TiO_2$ contents in the fibers. The other factors could be considered as strength and spinning oil which also revealed difference on the dye exhaustion. The experimental results showed that $TiO_2$ contents within the fibers influenced reflectance(%) behaviors. Furthermore, fiber strength and spinning oil could be considered other major factors to impart the dyeing irregularity and barre' effect.

• Macromolecular Research
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• v.11 no.1
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• pp.62-68
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• 2003

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 18$0^{\circ}C$ 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.

• Textile Coloration and Finishing
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• v.6 no.4
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• pp.34-39
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• 1994

For the purpose of obtaining high modulus PET tire cord fiber by high spinning speed, the change of initial modulus and taut tie molecules (T.T.M) fraction with the PET tire cord fibers by different spinning speed is investigated. Initial modulus decreased with increasing spinning speed but increased above spinning speed of 1500m/min. Therefore, high modulus PET tire cord fiber may be obtained above spinning speed of 3500m/min. It was found that the initial modulus of fibers depends on fraction of T.T.M.

• Journal of the Korean Society of Clothing and Textiles
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• v.15 no.4 s.40
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• pp.431-435
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• 1991

The dispersion and Poiar force components of the surface free energy of PET fibers untreated and treated with hydrophilic chemicals, such as nonionic-soil release polymer (SRP), anionic, nonionic and hydrophilic silicone, were determined using harmonic-mean and geometric-mean methods. Contact angles of water and methylene iodide on the fibers were determined from the adhesion tensions using tensiometric method. Fibers treated with hydrophilic chemicals have the increased polar force component and the decreased dispersion force component. The adhesion tensions of triolein for the hydrophilic treated fibers were smaller than that for untreated fiber.

• Clean Technology
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• v.13 no.4
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• pp.244-250
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• 2007

Sorption of C. I. Disperse Yellow 54 dye in poly(trimethylene terephthalate) (PTT) and poly (ethylene terephthalate) (PET) textile fibers were measured at various pressures, temperatures, and times in the presence of supercritical carbon dioxide and thereby the diffusivities of the dye in the fibers were calculated. The diffusivity of dye in the polymeric fibers was very low, only in the order of $10^{-12}\;cm^2/sec$, but increased with increasing temperature at constant pressure and with increasing pressure at constant temperature. The diffusivity in PTT fibers were about 1.5 to 3 times as large as that in PET fibers. As the fiber was very thin, the dye distribution in the fiber was almost uniform everywhere inside the fiber.

• Journal of the Korea Concrete Institute
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• v.19 no.2
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• pp.233-239
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• 2007

The main objective of this study was to evaluate the effect of recycled PET fiber made from waste PET bottle on the control of plastic shrinkage cracking of cement based composites. PET is blown as a plastic material and used in a variety products such as a beverage bottle. However, waste PET bottles are thrown after the usage, raising huge problems in terms of the environment. Thus, the research on the method to recycle the PET bottles indicates important aspects in environment and economy. The method to recycle waste PET bottles as a reinforcing fiber for cement based composites is one of effective methods in terms of the recycle of waste PET bottles. In this research, the effect of recycled PET fiber geometry and length on the control of plastic shrinkage was examined through thin slab tests. A test program was carried out to understand the influence of fiber geometry, length and fiber volume fraction. Three type of recycled PET fibers including straight, twist crimped and embossed type. Three volume fraction and two fiber length were investigated for each of the three fiber geometry. Test results indicated that recycled PET fibers are effective in controlling plastic shrinkage cracking in cement based composites. In respect to effect of length of fiber, longer fiber was observed to have efficient cracking controlling with low volume fraction in same fiber geometry while shorter fiber controled plastic shrinkage cracking efficiently as addition rate increase. Also, embossed type fibers were more effective in controlling plastic shrinkage cracking than other geometry fiber at low volume fraction. But, for high volume fraction, straight type fibers were most effective in plastic shrinkage cracking controlling in cement based composites.

• Textile Coloration and Finishing
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• v.8 no.5
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• pp.68-75
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• 1996

Even if fibers are practically identical with respect to chemical composition and denier, the dyeabilities are freqently a little different in an industrial processing. It is difficult to interpret the numerical values of dye diffusion coefficients from a dye solution into fibers. The main reasons are the multicomponent nature of the diffusion process and the inhomogeneities of the substrate, so-called, various kinds of ordered and disordered regions of polymers, void and pores. The equilibrium dye adsorptions and dyeing rates of a disperse dye into the several PET fibers having the same denier were determined at various temperatures. The dyeability of examined samples was divided into two groups, that is, lower dye adsorption fiber and higher ones at the lower temperatures. This result was discussed with the degree of crystallinity, DSC diagram, X-ray diffractometry and Porosimetry of the PET fiber, and an appropriate model for fine structure of PET fiber was proposed.

• Computers and Concrete
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• v.21 no.6
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• pp.669-679
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• 2018

In this paper the behavior of reinforced concrete (RC) beam-column connections under cyclic loading was analyzed. The specimens, manufactured in a reduced-scale were made of (a) recycled aggregate concrete (RAC) by replacing 30% of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) and (b) RAC incorporating Polyethylene terephthalate (PET) fiber i.e., PET fiber-reinforced concrete (PFRC) at the joint region. PET fiber (aspect ratio=25) of 0.5% by weight of concrete used in the PFRC mix was obtained by hand cutting of post-consumer PET bottles. A reference specimen was also prepared using 100% of NCA and subjected to similar loading sequence. Comparing the results the structural behavior under cyclic loading of RAC specimens are quite similar to the reference specimens. Damage tolerance, load resisting capacity, stiffness degradation, ductility, and energy dissipation of the RAC specimens enhanced due to addition of PET fibers at the joint region. PFRC specimens also presented a lower damage indices and higher principal tensile stresses as compared to the RAC specimens. The results obtained gave experimental evidence on the feasibility of RAC for structural use. Using PET fibers as a discrete reinforcement is recommended for improving the seismic performance of RAC specimens.