Production Of Polyethylene Terephthalate Research Articles

Speciation of Antimony in PET Bottles Produced in Japan and China by X-ray Absorption Fine Structure Spectroscopy

The oxidation state and coordination environment of antimony (Sb) incorporated into polyethylene terephthalate (PET) bottles were estimated based on X-ray absorption fine structure (XAFS) at Sb K-edge. Prior to XAFS analyses, Sb concentrations in 177 PET bottles collected in Japan and China were determined, showing that 30.5% and 100% of Japanese and Chinese PET bottles, respectively, contained more than 10 mg/kg of Sb. Most of the bottles used for aseptic cold filling and carbonated drinks contained a larger amount of Sb. Extended X-ray absorption fine structure (EXAFS) showed that the first neighboring atom of Sb in PET was estimated to be oxygen with a coordination number of about three. In addition, the contribution of Sb to Sb shell was discounted in the EXAFS, showing that Sb was not present as Sb2O3 in PET, although Sb was initially added as Sb2O3 in the production of PET. This information is consistent with the coordination environment estimated from the polycondensation reaction catalyzed by Sb, where Sb can be present as either Sb glycolate or Sb glycolate binding to the end group of the PET polymer. X-ray absorption near-edge structure (XANES) showed that Sb(III) initially added as Sb2O3 into PET was partially oxidized and the Sb(V) fractions reached approximately 50% in some samples. However, the oxidation state and coordination environment of Sb in PET had no relationship with the concentrations of Sb that leached into water from PET. Based on the present XAFS results and previous studies on the effects of temperature and others, it was concluded that the leaching behavior of Sb into water is primarily due to the degradation of PET itself, but is not related to the Sb species in the PET bottles.

Screening of tropical fungi producing polyethylene terephthalate-hydrolyzing enzyme for fabric modification

Microfungi were selectively isolated for production of polyethylene terephthalate (PET) fiber-degrading enzymes potentially to be used to modify the surface of polyester fabric. A range of fungi were isolated from plant surfaces and soil samples using a polycaprolactone (PCL) plate-clearing assay technique, and screened for cutinolytic esterase (cutinase) activity. Twenty-two of 115 isolates showed clearing indicating the production of cutinase. The ability of the fungi to produce cutinase in mineral medium (MM) using either potato suberin or PET (1 cm of untreated pre-washed PET fiber) fiber as substrates was assessed based on the hydrolysis of p-nitrophenyl butyrate (p-NPB). All isolates exhibited activity towards p-NPB, isolate PBURU-B5 giving the highest activity with PET fiber as an inducer. PBURU-B5 was identified as Fusarium solani based on its conidial morphology and also nucleotide sequencing from internal transcribed spacer region of the ribosomal RNA gene (rDNA-ITS). Enzymatic modification of PET cloth material properties using crude enzyme from strain PBURU-B5 showed hydrolysis of ester bonds of the PET fiber. The modification of the PET fabric resulted in increase of water and moisture absorption, and general enhancement of hydrophilicity of the fabric, properties that could facilitate processing of fabric ranging from easier dyeing while also yielding a softer feeling fabric for the user.

Exposure to antimony from polyethylene terephthalate (PET) trays used in ready-to-eat meals

Antimony residues, a result of the use of a polycondensation catalyst in the production of polyethylene terephthalate (PET) oven-proof trays, were analysed in ready-to-eat meals. The toxicity of antimony has raised concerns about consumer safety; therefore, the migration of small fractions of these residues into ready meals and foods as a result of cooking directly in the PET trays was studied. A straightforward approach of measuring real samples was selected to obtain accurate exposure data. Background antimony concentration was determined separately from a series of lunch meals, which ranged from not detectable to 3.4 µg kg−1. Microwave and conventional oven-cooking caused a distinct increase in the concentration of antimony in food and ready meals of 0–17 and 8–38 µg kg−1, respectively, depending, to a certain extent, on the industrial preparations. The migrated quantities of antimony corresponded to 3–13 µg. For comparison, PET roasting bags and ready-made dough products in PET baking dishes were also evaluated. About half of the products prepared at a temperature of 180°C exceeded the specific migration limit set for food contact material by the European Commission. However, the migrated amounts of antimony relative to the accepted tolerable daily intake (TDI) show that exposure from this type of food is currently not of toxicological concern.

Textural development and hydrogen adsorption of carbon materials from PET waste

Polyethyleneterephthalate (PET) has become one of the major post-consumer plastic wastes. PET products present a problem of considerable concern due to the huge amount of solid waste produced. The disposal of this waste, together with its low bio- and photo−degradability represents a serious challenge for industrial countries all over the world. Pyrolysis could provide an alternative and economically viable route for processing PET waste due to the potential uses of different by-products: energy from the pyrolysis gases (58% yield in this work), recovery of terephthalic acid and other subproducts (20%), and a solid residue (22%), which has shown a high textural development after activation. The pyrolysis of PET waste was performed in a quartz reactor (i.d. 35mm) under an inert atmosphere. Further activation was carried out at a temperature of 925°C, with a flow rate of 10mlmin−1 of CO2. A series of carbon materials with different burn-off degrees was obtained. Textural characterisation of the samples was carried out by performing N2 adsorption isotherms at −196°C. Changes in the morphological and structural properties of chars were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The carbons obtained were isotropic and highly microporous materials with apparent BET surface areas of up to 2500m2g−1. The suitability of the samples for hydrogen storage was studied by performing H2 adsorption measurements in the 0–1bar pressure range. Adsorption–desorption experiments showed that reversible physisorption takes place in all the samples. The hydrogen adsorption capacities of the activated PET waste compare favourably well with those attained with high-value carbon materials.

ＩＣＰ‐ＭＳを用いたポリエチレンテレフタレート（ＰＥＴ）容器におけるアンチモン，ゲルマニウムの溶出試験法の検討

A simple and rapid test has been developed to quantitatively measure the migration of antimony (Sb) and germanium (Ge) from polyethylene terephthalate (PET) products. The PET product was soaked in 4% acetic acid (2 mL/cm2) for 30 min at 60 degrees C and 95 degrees C. The test solution was analyzed by ICP-MS. Recoveries of spiked Sb (0.025 microg/mL) and Ge (0.05 microg/mL) were 101% and 100%, respectively, with relative standard deviations (RSDs) of 2.3% and 1.7%. In ten successive analyses, Sb and Ge in the 4% acetic acid solution were analyzed with RSDs of 1.7% and 2.2%. Sb and Ge were not subject to interference from other elements simultaneously present in the 4% acetic acid solution. This method is simple, rapid and safe, requiring no pretreatment or use of the hazardous solvent carbon tetrachloride. Therefore, this test is a useful method to analyze Sb and Ge migration from PET products.

Asahi Kasei gets metallocene HDPE marketing rights from Dow

This paper briefly reviews the development history of polyethylene terephthalate (PET) and the recycling of PET. As one of the most promising way to degrade PET into oligomers and monomers that can be used for the production of high-quality PET, catalytic glycolysis is highlighted in this review. The developments on metal salt, metal oxide and ionic solvent catalysts for glycolysis of PET are systematically summarized, besides, the proposed catalytic mechanisms of ionic liquids (ILs) and deep eutectic solvents (DESs) are presented. The metallic catalysts show high catalytic performance but causing serious environmental pollution and high waste treatment costs, thereby it is proposed that metal-free catalysts, especially ILs and DESs can be the “greener” alternatives to address the PET waste problem. Additionally, the studies related to the glycolysis kinetics are discussed in this review, showing the results that PET glycolysis process consists of heterogeneous and homogeneous depolymerization, and different models should be used to investigate different depolymerization stages in order to obtain a more realistic picture.

Analytical Method for Formaldehyde, Acetaldehyde and PET Cyclic Oligomers in Polyethylene Terephthalate Products

Analytical Method for Formaldehyde, Acetaldehyde and PET Cyclic Oligomers in Polyethylene Terephthalate Products

전과정 평가를 이용한 PET 공정의 환경성 분석 및 개선

PET(polyethylene terephthalate) resin is a polyester manufactured by the polycondensation reaction of terephthalic acid(TPA) and ethylene glycol(EG) or dimethyl terephthalate(DMT) and EG. The PET chips are used to produce polyester fiber, polyester films, PET bottle or engineering plastics. Two different PET production systems are compared using life cycle assessment(LCA) and analyzed from the environmental point of view. The unit processes that have to be improved for a better production system have been identified.

The design of polymer filtration systems: A general review

In the production of polyethylene terephthalate (PET) polymer resins and fibers, the use of primary polymer filtration systems has become an industry standard. Over the years, advancements in understanding the process requirements for filtration have resulted in the ability to design more efficient polymer filtration systems. The improvements have been by both the end-user and the filter system vendor. The end-users have developed methods and techniques to improve the performance of the filter and a better understanding of the impact the filter system has on the process. This understanding has been required to meet the everchanging requirements of the polymer customer.

An integrated neural-network and expert-system approach to the supervision of reactor operating states in polyethylene terephthalate production

With the emphasis on quality indices in polyethylene terephthalate (PET) production, it is highly desirable to assess, and subsequently to maintain, individual reactors at satisfactory operating states. To fulfil these aims, it is proposed to use an approach that integrates artificial neural networks (ANNs) with an expert system (ES); the purpose of the former is to estimate the quality indices from reactor process variables, whilst that of the latter is to assess current operation, and thence to advise on, for instance, the application of optimisation procedures to any of the reactor controllers. In addition, an expert system is used to filter plant measurements before they are input to the ANNs; the aim is to suppress gross errors that can cause the ANNs to output incorrect conclusions. The ANN training algorithm is based on a Quasi-Newton method with a self-scaling variable metric (SSVM), because simulation results show that the algorithm has high performance especially in terms of its speed of convergence. The work was implemented on a large-scale PET plant, with the software installed as an Application Module of a Honeywell TDC-3000 distributed control system.

EXAFS Study of a Germanium Catalyst in PET Polymer

Despite of its usefulness in gaining valuable structural information on a variety of catalysts, XAFS has not been previously used to study the catalysts remaining in polymers. In the production of PET (polyethylene terephthalate) bottles, germanium oxide is used as a polymerization catalyst to improve transparency, and the catalyst remains in those products at very low concentration levels of a few tens of ppm. In the present study, the structure of germanium remaining in a PET bottle was determined by use of the EXAFS method. It was found that germanium in the PET, forming a crystalline germanium oxide structure, has a somewhat less ordered structure than germanium oxide.

Condensers for volatile products in the production of polyethyleneterephthalate

Condensers for volatile products in the production of polyethyleneterephthalate

Influence of the additives in polyethylene terephthalate production on the color of the polymer

Influence of the additives in polyethylene terephthalate production on the color of the polymer

Note on the interaction of the catalyst in polyethylene terephthalate production with the ethylene glycol and orthophosphoric acid

Note on the interaction of the catalyst in polyethylene terephthalate production with the ethylene glycol and orthophosphoric acid

Horizontal condensation polymerization reactors for polyethyleneterephthalate production (Survey of foreign patents)

Horizontal condensation polymerization reactors for polyethyleneterephthalate production (Survey of foreign patents)

Accelerated polycondensation in the production of polyethylene terephthalate

Accelerated polycondensation in the production of polyethylene terephthalate

Formation of diethylene glycol as a side reaction during production of polyethylene terephthalate

AbstractPolymers of poly(ethylene terephthalate) (PET) always contain a certain amount of incorporated diethylene glycol (DEG), substituting the incorporated glycol. DEG is formed in a side reaction during the ester interchange of dimethyl terephthalate (DMT) with ethylene glycol or during direct esterification of terephthalic acid with ethylene glycol, and to a smaller extent during the polycondensation of the low‐molecular material. DEG is formed via an unusual type of reaction: ester + alcohol → ether + acid. Some evidence of this type of reaction is given by the formation of dioxane in low molecular PET and of methyl Cellosolve and methyl carbitol during the ester interchange of DMT with ethylene glycol and diethylene glycol, respectively. The strongest support for this type of reaction, however, was obtained from kinetic data. Polyesters of low molecular weight with OH group contents ranging from 3 to 0.5 mole/kg were heated at 270°C in sealed tubes for 1–7 hr. The kinetic equation for the proposed reaction is: d[DEG]/dt = k[OH] [ester]. With the aid of one rate constant the formation of DEG in all esters could be described.