Encontrados 11 documentos, a visualizar página 1 de 2

Avaliação da hidratação de pastas cimentícias com elevados teores de adições mi...

O uso de adições minerais é uma prática comum na produção de materiais cimentícios. No entanto, a possibilidade de substituir elevados teores de cimento Portland por adições minerais em betões torna pertinente e necessário o estudo da interacção química dessas adições na hidratação conjunta com o cimento. Este artigo avalia a hidratação de misturas de cimento Portland e adições minerais, recorrendo a técnicas d...

Electrical and thermal properties of polyurethane/carbon nanotubes composites

The aim of this work was to study the effect of dispersing small amounts of CNT on the thermal diffusivity and electrical resistivity of PU/CNT composites. The PU nanocomposites were prepared with 0.5% and 1% weight of CNT. The composites were prepared by dispersion of the CNT in poly(propylene glycol) (PPG) followed by in situ polymerization, by mixing with 4,4′-Methylene di-p-phenyl diisocyanate (MDI). The PP...

Desenvolvimento de um eco- compósito moldado composto de fibras recicladas celu...

Study of welding strengh in pvc profiles

Polyvinyl chloride, PVC, is one of the most widely produced and used plastic, being commonly used in civil industry due to its wide range of mechanical properties (from rigid to flexible), low cost, durability, and easy to assemble. Due to its good mechanical and thermal properties, PVC can be used to produce window and door frames, protecting the interior from the external actions, such as noise and temperatu...

Using matlab to compute heat transfer In free form extrusion

Capítulo 22

Waste fibre reinforced ecocomposites

With a significant production of waste fibrous material, textile companies are now looking for applications where waste materials could be an added-value material. One viable application of these waste materials is in the combination with polymeric matrices, producing composite materials with interesting properties for specific applications, from furniture to thermal and acoustic insulations. The aim of this wo...

Biodegradability assessment of aliphatic polyesters using standard methods

Important information concerning polymer’s final fate in the environment can be achieved in biodegradation studies performed in the aquatic environment. In this context, the focus of the present work was to evaluate the biodegradability level of blends containing aliphatic polyesters using standard methods. Blends of high density polyethylene (HDPE) and five biodegradable polymers (poly(lactic acid) (PLA), poly...

Preparation of biodegradable materials by reactive extrusion

This work aimed to prepare biodegradable polymeric materials based on blends of a synthetic high density polyethylene (HDPE) and biodegradable polymers such as polylactic acid (PCL) and poly(caprolactone) (PLA), in a co-rotating twin-screw extruder. A polyethylene modified with maleic anhydride was used as compatibiliser. The mechanical results showed that the addition of PLA improves the blends stiffness while...

System providing discomfort monitoring for people in wheelchairs

This article describes a project that aims to develop a system that provides people in wheelchair a relief to the level of the sensitive perception of discomfort, assuring greater independence, welfare, quality of life and the prevention of illnesses/wounds. The project is based on the development of textile and polymer applications (cushions, mattresses and mattresses overlays) with functions of pressure and h...

Preparation of biodegradable materials by reactive extruction