PET Powder Research Articles

A novel eco-friendly thermal-insulating high-performance geopolymer concrete containing calcium oxide-activated materials with waste tire and waste polyethylene terephthalate

This research introduces a novel Eco-friendly thermal-insulating high-performance geopolymer concrete based on calcium oxide-activated materials (TIHPGC-CAM) that uses recycled tire and PET powders as aggregate replacements. This is the first study to use these materials for TIHPGC-CAM production. A new mixing method was developed for better compaction of TIHPGC-CAM with scrap tire and PET powders. The mechanical and thermal properties of the TIHPGC-CAM were evaluated by various tests. The results showed that replacing the aggregates with 10% scrap tire or PET powder increased the energy absorption capacity by 143% and 107%, respectively, while reducing the mechanical properties by about 10% and 7%, respectively. Replacing 50% of the aggregates with scrap tire or PET powder decreased the thermal conductivity coefficient by 70% and 60%, respectively, and reduced the temperature change slope under heat radiation. An equation was proposed to predict the thermal conductivity of TIHPGC-CAM for sustainable construction.

Upcycling of waste brick powder and PET as robust and flexible Janus membrane with asymmetric wettability for switchable emulsion separation

Superwetting membranes were widely studied in the field of oil/water separation due to their excellent separation efficiency and good recoverability, but they still suffer from the disadvantages of expensive reagents, complicated processes, and narrow scope of application. Herein, a robust and flexible Janus membrane with asymmetric wetting properties was constructed using discarded PET and bricks powder as building blocks, for various types of emulsions separation. Given the cross-linking effect of acrylic resin, the superhydrophilic crushed waste bricks powder (WBP) was orderly assembled on the electrospinning PET nanofiber membrane, achieving asymmetric wettability on each side: the high-hydrophobic PET side had underwater superoleophilicity, while superhydrophilic WBP side had underwater superoleophobicity. Janus membrane exhibit excellent corrosion resistance and can maintain stable contact angles in different pH environments. Due to its highly porous and surface anisotropic nature, Janus membrane showed excellent separation efficiency and separation flux for both oil-in-water emulsions (separation efficiency up to 99.4%, separation flux up to 196 L m−2 h−1) and oil-in-water emulsions (separation efficiency up to 99.3%, separation flux up to 792 L m−2 h−1 bar−1). More importantly, Janus membranes exhibited outstanding reusability. This Janus membrane shows great potential in the fields of waste upcycling and emulsion separation.

Mortar with Substituted Recycled PET Powder: Experimental Characterization and Data-Driven Strength Predictive Models

Mortar with Substituted Recycled PET Powder: Experimental Characterization and Data-Driven Strength Predictive Models

Inelastic Neutron Scattering from Thin Film Biaxially Oriented Polyethylene Terephthalate.

Recent interest in emerging processes for polymer manufacturing and bio-based chemistries for direct chemical recycling/upcycling has motivated new research focused on a deeper understanding of atomic-scale polymer properties and how they influence macroscopic phenomena. Uncovering the fundamental properties of polymers that give rise to macroscopic behavior could enable new pathways for improved recyclability or utilization of alternative "greener" polymer analogues. In this study, the neutron vibrational spectrum was measured for a film of biaxially oriented polyethylene terephthalate (BoPET) using inelastic neutron scattering (INS), to investigate the relationship between the structure and dynamics of a widely used polymer. Compared to conventional spectroscopic techniques, the use of INS is advantageous for polymeric materials due to the absence of selection rules (i.e., all transitions are allowed), broad-band energy range, and considerable sensitivity to hydrogen modes. In order to distinguish the vibrational modes caused by trans and gauche rotational isomerism, the normal modes of vibration were calculated from a density functional theory-optimized structure of crystalline PET (cPET), representative of the all-trans state, and compared with INS from "highly crystalline" PET powder. Although in- and out-of-plane wagging of hydrogens on the ring structure exhibit significant contribution to both BoPET and cPET spectra, the wagging, rocking, and twisting modes of hydrogen on the ethylene glycol group are, in most cases, conformation-specific. These results were further rationalized by investigating the role of hyperconjugation in stabilizing both conformations using the natural bond order method. Through comparison of experimental and calculated INS results, this work provides the fundamental basis for discovering the role of structure and dynamics in shaping the macroscopic properties of PET and polymer analogues.

Optimization of the static mechanical properties of two bituminous concretes modified by partial bitumen replacement with a mass-total of tire powder, plastic bottle powder, and sulfur, depending on the production procedure

This paper examines the effect of the manufacturing process on the static mechanical properties of modified bituminous concrete by partially replacing the bitumen with the mass sum of tyre powder, plastic bottle powder, and sulfur. This optimization is in response to the persistence of pavement degradation despite multiple solutions based on material type and method of obtaining doped bituminous concrete. These solutions are high modulus mixes (EME), bituminous concretes doped with rubber or plastics and cross-linked bituminous concretes on the one hand, and bituminous composites manufactured by dry or wet process (Shaoula; 2008), after partial substitution of conventional materials by dopants or by adding dopants on the other.To better understand the evolution of the static mechanical properties of neo-bituminous concrete using the Duriez (NF P 98-251-1) and Marshall (NF P 98-251-2) tests, the product was manufactured using the wet process and the dry process (Shaoula; 2008), respectively, after formulation. Formulation translated by 5%, 10%, and 15% substitution of bitumen by the mass sum of PUNR powder, PET powder, and sulfur at 40%, 28%, and 32%, respectively. All of this is preceded by component characterization in accordance with relevant standards. It is discovered that bituminous concretes modified and manufactured using the wet process are quite compact, stable, and resistant than the control composite on the one hand, and clearly preferential to those manufactured using the dry process on the other.

Biological degradation of polyethylene terephthalate by rhizobacteria.

In view of the growing demand for plastic products, an enormous proportion of plastic waste causing the biological issue is produced. Plants in collaboration with their rhizobacteria partners are also exposed to these contaminants. The study aims to determine the rhizobacterial ability to biodegrade PET plastic. We isolated the rhizobacteria capable of degrading the PET plastic in minimal salt media using it as a sole carbon source. The three rhizospheric isolates, namely Priestia aryabhattai VT 3.12 (GenBank accession No. OK135732.1), Bacillus pseudomycoides VT 3.15 (GenBank accession No. OK135733.1), and Bacillus pumilus VT 3.16 (GenBank accession No. OK1357324.1), showed the highest degradation percentage for PET sheet and powder. The biodegradation end products post 28days for PET sheet and 18days of PET powder were studied by Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), and scanning electron microscopy (SEM). Our results showed significant biodegradation of PET plastic, and the rate of degradation could account for over 65%. The present study proves soil rhizobacteria's potential and capabilities for efficient degradation of PET plastic occurring at the waste sites. It also implies that rhizobacteria could be beneficial in the remediation of PET waste in future applications.

Powder bed fusion of aluminum –poly(ethylene terephthalate) hybrid powder: Process behavior and characterization of printed parts

This study shows that a dry mix of aluminum (Al) and Poly(ethylene terephthalate) (PET) powders can be successfully used for freeforming with powder bed fusion (PBF). The Al-PET powder had a narrower processing window than PET powder, which was due to the Al particles acting as a nucleating agent, thus shifting the melt crystallization temperature to higher values. However, with some process adjustments, curl could be overcome and tensile bars and complex shapes could be printed. While the tensile modulus of the Al-PET composites was higher than PET, the tensile strength and impact resistance decreased. This performance was unlike our previous work of injection moulding (IM) of the same Al-PETs, where an unusual simultaneous increase in tensile modulus, tensile strength, and impact resistance occurred. The reason for the decrease in the tensile strength and impact resistance in Al-PET articles made by PBF was the voids that were inherent from the PBF process, and the added interfacial voids that sometimes occurred between Al particles and PET. Nevertheless, besides the freeforming capability, the advantage of PBF over IM for making Al-PET composites is the crystallization of the PET phase in the article, which is more difficult to achieve with PET by IM. With further optimized compositions of Al-PET, freeform printing of thermally conductive and heat dissipating articles should be possible.

Enhanced Extracellular Production of IsPETase in Escherichia coli via Engineering of the pelB Signal Peptide.

Poly(ethylene terephthalate) (PET) is one of the most commonly used plastics worldwide and its accumulation in the environment is a global problem. PETase from Ideonella sakaiensis 201-F6 was reported to exhibit higher hydrolytic activity and specificity for PET than other enzymes at ambient temperature. Enzymatic degradation of PET using PETase provides an attractive approach for plastic degradation and recycling. In this work, extracellular PETase was achieved by Escherichia coli BL21 using a Sec-dependent translocation signal peptide, pelB, for secretion. Furthermore, engineering of the pelB through random mutagenesis and screening was performed to improve the secretion efficiency of PETase. Evolved pelB enabled higher PETase secretion by up to 1.7-fold. The improved secretion of PETase led to more efficient hydrolysis of the PET model compound, bis (2-hydroxyethyl) terephthalic acid (BHET), PET powder, and PET film. Our study presents the first example of the increasing secretion of PETase by an engineered signal peptide, providing a promising approach to obtain extracellular PETase for efficient enzymatic degradation of PET.

Poly(ethylene terephthalate) Powder-A Versatile Material for Additive Manufacturing.

The 3D printing of articles by the effect of a directed laser beam on a plastic powder is a demanding process, and unlike injection molding, very few polymers work well enough with it. Recently, we reported that poly(ethylene terephthalate) (PET) powder has intrinsically good properties for 3D printing. Basic mechanical properties were shown earlier and it was demonstrated that unfused but heat-exposed PET powder does not degrade quickly allowing good re-use potential. In this work, we conducted a detailed comparison of the mechanical properties of PET and polyamide 12 from different build orientations. PET powders with two different molecular weights were used. With the high molecular weight powder, the processing parameters were optimized, and the printed bars showed little difference between the different orientations, which means there is low anisotropy in mechanical properties of built parts. Based on processing experience of the first powder, the second powder with a lower molecular weight was also very printable and complex parts were made with ease from the initial printing trials; since the process parameters were not optimized then, lower mechanical properties were obtained. While the intrinsic material properties of PET (melting and re-crystallization kinetics) are not the best for injection molding, PET is eminently suitable for powder bed fusion.

Characterization of Recycled Polyethylene Terephthalate Powder for 3D Printing Feedstock

This paper assessed the suitability of PET powder produced by crushing used plastic bottles as 3D printing feedstock. Characterization of the powder was done through determining its flow property, coefficient of friction, bulk density, flexural and tensile strengths and compared with those of ABS, PLA, PVA, Nylon and HDPE which are used conventionally 3D printing of plastic parts. Two grades of PET bottles were used in this study: grade one which is designated PET1 with intrinsic viscosity values ranging from 0.78-0.80 (used for water bottles) and grade two which is designated PET2 with intrinsic viscosity values ranging from 0.80-0.85 (used for carbonated drinks bottles). The results of the tests performed showed that PET1 has bulk density, coefficient of friction, flexural strength and tensile strength values of 0.16 g/m3, 0.43, 82.1 MPa and 63.4 MPa respectively while PET2 has bulk density, coefficient of friction, flexural strength and tensile strength values of 0.15 g/m3, 0.22, 82.7 MPa and 57.8 MPa respectively. The Experimental results show that both PET1 and PET2 have very good flow property, and are suitable for 3D printing. This study solves two major problems: plastic waste management and availability of locally produced 3D printing feedstock, which is currently the greatest challenge of 3D printing in Nigeria. Keywords— 3D printing feedstock, Characterization, Intrinsic viscosity, PET powder.

Structural behavior of concrete beams and columns reinforced with Waste Plastic incorporated GFRP (WPGFRP) rebars

Experimental investigations were carried out on novel Waste Plastic incorporated GFRP (WPGFRP) rebars and concrete specimens reinforced with the novel WPGFRP rebars. The WPGFRP rebars were manufactured through pultrusion, using waste plastic (PET powder) as a strength additive filler and various engineering properties are assessed. Tests results indicate that use of PET powder in GFRP rebars which leads to the WPGFRP rebars, increases tensile and compressive strengths of rebars by 17.2% and 19.3% respectively, hence proving to be a strength additive material. Three types of beams and columns were tested for flexure capacity (two-point loading) and axial compression, respectively. First type (Conventional) consists of beams and columns reinforced with Fe500 Steel rebars and stirrups/ties. While both second (Total-FRP) and third (Hybrid) types of beams and columns were reinforced with novel WPGFRP rebars, however differ in the material of their stirrups/ties. WPGFRP stirrups/ties were used in second type of members while Fe500 Steel stirrups/ties were provided in third type. Results indicate that the performance of Hybrid members is superior to that of Conventional and Total-FRP members, in terms of first crack load and failure load. However, large flexural deformations and compressive strains were also observed in case of Hybrid beams and columns, respectively.

EPA finds risks with flea collar chemical

Tetrachlorvinphos (TCVP), an organophosphate insecticide used to control fleas and ticks on pets and livestock, may pose a health risk to people in their homes and to workers who apply it, EPA says. These conclusions are in a final human health assessment the agency released on Jan. 4. The agency has contacted pesticide makers to discuss ways to reduce exposure to the chemical. EPA plans to propose a rule requiring such reductions later this year. In the meantime, the agency is advising consumers to keep children away from TCVP pet collars, spray, and powder products, and to wash hands thoroughly with soap and water after handling TCVP products. The agency conducted the assessment in response to a 2009 petition from the Natural Resources Defense Council to ban pet products containing TCVP. The environmental group claims that the pesticide poses unacceptable risks to children’s developing brains and nervous systems. EPA initially

Ultrasound-enhanced enzymatic hydrolysis of poly(ethylene terephthalate)

The application of ultrasound was found to enhance enzymatic hydrolysis of poly(ethylene terephthalate) (PET). After a short activation phase up to 6.6times increase in the amount of released products was found. PET powder with lower crystallinity of 8% was hydrolyzed faster when compared to PET with 28% crystallinity. Ultrasound activation was found to be around three times more effective on powders vs. films most likely due to a larger surface area accessible to the enzyme.

Infection Trace of Pine Wilt Disease Based on Terahertz Spectroscopic Technology

In this study, we present the terahertz spectroscopic features of pine needle infected by pine wilt disease during different infection stages by applying terahertz spectroscopic techniques. We measure the absorption variation of the pine needle samples with infection time by Terahertz Time Domain Spectroscopy (THz-TDS). The absorption intensity in the frequency region of 0-2.5 THz increases gradually with infection time. While the pine wood is infected above four months, the absorption intensity reaches to maximum. However, the calculated relative refractive index compared with the reference signal of PET powder reduces with infection time. The higher frequency measurement by Fourier Transform Infrared spectroscopy (FTIR) doesn't show the absorption variation of the samples due to huge signal attenuation in the transmission path of the samples. This study demonstrates that the relation of absorption intensity and refractive index of the pine needle sample with the infection time. We can trace the infection extent of the pine wood by measuring its terahertz spectroscopic property.

Usage of the waste PET as filler in phenolic resins molds

The main aim in this work was to investigate usage of the waste PET powder as filler in “high ortho” novolac resin (N)-wood flour (WF) molds. At first, N was synthesized and then purified. The N after grinding to powder was mixed at different weight ratios (60, 80, and 95 %) with waste PET powder (WF-free). In addition, N was mixed 20 % with waste PET powder (with WF). The mixtures were molded to obtain test pieces in standard dimensions by Buehler Metaserv. Thus, we prepared molds from blends of novolac resin and waste PET powder. The effect of waste PET on the mechanical properties of the molds was investigated with mechanical measurements, such as compression strength, elastic modulus, strain to failure, and hardness. Using 20 % (wt) waste PET powder in the molds did not cause any significant change in compression strength, elastic modulus, strain to failure, and hardness values.

Effect of Nanodisperse Carbon Fillers and Isocyanate Chain Extender on Structure and Properties of Poly(ethylene terephthalate)

The effect of diisocyanate chain extender (CE) on the mechanical, rheological, and relaxation properties, as well as on molecular weight and crystallizability, of starting poly(ethylene terephthalate) (PET) and its composites containing carbon nanomaterials (CNM) such as carbon nanotubes (CNTs) and commercial carbon (CC) has been studied. The composites were compounded in molten PET using twin‐screw extruder (screw diameter 35 mm; L/D = 40). To improve the distribution of CNM in the polymeric matrix (before introduction into the melt), they were blended with PET powder and subjected to an ultrasonic treatment in methylene chloride. The salient features of the materials structure were estimated based on DSC and relaxation spectrometry (dynamic mechanical analysis) data. It has been found that CNM additives partly suppress the PET‐chain extension reactions which take place during interaction between macromolecular end groups and CE. Besides, both CNT and CC favour crystallizability of the modified PET owing to nucleation of the crystallization process. The influence of CNT appears to be more effective than that of CC. Enhancements in true mechanical strength and deformability of PET/CE/CNM composites, as against PET/CE materials, were found to be most clearly exhibited by the CNT‐containing composites.

Recycled Poly(Ethylene Terephthalate) Resins as Corrosion Protective Organic Coatings of Steel Pipelines

In this work, modification and application of Poly (ethylene terephthalate) (PET) waste as organic coating were reported. A potential application of PET coating is to provide protection against corrosion in automobile fuel tanks. PET powder was obtained from post-consumer beverage bottles. The corrosion resistance of the coating was evaluated by total and partial immersion tests in gasoline, diesel oil and alcohol. PET waste was depolymerized in the presence of glycols or ethanol amines and manganese acetate as a catalyst. The produced oligoesters were used to prepare epoxy, alkyd, vinyl ester and polyurethane organic coatings. The cured epoxy, alkyd, polyurethane and unsaturated polyester resins were evaluated as corrosion protective coating application of steel. The recent advances in manipulating patterned recycled PET arrays and patents are reviewed with a focus on the progress of the recycled products and applications. Keywords: Recycled PET, corrosion protection, organic coatings, epoxy resins, alkyd resins, flame spray coating, coating characteristics, terephthalic acid, ethylene glycol, alkaline hydrolysis, unsaturated polyesters, lead-tin-coated steel, Powder Coatings, solid polyesters, GLYCOLYZED PET

The properties of polyolefins modified with PET powder

AbstractThe polyolefin and poly(ethylene terephthalate) (PET) products are the mostly current communal waste materials. The waste polymeric materials are generally difficult to separate, and therefore a processing of nonseparated materials presents an interesting alternative suggestion. The aim of our work was to analyze the possibility of reprocessing of polyolefins by a relative low temperature, and to study the effect of addition of PET solid powder on processing and application properties. The results of our investigations allow to conclude that the solid PET powder may play a role of a heterogeneous nucleator, acting as an α‐phase promoter of an isotactic polypropylene. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Microkinetics and Mass Transfer in Aqueous Alkaline Depolymerization of Poly (Ethylene Terephthalate)

Depolymerization of poly (ethylene terephthalate) (PET) in aqueous sodium hydroxide solution was undertaken in a batch process at 90–150°C and 1 atm pressure conditions by varying PET particle size in the range of 50–512.5 µm. Process time also was varied from 10–110 min to describe the effect of particle size of PET and mass transfer time on batch reactor performance. The particle size of PET and operation time required were optimized. Operation products consist of terephthalic acid (TPA) and ethylene glycol (EG) as monomers. A comprehensive model for the depolymerization of PET has been developed, taking into account kinetic data and the diffusion operation for the major by-products as monomers from the waste solid PET powder. The model prediction was undertaken by using our own laboratory data. Experimental data with analysis of depolymerized monomeric products (TPA and EG) of PET show good consistency with model results. Acid value as well as carboxyl-group concentrations of TPA significantly increases with operation time. The kinetic parameters for the depolymerization for the formation of monomers were under taken in this study, used for prediction of model results. The mass transport was described by using a classical diffusion equation according to Fick's law and a modified Wilke-Chang diffusion model. Diffusion coefficients were calculated with a change in temperature and charge ratios as a function of operation time to give an explanation of the process phenomena.

Chemical Recycling, Kinetics, and Thermodynamics of Hydrolysis of Poly(Ethylene Terephthalate) (PET) Waste in Sulfuric Acid in Presence of Phosphoric Acid

Poly(ethylene terephthalate) (PET) powder was depolymerized at atmos‐ pheric pressure in sulfuric acid in presence of 2.5 N phosphoric acid at 88–140°C. Particle sizes ranging from 50 to 512.5 µm and reaction time 30–200 min required for PET hydrolysis were optimized. Terephthalic acid (TPA) and ethylene glycol (EG) were produced by acid‐catalyzed heterogeneous PET hydrolysis. To avoid the carbonization/oxidation of EG and to reduce corrosion, reaction was undertaken below 150°C using less concentration of sulfuric acid at a lower reaction time. To enhance reaction rate, 2.5 N phosphoric acid was introduced during reaction. Ethylene glycol was recovered during hydrolysis by salting‐out technique. Terephthalic acid was separated out by using NaOH solution and then being acidified. Subsequently, TPA and EG were analyzed qualitatively and quantitatively. Yields of TPA and EG were almost equal to PET conversion. A modified shrinking‐core model based on obtained acid value of TPA explained depolymerization in sulfuric acid (in presence of phosphoric acid). Effective surface area is proportional to the degree of hydrolyzed PET (X), affected by formation and growth of pore and crack on PET powder. Hydrolysis rates as well as apparent rate constant are inversely proportional to particle size. Thermodynamics are also undertaken to determine activation energy, Arrhenius constant, equilibrium constant, Gibbs free energy, enthalpy, and entropy. Dependence of rate constant on reaction temperature was correlated by the Arrhenius plot, which shows an activation energy of 56.8 kJ mol−1 and a Arrhenius constant of 530.3 L min−1 cm−2.