Virgin and recycled polypropylene composites reinforced with sisal by-product

Foram estudadas as propriedades térmicas e mecânicas de compósitos de polipropileno, virgem e reciclado, reforçados com 30% em massa de fibras residuais de sisal, assim como o perfil de processamento e a morfologia da matriz polimérica. Para tanto, foram determinadas a resistência à tração, o módulo de Young, alongamento na ruptura, e energia de impacto. As amostras também foram caracterizadas por MEV, DMTA e TG. Para ambos os compósitos de polipropileno, virgem e reciclado, com a adição das fibras, o alongamento na ruptura mostrou uma queda significativa, enquanto que a resistência à tração não sofreu grandes variações. Houve um aumento significativo nos valores de tração na ruptura e de energia de impacto com a adição das fibras de sisal na matriz de polipropileno. As análises térmicas mostraram ligações secundárias, como as ligações polares, entre as fibras e a matriz, concordando com o comportamento mecânico dos compósitos. Constatou-se que a temperatura de transição vítrea não variou após a adição da fibra.The mechanical and thermal properties of virgin and recycled polypropylene composites reinforced with 30% by mass of residual sisal fibers were studied, in addition to an analysis of the extrusion process and morphology of the polymeric matrix. Tensile strength, Young's modulus, elongation at break, and impact energy were determined. The samples were also characterized by SEM, DMTA and TG analyses. Elongation at break of the composites presented a significant decrease, while the tensile strength was not affected significantly by addition of sisal fibers. A significant increase was observed in the tension of rupture and in the impact energy of the composite reinforced with sisal fiber. The thermal analyses indicated secondary interactions, such as polar interactions, between the fibers and the matrix, consistent with the mechanical behavior of the composites. The glass transition temperature has not changed after fiber addition.Universidade Federal de São Carlos - Departamento de Engenharia de MateriaisFinepCNP

Projeto de uma planta para manufatura de produtos pecuários a partir do reaproveitamento de resíduos plásticos industriais e fibras vegetais

O presente trabalho discute o projeto conceitual de um sistema de produção sustentável para manufaturar equipamentos destinados à alimentação e suplementação de bovinos – os produtos são fabricados de materiais compostos végeto-poliméricos obtidos de uma combinação de resíduos de filmes plásticos e fibras vegetais. Este artigo se refere a um projeto de inovação tecnológica do Conselho Nacional de Desenvolvimento Científico e Tecnológico, Programa de Formação de Recursos Humanos em Áreas Estratégicas (CNPq-RHAE). As atividades de pesquisa foram realizadas em parceria entre duas universidades federais brasileiras e um fabricante de embalagens plásticas flexíveis e possibilitou a elaboração de um plano para implantar uma nova unidade de negócios. Por fim, a nova unidade fabril está alinhada com a Política Nacional de Resíduos Sólidos (Lei Federal nº 12.305/2010), permitindo agregar valor aos resíduos para produzir novos produtos pecuários

Reprocessability of PHB in extrusion: ATR-FTIR, tensile tests and thermal studies

Mechanical recycling of biodegradable plastics has to be encouraged, since the consumption of energy and raw materials can be reduced towards a sustainable development in plastics materials. In this study, the evolution of thermal and mechanical properties, as well as structural changes of poly(hydroxybutyrate) (PHB) up to three extrusion cycles were investigated. Results indicated a significant reduction in mechanical properties already at the second extrusion cycle, with a reduction above 50% in the third cycle. An increase in the crystallinity index was observed due to chemicrystallization process during degradation by chain scission. On the other hand, significant changes in the chemical structure or in thermal stability of PHB cannot be detected by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA), respectively.National Foundation for Science and Technology Development (CNPq)Univ Fed Rio Grande Norte UFRN, Dept Mat Engn DEMat, Natal, RN, BrazilUniv Fed Sao Carlos UFSCar, Dept Mat Engn DEMa, Sao Carlos, SP, BrazilUniv Fed Paraiba UFPB, Dept Mat Engn DEMAT, Joao Pessoa, Paraiba, BrazilUniv Fed Rio Grande Norte UFRN, Dept Chem DQ, Natal, RN, BrazilUniv Fed Sao Paulo UNIFESP, Inst Sci & Technol ICT, Sao Jose Dos Campos, SP, BrazilUniv Fed Sao Paulo UNIFESP, Inst Sci & Technol ICT, Sao Jose Dos Campos, SP, BrazilWeb of Scienc

Development and characterization of polymeric blends and composites using biodegradable polymers

This work presents theoretical information and experimental data on the behavior of biodegradable polymers and blends of biodegradable PHB polymer with copolyesters that are also biodegradable. Binary mixtures were made of the biodegradable polymer poly(hydroxybutyrate) PHB and biodegradable copolyesters, Eastar Bio® and Ecoflex®, in the following PHB/copolyester compositions: 100/0, 90/10, 75/25, 50/50, and 0/100. For the PHB/copolyester blend of 75/25, modifications with 30% of wood powder in two different grain sizes were studied. The polymeric blends were prepared and their mechanical and thermal properties and morphology evaluated. An analysis of their biodegradation in soil was also made. It was found that the mechanical properties of PHB polymer are improved by incorporating 50% of copolyester into the polymeric blend. Analyses of the melt flow index also revealed that the three polymers studied here are unstable and degrade along time, a behavior displayed particularly strongly by Easter Bio. A thermal analysis by Differential Scanning Calorimetry indicated that these polymers have a very slow crystallization rate. A Dynamic Mechanical Thermal Analysis of the blends indicated they are immiscible, as indicated by two different Tg peaks very close to the Tg of the pure polymers. All the polymers subjected to the soil biodegradation tests underwent degradation with a loss in mass, although only superficial alterations which did not interfere in their mechanical properties occurred during the 90-day evaluation period.Universidade Federal de Minas GeraisEste trabalho apresenta informações teóricas e dados experimentais sobre o comportamento de polímeros biodegradáveis e de blendas do polímero biodegradável com copoliésteres também biodegradáveis. Efetuou-se a mistura binária do polímero biodegradável poli(hidroxibutirato) PHB e copoliésteres biodegradáveis, Eastar Bio® e Ecoflex®, nas composições PHB/copoliéster (100/0, 90/10, 75/25, 50/50, 0/100). Para a blenda PHB/copoliéster (75/25) foram estudadas modificações com 30% de pó-de-madeira, em duas granulometrias diferentes. Após preparadas, as blendas poliméricas foram avaliadas segundo as propriedades mecânicas e térmicas, e a morfologia. Foi realizada também análise de biodegradação em solo. Foi verificado que para melhorar as propriedades mecânicas do polímero PHB é necessário incorporar 50% de copoliéster na blenda polimérica. Verificou-se também através das análises de índice de fluidez, que os três polímeros estudados são instáveis e degradam ao longo do tempo, sendo que para o Eastar Bio este comportamento é muito acentuado. Através da análise térmica por Calorimetria Exploratória Diferencial notou-se que os polímeros possuem uma taxa de cristalização bem lenta. Pode-se perceber que as blendas formadas são imiscíveis, caracterizando-as pela técnica de Análise Térmica Dinâmico-Mecânica, isto é, há formação de dois picos de Tg distintos e bem próximos aos valores de Tg dos polímeros puros. Nos ensaios de biodegradação em solo, pode-se verificar que todos os polímeros submetidos ao teste degradaram-se com perda de massa, porém, para o tempo avaliado (90 dias) somente houve alteração superficial, não interferindo em suas propriedades mecânicas

Biodegradation in Soil of the PHB/Wood Flour (80/20) and PHB/Sisal Fiber (80/20) Tubes

<div><p>This paper presents the results of a study that aimed to monitor and evaluate biodegradation in soil, by the mass loss and the mechanical properties of plastic tubes. For this work, there were extruded and injected plastic tubes made of biodegradable polymer poly(hydroxybutyrate) - (PHB) and composite PHB/Wood Flour and PHB/Sisal Fiber, both with 20% fiber. There were used three biodegradation test devices for 30, 60 and 90 days. At the end of each test, the biodegraded samples were taken from soil, washed thoroughly with water, dried and weighed to evaluate the mass loss. Mechanical properties were evaluated using flexural tests before and after biodegradation in soil. Based on the results, it was observed that all the studied tubes lost mass over the biodegradation test, and the tubes of biodegradable composites lost more weight than pure PHB.</p></div

Reprocessability of PHB in extrusion: ATR-FTIR, tensile tests and thermal studies

Abstract Mechanical recycling of biodegradable plastics has to be encouraged, since the consumption of energy and raw materials can be reduced towards a sustainable development in plastics materials. In this study, the evolution of thermal and mechanical properties, as well as structural changes of poly(hydroxybutyrate) (PHB) up to three extrusion cycles were investigated. Results indicated a significant reduction in mechanical properties already at the second extrusion cycle, with a reduction above 50% in the third cycle. An increase in the crystallinity index was observed due to chemicrystallization process during degradation by chain scission. On the other hand, significant changes in the chemical structure or in thermal stability of PHB cannot be detected by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA), respectively