The use of biodegradable polymers is an interesting way to reduce the polymeric waste accumulation in the environment. However, the addition of fillers to biodegradable polymer matrices may decrease their biodegradability. Glassy carbon (GC) is a promising carbon material that can be employed as a filler in the production of antistatic packaging utilized to protect electronic components. The use of a biodegradable polymeric matrix such as poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) can be an excellent alternative for the preparation of green composites to be used in these packages. This work aims to evaluate the effect of the GC addition and the GC particle size on the biodegradability of the PHBV matrix, as well as to study the result of the employment of a previous photodegradation treatment on the biodegradation in aqueous medium of PHBV/GC composites. Scanning electron microscopy, residual weight measurement (%) and surface roughness showed that GC does not interfere negatively with PHBV biodegradability. Differential scanning calorimetry analysis and residual weight measurement permitted to suggest that the increase in the crystallinity degree of PHBV and PHBV/GC samples occasioned by the ultraviolet radiation hindered the water and enzyme access to the bulk of the materials, decreasing the biodegradability.

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Molécula Imobiliária é uma proposta de jogo de tabuleiro para desenvolver a aprendizagem de conceitos de genética aos estudantes, que irão trabalhar em grupos e trocar informações entre si. O desafio é responder as perguntas do jogo de forma correta, ganhar o máximo de moedas e comprar nucleotídeos para formar a maior molécula de DNA. Quanto maior a quantidade de moedas adquiridas, maior a quantidade de nucleotídeos e, consequentemente, a possibilidade de o grupo ganhar o jogo, e melhorar seu conhecimento sobre os temas de genética abordados. Nesse estudo, apresentamos nosso produto educacional para o Ensino de Ciências e Biologia, bem como avaliamos a jogabilidade deste tabuleiro. Nesse sentido, a Molécula Imobiliária, constou ser um bom material paradidático e que contribui no processo criativo e motivador no ensino e aprendizagem acerca de determinados conceitos da genética no Ensino Médio. Esta proposta de jogo, contribuiu para a construção coletiva do conhecimento, assim como, o desenvolvimento de outras habilidades relevantes para formação de um discente, como trabalho em equipe, liderança e colaboração. Dessa forma, concluímos que o jogo atende a sua proposta, por ser um instrumento didático facilitador e lúdico para o ensino da genética e ainda contribui como alternativa metodológica docente perante as diversas aplicabilidades possíveis.

The search for environmentally friendly materials has motivated a lot of investigations in academia and industry. In this regard, biodegradable polymers have stood out as an alternative material mainly to replace synthetic polymers and in the production of materials from renewable resources [1, 2]. However, with the advancement in the production and use of biodegradable polymers, new questions have arisen in the literature. The effective biodegradation of these materials when disposed of in a conducive environment. The possibility of recycling increases their useful life

The development of biodegradable polymers has been stimulated owing to the inappropriate litter disposing in order to replace conventional polymers with long‐time degradation. As their performance is a challenge to this replacement, the insertion of additives in biodegradable polymers such as poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) consists in an effective way of adjusting their properties. For this reason, it was analyzed the incorporation of tributyrin (TB) in the matrix of PHBV as a plasticizer, so that higher plastic deformation is achieved. Samples of neat PHBV and with plasticizer concentrations of 5, 10, and 15 wt% were prepared by double screw extruder followed by press molding under temperature. Plasticizer exudation test confirmed the presence of TB in the samples of PHBV. Mechanical test showed the highest value of tensile strength and elongation at break for PHBV/5TB, with 23.4 MPa and 2.84%, respectively. It was observed at differential scanning calorimetry and dynamic mechanical thermal analysis that the PHBV/5TB resulted in an increase of 3% on crystallinity, a decrease of 3% on melting temperature, and a decrease of 46% and 29% on glass transition temperature by E″ and tan δ curves, respectively, compared with neat PHBV. Thus, PHBV/5TB was determined as the most appropriate composition for enhancing processability and properties of PHBV.

Representação social de estudantes do ensino fundamental e superior sobre escorpiões Social representation of elementary and higher education students about scorpions