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[pt] A geração e consumo crescente de embalagens PET representa um grande problema ambiental, pois o resíduo destes produtos acaba sendo descartado inadequadamente na natureza ou sendo simplesmente disposto nos aterros. Com o objetivo de atenuar este problema pesquisas foram desenvolvidas nos últimos anos buscando oferecer um destino mais nobre para o resíduo de PET, especialmente para as garrafas PET. Neste contexto, a presente pesquisa propõe o uso do resíduo de garrafas PET, sob a forma de pó, triturado e fibras, como material alternativo para camadas de base em pavimentos. Misturas de Solo-PET, utilizando um solo argiloso com inserção de pó de PET nas porcentagens de 10, 20 e 30 por cento, inserção de PET triturado nas porcentagens de 3, 5 e 7 por cento, e inserção de fibras de PET nas porcentagens de 0,25 e 0,50 por cento, foram avaliadas geotecnicamente por meio de ensaios de caracterização física, ensaios de compactação e ensaios de módulo de resiliência. Os ensaios mecânicos foram realizados nas amostras recém-compactadas e em corpos de prova aquecidos, avaliando ainda a influência do aquecimento no módulo de resiliência. Também foi utilizado o programa computacional SisPav para simular o dimensionamento de um pavimento típico composto pelos materiais estudados. Os resultados obtidos apontam que a inserção de PET nas misturas tem influência sobre o comportamento mecânico do solo, sendo constatado que menores teores possibilitam maiores valores de módulo resiliência. Ainda, a mistura com 10 por cento de pó de PET foi considerada mais eficiente. Conclui-se que a utilização de um solo argiloso adicionado com PET como material alternativo em base de pavimentos é tecnicamente viável e representa uma boa solução para a destinação deste resíduo bem como para a mitigação de seu potencial agressivo ao meio ambiente. / [en] The growing production and consumption of PET packaging represents a major environmental problem because they end up being improperly discarded in nature or simply disposed in landfills. With the aim to attenuate the environmental problem researchers were developed in the last years, in order to offer a nobler destination for this waste, especially for PET bottles. In this context, this research proposes the use of PET bottles waste, in form of powder, crushed and fibers as an alternative material for pavements base. Soil-PET mixtures, using a clayey soil with the addition of PET powder in percentages of 10, 20 and 30 percent, addition of crushed PET in percentages of 3, 5 and 7 percent and addition of PET fiber in percentages of 0,25 and 0,5 percent, were geotechnically evaluated by physical characterization tests, compaction tests and Resilient Modulus tests. The mechanical tests were performed on freshly compacted samples and also on heated specimens, evaluating the influence of heating in the resilient modulus. The computer program SisPav was also used to simulate the mechanistic empirical design for a typical pavement structure composed of the researched material. The results indicate that the insertion of PET influences the mechanical behavior of the soil, and it was verified that lower contents of PET allows higher values of resilient modulus. It can be concluded that the use of a clayey soil added with PET, as an alternative material in pavements base, is technically feasible and represents a good solution for the destination of this waste as well as for the mitigation of its aggressive potential to the environment.

På grund av den rådande klimatförändringen och de globala problem som plast orsakar i miljön blir det allt viktigare att dagens linjära materialanvändning ändras till en cirkulär användning. Inom fordonsindustrin har kravet på ökad tillgänglighet och kvalitet på återvunna material identifierats. Som följd startades forskningsprojektet Sustainable Vehicle Interior Solutions (SVIS) samordnat av RISE IVF där behovet av en mer hållbar produktion av fordonsinteriörer tas upp. Ett mål är att minska och återvinna produktionsavfall. Den här studien undersöker möjligheten att återvinna textil och plast från en interiör komponent av multimaterial, som i detta fall är en textilklädd plaststolpe. Stolpen är gjord av polykarbonat (PC)/poly(akrylnitril-butadien-styren) (ABS) plast och polyestertextil (PET). Mekanisk återvinning utfördes på den textilklädda stolpen. Möjligheten att separera textil från plast undersöktes och testades i en kvarn med en dammavskiljare. Prover innehållande olika mängder PET förberedes och återvanns för att studera påverkan av PET på materialegenskaperna. Två olika kompatibiliseringsmedel användes för att undersöka om blandningarnas kompatibilitet ökade. Hur väl textil separerats från plast analyserades genom jämförelse av bulkdensitet mellan proverna. För att undersöka effekten av kompatibiliseringsmedel och hur förekomsten av PET påverkar PC/ABS utfördes mekanisk testning, DSC och SEM. Resultaten visade att separationen av textil från plast inte var fullständig på grund av mycket hög vidhäftning mellan textilen och plasten. Bibehållna mekaniska egenskaper, förutom brottförlängning, erhölls för alla återvunna prover oavsett PET-mängd. Därför var det möjligt att dra slutsatsen om att förekomsten av PET inte påverkar materialets egenskaper negativt och att separation eller tillsats av kompatibiliseringsmedel inte är nödvändigt. Vidare visar resultaten att PET blir blandbar med PC men inte påverkar ABS-fasen. Kemisk återvinning genom glykolys utfördes på svart och beige polyestertextil av PET erhållet som avklipp från produktionen av stolparna. Glykolysen utfördes i laboratorieskala med etylenglykol (EG) som lösningsmedel. Reaktionen ägde rum vid 230℃ under 1 timme med överskott av lösningsmedel och en Mg-Al blandad oxidkatalysator. Slutprodukten separerades från rester genom flera filtreringssteg och analyserades med DSC. Från resultatet observerades det att den erhållna slutprodukten var den önskade bis(2-hydroxyetyl) tereftalat (BHET) monomeren. Färgämnen från textilen fanns fortfarande kvar i monomeren efter depolymerisation. Därför utfördes avfärgning. För den svarta textilen testades adsorption med aktivt kol och extraktion med etylenglykol som avfärgningsmetoder. För den beige textilen utfördes enbart adsorption med aktivt kol. De avfärgade produkterna analyserades genom färgmätning och/eller genom jämförelse med varandra. Resultatet visade att adsorption med aktivt kol är en effektiv avfärgningsmetod för den beige textilen, men inte för den svarta textilen. Framgångsrik avfärgning av den svarta textilen erhölls istället genom extraktion med etylenglykol. Sammanfattningsvis, mekanisk återvinning av den textilklädda stolpen resulterar i bibehållna värden för de mekaniska egenskaperna hos det återvunna materialet, förutom för brottförlängnigen. Detta bör göra det återvunna materialet lämpligt för användning i fordonsapplikationer, men inte för återvinning i ett slutet kretslopp (closed loop recycling) på grund av säkerhetsaspekter hos stolpen. Om hög kraft appliceras måste materialet kunna ändra form utan att gå sönder. Återvinning genom glykolys visar potential för att den avklippta polyestertextilen kan återvinnas i ett slutet kretslopp eftersom den avfärgade monomeren skulle kunna ompolymeriseras till ny PET. Det kan undersökas i framtida studier. / Due to the current climate change and the global problems plastics cause in the environment, it becomes increasingly important that today’s linear use of materials is changed to a circular use. In the automotive industry, the demand for increased availability and quality of recycled materials has been recognized. Following this, the research project Sustainable Vehicle Interior Solutions (SVIS) coordinated by RISE IVF was started in which the need for a more sustainable production of vehicle interiors is addressed. An objective is to reduce and recycle production waste. This study investigates the possibility to recycle textile and plastic from an interior multi-material component which in this case is a textile dressed plastic pillar. The pillar is made of polycarbonate (PC)/poly(acrylonitrile butadiene styrene) (ABS) plastic and polyester (PET) textile.  Mechanical recycling was performed on the textile dressed pillar. The possibility to separate textile from plastic was investigated and tested in a mill with a dust separator. Samples containing different amounts of PET were prepared and recycled to study the influence of PET. Two different compatibilizers were used to investigate potential improvement in compatibility of the blends. The level of separation of textile from plastic was analyzed by comparison of bulk density between the samples. To investigate the effect of compatibilizers and how the presence of PET influences the PC/ABS, mechanical testing, DSC and SEM were performed. The results showed that the separation of textile from plastic was not complete due to very high adhesion between the textile and plastic. Retained mechanical properties, except for the strain at break, were obtained for all recycled samples. Therefore, it could be concluded that the presence of PET does not affect the properties of the material negatively and separation or addition of compatibilizer is unnecessary. The results further show that PET becomes miscible with PC but does not affect the ABS phase. Chemical recycling through depolymerization with glycolysis was performed on black and beige polyester (PET) textile waste obtained as cut-off from the production of the pillars. The glycolysis was performed in lab-scale with ethylene glycol (EG) as solvent. The reaction took place at 230℃ for 1h with excess of solvent and a Mg-Al mixed oxide catalyst. The final product was separated from residues through several filtration steps and analyzed with DSC. From the result it could be observed that the obtained final product was the desired bis(2-hydroxyethyl) terephthalate (BHET) monomer. Dyes from the textile were still present in the monomer after depolymerization. Therefore, decolorization was performed. For the black textile, adsorption with active carbon and extraction with ethylene glycol were tested as decolorization methods. For the beige textile, solely adsorption with active carbon was performed. The decolorized products were analyzed by color measurement and/or through comparison to each other. The result showed that adsorption with active carbon is an effective decolorization method for the beige textile, but not for the black textile. Successful decolorization of the black textile was instead obtained by extraction with ethylene glycol.  To conclude, mechanical recycling of the textile dressed pillar results in retained values of the mechanical properties of the recycled material, except for the strain at break. This should make the recycled material suitable for use in automotive application, though not closed loop recycling because of safety aspects of the pillar. If high force is applied, the material needs to be able to change shape without breaking. Recycling through depolymerization shows potential for closed loop recycling of the polyester textile cut-off since the decolorized monomer could be repolymerized into new PET. This could be investigated in future studies.

In recent decades the quality and safety of bottled water has come into question, while bottled water sales and demand have steadily grown. It is important that consumers as well as manufacturers are made aware of the microbial environment of bottled water. Many studies have been implemented to evaluate the microbiological content of bottled water. Although some laboratory studies have shown that microbial counts of bottled water can reach as high as 16^3 CFU/mL, few studies, if any, have studied the impact of storage location on bottled water microbial activity. This document reports on an investigation that evaluated the microbiological quality of bottled water relative to storage conditions and storage duration. Unlike previous studies that evaluated bottled water having been stored under the laboratory conditions, the work conducted in this study evaluated storage scenarios that included a car trunk, covered porch, indoor cabinet and refrigerator. These storage conditions allow for comparison of prior studies conducted in the laboratory to more realistic storage coniditions used by consumers. Analyses of bottled water under these alternative storage conditions indicated that microbial growth did occur in stored water and varied between lcoation and holding time. It was determined that heterotrophic plate counts (HPCs) were greater in warmer storage environments as was exhibited by the refrigerated and indoor locations. Additionally, mathematical models were developed in this work that predicted the microbial growth rate in bottled water as a function of holding time, using commonly available statistical software that evaluated data predicted using an exponential model (R2 correlation of up to 0.84) for two different storage conditions. Although increased levels of HPC bacteria are generally safe for those in good health, they are used as an indicator test for microbial quality. Furthermore, higher levels of HPC have also been shown to pose some additional health risks to immunocomprimised individuals. Therefore, results from the study would indicate that it may be beneficial for consumers to store their bottled water indoors or in a refrigerator.

Yes / Antioxidant active packaging was prepared by coating a citrus extract on the surface of polyethylene terephthalate (PET) trays which had been either treated with an atmospheric pressure plasma jet or left untreated. The surface characteristics of the packaging were examined, as were its stability and antioxidant efficacy following storage for up to 24 weeks under the following three storage conditions: room temperature, 0 % relative humidity (RH) or 50 °C. Plasma pretreatment increased coating density, thickness and roughness, and oxygenated functional groups at the polymer surface, whereas water contact angle decreased. Trays stored at room temperature did not lose their antioxidant efficacy over 24 weeks and plasma pretreatment enhanced the efficacy from week 8 onwards. Gravimetric analysis of the coating revealed a loss of antioxidant compounds only after 16 weeks. Trays stored at 0 % RH lost coating from week 1 onwards, with lower loss in plasma pretreated trays, while loss of coating was highest at 50 °C, with lower loss in plasma pretreated trays only after 24 weeks. Overall, the surface characteristics of the antioxidant active packaging were modified by plasma pretreatment of the PET surface, with some improvement in antioxidant efficacy, and the efficacy of the packaging in delaying oxidative deterioration in cooked meats was retained during storage at ambient temperature.

Elevated reaction temperatures are crucial for the efficient enzymatic degradation of polyethylene terephthalate (PET). A disulfide bridge was introduced to the polyester hydrolase TfCut2 to substitute its calcium binding site. The melting point of the resulting variant increased to 94.7°C (wild-type TfCut2: 69.8 °C) and its half-inactivation temperature to 84.6 °C (TfCut2: 67.3 °C). The variant D204C-E253C-D174R obtained by introducing further mutations at vicinal residues showed a temperature optimum between 75 and 80 °C compared to 65 and 70 °C of the wild-type enzyme. The variant caused a weight loss of PET films of 25.0 +/- 0.8% (TfCut2: 0.3 +/-0.1%) at 70 °C after a reaction time of 48 h. The results demonstrate that a highly efficient and calcium-independent thermostable polyester hydrolase can be obtained by replacing its calcium binding site with a disulfide bridge.

Also aged bottles are safer to use than new bottles because their chemical leaching was found to be lower than that of new bottles. This study recommends the reassessment of the absence of international guidelines for acetaldehyde in water and foods. The study also recommends that the amount of acetaldehyde that can be added to soft drinks as flavouring agent should be below the specific migration limit (SML) for migration of acetaldehyde from PET bottle into bottle contents. This is essential since the SML was designed to ensure that exposure to acetaldehyde, as a result of intake of bottled water and soft drinks in PET bottles, is below the tolerable daily intake (TDI) for acetaldehyde. As antimony was reported to go beyond the safe limits in some Nigerian bottled water and soft drinks after 11 months of storage this study discourages the use of bottle contents stored for a very long time.

The enzymatic degradation of polyethylene terephthalate (PET) occurs at mild reaction conditions and may find applications in environmentally friendly plastic waste recycling processes. The hydrolytic activity of the homologous polyester hydrolases LC cutinase (LCC) from a compost metagenome and TfCut2 from Thermobifida fusca KW3 against PET films was strongly influenced by the reaction medium buffers tris(hydroxymethyl)aminomethane (Tris), 3-(N-morpholino)propanesulfonic acid (MOPS), and sodium phosphate. LCC showed the highest initial hydrolysis rate of PET films in 0.2 M Tris, while the rate of TfCut2 was 2.1-fold lower at this buffer concentration. At a Tris concentration of 1 M, the hydrolysis rate of LCC decreased by more than 90% and of TfCut2 by about 80%. In 0.2 M MOPS or sodium phosphate buffer, no significant differences in the maximum initial hydrolysis rates of PET films by both enzymes were detected. When the concentration of MOPS was increased to 1 M, the hydrolysis rate of LCC decreased by about 90%. The activity of TfCut2 remained low compared to the increasing hydrolysis rates observed at higher concentrations of sodium phosphate buffer. In contrast, the activity of LCC did not change at different concentrations of this buffer. An inhibition study suggested a competitive inhibition of TfCut2 and LCC by Tris and MOPS. Molecular docking showed that Tris and MOPS interfered with the binding of the polymeric substrate in a groove located at the protein surface. A comparison of the Ki values and the average binding energies indicated MOPS as the stronger inhibitor of the both enzymes.

A qualidade dos procedimentos clínicos realizados na prática odontológica está intimamente ligada às propriedades dos materiais e tecnologias aplicadas à reabilitação oral. No caso das overdentures, uma falta de retenção entre a prótese e o implante pode ocorrer pelo excesso de fadiga das cápsulas que os conectam. Isso leva a um insucesso no tratamento e perda de função, reduzindo a durabilidade e qualidade de vida dos pacientes. Diante dessa problemática o presente estudo propôs um novo material que seja capaz de solucionar ou minimizar este problema, visando uma longevidade do tratamento reabilitador. O objetivo desse trabalho foi comparar um material inédito na odontologia com os já existentes, na confecção de cápsulas para retenção de overdenture, antes e após o envelhecimento artificial por termociclagem (10.000 ciclos = 1 ano clínico). O material estudado foi o Politereftalato de Etileno (PET) que vem se demonstrando um material promissor para tal função devido a sua biocompatibilidade e suas características físicas e mecânicas. O PET foi comparado com poliacetal, polietileno e teflon já utilizados para esta função (n=20). Os materiais foram submetidos aos ensaios resistência à compressão, rugosidade e dureza superficial, resistência à fadiga, arrancamento, resistência de união e análise em estereomicroscópio e microscopia eletrônica de varredura. Para responder aos objetivos do estudo foram utilizadas, além de técnicas básicas de análise exploratória como média, mediana, desvio padrão e intervalo de confiança para média (IC 95%), a análise inferencial de comparação de média de ANOVA Two-Way com Medidas Repetidas. Houve influência do envelhecimento artificial apenas na variável fadiga, em todos os tempos analisados. Em relação a rugosidade o PET (0,9168) apresentou as menores médias, juntamente com o Poliacetal (0,5160) (p=0,001). Para Dureza superficial não houve diferença entre os grupos. Na Resistência à Compressão o Poliacetal (109,88) apresentou os maiores valores de tensão, não havendo diferença estatisticamente significante do PET(101,02)(p=0,003). No ensaio de arrancamento PET (484,4) e Poliacetal (443,7) apresentaram os maiores valores de força máxima (p=0,033). Em relação a Fadiga PET e Poliacetal apresentaram os maiores valores em todos os tempos analisados (p<0,001). Através da análise por estereomicroscopia, o padrão de fratura do Poliacetal e PET foi coesiva, os demais foram adesiva. Pela microscopia eletrônica de varredura, não foi observado alteração de superfície apenas pelo Polietileno. Conclui-se que o PET apresentou ótimos resultados para as variáveis propostas, sugerindo seu uso para confecção de componentes protéticos / The quality of clinical procedures performed in dental practice is closely linked to the properties of materials and technologies applied to oral rehabilitation. In the case of overdentures, a lack of retention between the prosthesis and the implant can occur due to the excess fatigue of the capsules that connect them. This leads to unsuccessful treatment and loss of function, reducing the durability and quality of life of patients. Faced with this problem, the present study proposed a new material that is capable of solving or minimizing this problem, aiming at a longevity of the rehabilitation treatment. The objective of this study was to compare a new material in dentistry with existing ones, in the manufacture of capsules for retention of overdenture, before and after artificial aging by thermocycling (10,000 cycles = 1 year clinical).The material studied was polyethylene terephthalate (PET), which has been shown to be a promising material for this function due to its biocompatibility and its physical and mechanical characteristics. PET was compared with polyacetal, polyethylene and teflon already used for this function (n=20). The materials were submitted to the tests of compressive strength, roughness and surface hardness, fatigue strength, pullout, bond strength and stereomicroscopic analysis and scanning electron microscopy. In order to respond to the objectives of the study, we used, besides basic exploratory analysis techniques such as mean, median, standard deviation and confidence interval for mean (95% CI), the inferential analysis of the comparison of mean two-way ANOVA with Repeated Measurements . There was influence of artificial aging only on the variable fatigue, at all times analyzed. In relation to the roughness, the PET (0,9168) presented the lowest averages, together with the Polyacetal (0,5160) (p = 0.001). For superficial hardness there was no difference between the groups. In the Compression Resistance the polyacetal (109,88) had the highest values of tension, and there was no statistically significant difference of PET (101,02) (p= 0.003). The PET (484,4) and polyacetal (443,7) tear test the highest values of maximum strength were found (p = 0.033). In relation to PET Fatigue and Polyacetal presented the highest values in all times analyzed (p <0.001). Through stereomicroscopy analysis, the fracture pattern of Polyacetal and PET was cohesive, the others were adhesive. By scanning electron microscopy, no surface change was observed only by Polyethylene. It is concluded that PET presented excellent results for the proposed variables, suggesting its use for the preparation of prosthetic components