Recycled PET Bottles Research Articles

Recycled PET/MWCNT-ZnO quantum dot nanocomposites: Adsorption of Cd(II) ion, morphology, thermal and electrical conductivity properties

This paper investigates the possibility of utilizing recycled PET bottle waste as matrix of novel composites. The effect of various MWCNT-ZnO quantum dot (QD) loadings (1, 2 and 4 by weight) on the morphology, thermal, electrical conductivity properties and water treatment of PET was studied. Results showed that the incorporation of MWCNT-ZnO QDs into the PET matrix causes that the pure polymer undergoes transition from electrically insulated to conductive at room temperature. Enhancement in thermal stability was obtained by the 4wt% MWCNT-ZnO loading. Our results also show that rPET/MWCNT-ZnO QD composites can be used as absorbents for easy, convenient, and efficient removal of Cd(II) ions from aqueous solution. Actually, plastic waste was used and changed it to a valuable composite with potential of heavy metal adsorption as well as high electrical conductivity.

The effect of recycled fibers on the washing performance of denim fabrics

In this study, denim fabrics were produced with yarns obtained from cotton fibers (CO), recycled cotton fibers obtained from yarn wastes (r-CO), and fibers produced from recycled PET bottles (r-PET). Enzyme and stone washing processes were applied systematically on these fabrics. Mass per unit area, breaking force, elongation at max force, tear strength, air permeability, and circular bending rigidity of fabrics were measured. The findings showed that r-CO fiber has negative effect on tear and breaking force. Breaking force, elongation at max force, and tear strength values of the fabrics increased depending on the increase in r-PET content. However, fabric handle was negatively affected associated with the r-PET ratio due to the increase in stiffness. Mass per unit area, breaking force, air permeability, and circular bending rigidity values of fabrics decreased after the washing processes. The effect of fibers on enzyme- or stone-washed fabrics showed a change according to finished fabrics. It can be said that fabrics containing r-PET are more resistant than cotton and recycled cotton in various aggressive denim washing methods such as bleaching or different washing process conditions such as rising temperature, and time.

The potential use of recycled PET bottle in nanocomposites manufacturing with modified ZnO nanoparticles capped with citric acid: preparation, thermal, and morphological characterization

We devised a fast and facile potential practical application by incorporating the guest ZnO nanoparticles (NPs) into poly(ethylene terephthalate) (PET) as a host polymer that recycled by dissolution/reprecipitation method.

Comprehensive evaluation on PET bottle recycling system

Comprehensive evaluation on PET bottle recycling system

Characterization of Rigid Polyurethane Foam Prepared from Recycling of PET Waste

Poly (ethylene terephthalate) (PET) waste bottles were recycled to prepare RPUFs (rigid polyurethane foams) by using propylene glycol (PG) in different glycol/polymer molar ratios. The glycolysis products were characterized, after that, they reacted with poly methylene diphenyl diisocyanate (PMDI) in the presence of blowing, co-blowing and second blowing agents to produce the RPUFs. The prepared foams were characterized and compared to foam that is produced by original polyol. It was found that the glycolysis products have possibility for the fabrication of RPUFs with proper properties depending on the blowing agent type and density, also they have similar thermal stability compared to that one produced by original polyol. This may provide an advantage in the future planning for recycling of PET bottles to enhance the mechanical and thermal properties of PU.

Aromatic evolution of wine packed in virgin and recycled PET bottles

The evolution of the aromatic profile of a rosé wine packed in glass, virgin and recycled PET bottles was studied. Wine stored in PET and glass bottles was clearly differentiated after 5months of storage but only by a limited number of compounds. More pronounced decrease of oxygen sensitive compounds such as methionol was observed in PET bottles as well as the apparition of oxidative and ageing aroma compounds such as ethyl pyruvate, furfural or dioxanes in higher concentration. Compared to virgin PET bottles, recycled PET bottles induced slight changes favouring the presence of esters and alcohols. The chemical evolution of wine was the most important phenomenon that explains the loss of flavour rather than the sorption into PET. Because of their moderate oxygen permeability, the use of virgin PET and recycled PET bottles could be adapted for short conservation of wine but detrimental to aromatic quality if long conservation is intended.

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.

The effect of technological parameters on the foaming of injection molded, recycled PET

The foaming of regranulate made from recycled PET bottles was examined, varying two important technological parameters: holding pressure, and the amount of material injected into the mold cavity, which was controlled with the switchover point. It was shown with optical and density tests that these parameters have a significant effect on the foam structure, which greatly influences mechanical properties.

Synthesize of Polydiacetylene Containing Copolyurethane Using Polyol Product Derived from Chemical Recycling of PET Bottles

Polyurethane display excellent mechanical and chemical properties. In this work polyurethane containing diacetylene unit was synthesized by two step polymerization with methylene diphenyl diisocyanate (MDI), diol from the mixture of PET glycolysed products and hexadiyne-1,6-diol as chain extender with a molar ratio of NCO:OH (1:1). The reaction was carried out at 80 ̊C for 2 hrs. The obtained polyurethane was characterized using Fourier transform infrared spectroscopy (FTIR), 1H NMR spectroscopy for it functionalities. The thermal behavior of polyurethane was investigated using differential scanning calorimetry (DSC). The result shows that polyurethane containing diacetylene unit could be crosslink by thermal that cause the polyurethane undergoes a color change under thermal treatment and hence heated environment.

Analysis of recycled PET bottles products by pyrolysis-gas chromatography

The impact of the contaminants in post used PET bottles on the decomposition of polymer itself after recycling process was analyzed. For that reason sorption experiments of harmful substances to PET bottles were performed. In order to monitor the presence of contaminants in recycled PET and evolution of thermal decomposition products of samples: virgin PET, contaminated PET flakes (PET K) and recycled PET (PET RM) were studied. The thermal degradation products of PET were achieved by pyrolysis using Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS), temperature-programmed evolved gas analysis-mass spectrometry (EGA-MS) and thermogravimetric analysis (TGA). Reactive pyrolysis with tetramethyl ammonium hydroxide (TMAH) was also performed to gather additional information about degradation products in studied samples. The pyrolysis products analysis of the studied PET samples indicate some changes in decomposition mechanism of PET samples that pass through contamination process due to some diversity in their chemical and structural composition.

Use of recycled waste pet bottles fibers for the reinforcement of concrete

In the present paper the results of some tests performed on concrete specimens reinforced with fibers made from waste polyethylene terephthalate (PET) bottles are reported. The fibers have been obtained by simply cutting the bottles; the fibers are then added to the mix concrete or they are used as discrete reinforcement of specimens and little beams in substitution of steel bars. The tests are to be considered as an approach to a more extensive investigation on the use of PET as a reinforcing material for concrete and masonry structures. The results that have been obtained are very interesting, especially regarding the adherence between PET and concrete, suggesting a possible use of this material in the form of flat or round bars, or networks for structural reinforcement.

Microwave Synthesis and Antibacterial Activity of 1,4-Bis (5-aryl-1,3,4-oxadiazole-2-yl) Benzene Derivatives from Terephthalic Dihydrazide Obtained Through Aminolysis of PET Bottle Waste

Recycling of waste PET bottles was attempted using aminolytic depolymerization with hydrazine monohydrate in the presence of NiCl2 and MgCl2 as catalysts, under reflux. The reaction was carried out in a domestic microwave oven of 700 W with suitable modification. Terephthalic dihydrazide (TPDH) was obtained in only 10 min as a pure product with 86 % yield as compared to 4 h by conventional heating. Various 1,4-bis(5-aryl-1,3,4-oxadiazole-2-yl) benzene (2a–f) derivatives were prepared from TPDH by treatment with appropriate aromatic acids in the presence of phosphoryl chloride and thionyl chloride, under microwave irradiation, which required only 20 min. The structures of the synthesized compounds were confirmed by FTIR, melting point and NMR. These compounds were found to possess antibacterial activity comparable to commercial products.

LCA of waste prevention activities: A case study for drinking water in Italy

The strategic relevance of waste prevention has considerably increased worldwide during recent years, such that the current European legislation requires the preparation of national waste prevention programmes in which reduction objectives and measures are identified. In such a context, it is possible to recognise how, in order to correctly evaluate the environmental consequences of a prevention activity, a life cycle perspective should be employed. This allows us to go beyond the simple reduction of the generated waste which, alone, does not automatically imply achieving better overall environmental performance, especially when this reduction is not pursued through the simple reduction of consumption. In this study, the energetic and environmental performance of two waste prevention activities considered particularly meaningful for the Italian context were evaluated using life cycle assessment (LCA) methodology. The two activities were the utilisation of public network water (two scenarios) and of refillable bottled water (two scenarios) for drinking purposes, instead of one-way bottled water (three scenarios). The energy demand and specific potential impacts of the four waste prevention scenarios and of the three baseline scenarios were compared with the aim of evaluating whether, and under what conditions, the analysed prevention activities are actually associated with overall energetic and environmental benefits. In typical conditions, the use of public network water directly from the tap results in the best scenario, while if water is withdrawn from public fountains, its further transportation by private car can involve significant impacts. The use of refillable PET bottled water seems the preferable scenario for packaged water consumption, if refillable bottles are transported to local distributors along the same (or a lower) distance as one-way bottles to retailers. The use of refillable glass bottled water is preferable to one-way bottled water only if a distance beneath 150 km separates bottling plants from local distributors and retailers (except for eutrophication indicator which is always slightly worse). To reduce waste generation and to achieve meaningful potential savings of natural resources, energy and greenhouse gas emissions, a reduction in one-way bottled water consumption in Italy is recommended in favour of the use of public network water and of the establishment of short distance-PET bottles based refilling systems. The development of closed loop recycling of one-way PET bottles, and especially the reduction of the distance along which one-way bottled water is transported, are also important.

Compatibilization of recycled poly(ethylene terephthalate) and polypropylene blends: Effect of compatibilization on blend toughness, dispersion of minor phase, and thermal stability

AbstractBlending of recycled polyethylene terephthalate (RPET) from waste bottles with polypropylene (PP) was performed in an attempt to enhance the processability of RPET. The idea of blending RPET with PP sprouted from the intention of recycling PET bottles together with their PP‐based caps. Therefore, preliminary blending of RPET with neat PP (RPET/PP) was performed at various PP and compatibilizer contents. Morphological analyses on the extruded pellets of uncompatibilized blends indicate that the PP particle size and state of dispersion at skin and core regions were vastly different. The particles at the skin were at least 10 times smaller than that at the core although the size distribution was very wide. With the incorporation of just 5 phr of compatibilizer, the particles at the core region became significantly smaller and appeared to emulate that of the skin region. Furthermore, the overall homogeneity of the blends was vastly improved irrespective of PP content in the blend. The reduction in particle size and improved homogeneity inherently reduced stress concentration points and enhanced the mechanical performance of the blends. More importantly, the incorporation of PP into RPET significantly increased the degradation temperature of the blends, provided the dispersion of PP phase in RPET was excellent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Effect of small amounts of poly(lactic acid) on the recycling of poly(ethylene terephthalate) bottles

Poly(ethylene terephthalate) (PET) is one of the most used commodity polymers, especially for food and beverage applications, and its recycling is of great importance because of the possible use in the textile and construction industries. On the other hand, the interest in biodegradable polymers has led, in recent years, to the use of materials such as poly(lactic acid) (PLA) also in the food and beverage industry. The presence of small amounts of PLA in the PET waste can significantly affect the post-consumer recycling process. In this work, the effect of the presence of small amounts of PLA on the recycling of PET bottles is investigated by rheological, mechanical, morphological and thermogravimetric analysis. The results indicate that this presence can significantly affect the rheological properties under non-isothermal elongational flow, while the mechanical properties were considerably affected only in some circumstances and the thermal stability was not significantly modified.

Experimental study of the thermo-mechanical properties of recycled PET fiber-reinforced concrete

This work presents an experimental study of thermal conductivity, compressive strength, first crack strength and ductility indices of recycled PET fiber-reinforced concrete (RPETFRC). We examine PET filaments industrially extruded from recycled PET bottle flakes with different mechanical properties and profiles. On considering a volumetric fiber dosage at 1%, we observe marked improvements in thermal resistance, mechanical strengths and ductility of RPETFRC, as compared to plain concrete. A comparative study with earlier literature results indicates that RPETFRC is also highly competitive over polypropylene-fiber-reinforced concrete in terms of compressive strength and fracture toughness.

マテリアルリサイクルの市場代替性に基づくライフサイクル評価：ペットボトルリサイクルのケーススタディ

マテリアルリサイクルの市場代替性に基づくライフサイクル評価：ペットボトルリサイクルのケーススタディ

Straw Blankets Sewn With Recycled Plastic Threads for Erosion and Urban Sediments Control

Soil erosion, transport and deposition of sediments represent invisible threats that along time can affect negatively the existing infrastructure of roads and dams, and the quality of air and water resources. In the last decades, a great number of researches were devoted to study erosion and sediments transportation processes. However, they addressed mostly areas of agriculture, water impoundments for dams, and land conservation. A lack of studies for erosion processes in urban areas is evident, in special those aiming to diminish the deposition of sediments originated from urban areas into the rivers and air, in special as airborne particulate. Traditionally, the costs associated in controlling erosion and sediments in urban areas are high and in some case, out of the range for most developing countries. Factors responsible for those high prices are the use of heavy equipments for soil grading and transportation, the use of costly building materials, and the need for employing more specialized personnel. In the case of gullies in urban areas, another concern is to ensure proper equipment access to the area for remediation operations. Hereby, it is presented a cost-effective method to recover an extensive gully erosion area of about 11,000 m2 located in urban area. Estimated sediments released from this area to the water resources and air were estimated on about 66,000,000 tons. In this study area, bioengineering works were performed in 60 days, with hardly any sediment generated outside the work area resulting from bioengineering operations. A combination of bioengineering techniques were chosen for this study area, which was a mixture of rigid and biological products including biologs, silt fence, biodegradable straw blankets sewn with plastic threads derived from recycled PET bottles, among others. An efficient drainage system was implemented for preventing upland flow, sub-seepage and seepage. Biologs were used aiming to fulfill a double role, the first as barrier to soil sediments flow, and the second as filler for empty spaces, avoiding expensive grading operations. All engineering works were concluded in about 60 days at a cost of US$ 0.89/m2. This price is cost-effective if compared with the traditional engineering cost of approximately US$ 2.92/m2 because it includes extensive use of grading and soil transportation. An environmental advantage of the bioengineering method is the immediate reduction of airborne particulates. Furthermore, the overall visual aesthetics improved shortly after the implementation of the works because the bare ground was substituted by native vegetation. After 6 months the vegetation in the gully erosion area was totally established. Monitoring was performed after 12 months and no erosion and sediment transport was visually noticed. The ease implementation of this technique without the need for specialized workers in combination with low prices makes this method a model for developing countries.

Recycling of PET bottles as fine aggregate in concrete

An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365 days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility.

Study on the Retention of Strength in Material from Recycled PET Bottles

廃PETボトルは，リサイクル操作時の加熱によって分子量が低下するとともに強度も低下するため，バージンPET樹脂 (V-PET) を添加して分子量を保持しているが，これらの定量的な効果は明らかになっていない。そこで，V-PET添加によって分子量を調整したモデルを調製し，長繊維としての利用を想定してこれらの関係を検討した。その結果，骨格として作用する一定割合の高分子量PETを添加すると降伏応力は保持され，添加量を増加して一定の分子量を維持する必要がないことがわかった。一方，混在する低分子量PETが起点となって破断伸び率が低下するため，V-PET添加量を増加してもこれは維持できない。その対策として低分子量PETの分子鎖を擬似的に繋げるアイオノマー化は，破断伸び率の低下抑制に有効であることが明らかになった。