Optically transparent membranes from bacterial cellulose (BC)/polycaprolactone (PCL) have been prepared by impregnation of PCL acetone solution into dried BC membranes. UV-Vis measurements showed an increase on transparency in BC/PCL membrane when compared with pristine BC. The good transparency of the BC/PCL can be related to the presence of BC nanofibers associated with deposit of PCL nano-sized spherulites which are smaller than the wavelength of visible light and practically free of light scattering. XRD results show that cellulose type I structure is preserved inside the BC/PCL membrane, while the mechanical properties suggested indicated that PCL acts as a plasticizer for the BC membrane. The novel BC/PCL membrane could be used for preparation of fully biocompatible flexible display and biodegradable food packaging
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.
16 April 2007 in Journal of Biomedical Materials Research Part A
The circular economy is one of the main strategies for mitigating the environmental impacts of civil construction due to the generation of construction and demolition waste (CDW). In this transition, evaluating alternatives for using buildings as material banks is a way to make the process of reusing construction components more efficient. Thus, the article aimed to evaluate the state of the art of publications on the relationship between the circular economy in civil construction and the conceptual model of buildings as material banks to mitigate the environmental impacts of CDW. The authors chose the methodological design of Systematic Literature Review, using the Scopus and Web of Science databases for research, with the following search strings: (“construction” or “civil construction” or “built environment” or “construction industry”) and (“circular economy” or “circular construction”) and (“material banks” or “BAMB” or “buildings as material banks” or “building stocks” or “building materials”) and (“construction waste” or “demolition waste” or “CDW” or “construction and demolition waste” or “environmental impacts”). After a screening in which only articles published in journals were selected, from 2013 to 2023, inclusion and exclusion criteria were applied, to evaluate only those that had a direct relationship with CDW management through circular economy strategies and buildings such as banks of material. As a result, 93 articles remained, which were analyzed using a quantitative and qualitative approach. The predominance of applied studies was also noted through case studies that evaluate the management of materials and waste in the urban environment. The qualitative analysis, carried out using a SWOT matrix, highlighted the strengths of the buildings, such as material banks, the potential reduction of resource extraction and urban mining, and promoting the circulation of construction products. However, the recycling of waste, such as aggregates, still stands out as the main end-of-life strategy adopted, even without occupying the top of the waste hierarchy.
1 February 2017 in Engenharia Sanitaria e Ambiental
Os processos relacionados com a produção de refeições para os consumidores são causadores de impactos para o meio ambiente. Este trabalho teve como objetivo identificar quais são as práticas de restaurantes brasileiros relacionadas com a temática da gestão ambiental e da sustentabilidade. Trata-se de um estudo de revisão sistemática de publicações no período de 2000 a 2015. Entre os resultados encontrados, destacam-se a geração de resíduos de alimentos no processo de produção e consumo das refeições, além de investigações sobre acondicionamento, reciclagem e destinação desses resíduos. São apresentadas também as temáticas de utilização de recursos (água e energia) e um panorama sobre a avaliação dos aspectos ambientais por meio da prática de certificação de restaurantes comerciais com selos de sustentabilidade. Estudos avaliativos dessa natureza são importantes para contribuir para o diagnóstico da realidade no segmento de produção de refeições e também para fomentar investigações futuras que apontem para a redução dos impactos ambientais nessa atividade.