A method to determine volatile contaminants in polyethylene terephthalate (PET) packages by HDC-GC-FID and its application to post-consumer materials

A simple and low cost method to determine volatile contaminants in post-consumer recycled PET flakes was developed and validated by Headspace Dynamic Concentration and Gas Chromatography-Flame Ionization Detection (HDC-GC-FID). The analytical parameters evaluated by using surrogates include: correlation coefficient, detection limit, quantification limit, accuracy, intra-assay precision, and inter-assay precision. In order to compare the efficiency of the proposed method to recognized automated techniques, post-consumer PET packaging samples collected in Brazil were used. GC-MS was used to confirm the identity of the substances identified in the PET packaging. Some of the identified contaminants were estimated in the post-consumer material at concentrations higher than 220 ng.g-1. The findings in this work corroborate data available in the scientific literature pointing out the suitability of the proposed analytical method.

Synthesis and NMR characterization of aliphatic-aromatic copolyesters by reaction of poly(ethylene terephthalate) post-consumer and poly(ethylene adipate)

An aliphatic-aromatic copolyester of poly(ethylene terephthalate), PET, and poly(ethylene adipate), PEA, PET-co-PEA, was synthesized by the high temperature melt reaction of post-consumer PET and PEA. As observed by NMR spectroscopy, the reaction yielded random copolyesters in a few minutes through ester-interchange reactions, even without added catalyst. The copolyesters obtained in the presence of a catalyst presented higher intrinsic viscosity than that obtained without the addition of catalyst, due to simultaneous polycondensation and ester-interchange reactions. The structure of the aliphatic-aromatic copolyesters obtained in different PET/PEA ratio is random as observed by NMR analysis.

A method to determine volatile contaminants in polyethylene terephthalate (PET) packages by HDC-GC-FID and its application to post-consumer materials

A simple and low cost method to determine volatile contaminants in post-consumer recycled PET flakes was developed and validated by Headspace Dynamic Concentration and Gas Chromatography-Flame Ionization Detection (HDC-GC-FID). The analytical parameters evaluated by using surrogates include: correlation coefficient, detection limit, quantification limit, accuracy, intra-assay precision, and inter-assay precision. In order to compare the efficiency of the proposed method to recognized automated techniques, post-consumer PET packaging samples collected in Brazil were used. GC-MS was used to confirm the identity of the substances identified in the PET packaging. Some of the identified contaminants were estimated in the post-consumer material at concentrations higher than 220 ng.g-1. The findings in this work corroborate data available in the scientific literature pointing out the suitability of the proposed analytical method.

Monopolistic product line competition with ex post consumer heterogeneity

We model monopolistic competition in product lines, assuming that consumer heterogeneity is the result rather than the cause of product variety. Our results contradict some well-known policy implications yielded by the standard monopolistic competition framework.

Post consumer pet depolymerization by acid hydrolysis

The reaction of post-consumer poly(ethylene terephthalate) with aqueous solutions of sulfuric acid 7.5M was investigated in terms of temperature, time and particle size. The reaction extent reached 80% in four days at 100 degrees C and 90% in 5 hours at 135 degrees C. TPA obtained was purified and considered in the same level of quality of the commercial one after tests of elemental analysis, particle size and color. It was concluded that the hydrolysis occurred preferentially at the chain ends and superficially, having as controller mechanism the acid diffusion into the polymer structure. The shrinking-core model can explain the reaction kinetics.

Characterization of Post-Consumer PET after Removal of the Original Surface: Influence of Raw Material

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PET containers in Brazil: Opportunities and challenges of a logistics model for post-consumer waste recycling

The use of post-consumer materials is directly related to reducing the cost of production and extraction of natural resources. Non-recyclable materials are randomly disposed in the environment. Brazil is one of the largest consumers of PET (polyethylene terephthalate) bottles. The purpose of this paper is to describe the opportunities and challenges of the logistics model for post-consumer PET bottle recycling in Brazil, while providing knowledge of its practices along the recycling chain. The results describe the need to educate those directly and indirectly involved in the process: to reduce consumption in order to reduce the amount of waste generated: to structure the post-consumer reverse chain and engage industrial sectors and government, through public policies, to support cleaner technologies along the PET bottle production chain. (C) 2010 Elsevier B.V. All rights reserved.

Optimization of neutral hydrolysis reaction of post-consumer PET for chemical recycling

The neutral hydrolysis reaction of post-consumer poly(ethylene terephthalate) in solid state was studied through the reaction of the polymer with water at the molar ratio 1:91 with autogenous pressure. Two sizes of post-consumer PET flakes and temperatures of 135 °C, 170°C and 205°C with pressures of 4.0 atm, 7.5 atm and 13.5 atm, respectively, were considered. With reaction time equal to 6h, the method reached 99% depolymerization at 205°C, 8.2% at 170 °C and 1.7% at 135°C. The reaction extension was measured by separating the terephthalic acid formed in the process and calculating by gravimetry how much material could still be reacted. Through the viscosimetry of diluted, solutions and the counting of carboxylic end groups in the remaining material from the gravimetric assay, it was possible to suggest that the reaction occurs randomly and in the whole volume of the polymeric particle and not solely on the surface. The terephthalic acid obtained and then purified was characterized by elemental analysis, magnetic nuclear resonance, size and panicle size distribution and spectrophotometry in the visible spectrum, and it was similar to the petrochemical equivalent, with purity recorded in carbon base equal to 99.9%.

Plasma Treatment to Improve the Surface Properties of Recycled Post-Consumer PVC

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative estimates of post-consumer solid waste /

Includes bibliographical references (p. 18).

Post consumer pet depolymerization by acid hydrolysis

The reaction of post-consumer poly(ethylene terephthalate) with aqueous solutions of sulfuric acid 7.5M was investigated in terms of temperature, time and particle size. The reaction extent reached 80% in four days at 100 degrees C and 90% in 5 hours at 135 degrees C. TPA obtained was purified and considered in the same level of quality of the commercial one after tests of elemental analysis, particle size and color. It was concluded that the hydrolysis occurred preferentially at the chain ends and superficially, having as controller mechanism the acid diffusion into the polymer structure. The shrinking-core model can explain the reaction kinetics.

Characterization of Post-Consumer PET after Removal of the Original Surface: Influence of Raw Material

Post-consumer cooking oil and soft drink PET bottles (PEToil and PETsoft drink) were ground and washed only with water (conventional washing). The polymer was then chemically washed (10min in an aqueous solution of sodium hydroxide 5mol center dot L-1 at 90 degrees C) and rinsed. The materials before and after chemical washing were characterized by intrinsic viscosity, differential scanning calorimetry, thermogravimetry, elemental analysis, scanning electron microscopy with X-ray spectrum microanalysis, and gas chromatography coupled to mass spectrometry. The results indicated that conventionally washed PEToil is the material that most differs among the four tested ones, and that the other three are more similar to each other and to what is expected for pure PET. For example, the composition of PEToil washed only in water contained 30 volatile organic compounds, 5 nonvolatile compounds, and 7 metals, while PETsoft drink washed conventionally and chemically contained 5 volatile organic compounds and no metal or nonvolatile organic compounds.

Unsaturated Polyester Resins from Recycled Polyethyleneterephthalate

Tämän diplomityön tarkoituksena oli tutkia miten kuluttajien kierrättämästä polyeteenitereftalaatista ( PET ) voi valmistaa tyydyttymättömiä polyesterihartseja. Työssä valmistettiin yleiskäyttöön soveltuva laminointihartsi sekä 'gel coat' -hartsi jota käytetään esim. veneiden pintamaalina. Yleishartsin depolymerointiin käytettiin propyleeniglykolia ja 'gel coat' -hartsin valmistamiseen neopentyyliglykolia. Polykondensaatiovaiheessa reaktioon lisättiin maleiinihappoa ja lopuksi hartsit liuotettiin styreeniin. Kirjallisuusosassa esitetään eri menetelmiä PET:n depolymeroimiseksi. Lisäksi esitetään eri vaihtoehtoja glykolien, happojen, katalyyttien ja vinyylimonomeerien valitsemiseksi tyydyttymättömien polyesterihartsien valmistuksessa. Analyysimenetelmiä nestemäisten ja kovetettujen hartsien tutkimiseen ja vertailuun käydään läpi kuten myös erilaisia sovelluksia polyesterihartsien käyttämiseksi. Kokeellinen osa todisti että PET-pullojäte voidaan prosessoida hartsiksiilman uusia investointeja prosessilaitteistoon. PET:n glykolyysi kesti viidestäseitsemään tuntia ja polykondensaatiovaihe kahdesta ja puolesta viiteen tuntiin. Hartsien molekyylipainot ja mekaanisten testien tulokset olivat vertailukelpoisia kaupallisten hartsien antamien tulosten kanssa. Glykolyysivaiheen momomeeri- ja oligomeeripitoisuudet mitattiin geelipermeaatiokromatografialla, jotta nähtiin miten pitkälle depolymerisaatio oli edennyt. Tätä tietoa voidaan hyödyntää uusien hartsireseptin suunnittelussa. Polymeeriketjussa jäljellä olevien C=C kaksoissidosten määrä ja niiden isomeraatioaste maleaattimuodosta fumaraattimuotoon mitattiin 1H-NMR -menetelmällä. Tislevesien koostumus määritettiin kaasukromatografialla, ja tulokset kertoivat katalyytin sisältämän kloorin reagoineen glykolien kanssa, johtaen suureen glykolikulutukseen ja muihin ei-toivottuihin sivureaktioihin. Hartsien sietokykyä auringon valolle mitattiin niiden UV-absorption avulla. Kummastakin hartsista valmistettiin 'gel coat' -maalit jotkalaitettiin sääkoneeseen, joka simuloi auringonpaistetta ja vesisadetta vuorotellen. Näistä 'gel coateista' mitattiin niiden kellastumista. Kummastakin hartsista tehdyt valut asetettiin myös sääkoneeseen ja IR-spektreistä ennen jajälkeen koetta nähtiin että C=O ja C-O esterisidoksia oli hajonnut.

A tecnologia da reciclagem de polímeros

Solid municipal waste contains a large volume of polymers and its final disposal is a serious environmental problem. Consequently, the recycling of the principal polymers present in the solid waste is an alternative. In this review we describe the mechanical and chemical recycling of polymers and the energy recovery from plastic wastes. Polymer recycling involves not only the development of processing technologies, but also the solution of many chemical and analytical problems. The technological, economical and social aspects of polymer recycling are also considered.

Plan de exportaciones de Colpet ltda.

Este trabajo consta de cinco capítulos acerca de Colpet Ltda trata sobre el problema de contaminación del residuo sólido POLIETILENO TEREFTALATO (PET), material utilizado para la fabricación de envases.