The use of residues, in partial or total substitution of aggregates or binders in concrete, presents interesting possibilities for obtaining eco-efficient concretes. Research has investigated the use of glass residue in Portland cement composite, whether as an aggregate or a supplementary cementitious material. However, there is still no consensus on the influence of the chemical composition of glass on the behaviour of the composites in which it is used. This paper analyse the influence of this composition on the performance of cement composites produced with microparticles of colourless and amber glass. Pozzolanicity was assessed by direct (Modified Chapelle, electrical conductivity) and indirect test (chemical characterization, X-ray diffraction, thermogravimetric analysis, differential thermal analysis and Strength Activity Index testing. The results show that microparticles of both glass display pozzolanic activity, with no significant differences between them. This confirms the potential for the use of glass microparticles as a supplementary material in cement composites.

O polipropileno (PP) tem uma degradação natural lenta e representa um importante constituinte na gestão dos resíduos sólidos, enquanto o poli(hidroxibutirato) (PHB) é um polímero biodegradável, mas tem as desvantagens de dificuldade de processamento e custo. O objetivo deste trabalho foi avaliar o efeito de nanopartículas de TiO2, do método de processamento e do envelhecimento acelerado na estrutura e propriedades da mistura PP/PHB/TiO2. As amostras foram produzidas por etapas de extrusão e injeção e foram caracterizadas por MEV/EDS, FTIR e análise térmica. Os resultados mostraram que a incorporação de 3% de nanopartículas de TiO2 levou a um aumento do tamanho médio da fase dispersa rica em PHB. A mudança na sequência da adição de nanopartículas de TiO2 permitiu guiar a incorporação desses nanocomponentes para a fase rica em PP. As misturas produzidas se mostraram mais estáveis termicamente do que PHB puro e a adição de TiO2 foi eficaz em aumentar a estabilidade térmica dos compósitos. As análises termogravimétricas e por FTIR mostraram que blendas contendo nanopartículas de TiO2 tiveram sua degradação mais afetada nos ensaios de envelhecimento acelerado. Os ensaios de extração com solvente mostraram que um maior conteúdo de produtos de fotodegradação puderam ser extraídos de amostras contendo mais elevadas concentrações de TiO2.

Polypropylene (PP) has a slow natural degradation rate. On the other hand, poly(hydroxybutyrate) (PHB) is biodegradable but has the disadvantages of cost and difficulty of processing. The aim of this work was to evaluate the effect of TiO2 nanoparticles, processing conditions and accelerated aging on the structure and properties of PP/PHB/TiO2 mixtures. Samples were prepared by extrusion and injection molding. The incorporation of 3% TiO2 nanoparticles led to an increase in the average size of the dispersed phase rich in PHB. Changes in the sequence of TiO2 nanoparticles incorporation were able to guide the inclusion of nanoparticles to the PP-rich phase. The produced composites were more thermally stable than pure PHB and the incorporation of TiO2 was effective to increase the thermal stability of the composites. Thermal and FTIR analyses showed that blends containing TiO2 nanoparticles had their degradation more affected by accelerated aging treatments. Solvent extraction results revealed that a larger amount of soluble products from the photodegradation could be extracted from samples containing TiO2 submitted to accelerated aging treatments.