Perspectives on the production, structural characteristics and potential applications of bioplastics derived from polyhydroxyalkanoates.

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.

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

In recent years, the inappropriate disposal of polymeric materials has increased due to industrial development and increase of population consumption. This problem may be minimized by using biodegradable polymers, such as bacterial cellulose and poly(hydroxybutyrate), from renewable resources. This work was aimed at monitoring and evaluating degradation of bacterial cellulose, vegetable cellulose and poly(3-hydroxybutyrate) using Thermogravimetric Analysis and Scanning Electron Microscopy. Controlled mass polymer samples were buried in pots containing soil. Samples were removed in 30 day intervals up to 180 days. The results show that the mass of the polymer increased in the first month when in contact with the soil but then it was degraded as evidenced by mass loss and changes on the sample surface.

/pdf/biodegradation-evaluation-of-bacterial-cellulose-vegetable-1x06iiwprw.pdf

Biodegradation evaluation of bacterial cellulose, vegetable cellulose and poly (3-hydroxybutyrate) in soil

Composite materials are material systems which consist of one or more discontinuous phases embedded in a continuous phase Thus, at least two distinct materials that are completely immiscible are combined to form a composite The continuous phase are termed matrix and the discontinuous phase can be a reinforcement (reinforcing agent) or filler Also, other additives as plasticizers, pigments, heat and light stabilizers are frequently added in order to provide certain properties The type and reinforcement geometry impart strength to the matrix and the resultant composite shows optimized properties such as high specific strength, stiffness and hardness with respect to the specific components [1]

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Biocomposites: Influence of Matrix Nature and Additives on the Properties and Biodegradation Behaviour

The objective of this study was to produce and characterise biodegradable thermoplastic starch (TPS) derived from the fruit of pejibaye palm (Bactris gasipaes Kunth) plasticised with glycerol and s...

https://www.tandfonline.com/doi/pdf/10.1080/10942912.2017.1372472

Biodegradable thermoplastic starch of peach palm (Bactris gasipaes kunth) fruit: Production and characterisation

Do inicio do seculo passado aos dias atuais o uso dos polimeros tem se tornado cada vez mais frequente na sociedade. Existe uma incrivel quantidade de artigos que utilizam polimeros como materia-prima para suas diferentes elaboracoes. A busca inicial por polimeros sinteticos esteve baseada em sua relativa inercia e resistencia a biodegradacao. Devido a essas caracteristicas, a enorme quantidade de lixo produzido nas cidades tornouse
um serio problema, estimulando a substituicao desse material de dificil degradacao por um polimero natural biodegradavel, o Polihidroxibutirato (PHB), alvo das pesquisas atuais.
A importância do PHB esta no fato de poder ser usado na fabricacao de diversos produtos. O tempo medio de degradacao desses bioplasticos e de 6 a 12 meses contra 40 a 50 anos ou ate 200 anos no caso dos polimeros sinteticos. Apesar da vantagem no criterio ambiental, os plasticos biologicos sao mais caros e, por serem menos flexiveis, tem
aplicacoes mais limitadas que os sinteticos. 

Palavras-chave: Polihidroxibutirato; PHB; Biodegradacao; Industria

/pdf/a-importancia-e-as-vantagens-do-polihidroxibutirato-plastico-1w8izd40qj.pdf

L B S de Souza

Papers

A importância e as vantagens do polihidroxibutirato (plástico biodegradável)