Recycled Polyethylene Terephthalate Fibers Research Articles

Preparation and Properties of Recycled PET Fibers Filled Polyethylene Composites

Responding to the resource waste and environmental damage, the recycled Polyethylene Terephthalate (PET) fibers were successfully obtained from waste PET textiles using a PFI mill. The high density polyethylene (HDPE)-based composites reinforced with recycled PET fibers were manufactured by melting blend. The mechanical properties of the composites were investigated by mechanical property test. The thermal stability and crystallinity were analyzed by Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC), and their microstructures were characterized by Scanning Electron Microscopy (SEM). The mechanical properties of the composites indicated the significant improvements in tensile, flexural and impact properties by increasing the recycled PET fibers to 20wt%. The morphological and structural results showed that the recycled PET fibers dispersed well in HDPE matrix with the help of PE-g-MAH as a compatibilizer. The thermal analysis revealed that the degree of crystallinity and crystallizing rate tended to increase, while the thermal stability remained stable. In addition, using PFI mill in dealing with the waste textiles will help open new ways for recycling of waste textiles.

Early age performance and mechanical characteristics of recycled PET fibre reinforced concrete

In this study the performance of concrete reinforced with fibres produced from waste non-biodegradable plastic, polyethylene terephthalate (PET), has been thoroughly investigated. The novelty of the study, to the authors’ knowledge, consists in the fact that fibres have been employed as directly shredded from collected waste plastic bottles, with no processing through, e.g., plastic melting and fibre spinning. Moreover, a comprehensive investigation has been herein undertaken, which ranges from the identification of the mechanical behaviour of the fibres to the assessment of their bond with the matrix and of the early age and hardened state properties of the recycled PET fibre reinforced concrete.Different types of shredded recycled PET fibres, straight and deformed, together with different fibre lengths, 30mm and 50mm, have been assessed, for varying percentage addition in concrete. The tensile properties and pull out characteristics of the fibres have been determined. The effects of fibres in mitigating plastic and restrained drying shrinkage cracking were then assessed and, finally, the compressive strength and the flexural performance of the fibre concrete were determined. The cracking potential of fibre-reinforced mortar thin slabs was also assessed.The use of shredded recycled PET fibres in concrete has been shown to lead to interesting improvements in performance for various fibre concrete characteristics and offers a potential alternative for this material.

Formation of Nanofibers from Pure and Mixed Waste Streams Using Electrospinning

New methods are needed to reprocess the excess of plastics in the waste stream. In this work, bottle-grade polyethylene terephthalate (PET), Styrofoam, and polycarbonate from compact discs (CDs) were spun into nanofibers as fine as ca. 100 nm in diameter using the electrospinning technique. The mechanical properties of the fibers were evaluated using microtensile testing. The elastic moduli ranged from 15 to 60 MPa, and displayed stiffnesses comparable or greater than fibers made from commercial polymers of equivalent molecular weight. Nanofibers were also prepared from blends of Styrofoam and recycled polycarbonate. Recycled PET fibers were tested for application in water filtration and had greater than 99% filtration efficiency of 1 μm particles. Nanofibers from both pure and mixed waste streams are expected to have applications in myriad areas such as ultra/microfiltration, composites, and tissue engineering.

Effect of Recycled PET Fibers on the Performance Properties of Knitted Fabrics

PET (polyethylene terephthalate) is mostly used in textile and packaging industries. PET Bottle wastes are separated from other wastes and after that some processes are applied to obtain PET flakes, such as breaking, washing, drying and etc. r-PET fibers are produced by melt spinning method from these recycled PET flakes. r-PET fibers have already been used for secondary textile products like as carpet bottoms, sleeping bags and insulation materials. In this study usability of recycled PET fibers in apparel industry were researched. Comparative investigations of bursting strength, abrasion resistance, air permeability, surface friction, circular bending rigidity and dimensional stability properties were done to knitted fabrics produced from r-PET and blends with PET and cotton fibers. It was found that, instead of PET, r-PET fibers can be blended in certain amounts without compromising fabrics performance.

Material and Structural Performance Evaluations of Hwangtoh Admixtures and Recycled PET Fiber-Added Eco-Friendly Concrete for CO₂ Emission Reduction.

In order to reduce carbon dioxide (CO2) emissions and produce an eco-friendly construction material, a type of concrete that uses a minimal amount of cement, yet still retains equivalent properties to ordinary cement concrete, has been developed and studied all over the world. Hwangtoh, a type of red clay broadly deposited around the world, has traditionally been considered an eco-friendly construction material, with bonus advantages of having health and cost benefits. Presently, Hwangtoh is not commonly used as a modern construction material due to properties such as low strength and high rates of shrinkage cracking. Recent studies, however, have shown that Hwangtoh can be used as a mineral admixture to improve the strength of concrete. In addition, polyethylene terephthalate (PET) fibers recycled from PET bottle waste can be used to control shrinkage cracks in Hwangtoh concrete. Therefore, in this study, performance verification is conducted on newly developed Hwangtoh concrete mixed with short recycled PET fibers. The results show that Hwangtoh concrete has compressive strength, elastic modulus, and pH properties that are similar to these features in ordinary cement concrete. The properties of carbonation depth and creep strain of Hwangtoh concrete, however, are larger and smaller, respectively, than in ordinary cement concrete. According to flexural tests, reinforced concrete (RC) specimens cast with Hwangtoh admixtures (with and without PET fibers) possess similar or better capacities than ordinary RC specimens. The addition of PET fibers significantly improves the structural ductility of RC specimens under normal environmental conditions. However, the implementations of the concrete in aggressive environment must be carefully considered, since a previous study result indicates degradation of its durability performance in aggressive environments, such as seawater [1]. The results of this study validate the possibility of using eco-friendly Hwangtoh concrete reinforced with recycled PET fibers as a structural material for modern construction.

Recycled-PET fibre based panels for building thermal insulation: Environmental impact and improvement potential assessment for a greener production

A screening of Life Cycle Assessment for the evaluation of the damage arising from the production of 1 kg of recycled Polyethylene Terephthalate (RPET) fibre-based panel for building heat insulation was carried out according to the ISO 14040:2006 and 14044:2006. All data used were collected on site based on observations during site visits, review of documents and interviews with technical personnel and management. These data were processed by using SimaPro 7.3.3, accessing the Ecoinvent v.2.2 database and using the Impact 2002+ method. The study showed damage to be equal to 0.000299 points mostly due to the: 1) PET thermo-bonding fibre supply from China by means of a freight-equipped intercontinental aircraft; 2) production of bottle-grade granulate PET; 3) medium voltage electricity consumption during the manufacturing of RPET fibre panel. It was also highlighted that there were environmental benefits due to recycling through mainly avoiding significant emissions and reduced resource consumption. An improvement assessment was carried out to find solutions aimed at reducing the damage coming from the most impacting phases. Furthermore, the environmental impacts due to the production of the analysed RPET fibre-based panel were compared to other materials with the same insulating function, such as polystyrene foam, rock wool and cork slab. Finally, the environmental benefits of the recycling of PET bottles for flake production were highlighted compared to other treatment scenarios such as landfill and municipal incineration.

재생 PET 섬유가 보강된 RC 슬래브의 구조성능 평가

본 연구는 재생 PET 섬유의 구조보강성능을 규명하기 위한 연구의 일환으로 수행되었다. 재생 PET 섬유의 구조보강성능을 규명하기 위하여 철근 콘크리트 슬래브 부재를 제작하여 휨 성능을 수행하고 기존 합성섬유인 PP 섬유와 합성섬유를 혼입하지 않은 Plain 시편과 비교하였으며, 또한 섬유의 혼입율에 따른 거동을 평가하였다. 실험결과 압축강도는 섬유의 혼입율이 증가할수록 감소하는 것으로 나타났으며 감소 비율은 약 2~7%정도로 나타났다. 휨 실험결과로부터 Plain 시편의 극한성능이 가장 우수한 것으로 나타났으며, 에너지 흡수 능력과 연성지수는 재생 PET 섬유를 0.5% 혼입한 시편이 가장 우수한 것으로 평가되었다. 보 시편에 적용한 경우에는 Plain 시편에 비해 연성능력 뿐 아니라 극한성능도 증가되는 것으로 나타났으나 슬래브 시편의 경우 연성능력은 증가되나 극한성능이 감소하는 것을 확인 할 수 있어 보 시편에 비해 상대적으로 보강효과가 적게 나타나고 있다. 따라서 슬래브 구조물에 적용할 경우에는 배합과 혼입량을 적절히 사용해야 할 것으로 사료된다. This study was performed to verify the structural reinforcing effect of recycled polyethylene terephthalate (PET) fiber. In order to verify the structural reinforcing capacity of RPET fiber, recycled PET fiber added RC slab specimens were prepared to examine the flexural capacity while those of plain concrete and those of added with PP fiber, and the behavior of the specimens were also evaluated. The result shows that the compressive strength reduces as the fiber volume fraction increases, and the rate of reduction varies from 2% to 7%. The result of the flexural capacity shows that the ultimate capacity of plain specimens is the highest compare to those fiber reinforced specimens, but it has shown that specimens reinforced by 5% PET fiber has the highest energy absorption and the ductility index. In the application of PET fiber in slab specimens has shown that ductility capacity have increased where the ultimate capacity decreasing. That is the different tendency of beam specimens, which the ultimate capacity and the ductility of those have both shown the improvement compare to plain concrete specimens, which means the reinforcing effect of PET fiber in slab is less strong than in beam. Therefore, the application of PET fiber in slab structures as reinforcement needs the proper mix proportion of concrete and volume fraction of PET fiber with deep consideration of the structures.

Mechanical properties of recycled PET fibers in concrete

Fiber-reinforced concrete represents the current tendency to apply more efficient crack-resistant concrete. For instance, polyethylene terephthalate (PET) is a polyester polymer obtained from recyclable bottles; it has been widely used to produce fibers to obtain cement-based products with improved properties. Therefore, this paper reports on an experimental study of recycled-bottle-PET fiber-reinforced concrete. Fibers with lengths of 10, 15 and 20 mm and volume fractions of 0.05, 0.18 and 0.30% related to the volume of the concrete were used. Physical and mechanical characterization of the concrete was performed, including the determination of compressive strength, flexural strength, Young’s modulus and fracture toughness as well as analysis using mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Flexure and impact tests were performed after 28 and 150 days. No significant effect of the fiber addition on the compressive strength and modulus of elasticity was observed. However, the Young’s modulus was observed to decrease as the fiber volume increased. At 28 days, the concrete flexural toughness and impact resistance increased with the presence of PET fibers, except for the 0.05 vol.% sample. However, at 150 days, this improvement was no longer present due to recycled-bottle-PET fiber degradation in the alkaline concrete environment, as visualized by SEM observations. An increase in porosity also has occurred at 365 days for the fiber-reinforced concrete, as determined by MIP.

Bonding characteristics of recycled polyethylene terephthalate (PET) fibers coated with maleic anhydride grafted polypropylene in cement‐based composites

AbstractIn this study, we sought to enhance the bond performance between recycled polyethylene terephthalate(PET) fibers and cement‐based composites using a hydrophilization treatment with hydrophilic maleic anhydride grafted polypropylene (mPP). The bond performance was evaluated with bone‐shaped specimens after the hydrophilization treatment. The effects of the concentration of mPP in the solution in which the PET fibers were immersed (0, 5, 10, 15, and 20%) and the three types of shapes on the surface energy of the recycled PET fibers were evaluated. The pullout behavior, bond strength, and interfacial energy all increased with the concentration of mPP to 15% but decreased at 20%. This occurred because 15% mPP coated the recycled PET fiber thoroughly, whereas a 20% mPP coating resulted in partial cracks, which led to fractures on application of a pullout load. Of the fiber shapes, the embossed fibers demonstrated the best bond behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Physical and mechanical behaviour of recycled PET fibre reinforced mortar

This study investigated the utilization of polyethylene terephthalate (PET) bottle fibre recycled as fibre-reinforced renders mortar. The fibres were obtained by simple mechanical cutting from bottles. Investigation was carried out on cement-lime mortar samples. Different volumes of fibres, i.e. 0%, 0.5%, 1.0% and 1.5%, were introduced in dry mortar mixes. Specifically, the mechanical properties as flexure, compressive strengths and mortar toughness were measured. The results indicate that the incorporation of PET fibres significantly improve the flexural strength of mortars with a major improvement in mortar toughness. The maximum volume of PET fibre for a desired workability was 1.5%.

Open-loop recycling: A LCA case study of PET bottle-to-fibre recycling

This study assesses the environmental impact of polyethylene terephthalate (PET) bottle-to-fibre recycling using the methodology of life-cycle assessment (LCA). Four recycling cases, including mechanical recycling, semi-mechanical recycling, back-to-oligomer recycling and back-to-monomer recycling were analysed. Three allocation methods are applied for open-loop recycling, i.e. the “cut-off” approach, the “waste valuation” approach and the “system expansion” approach. Nine environmental impact indicators were analysed, i.e. non-renewable energy use (NREU), global warming potential (GWP), abiotic depletion, acidification, eutrophication, human toxicity, fresh water aquatic ecotoxicity, terrestrial ecotoxicity and photochemical oxidant formation. The LCA results are compared with virgin PET fibre and other commodity fibre products, i.e. cotton, viscose, PP (polypropylene) and PLA (polylactic acid). The LCA results show that recycled PET fibres offer important environmental benefits over virgin PET fibre. Depending on the allocation methods applied for open-loop-recycling, NREU savings of 40–85% and GWP savings of 25–75% can be achieved. Recycled PET fibres produced by mechanical recycling cause lower environmental impacts than virgin PET in at least eight out of a total of nine categories. Recycled fibres produced from chemical recycling allow to reduce impacts in six to seven out of a total of nine categories compared to virgin PET fibres. Note that while mechanical recycling has a better environmental profile than chemical recycling, chemically recycled fibres can be applied in a wider range of applications than mechanically recycled fibres.

Long-term performance of recycled PET fibre-reinforced cement composites

This study investigated the long-term durability performance of recycled polyethylene terephthalate (PET) fibre-reinforced cement composites. Specifically, chloride permeability, repeated freeze–thaw, and various chemical environment tests were conducted. Five types of chemical environments were considered, alkaline, salt, CaCl 2, sulfuric acid, and sodium sulfate. Recycled PET fibre-reinforced cement composite was not different from plain concrete in terms of chloride permeability. The repeated freeze–thaw test results showed excellent endurance characteristics of recycled PET fibre-reinforced cement composite. Recycled PET fibre-reinforced cement composites showed reduced compressive strength in alkaline and sulfuric acid environments. However, recycled PET fibres and recycled PET fibre-reinforced cement composites were largely unaffected by salt, CaCl 2, and sodium sulfate environments.

Effects of the geometry of recycled PET fiber reinforcement on shrinkage cracking of cement-based composites

In this study, the reinforcing fibers were constructed with three different geometries, i.e., embossed, straight, and crimped, from waste polyethylene terephthalate (PET) bottles and used them to control plastic shrinkage cracking in cement-based composites. Pullout tests evaluated how the fiber geometry and fraction by volume (0.1–1.00%) affected the rate of moisture loss and controlled the plastic shrinkage cracking characteristics. The fiber geometry and fraction by volume did not affect the total moisture loss or moisture loss per hour; the moisture loss per hour exceeded 0.5 kg/m 2/h in 5 h after casting, causing plastic shrinkage cracking. However, increased fractions of recycled PET fiber resulted in improved control of the plastic shrinkage cracking. At a fraction of 0.25%, the plastic shrinkage was reduced, but no further improvements were observed when the fraction of fiber was increased to 0.5%. Fiber geometry also affected the control of plastic shrinkage cracking up to a fiber fraction of 0.25%.