Ethylene Terepthalate Research Articles

Catalytic pyrolysis of polyolefin and multilayer packaging based waste plastics: A pilot scale study

The catalytic pyrolysis of different types of polyolefin and multilayer packaging based plastic wastes in the presence of commercial zeolite catalyst was studied in the batch pilot scale reactor. Different types of multi-layer plastics such as biaxial oriented polypropylene (BOPP), metalized biaxial oriented polypropylene layers (MET/BOPP), poly ethylene terepthalate (PET), metalized polyethylene-terepthalate (MET/PET), PET combined polyethylene (PET/PE) and mixed polyolefin plastic wastes obtained from the municipal corporation were pyrolyzed to determine the oil, gas and char distribution. BOPP based plastic waste exhibited higher oil yield and calorific value (65–70%, 45.14 KJ/g) compared to PET based MLPs (17.8 %, 30 KJ/g) and laminated metalized plastics (13 %, 37 KJ/g). Modifying the feed composition by mixing of polyolefins-based waste plastics with PET based MLPs and BOPP/MET BOPP doubled the liquid yield and notably altered the physicochemical characterization of the resulted pyrolysis oil. Char yield in the polyolefins-based waste is observed to be lesser than the MLP based waste plastics. GC–MS analysis revealed the percentage area of hydrocarbons compounds of the pyrolysis oil obtained from PET based MLP experiments contains high fractions of medium and heavier range hydrocarbons (C11 – C20, C21 – C30). Sulfur content in the oil from different MLPs was measured as below the detection limit. Functional groups of hydrocarbons of oil were analyzed using FT-IR. Solids were characterized for the presence of heavy metals such as Al, Cr, Cu, Co, Pd, and Ni.

Influence the loading effect on modification of PET film and fiber by Argon Plasma

Poly(ethylene terepthalate) films and fabrics were modified by low-pressure argon plasma at different area of samples been treated. Contact angles for water and glycerol were measured and surface energy was calculated for film surface characterization. Height of water capillary rise was measured for fabric. The changes in chemical structure of surface layer were analyzed by ATR-FTIR method. Influence of sample area on non-homogeneity of plasma modification was shown. Some experiments were performed with polypropylene treatment in flowing plasma afterglow to confirm the reactions of oxygen active species originated from gas products of poly(ethylene terepthalate) etching in argon plasma.

Kinetic Studies on Saponification of Poly(ethylene terephthalate) Waste Powder Using Conductivity Measurements

Conductometric measurement technique has been deployed to study the kinetic behavior during the reaction of poly(ethylene terepthalate) (PET) and NaOH. A laboratory made arrangement with facility of continuous stirring was used to carry out experiments at desired temperature. With conductometry, the determination of kinetic as well as thermodynamic parameters becomes more simple and faster as compared to gravimetry. Chemical kinetics of this reaction shows that it is a second order reaction with reaction rate constant 2.88×10-3 g−1 s−1 at 70°C. The specific reaction rates of the saponification reaction in the temperature range at various temperatures (50–80°C) were determined. From the data, thermodynamic parameters such as activation energy, Arrhenius constant (frequency factor), activation enthalpy, activation entropy, and free energy of activation obtained were 54.2 KJ g−1, 5.0×106 min−1, 90.8 KJ g−1, -126.5 JK−1 g−1, and 49.9 KJ g−1, respectively.

Memristive Behavior in Electrohydrodynamic Atomized Layers of Poly[2-methoxy-5-(2'-ethylhexyloxy)–(p-phenylenevinylene)] for Next Generation Printed Electronics

Poly[2-methoxy-5-(2'-ethylhexyloxy)–(p-phenylenevinylene)] (MEH:PPV) based organic memristor (memory resistor) has been fabricated on the indium–tin oxide (ITO) coated poly(ethylene terepthalate) (PET) substrate by the electrohydrodynamic atomization (EHDA) technique. Thin jet containing MEH:PPV polymer was generated through a capillary under electrical stresses. The jet was broken into small droplets by adjusting the distance from nozzle to substrate and collected over the substrate under normal room conditions, consequently a high quality layer of MEH:PPV was achieved with an average thickness of 168 nm. The layer was morphologically characterized by a field emission scanning electron microscope (FESEM) analysis. X-ray photoelectron spectroscope (XPS) analysis was also carried out to confirm the chemistry of the deposited material. Electrically, ITO/MEH:PPV/Ag fabricated memristor was found to be switchable between high state and low state between ±4 V. The research work provides the memristive behavior in electrohydrodynamic atomized layers of MEH:PPV to be used for the next generation printed electronics application.

Fabrication of self-supporting antireflection-structured film by UV–NIL

Ultraviolet nanoimprint lithography (UV-NIL) is a powerful tool for the fabrication of films with antireflection (AR) structures (AR films), which are widely used in flat panel displays, mobile phone displays, solar cell surfaces, optical lenses, and so on. To fabricate the AR films, fabricated AR structures are replicated onto a UV photocurable polymer (resin) on top of a transparent poly (ethylene terepthalate) (PET) film. However, the interface between the AR structured polymer and the PET film causes high interface reflection. Therefore, a self-supporting AR polymer film that can eliminate interface reflection is required. In our previous research, polyvinyl alcohol (PVA) film was used as the intermediate film to obtain a self-supporting polymer film, but the durability of this self-supporting film was very low. In this study, instead of PVA film, we used polypropylene (PP) film as the intermediate film, which gives more stability to the self-supporting AR polymer film. The release and adhesive force of the self-supporting film were also evaluated. The fabricated self-supporting AR structure film exhibited 0.2-0.3% reflectivity in the spectrum range 430-950nm.

Microwave assisted glycolysis of poly(ethylene terepthalate) for preparation of polyester polyols

AbstractThe generic aim of the present work is to reduce the time required for glycolytic depolymerization of PET by employing microwave irradiation instead of the conventional heating process. Glycolysis of PET was performed in the presence of glycols of different molecular weight under microwave irradiation. Experimental conditions like PET : glycol ratio, reaction time and concentration of glycerol were optimized to maximize the product yield. In the presence of ethylene glycol, bis‐(hydroxyethyl) terephthalate (BHET) could be obtained in excellent yields in significantly lesser time (30 min) as compared to 8–9 h by conventional heating process. The BHET yield could further be increased by a second step glycolysis of the residual oligomers. This increased efficiency of the microwave assisted process has been attributed to the high microwave absorption capacity of glycols which results from their high loss factor. PET could also be glycolysed in the presence of higher glycols, however the reactivity of diols was found to decrease with increase in the molecular weight. The polyols obtained were reacted with aromatic diphenylmethane diisocyanate to prepare polyurethane foams, which were characterized by various techniques for determination of their physical, mechanical and structural properties. The compressive strength of the polyurethane foams was found to be inversely proportional to the molecular weight of the glycolysed polyol used for its preparation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

CFD modeling of the melt spinning of poly (ethylene terepthalate) at low take-up velocities

In this study, a model was formulated to describe the melt spinning of Poly (ethylene terepthalate) (PET) at different quench air speeds and temperatures, mass throughputs and a low range of take-up velocities. The constitutive equations of the Newtonian model were used for modeling, which assumed the flow of polymer was viscous. To simulate the influence of the process parameters on the melt spinning process, a fiber model was used and coupled with computational fluid dynamics (CFD) calculations of the quench air flow. In the fiber model, energy, momentum and mass balance were solved for the polymer mass flow. The formulation was implemented in the Fluent Continuous Fiber Model. Numerical predictions of the model were compared with experimental data reported in the literature for PET. The take up speed, mass throughput and the temperature of melt spinning were the primary parameters of final fiber properties for both simulation and experimental results. In the simulation results, the effects of take-up speed and mass throughputs were clearly different at high take-up velocities and low mass throughputs because of viscoelastic behavior of polymers in the melt spinning. The Newtonian model was more reasonable for lower take-up speeds and higher mass throughputs. Key words: Melt spinning, poly (ethylene terepthalate), modeling, process parameters.

Composite coating of 58S bioglass and hydroxyapatite on a poly (ethylene terepthalate) artificial ligament graft for the graft osseointegration in a bone tunnel

The purpose of this study was to determine the effect of the combination of hydroxyapatite (HA) and bioglass (BG) on polyethylene terephthalate (PET) artificial ligament graft osseointegration within the bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells proved that this HA/BG composite coating can promote the cell compatibility of grafts. A rabbit extraarticular tendon-to-bone healing model was used to evaluate the effect of this composite coating on PET artificial ligaments in vivo. The final results demonstrated that HA/BG coating improved new bone formation at the graft-bone interface and increased the load-to-failure property of graft in bone tunnel compared to the control group at early time. The study has shown that HA/BG composite coating on the PET artificial ligament surface has a positive effect in the induction of artificial ligament osseointegration within the bone tunnel.

Influence of liquid crystalline polymer and recycled PET as minor blending components on rheological behavior, morphology, and thermal properties of thermoplastic blends

AbstractIn this study, the potential of recycled poly(ethylene terepthalate) (rPET) as a well‐defined reinforcing material for the in situ microfibrillar‐reinforced composite (iMFC) was investigated in comparison with that of liquid crystalline polymer (LCP). Each dispersed phase (LCP or rPET) was melt blended with high density polyethylene (PE) by using extrusion process. The rheological behavior, morphology, and the thermal stability of LCP/PE and rPET/PE blends containing various dispersed phase contents were investigated. All blends and LCP exhibited shear thinning behavior, whereas Newtonian fluid behavior was observed for rPET. The incorporation of LCP or rPET into PE significantly improved the processability. A potential of rPET as a processing lubricant by bringing down the melt viscosity of the blend system was as good as LCP. The elongated LCP domains were clearly observed in as‐extruded strand. Although the viscosity ratio of the rPET/PE system was lower than that of the LCP/PE blend system, most rPET domains appeared as small droplets. An addition of LCP and rPET into the PE matrix improved the thermal resistance significantly in air but not in nitrogen. The obtained results suggested the high potential of rPET as a processing aid and good thermally resistant material similar to LCP. Copyright © 2009 John Wiley & Sons, Ltd.

Perfusion bioreactor system for human mesenchymal stem cell tissue engineering: Dynamic cell seeding and construct development

Human mesenchymal stem cells (hMSCs) have great potential for therapeutic applications. A bioreactor system that supports long-term hMSCs growth and three-dimensional (3-D) tissue formation is an important technology for hMSC tissue engineering. A 3-D perfusion bioreactor system was designed using non-woven poly (ethylene terepthalate) (PET) fibrous matrices as scaffolds. The main features of the perfusion bioreactor system are its modular design and integrated seeding operation. Modular design of the bioreactor system allows the growth of multiple engineered tissue constructs and provides flexibility in harvesting the constructs at different time points. In this study, four chambers with three matrices in each were utilized for hMSC construct development. The dynamic depth filtration seeding operation is incorporated in the system by perfusing cell suspensions perpendicularly through the PET matrices, achieving a maximum seeding efficiency of 68%, and the operation effectively reduced the complexity of operation and the risk of contamination. Statistical analyses suggest that the cells are uniformly distributed in the matrices. After seeding, long-term construct cultivation was conducted by perfusing the media around the constructs from both sides of the matrices. Compared to the static cultures, a significantly higher cell density of 4.22 x 10(7) cell/mL was reached over a 40-day culture period. Cellular constructs at different positions in the flow chamber have statistically identical cell densities over the culture period. After expansion, the cells in the construct maintained the potential to differentiate into osteoblastic and adipogenic lineages at high cell density. The perfusion bioreactor system is amenable to multiple tissue engineered construct production, uniform tissue development, and yet is simple to operate and can be scaled up for potential clinical use. The results also demonstrate that the multi-lineage differentiation potential of hMSCs are preserved even after extensive expansion, thus indicating the potential of hMSCs for functional tissue construct development. The system has important applications in stem cell tissue engineering.

Chemical oxidative grafting of conducting poly(N‐methyl aniline) onto poly(ethylene terepthalate)

AbstractDetailed studies on the peroxidisulfate (PDS) initiated graft copolymerization of N‐methyl aniline (NMA) with poly(ethylene terepthalate) (PET) were carried out in p‐tolene sulfonic acid medium under nitrogen atmosphere. Experiments were designed to follow the rate of formation Rh of the poly(N‐methyl aniline (PNMA), simultaneously with the rate of grafting of PNMA onto PET. Effects of concentration of NMA, PDS, PET, time, and temperature on Rh and graft parameters were followed. Kinetic equations were deduced to correlate the changes in the rate with experimental conditions. Graft copolymers were isolated and grafting of PNMA onto PET was confirmed through FTIR, thermogravimetric analysis, and conductivity measurements. Tensile measurements showed that grafting of PNMA did not alter the tensile properties of PET. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 596–605, 2005

Temperature dependence of the optical band gap and refractive index of poly(ethylene terepthalate) oligomer–DDQ complex thin film

The temperature dependence of the optical band gap and refractive index dispersion of thin film of poly(ethylene terepthalate) oligomer–DDQ charge transfer complex has been investigated. The absorption edge shifts to the lower energy as consequence of the thermal annealing on film and the fundamental absorption edge corresponds to a direct energy gap. The temperature coefficient of the optical band gap for the film was found as d E g/d T = − 3.15 × 10 −3 eV/K. The temperature dependence of the refractive index has also been investigated and it is observed that the refractive index changes by annealing temperatures.

A study of ta-C, a-C:H and Si-a:C:H thin films on polymer substrates as a gas barrier

Two types of diamond-like carbon (DLC) films were grown on Poly (ethylene terepthalate) (PET) substrates have been investigated for density, internal stress, gas permeability and structural properties by an X-ray reflectometry, surface profilometer, Raman spectroscopy and water vapour permeation analysis system, respectively. The high density tetrahedral amorphous carbon (ta-C) films (3.27 g/cm 3) prepared by filtered vacuum cathodic arc (FCVA) showed unexpected high water vapour transmission rate (WVTR) (1.3 g/m 2 day) and a surface covered by a network of deep micro-cracks, which is due to intrinsic stress inside the ta-C films (up to 12 GPa). The soft Si doped hydrogenated amorphous carbon (Si-a:C:H) films prepared by plasma enhanced chemical vapour deposition (PECVD) exhibited low transmission rate (0.03 g/m 2 day) with a water vapour reduction factor up to 98% and a surface almost completely free of micro-cracks. Si incorporation in the a-C:H films reduced both the film density from 2.3 g/cm 3 to 1.85 g/cm 3 and the compressive stress to <0.5 GPa. This could be understood by two possibilities. Firstly, the increasing in the hydrogen content within the films (as indicated by increasing the Raman background slope) developed more polymer–like bonds, which weakens the microstructure. Second, replacing the stronger CC bonds (3.7 eV) by CSi (3.21 eV) bonds where the relaxation of residual stress would occur with large strains in the CSi bonds.

On the crystallization mechanism of poly(ethylene terepthalate) in its blends with poly(vinylidene fluoride)

The overall crystallization rates of poly(ethylene terepthalate) (PET) in its blends with poly(vinylidene fluoride) (PVF 2) were studied by differential scanning calorimetry. At a fixed temperature the crystallization rate of PET decreased with increase in φ PVF 2 (φ PVF 2 = volume fraction of PVF 2) in the blend. However, at a fixed undercooling, initially there was almost an invariant rate with φ PVF 2 , but it increased at higher PVF 2 concentrations. The Avrami analysis indicated that the nucleation process of PET changed from three-dimensional heterogeneous nucleation to two-dimensional heterogeneous nucleation due to blending in major cases. Analysis of crystallization rate according to the extended form of Lauritzen–Hoffman (L–H) growth-rate theory indicated regime-I to regime-II transition both in pure PET as well as in the blends. The undercooling (Δ T) required for the regime transition was almost the same for both the pure polymer and the blends except for the blend composition φ PET=0.35. A jump in the crystallization rate was observed at the regime transition temperatures for the blends with higher φ PVF 2 . This phenomenon has been attributed to the different diffusion processes occurring in the two regimes. Analysis of the lateral surface free energy ( σ) obtained from the nucleation constant ( K g) indicated that there might be some chain extension of PET due to blending.

Electron induced modification in poly(ethylene terephthalate)

The effect of 100 kGy dose of 2 MeV electron irradiation on Poly(ethylene terepthalate) (PET) has been studied by different characterisation techniques such as the Fourier transformed IR spectroscopy, electron spin resonance spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction analysis. Oxidative degradation leading to amorphisation of the polymer has been observed from spectral analysis. The thermal stability of the polymer was found to decrease due to electron irradiation. The thermal decomposition temperature as well as the melting temperature in case of irradiated PET was found to be decreased due to electron bombardment. A decrease in crystallinity of the polymer has also been observed after irradiation.

The FT-Raman spectroscopic study of polymers at temperatures in excess of 200°C

Two polymers, isotactic polypropylene and poly(ethylene terepthalate) were studied at temperatures below, at and above their melting points. FT-Raman spectra at temperatures over 200°C were obtained using a cut off filter at 1490 nm to remove the black body radiation. Results confirm the retention of some crystallinity for a few degrees above the melting point. The significance is discussed.

Covalent linkage of recombinant hirudin to poly(ethylene terephthalate) (Dacron): creation of a novel antithrombin surface

Thrombus formation and intimal hyperplasia on the surface of implantable biomaterials such as poly(ethylene terepthalate) (Dacron) vascular grafts are major concerns when utilizing these materials in the clinical setting. Thrombin, a pivotal enzyme in the blood coagulation cascade primarily responsible for thrombus formation and smooth muscle cell activation, has been the target of numerous strategies to prevent this phenomenon from occurring. The purpose of this study was to covalently immobilize the potent, specific antithrombin agent recombinant hirudin (rHir) to a modified Dacron surface and characterize the in vitro efficacy of thrombin inhibition by this novel biomaterial surface. Bovine serum albumin (BSA), which was selected as the ‘basecoat’ protein, was reacted with various molar ratios of the cross-linker sulphosuccinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (sulpho-SMCC; 1:5-1:50). These BSA-SMCC complexes were then covalently linked to sodium hydroxide-hydrolysed Dacron (HD) segments via the cross-linker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Covalent linkage of these complexes to HD (HD-BSA-SMCC) was not affected by any of the sulpho-SMCC cross-linker ratios assayed. rHir, which was initially reacted with 2-iminothiolane hydrochloride (Traut's reagent) in order to create sulphydryl groups, was then covalently bound to these HD-BSA-SMCC surfaces (HD-BSA-SMCC-S-rHir). The 1:50 (BSA: sulpho-SMCC) HD-BSA-SMCC-S-rHir segments bound 22-fold more rHir (111 ng per mg Dacron) compared to control segments and also possessed the greatest thrombin inhibition of the segments evaluated using a chromogenic substrate assay for thrombin. Further characterization of the HD-BSA-SMCC-S-rHir segments demonstrated that maximum thrombin inhibition was 20.43 NIHU, 14.6-fold greater inhibition than control segments (1.4 NIHU). Thrombin inhibition results were confirmed by 125L-thrombin binding experiments, which demonstrated that the 1:50 HD-BSA-SMCC-S-rHir segments had significantly greater specific thrombin adhesion compared to control segments. Non-specific 125I-thrombin binding to and release from the 1:50 HD-BSA-SMCC-S-rHir segments was also significantly less than the control segments. Thus, these results demonstrate that rHir can be covalently bound to a clinically utilized biomaterial (Dacron) while still maintaining its ability to bind and inhibit thrombin.

In‐line monitoring of titanium dioxide content in poly(ethylene terephthalate) extrusion

AbstractPeak absorbance changes correlated to changes in species concentration have been the norm in applied spectroscopy, while baseline shifts have been more of an inconvenience. Taking the first or second derivative of the spectra eliminates these baseline shifts. However, with multivariate techniques becoming more readily available, repeatable baseline changes may now be monitored and correlated to specific physical changes. This concept has been studied by monitoring the concentration of titanium dioxide (TiO2), a white inorganic filler, in molten poly(ethylene terepthalate) (PET). Various mixtures of filled and unfilled PET resins were run through a single‐screw extruder, and near infrared spectra were collected in‐line by using a flow cell, housing two fiber‐optic probes, and mounted downstream of the extruder. The presence of titanium dioxide caused the scattering of light that resulted in a systematic baseline shift. The baseline shifts were correlated to the TiO2 concentration data. Multivariate techniques involving the use of singular value decomposition (SVD) to perform partial least squares regression (PLS) were applied to quantitatively determine TiO2 content in the PET melt stream. Standard error of prediction (SEP) values of about 1% were obtained for a model based on two factors.

Heat transfer and material removal in pulsed excimer-laser-induced ablation: Pulsewidth dependence

The pulsewidth-dependent ablation of polyimide, poly(methylmethacrylate), poly (etheretherketone), poly(ethylene terepthalate), and poly(ethersulphone) exposed to 248 and 308 nm, nanosecond UV laser pulses was modeled assuming one-dimensional heat transfer and a published model [G. H. Pettit and R. Sauerbrey, Appl. Phys. A 56, 51 (1993)] for photon absorption. The polymers were assumed to degrade/ablate after reaching a threshold temperature determined either from published temperature calculations of the ablating surface or the ceiling temperature. Since heat transfer calculations suggest that this temperature is reached before the end of the laser pulse, it was assumed that the degraded/ablated material continues to attenuate the incoming laser energy for the remaining duration of the laser pulse. Since the fluence-dependent absorption coefficient of this degraded material is unknown, it was obtained by fitting the experimental pulsewidth dependent ablation rate data of Schmidt, Ihlemann, and Wolff-Rottke (unpublished). The resulting values are consistent with mass spectrometric analysis of the ablation products and with the absence or occurrence of incubation. The threshold fluences and ablation rates predicted by this model are in good agreement with reported literature values; however, the use of a well-defined threshold temperature in the model leads to a different limiting etch rate dependence on the fluence at the threshold.

The use of continuous fiber reinforcement in dentistry

Fiber-reinforced composite (FRC) formulations were developed to serve as structural components for various dental appliances such as prosthodontic frameworks, retainers and splints. Poly(ethylene terepthalate glycol) and poly(1,4-cyclohexylene dimethylene terephthalate glycol) reinforced with continuous S-2 glass fibers were pultruded into continuous lengths with small rectangular cross sections. The microstructure was evaluated with SEM and optical microscopy. Fiber content and flexure properties were measured and compared to previous results by other authors. The present FRC contained 43–45 volume % fiber, which compared favorably with the 5–15 volume % fiber reported by all earlier investigators of dental FRC. The present materials achieved 65% of the theoretically expected modulus, in contrast to the typical value of 40% calculated in the earlier reports. The flexural strength and modulus of the experimental FRC were approximately 565 MPa and 20 GPa, respectively. The present FRC can be formed into individualized devices, and free fibers need not be manipulated by the operator. The improved properties and handling justify further study of these FRC as structural dental materials.