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Abstract(s)
Atualmente, o policloreto de vinilo (PVC) é um dos plásticos mais utilizados pelo Homem devido à sua versatilidade, permitindo o seu uso nas mais diversas aplicações. Contudo, a sua degradação lenta acaba por gerar um grande impacto ambiental. Assim, tornou-se necessário encontrar uma alternativa surgindo os plásticos biodegradáveis.
Neste sentido, surgiu este projeto que consistiu no desenvolvimento de um revestimento de estofos contract com carácter mais biodegradável. Este trabalho foi dividido em duas fases. A primeira fase compreendeu o desenvolvimento do produto e respetiva caracterização física e a segunda fase compreendeu o estudo da biodegradação do mesmo.
Na primeira fase, foi realizada a substituição do plastificante utilizado por um com carácter mais biológico e a substituição da azodicarbonamida, agente expansor, por amido. Após as substituições foram realizados três estudos à escala laboratorial: estudo da substituição da carga por amido, estudo do masterbatch de amido e estudo da quantidade de masterbatch na formulação em diferentes percentagens em peso.
Os estudos realizados permitiram concluir que o uso de um masterbatch contendo uma proporção, em peso, de 70:55:25 de amido/plastificante biológico/água, conduz à formação de uma película sem defeitos e há uma boa adesão ao revestimento. Concluiu-se também que o grau de expansão obtido com as substituições efetuadas é inferior ao do produto convencional.
Com este resultado, produziu-se à escala piloto o produto bio versão 16.1., e o produto convencional e fez-se a sua caracterização física.
Quanto à caracterização física, concluiu-se que as modificações efetuadas originaram um produto com características mecânicas idênticas às do produto convencional, cumprindo as especificações impostas para estofos contract. Apenas se verificou uma exceção no ensaio de resistência ao rasgamento em que o valor obtido foi inferior em 22,0 % ao valor especificado.
A segunda fase deste trabalho consistiu no estudo da biodegradabilidade dos produtos convencional e bio versão 16.1., através da realização do teste de Sturm. Nestes produtos foram ainda realizadas análises de perda de massa e análises por termogravimetria (TG) e calorimetria diferencial de varrimento (DSC) antes e depois do ensaio de biodegradação. Nesta fase foi ainda realizada a caracterização do solo utilizado no teste de Sturm.
Relativamente à caracterização do solo, esta avaliou quatro parâmetros: razão carbono/azoto, matéria orgânica, pH e humidade. Quanto à razão C:N obteve-se uma razão igual a 41:1, sendo esta razão considerada elevada, logo os microrganismos tenderão a ter um crescimento mais lento, conduzindo a uma degradação mais demorada. Para o teor de matéria orgânica obteve-se 38,82 %, o que é considerado benéfico para este estudo. Quanto ao pH obteve-se um valor de 6,07 unidades de Sorensen e uma percentagem de humidade de 53,2 % que, de acordo com a literatura corresponde aos valores ótimos para este estudo.
No teste de Sturm, da análise do comportamento relativo à libertação de dióxido de carbono (CO2) em função do tempo verificou-se que ambos produtos e o branco apresentavam a mesma tendência, isto é, ocorreu um crescimento da produção de dióxido de carbono nos primeiros dias para um valor de 1,20 gramas, mas na etapa seguinte há uma diminuição desse valor para 0,20 gramas. Deste modo, concluiu-se que os microrganismos, possivelmente, se encontram num período de adaptação ao meio, daí a produção de dióxido de carbono se manter constante sem nunca atingir valores nulos. Esta adaptação pode ser justificada através dos valores obtidos para a caracterização do solo.
Através do ensaio de perda de massa, verificou-se que o produto convencional apresentou a menor perda de massa, correspondente a 1,93 % e o produto bio versão 16.1. apresentou uma perda de massa mais elevada correspondente a 6,50 %.
Nos resultados obtidos nas análises termogravimétricas realizadas ao produto convencional e ao produto bio versão 16.1. antes e depois do teste de Sturm verificou-se que, a temperatura de início de perda de massa (Tonset), para o produto convencional sofreu um aumento pouco significativo comparativamente ao valor obtido antes do ensaio. Pelo contrário, no produto bio versão 16.1., esta diferença já é mais significativa, tendo-se verificado que a (Tonset), diminuiu aproximadamente 5°C após o ensaio de biodegradação. Estes resultados foram também confirmados com as análises de calorimetria diferencial de varrimento (DSC), em que se verificam diferenças nas Tonset e Toffset.
Em síntese, os resultados obtidos ao longo deste trabalho permitem concluir que a substituição do plastificante utilizado por um plastificante mais biológico e que a substituição do masterbatch de azodicarbonamida por um masterbatch de amido/plastificante/água origina um produto com indícios de biodegradabilidade e que cumpre especificações exigidas para revestimentos de estofos contract, embora não apresente o mesmo grau de expansão que o produto convencional.
Currently, polyvinyl chloride (PVC) is one of the most used plastics by the human being mainly because of its versatility, allowing its use in the most diverse applications. However, their slow degradation generates a great environmental impact. Therefore, it became necessary to find an alternative occurring this way the biodegradable plastics. In this way, has emerged this project, which consisted in the development of a contract mat coating with a more biodegradable character. This work was divided into two phases. The first phase consisted in the development of the product and its physical characterization and the second phase consisted in the study of the biodegradation of the same. In the first phase, was made the substitution of the plasticizer used by one with a more iological character and the substitution of the azodicarbonamide, the blowing agent, by starch. After the substitutions, three laboratory-scale studies were carried out: the substitution of the filler to starch, the study of the starch masterbatch and the study of the amount of masterbatch in the formulation in different weight percentages. The results showed that the use of a masterbatch containing a weight ratio of 70:55:25 of starch / biological plasticizer / water leads to good results in terms of aesthetic appearance, that is, there are no defects in the film and also good adhesion to the coating. It was also concluded that the degree of expansion obtained with the substitutions made is lower than the conventional product. With this result, the bio product version 16.1., and the conventional product were produced at pilot scale and it was made their physical characterization. As for the physical characterization, it was concluded that the modifications made originated a product with mechanical characteristics identical to those of the conventional product, fulfilling the specifications imposed for contract upholstery. Only one exception was found in the tear strength test where the value obtained was lower in about 22,0 % than the value specified. The second phase of this work consisted in the study of the biodegradability of conventional and bio version 16.1 products, and it was realized by the Sturm test. In this products were also realized mass loss analysis and thermogravimetric (TG) and differential scanning calorimetry (DSC) analysis. In this phase was additionally made the characterization of the soil used in the Sturm test. Regarding the soil characterization, it evaluated four parameters: carbon/nitrogen ratio, organic matter, pH and humidity. As for the C:N ratio, a ratio of 41: 1 was obtained, and this ratio was considered high, so the microorganisms will tend to have a slower growth, leading to a more time-consuming degradation. The organic matter content was 38.82%, which is considered beneficial for this study. As for pH, a value of 6.07 units in the Sorensen scale and a percentage of humidity of 53,2 % which in the literature corresponds to the ideal values for this study. In the Sturm test, the analysis of the behavior related to the release of carbon dioxide (CO2) as a function of time showed that both products showed the same tendency, that is, there was an increase of carbon dioxide production in the first days to a value of 1.20 grams, but in the following step there is a decrease of that value to 0.20 grams. So, it was concluded that the microorganisms are possibly in a period of adaptation to the environment, hence the production of carbon dioxide remains constant without ever reaching zero values. This adaptation can be justified by the values obtained for soil characterization. Through the mass loss test, it was found that the conventional product had the lowest mass loss corresponding to 1.93% and the bio product version 16.1. presented a higher mass loss corresponding to 6.50%. In the results obtained through the thermogravimetric analyzes, realized on conventional and bio version 16.1. products, before and after the Sturm test, it was verified that the temperature of the beginning of mass loss (Tonset) for the conventional product showed a slight increase compared to the value obtained before the test. In contrast, in the bio version 16.1. product, this difference is already more significant and it has been found that the Tonset decreased by approximately 5°C after the biodegradation test. These results were also confirmed with differential scanning calorimetry (DSC) analyzes, where differences in the Tonset and Toffset were observed. In summary, the results obtained in this work allow to conclude that the replacement of the plasticizer used by a more biological plasticizer and that the substitution of azodicarbonamide masterbatch by a masterbatch of starch / plasticizer / water gives rise to a product with indications of biodegradability and that it complies specifications required for contract upholstery coatings, although it does not exhibit the same degree of expansion as the conventional product.
Currently, polyvinyl chloride (PVC) is one of the most used plastics by the human being mainly because of its versatility, allowing its use in the most diverse applications. However, their slow degradation generates a great environmental impact. Therefore, it became necessary to find an alternative occurring this way the biodegradable plastics. In this way, has emerged this project, which consisted in the development of a contract mat coating with a more biodegradable character. This work was divided into two phases. The first phase consisted in the development of the product and its physical characterization and the second phase consisted in the study of the biodegradation of the same. In the first phase, was made the substitution of the plasticizer used by one with a more iological character and the substitution of the azodicarbonamide, the blowing agent, by starch. After the substitutions, three laboratory-scale studies were carried out: the substitution of the filler to starch, the study of the starch masterbatch and the study of the amount of masterbatch in the formulation in different weight percentages. The results showed that the use of a masterbatch containing a weight ratio of 70:55:25 of starch / biological plasticizer / water leads to good results in terms of aesthetic appearance, that is, there are no defects in the film and also good adhesion to the coating. It was also concluded that the degree of expansion obtained with the substitutions made is lower than the conventional product. With this result, the bio product version 16.1., and the conventional product were produced at pilot scale and it was made their physical characterization. As for the physical characterization, it was concluded that the modifications made originated a product with mechanical characteristics identical to those of the conventional product, fulfilling the specifications imposed for contract upholstery. Only one exception was found in the tear strength test where the value obtained was lower in about 22,0 % than the value specified. The second phase of this work consisted in the study of the biodegradability of conventional and bio version 16.1 products, and it was realized by the Sturm test. In this products were also realized mass loss analysis and thermogravimetric (TG) and differential scanning calorimetry (DSC) analysis. In this phase was additionally made the characterization of the soil used in the Sturm test. Regarding the soil characterization, it evaluated four parameters: carbon/nitrogen ratio, organic matter, pH and humidity. As for the C:N ratio, a ratio of 41: 1 was obtained, and this ratio was considered high, so the microorganisms will tend to have a slower growth, leading to a more time-consuming degradation. The organic matter content was 38.82%, which is considered beneficial for this study. As for pH, a value of 6.07 units in the Sorensen scale and a percentage of humidity of 53,2 % which in the literature corresponds to the ideal values for this study. In the Sturm test, the analysis of the behavior related to the release of carbon dioxide (CO2) as a function of time showed that both products showed the same tendency, that is, there was an increase of carbon dioxide production in the first days to a value of 1.20 grams, but in the following step there is a decrease of that value to 0.20 grams. So, it was concluded that the microorganisms are possibly in a period of adaptation to the environment, hence the production of carbon dioxide remains constant without ever reaching zero values. This adaptation can be justified by the values obtained for soil characterization. Through the mass loss test, it was found that the conventional product had the lowest mass loss corresponding to 1.93% and the bio product version 16.1. presented a higher mass loss corresponding to 6.50%. In the results obtained through the thermogravimetric analyzes, realized on conventional and bio version 16.1. products, before and after the Sturm test, it was verified that the temperature of the beginning of mass loss (Tonset) for the conventional product showed a slight increase compared to the value obtained before the test. In contrast, in the bio version 16.1. product, this difference is already more significant and it has been found that the Tonset decreased by approximately 5°C after the biodegradation test. These results were also confirmed with differential scanning calorimetry (DSC) analyzes, where differences in the Tonset and Toffset were observed. In summary, the results obtained in this work allow to conclude that the replacement of the plasticizer used by a more biological plasticizer and that the substitution of azodicarbonamide masterbatch by a masterbatch of starch / plasticizer / water gives rise to a product with indications of biodegradability and that it complies specifications required for contract upholstery coatings, although it does not exhibit the same degree of expansion as the conventional product.
Description
Keywords
Revestimento Amido Teste de Sturm Biodegradabilidade Coating Starch Sturm test Biodegradability