Study of parcial replacement of poly(butylene-adipate-co-terephthalate) by whey protein isolate : incorporation of bio-based materials in polymer blends

Orientadores: Ana Rita Morales, Mathias StraussTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuímicaResumo: Estudos sobre a utilização de proteínas como materiais para embalagens são recentes e promissores. As proteínas possuem boas propriedades de barreira ao oxigênio e podem ser adicionadas à matriz de polímeros comerciais para melhorar suas propriedades. Este trabalho teve como objetivo estudar o efeito da substituição parcial de um polímero proveniente do petróleo, o poli(adipato-co-tereftalato de butileno) (PBAT), pelo isolado proteico do soro de leite termoplástico (IPST). A proteína, em sua forma natural, não é processável e sua desnaturação e plastificação são necessárias para transformá-la em um material termoplástico. Para a obtenção do IPST, as condições de processamento e os plastificantes glicerol e polietilenoglicol (PEG) foram estudados. Blendas de PBAT/IPST foram preparadas em um reômetro de torque, e caracterizadas quanto às propriedades reológicas por reometria de placas paralelas e morfológicas por microscopia eletrônica de varredura. Nas blendas com glicerol como plastificante, a cera de abelha foi adicionada com intuito de melhorar sua barreira ao vapor da água. As propriedades estruturais das blendas com glicerol foram estudadas por espectroscopia Raman. As blendas PBAT/IPST com glicerol mostraram a presença de domínios de IPST com interface bem definida e sem adesão com a matriz de PBAT. Isso foi associado à predominância da componente elástica do IPST e do PBAT nas condições de processo e à razão de viscosidade entre os componentes em não favorecer um alto nível de dispersão e mistura. Estas blendas foram consideradas incompatíveis e por este motivo as propriedades de barreira ao oxigênio e ao vapor da água não foram estudadas nesta etapa. A cera de abelha não influenciou nenhuma propriedade estudada. O PEG, como plastificante, e a adequação das condições de preparação do IPST e de processamento reduziram a razão de viscosidade entre os polímeros e a componente elástica do IPST e do PBAT. As blendas com PEG apresentaram morfologia homogênea, tamanho de domínios reduzido e não houve presença de interfaces bem definidas e visíveis entre a fase dispersa e a matriz. Além disso, as blendas com PEG foram estudadas por microscopia de força atômica com espectroscopia de infravermelho integrada, em que se observou a presença de ambos os polímeros em cada fase, o que é um indício de miscibilidade parcial. As propriedades de desempenho avaliadas foram as mecânicas por ensaios de tração e de permeabilidade ao oxigênio e ao vapor da água. A adição de 30% de IPST nas blendas com PEG mostrou redução de 20% no coeficiente de permeabilidade ao oxigênio. A presença do IPST causou aumento no módulo de Young e no coeficiente de permeabilidade ao vapor da água da blenda. O comportamento dos sistemas foi discutido em termos das interações entre os componentesAbstract: The study of proteins as packaging materials is recent and promising. Proteins have good oxygen barrier properties and it could be added to commercial polymer matrix to improve its properties. The objective of this work was to study the effect of partial substitution of a commercial petroleum polymer, poly(butylene adipate-co-terephthalate) (PBAT), by the thermoplastic whey protein isolate (WPIT). Protein, in its natural form, is not processable and its denaturation and plasticization are necessary to transform it into a thermoplastic material. To obtain WPIT, processing conditions and plasticizers as glycerol and polyethylene glycol (PEG) were studied. PBAT/WPIT blends were prepared using a torque rheometer and characterized for rheological properties by parallel plate and morphological properties by scanning electron microscopy. Blends with glycerol as plasticizer received an addition of beeswax in order to improve its water vapor barrier. The structural properties of glycerol blends were studied by Raman spectroscopy. Glycerol blends showed the presence of well-defined WPIT domains with no adhesion to PBAT matrix. This behavior was associated with the predominance of elastic component of WPIT and PBAT in process conditions as well as the viscosity ratio between components in not favoring a high level of dispersion and mixing. As these blends were considered incompatible, oxygen and water vapor barrier properties were not studied. Beeswax did not influence any property studied. PEG, used as plasticizer, improved WPIT preparation as well as blends processing conditions, which reduced the viscosity ratio between polymers and the elastic component of WPIT and PBAT. PEG blends presented homogeneous morphology, reduced domain size and there were no well-defined and visible interfaces between the dispersed phase and the matrix. Moreover, PEG blends were studied by atomic force microscopy-based infrared spectroscopy, which showed the presence of both WPIT and PBAT in each phase, which is an evidence of partial miscibility. The performance properties evaluated were mechanical properties by tensile test and tests of oxygen and water vapor permeability. With the addition of 30% of WPIT, PEG blends showed a reduction of 20% in the oxygen permeability coefficient. The presence of WPIT in blend caused an increase in Young's modulus as well as in water vapor permeability coefficient. The behavior of the systems was discussed in terms of the interactions between the componentsDoutoradoEngenharia QuímicaDoutora em Engenharia Quimica163257/2015-9CNPQCAPE

Mechanical recycling simulation of polylactide using a chain extender

This work studied the commercial chain extender effectiveness on the mechanical recycling simulation of a pristine PLA using a single‐screw extruder. We processed the material by two extrusion cycles to simulate a recycling process. In the second extrusion, part of the material was processed with chain extender and we evaluated its molecular weight, thermal degradation, melt flow index (MFI), thermal transitions, and mechanical properties. The molecular weight for the extruded neat PLA decreased and the MFI and crystallinity degree increased while the mechanical properties worsened. The onset thermal degradation occurred at lower temperature for the processed material. With the introduction of the chain extender, there was a recovery of properties with the increase in the polymer molecular weight, decrease in the MFI and crystallinity degree, and an improvement in both thermal stability and mechanical properties in relation to recycled PLA without this component37620532060COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2014/09883‐

Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options

[EN] Poly(hydroxy acids) have been gaining increasing attention in the search for novel sustainable materials to replace petrochemical polymers in packaging applications. Poly(hydroxy acids) are polyesters that are obtained using hydroxy acids as the starting materials, which are derived from renewable resources and biowaste. These biopolymers have attracted a lot of attention since some of them will be in the near future competitive in price to polyolefins, show excellent mechanical and barrier properties, and can be potentially recycled by physical and chemical routes. Most of the current poly(hydroxy acids) are mainly prepared by ring-opening polymerization (ROP) of cyclic monomers derived from hydroxy acids. However, their direct polymerization has received much less attention, while one of the advantages of hydroxy acids resides in the presence of an electrophile and a nucleophile in a single molecule that makes them ideal A-B type monomers for self-condensation. This review focuses on the preparation of poly(hydroxy acids) by the self-condensation polymerization of hydroxy acids. Moreover, their end-of-life options are also evaluated considering not only their biodegradability but also their potential to be chemically recycledThe authors thank the European Commission (EC) for financial support through the project SUSPOL-EJDH2020-ITN-2014-642671 and the Spanish Ministry of Science and Innovation (MICI) through the projects RTI2018-097249-B-C21, MAT2017-83373-R, and MAT-2016-78527-P. S. Torres-Giner also acknowledges MICI for his Juan de la Cierva-Incorporacion contract (IJCI-2016-29675) and the financial support received during his stay at the Institute for Polymer Materials (POLYMAT)Gabirondo, E.; Sangroniz, A.; Etxeberria, A.; Torres-Giner, S.; Sardon, H. (2020). Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options. Polymer Chemistry. 11(30):4861-4874. https://doi.org/10.1039/D0PY00088DS48614874113

Toward greener polymeric blends: study of PBAT/Thermoplastic whey protein isolate/Beeswax blends

This work evaluated the effects of partial substitution of PBAT by thermoplastic whey protein isolate (WPIT) with addition of beeswax through blends processing and their morphological, mechanical, structural, thermal and rheological properties. Whey protein isolate (WPI) was denatured at 90 degrees C, using glycerol as plasticizer, to be transformed in a thermoplastic material and subsequently blended with PBAT using a torque rheometer at 130 degrees C. Addition of 10 and 30% of WPIT in the PBAT matrix was investigated with and without beeswax. Blends were pressed as films with similar to 320 mu m of thickness. Scanning electron microscopy (SEM) analysis of PBAT/WPIT blends films revealed the presence of domains. These domains are compounded of whey protein, while at the continuous phase a moderate degree of mixture between PBAT and WPIT was observed by Raman analyses. WPIT did not alter the degree of crystallinity and the glass-transition temperature (T-g) of the PBAT in the blends. Thermogravimetric curves of the blends showed decomposition stages related to WPIT and PBAT phases. Thermal stability of blends decreased in comparison to WPIT, which was associated to the cleavage of disulfide bonds of WPIT during processing and causes other kind of interaction between components. Besides, blends containing WPIT remained non-rigid polymers with Young's modulus below 70MPa. The tensile strength and elongation at break decreased due the presence of WPIT. Beeswax did not influence the thermal and mechanical properties explored in this study271021312143CNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico163257/2015-9The authors acknowledge the Brazilian Nanotechnology National Laboratory (LNNano/CNPEM) for the use of materials characterization (SEM, TG and DSC) and polymers processing facilities. National System of Laboratories for Nanotechnology (SisNANO/MCTI) is also acknowledged for its financial support in infrastructure and equipment at the LNNano. MFCA thanks CNPq (process number 163257/2015-9) for the fellowship. Ivanei Pinheiro, Mariane Pereira, Elizabeth Sanches, Renata Brandão, Mayara Calderaro, and Patrícia Souza are thanked for they support on materials analyses and valuable discussion

Life Cycle Assessment Of Poly(lactic Acid) (pla): Comparison Between Chemical Recycling, Mechanical Recycling And Composting

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)This paper presents a life cycle assessment (LCA) comparing three forms of poly(lactic acid) (PLA) disposal: mechanical recycling, chemical recycling and composting. The LCA data was taken from lab scale experiments for composting and hydrolysis steps. Polymerization data in chemical recycling was obtained from computer simulation. Mechanical recycling data from lab scale were combined with the data from a plastics commercial mechanical recycling plant. The analysis considered two different product systems based on the input of the recycled PLA in the product system. Considering the categories: climate change, human toxicity and fossil depletion, the LCA showed that mechanical recycling presented the lowest environmental impact, followed by chemical recycling and composting. Among the forms of recycling, the most important input was the electricity consumption.244372384FAPESP [2014/09883-5]CAPESFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Quality evaluation of solvent-cast 3D printing of poly(lactic acid) films

This study aims to analyse the process conditions in the production of poly(lactic acid) (PLA) films by solvent-cast 3D printing. The films were evaluated according to thickness, roughness and visual aspect. An experimental design 22 was performed with centre point in triplicate to study solvent/PLA ratio and printing speed. The solvent/PLA ratio and printing speed had a significant negative effect on film thickness and positive effect on film roughness. The film that presented the best classification in the visual aspect was the one moulded with the highest printing speed and solvent/PLA ratio43CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESsem informaçã

Life cycle assessment of Poly(Lactic Acid) (PLA): comparison between chemical recycling, mechanical recycling and composting

This paper presents a life cycle assessment (LCA) comparing three forms of poly(lactic acid) (PLA) disposal: mechanical recycling, chemical recycling and composting. The LCA data was taken from lab scale experiments for composting and hydrolysis steps. Polymerization data in chemical recycling was obtained from computer simulation. Mechanical recycling data from lab scale were combined with the data from a plastics commercial mechanical recycling plant. The analysis considered two different product systems based on the input of the recycled PLA in the product system. Considering the categories: climate change, human toxicity and fossil depletion, the LCA showed that mechanical recycling presented the lowest environmental impact, followed by chemical recycling and composting. Among the forms of recycling, the most important input was the electricity consumption24372384COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2014/09883-