PET Fibers Research Articles

Response of Conductive and PTFE-Coated Polyester Filters to Cold Fly Ash at Different Dust Charge Levels

The present study embodies the response of two different filter media viz. conductive filter media (stainless steel blended with PET fibers) and PTFE-Coated polyester filter media, at four different charge levels (0 kV, 4 kV, 8 kV, and 12 kV) and at a particular dust concentration (50 g/m3) on pulse-jet filtration process performance. The filter media were tested at ISO-11057 standard with conducting 200 pulsing cycles at final measuring phase. Emission values in terms of PM2.5 and PM10 mass concentration and number particle concentration were comparatively lower while using PTFE-coated filter media in comparison with conductive filter media. Downstream emission values largely reduced for both filter media, particularly at high charge level. PTFE-coated filter media exhibit lower residual pressure drop as compared to conductive filter media when measuring the phase of filtration operation, whereas on the contrary D10, D50, and D90 values were found higher for PTFE-coated filter media and higher charge level. Overall, it can be summarized that PTFE-coated media at higher dust charge levels showed better filtration results.

Manufacturing and properties of r-PETG/PET fibre composite – Novel approach for recycling of PETG plastic scrap into engineering compound for injection moulding

The study proposes utilisation of recycled PETG foils as a matrix for manufacturing of a composite reinforced with short PET fibres. With 70/30 wt-% filling ratio its notched impact strength of ∼12.8 kJ/m2 is twice higher than native PETG, 6-fold higher than the r-PETG and on the level of PP reinforced with the same content of glass fibres. Its good mechanical properties allow it to be applied as an engineering compound for injection moulded goods. The reuse of PETG foils as a matrix reinforced with inexpensive PET fibres gives a cost advantage and proposes a smart solution for recycling of problematic waste material. In order to be able to reprocess the r-PETG, the molecular weight of matrix material is restored during compounding by means of an efficient epoxy chain extender. A simple manufacturing method allows it to be implemented at plastic processing plants using standard machinery without additional installation costs.

Development of nonwoven automotive carpets made of recycled PET fibers with improved abrasion resistance

In this study, velour design molded automotive carpets made of recycled polyethylene terephthalate (PET) fibers were developed via needle-punching process to improve their abrasion resistance properties. Initially, virgin PET fibers and recycled PET (rPET) fibers derived from PET bottle wastes were supplied from different producers and they were tested in terms of their fiber properties such as fiber length, crimp, tensile strength, elongation, tenacity, and intrinsic viscosity. It was demonstrated that recycled fibers from bottle wastes used in the study have lower tenacity and higher elongation than virgin PET fibers. In the second part, rPET fibers to be used in manufacturing in terms of their desired properties were selected. Subsequently, molded automotive carpets were produced from the selected rPET fibers and virgin PET fiber blends with adjusted manufacturing and molding parameters. Developed carpets were tested for abrasion resistance performance and they were evaluated according to requested specification. Results showed that carpets made of 85% rPET + 15% bicomponent PET had almost equal performance in terms of both fiber loss and carpet appearances with carpets consisting of 80% PET + 20% bicomponent PET. Carpets made of recycled PET fibers offer the manufacturer low raw material costs in addition to ecological advantages.

Solvent retention in electrospun fibers affects scaffold mechanical properties.

Electrospinning is a robust material fabrication method allowing for fine control of mechanical, chemical, and functional properties in scaffold manufacturing. Electrospun fiber scaffolds have gained prominence for their potential in a variety of applications such as tissue engineering and textile manufacturing, yet none have assessed the impact of solvent retention in fibers on the scaffold’s mechanical properties. In this study, we hypothesized that retained electrospinning solvent acts as a plasticizer, and gradual solvent evaporation, by storing fibers in ambient air, will cause significant increases in electrospun fiber scaffold brittleness and stiffness, and a significant decrease in scaffold toughness. Thermogravimetric analysis indicated solvent retention in PGA, PLCL, and PET fibers, and not in PU and PCL fibers. Differential scanning calorimetry revealed that polymers that were electrospun below their glass transition temperature (Tg) retained solvent and polymers electrospun above Tg did not. Young’s moduli increased and yield strain decreased for solventretaining PGA, PLCL, and PET fiber scaffolds as solvent evaporated from the scaffolds over a period of 14 days. Toughness and failure strain decreased for PGA and PET scaffolds as solvent evaporated. No significant differences were observed in the mechanical properties of PU and PCL scaffolds that did not retain solvent. These observations highlight the need to consider solvent retention following electrospinning and its potential effects on scaffold mechanical properties.

Flame-Retardant and Wear Comfort Properties of Modacrylic/FR-Rayon/Anti-static PET Blend Yarns and Their Woven Fabrics for Clothing

This study examined the flame retardant, anti-static, and wear comfort properties of woven fabrics from two types of yarns composed of modacrylic, FR-rayon, cotton, and anti-static PET fibers. The FR-rayon-blended modacrylic fabric mixed with anti-static PET fibers exhibited better flame-retardant and anti-static properties than those of the cotton-blended modacrylic fabric. In addition, the absorption and drying properties of the FR-rayon-blended modacrylic fabric were superior to those of the cotton-blended modacrylic fabric. The thermal conductivity of the FR-rayon-blended fabric was lower than that of the cotton-blended one, whereas the water vapor permeability was slightly higher than that of the cotton-blended one. These wear comfort properties of the FR-rayon-blended fabric were attributed to the micro-pores and longer fiber length of the FR-rayon fibers, as well as their yarn and fabric structural parameters. This study suggests that FR-rayon-blended modacrylic fabric has better flame-retardant and anti-static properties in both twill and rip weaves with good warmth keepability, and higher water and vapor transmission properties than cotton-blended one. In addition, the FR-rayon-blended modacrylic clothing exhibited a better wear comfort feel than the cotton-blended one due to the lower microclimate humidity. This means that FR-rayon-blended modacrylic fabric makes it more comfortable to wear than cotton-blended one.

Advanced fabrication and properties of hybrid polyethylene tetraphalate fiber–silica aerogels from plastic bottle waste

Recycled polyethylene tetraphalate (rPET) fiber–silica aerogels are successfully developed from rPET fibers obtained from PET plastic bottle waste and tetraethoxysilane (TEOS). The rPET – silica aerogels are prepared through a direct gelation of silica on PET. rPET fibers are treated with dichloromethane to partially dissolve the fibers. The fibers are then dipped and allow to swell in TEOS/ethanol mixture, with the pH controlled to 2.5 using HCl to promote hydrolysis. After the acid hydrolysis, the pH was controlled to 7 with an ammonium hydroxide solution (NH4OH) to promote condensation. The surface modification is carried out in a trimethylchlorosilane (TMCS)/n-hexane solution and washed with n-hexane to dry at room temperature to prevent shrinkage. The developed rPET – silica aerogels exhibit super-hydrophobicity with an average water contact angle of 149.9°. Their thermal conductivity is approximately 0.037 W/m K. They have a very low compressive Young’s Modulus (0.95–4.19 kPa) and hence very soft. By utilizing rPET fibers, this work provides an alternative method of recycling PET plastic wastes which ultimately helps in reducing its detrimental impact to the environment. The developed aerogels can be used in several industrial applications such as heat insulation, filtering, sound insulation and absorption.

(Keynote) Dimensional Change of Oriented Polymers upon Heating

Molecular orientation can be incorporated to the polymeric materials through either stretching in a solid state or elongation in a molten state. When a polymer has molecular orientation in a glassy state, shrinkage may proceed when temperature is increased above its glass transition temperature. Degree of shrinkage may vary depending on the temperature reached and the degree of molecular orientation. In the case of crystalline polymers, however, shrinkage may be suppressed because of the occurrence of crystallization prior to the shrinkage. It should be noted that the crystallization rate can be accelerated significantly with the increase of molecular orientation. Accordingly, there can be a critical degree of molecular orientation; below which orientation relaxation proceeds upon heating, whereas above which spontaneous orientation enhancement caused by crystallization proceeds upon heating. In some cases, even the spontaneous elongation of materials takes place along with the progress of crystallization. On the other hand, it is well known that the dynamics of polymeric materials is characterized by the wide range of relaxation time. This means that the state of molecular orientation can be manipulated through the combination of deformation/flow history and temperature history. Dimensional change of oriented polymeric materials upon heating is mainly governed by the oriented structure of relatively long relaxation time such as network structure of molecular entanglement. Based on this concept, we could prepare fibers which showed no birefringence but exhibited significant shrinkage with the increase of temperature. This is possible because birefringence merely reflects the degree of orientation of relatively short segments, i.e. short relaxation time, in the polymer chain. Concept of manipulating the oriented structure of wide range of relaxation period leads to the idea of controlling the state of molecular entanglement. Based on this concept, we speculated that the polymeric materials of high strength and high toughness can be prepared if the material has rather homogeneous state of molecular entanglement, i.e. narrow distribution of molecular weight between adjacent entanglement points. As-spun poly(ethylene terephthalate) (PET) fibers with rather homogeneous state of molecular entanglement was prepared through the control of melt spinning process. Applying the drawing and annealing processes to such as-spun fibers, high-strength PET fibers were prepared. To verify the applicability of the concept of homogeneous state of molecular entanglement, PET fibers prepared under various processing conditions were analyzed using the laser Raman spectroscopy. It was found that the narrow distribution of internal stress field and limited widening of such distribution upon applying the tensile stress to the fibers are the key factors for realizing the high-strength and high-toughness.

An Experimental investigation by utilizing Plastic waste and Alccofine in Self-Compacting Concrete

Background/Objective: This study aimed to investigate in properties of Self Compacting Concrete (Fresh & Hardened properties) by utilizing Alccofine and PET fibers as a replacement of cement and fine aggregate respectively, for enhancing the workability and durability of SCC. Methods/Statistical Analysis: The Mix design was done by Nan-Su method. In this investigation an experimental program carried out for M30 grade of concrete in SCC mixes with various percentage of plastic waste from 0.5% up to 1.25% as replacement of fine aggregate and 10% Alccofine as cement replacement. Different tests in fresh properties of SCC conducted for evaluation of workability such as (slump flow, V funnel, L box and U box) and in hardened properties of SCC (compressive, flexural, tensile strength, sulfate attack, abrasion resistance, XRD, SEM & EDS) were performed for evaluating the strength and durability of SCC. Finding: From the test results it observed that utilizing of 1% plastic waste and 10% Alccofine have best performance in workability and strength of self compacting concrete and it increase the durability of SCC. Applications/Improvement: Combination of Alccofine and PET fibers can be used in SCC as a strength and durability enhancer for having a suitable concrete and sustainable construction. Keywords: Alccofine, Durability, Plastic Waste, Self-Compacting Concrete, Workability

Studies on the Melt Spinning Process of Square 8-hole Hollow Polyester Fibre

In this paper, the shape of the spinneret capillary was discussed, and optimized spinneret capillaries were successfully processed by a computer numerical control processing method which takes a C-shape silver electrode as the basic unit. Based on the optimised spinning process, a new type of square 8-hole hollow PET fibre was prepared by the experimental method.

Mechanical properties of hybrid short fibers reinforced oil well cement by polyester fiber and calcium carbonate whisker

In the present work, a novel fiber hybridization containing PET fiber and CaCO3 whisker is developed to improve the multiscale cracking resistance, as well as to boost the toughness and mechanical performance of cement pastes. The mechanical properties, microstructure, the uniaxial and triaxial compression of hybrid fiber reinforced oil well cement pastes are investigated. The results indicate that after the introduction of mono PET fiber, the flexible strength and tensile strength were increased by 19.4% and 40.1%, but the compressive strength was decreased by 11.5%. Therefore, the CaCO3 whisker combined with the PET fiber is used to enhance the compressive strength of the cement matrix. Because PET fibers and CaCO3 whiskers are different in size, elasticity modulus and length-diameter ratio, the hybrid fiber can effectively interact with micro to macro cracks at multiple load stages. Hence, the hybridization contributes to enhancing multiscale cracking resistance from the microscale to the macroscale level, and the capability coefficients index of the cementious material are improved by 450.7% and 284.5% compared with those of control samples, respectively, under confining pressure. Moreover, the strategy enables to reduce the production cost of the cementing sheath of oil and gas well, and other large-scale construction project applications.

Centrifugally Spun Recycled PET: Processing and Characterization.

Centrifugal spinning, which is a high-productivity fiber fabrication technique, was used to produce a value-added product from recycled poly(ethylene terephthalate) (rPET). In the present study, rPET fibers, with fiber diameters ranging from submicron to micrometer in scale, were fabricated by spinning a solution of rPET in a mixture of dichloromethane and trifluoroacetic acid. The influence of the polymer solution concentration (the viscosity), the rotational speed of the spinneret, and the inner diameter of the needles on the formation and morphology and mechanical properties of the fibers were examined through scanning electron microscopy and using a tensile testing machine. The thermal behaviors of fibrous mats with various average diameters were also investigated through differential scanning calorimetry. The smoothest and smallest fibers, with an average diameter of 619 nm, were generated using an rPET solution of 10 wt % under a rotation speed of 15,000 rpm using needles having an inner diameter of 160 μm. The fibrous mats have an average tensile strength and modulus of 4.3 MPa and 34.4 MPa, respectively. The productivity and the mechanical properties indicate that centrifugal spinning is an effective technique to fabricate high-value product from rPET.

Poly(ethylene terephthalate) Fibers with a Thin Layer of Click‐Based Microporous Organic Network: Enhanced Capture Performance toward PM2.5

AbstractThis work shows that the adsorptive performance of fibrous membrane can be enhanced by microporous organic network (MON) chemistry. Copper species are introduced into the surface of poly(ethylene terephthalate) (PET) fibers through electroless deposition. Through the Cu2O‐catalyzed click reactions of tetra(4‐ethynylphenyl)methane with 1,4‐diazidobenzene, click‐based MON (C‐MON) layers are formed on the PET@Cu@Cu2O. Etching of copper species results in the formation of PET@C‐MON membranes that show enhanced removal performance by up to 13.3 times for particulate matters with smaller sizes than 2.5 µm (PM2.5), compared with pristine PET fibers.

Advanced Recycled Polyethylene Terephthalate Aerogels from Plastic Waste for Acoustic and Thermal Insulation Applications

This work presents for the first time, a simple, practical and scalable approach to fabricating recycled polyethylene terephthalate (rPET) aerogels for thermal and acoustic insulation applications. The rPET aerogels were successfully developed from recycled PET fibers and polyvinyl alcohol (PVA) and glutaraldehyde (GA) cross-linkers using a freeze-drying process. The effects of various PET fiber concentrations (0.5, 1.0 and 2.0 by wt.%), fiber deniers (3D, 7D and 15D) and fiber lengths (32 mm and 64 mm) on the rPET aerogel structures and multi-properties were comprehensively investigated. The developed rPET aerogels showed a highly porous network structure (98.3–99.5%), ultra-low densities (0.007–0.026 g/cm3), hydrophobicity with water contact angles of 120.7–149.8°, and high elasticity with low compressive Young’s modulus (1.16–2.87 kPa). They exhibited superior thermal insulation capability with low thermal conductivities of 0.035–0.038 W/m.K, which are highly competitive with recycled cellulose and silica-cellulose aerogels and better than mineral wool and polystyrene. The acoustic absorption results were also found to outperform a commercial acoustic foam absorber across a range of frequencies.

Wetting dynamics of polydimethylsiloxane mixtures on a poly(ethylene terephthalate) fiber

HypothesisThe wetting dynamics of liquids with identical surface tensions are mostly controlled by their viscosities. We therefore hypothesized that the wetting dynamics of one- (pure liquid) and two-component (mixture) polydimethylsiloxane (PDMS) on a poly(ethylene terephthalate) (PET) fiber with similar surface tensions and viscosities should be controlled by the same underlying physical mechanisms. ExperimentsWe studied the capillary rise of PDMS liquids on a PET fiber. We compared the different contact angle relaxations and characterized the transitions between the molecular-kinetic theory (MKT) and hydrodynamic approach (HD) for the PDMS mixtures and the pure liquids as a function of their viscosities. FindingsCompared to the pure PDMS liquid with a viscosity of 20 mm2/s that presents a contact angle relaxation following a t−1/2 scale law in agreement with HD, the PDMS mixture with a higher viscosity (27.4 mm2/s) shows a t−1 behavior predicted by the MKT. Moreover, the transition between MKT and HD appears in a regime with higher viscosities for PDMS mixtures than for pure liquids. Surface segregation of shorter PDMS chains or precursor film may be responsible for this shift.

Preparation and properties of bottle-recycled polyethylene terephthalate (PET) filaments

Bottle-recycled polyethylene terephthalate (R-PET) fibers were fabricated by the melt spinning method. Based on characteristics of R-PET chips, this study involved a primary exploration of the spinning parameters, including spinning temperature, spinning speed and spinneret plate. The properties of R-PET and original PET (O-PET) fibers were compared using scanning electron microscopy (SEM), tensile testing, sonic orientation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Apparent morphological observation displays an irregular cross-sectional shape and a scattered diameter distribution for R-PET fibers. Compared with O-PET fibers, R-PET fibers demonstrate a greater breaking strength and smaller elongation at break, resulting from the lower crystallinity and higher degree of orientation. Furthermore, the R-PET fibers have the same chemical structure as that of O-PET fibers demonstrated by FTIR spectroscopy, but TGA results show that thermal stability of R-PET fibers is significantly inferior to that of O-PET fibers, as a result of too many impurities and oligomers during the recycling process.

Synthetic Fiber Dyeing with New Pyrazole Disperse Dyes and Their Colorimetric and Fastness Properties

A series of disazo pyrazole disperse dyes were synthesized and reported at our previous work. These 8 synthesized disazo pyrazole disperse dyes (3a-3h) were applied to poly(lactic acid) (PLA), poly(ethylene terephthalate) (PET), and polyamide 6.6 fibers. Their colorimetric and color fastness properties were investigated. All studied fibers dyed with these synthesized dyes exhibited yellow-red shades. 3c (p-Cl), 3e (m-Cl), and 3h (o-Cl) disazo disperse dyes, having auxochrome -Cl, led to the lowest color yield values for all three studied fibers. The same dyes resulted in higher color strength with darker shades on the PET and PLA fabrics in comparison PA 6.6 fabrics. 3a (p-NO2), 3b (p-OCH3), 3d (m-NO2), 3f (o-NO2), and 3g (o-OCH3) disazo disperse dyes can be recommended for PLA and PET dyeing from the color point of view leading to medium to heavy depth of shades. The wash, alkaline and acidic perspiration, dry and wet rub, water and sea water fastness levels of PLA, PET, and PA 6.6 samples dyed with 3a-3h dyes were generally quite high and in the commercially acceptable range with few exceptions. Dyed PLA fabrics displayed better sublimation fastness levels than dyed PET and PA 6.6 fabrics. Synthesized disperse dyes resulted in high light fastness performance on especially PET and PLA fibers. Light fastness level was better for dyed PET samples by comparison with dyed PLA and PA 6.6 fabrics.

Preparation of Copper Sulfide Deposition on Modified Poly(Ethylene Terephtalate) Fibres with Good Conductivity

The immobilization of CuS on the surface of poly (ethylene terephtalate) (PET) fibres was carried out by the functionalization of PET fibres with chitosan (CS), followed by the chemical deposition method. Crosslinked chitosan with NH2 functionality was used as a chelator to absorb copper ions, which can successfully initiate CuS deposition in the following chemical deposition stage. The CuS-loaded fibres were characterised by scanning electron microscopy, X-ray diffraction, infrared spectroscopy and thermal gravimetry, respectively. The properties of tensile and conductivity were also investigated. The lowest surface resistance 42 Ω/cm of the treated PET fibres was obtained when the CS concentration was 1.0%.

Remarkable Reinforcement Effect in Sulfonated Aromatic Polymers as Fuel Cell Membrane

Fluorine-free aromatic ionomers are next generation materials for proton exchange membrane fuel cells (PEMFCs). In addition to high proton conductivity and chemical durability, a membrane must also have high mechanical durability under practical fuel cell operating conditions, where frequent humidity changes are involved. We herein demonstrate that a fluorine-free reinforced aromatic PEM exhibits much improved mechanical durability compared with the parent aromatic PEM under the humidity cycling test conditions. The parent PEM and the reinforcement material are a sulfonated polybenzophenone derivative (SPK, in house) and a nonwoven fabric (NF, composite of glass and PET fibers), both of which do not contain any fluorine atoms. Because the compatibility between the SPK and the reinforcement materials is high, an almost void-free, dense, homogeneous, and tough reinforced PEM is attainable even with thin membrane thickness (18 μm), leading to a reasonably high fuel cell performance. The reinforcement materia...

Preparation and Characterization of Flame Retardant PET Fiber via Melt Blending

Poly(ethylene terephthalate) (PET) fiber with excellent flame retardant property was prepared with introducing a containing phosphorus flame retardant 10-(2’,5’-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (ODOPB) into PET by melt blending method. The intrinsic viscosity of the modified PET was decreased after melt blending, indicated that ODOPB could promote the degradation of PET. The addition of ODOPB can increase the amount of carbon residue of PET, which can effectively reduce the heat transfer. The movement and regularity of PET molecular chain are affected by ODOPB, resulting in the reducing of the crystallization of PET. The Raman curves indicate that the addition of ODOPB can improve the regularity of carbon layer, which is conducive to achieve the effect of flame retardant. When the mass fraction of P is 0.7 %, the limiting oxygen index of sample reaches 32.4% and UL-94 vertical reaches V-2, the fiber fracture strength is 2.6 cN/dtex, which has excellent flame retardant and mechanical properties.

Influence of fibres on the rebar-concrete bond: further evidence of toughness enhancement

The bond between the rebar and the surrounding concrete plays a substantial role in the mechanical performance of a reinforced concrete member due to the stress transfer that occurs at the aforementioned interface. In this study direct rebar pull out tests were performed at different concrete maturities, fibre contents and fibre materials. PET fibres, that have a lower energy requirement during production and improved properties in comparison to polypropylene were used and their performance compared to steel fibres. The addition of fibres leads to a more ductile failure during pull-out. The improved energy absorption capacity is particularly important under seismic loading. Interestingly, a small amount of fibres is enough to notably improve the post-failure behaviour by reducing the softening slope of the stress-slip curve. An increase in fibre content beyond 0.1% for PET fibres does not improve the post-failure behaviour any further. However, steel fibres continue to improve the post-peak behaviour. Thus, the effect of steel fibres is more significant compared to PET fibres and the most pronounced at a high concrete maturity. An analytical model describing the bond stress slip response is proposed and matches the experimental observations well.