Materiales compuestos a partir de filamentos naturales y matriz plástica biobasada, y sus posibles aplicaciones tecnológicas

Séculi, Faust
Nowadays the problem of climate change on planet Earth has aggravated, it has become extremely important to find solutions that considerably reduce or even eliminate its causes. Among the set of solutions that have been underway for some years, the generation of environmentally friendly composite materials has been one of them. These materials are able to match the properties and characteristics of existing materials, which are mainly petroleum based or based on other none environmentally friendly materials. In this thesis we have obtained bio-based composite materials formed by natural reinforcement abaca fibers and a polymer matrix of high-density polyethylene (HDPE), and bio-based composite materials formed by natural reinforcement abaca fibers and a polymer matrix of bio polyethylene (BioPE). Composite materials have been characterised with abaca fiber content ranging from 20 to 50 wt%. This formulation has also been made by adding a coupling agent, in a content range of 2 to 10 wt%. This coupling agent is essential to ensure an appropriate bonding between phases, since natural fibres are hydrophilic in nature and plastic matrices are hydrophobic in nature. The nature of both phases results in an incompatibility that causes a loss in the mechanical capabilities of the composite material. The composites have been analysed for their mechanical, thermal, acoustic and life cycle properties, comparing both composites and comparing the composites with and without the coupling agent maleic anhydride (MAPE). The results obtained for tensile properties show how the addition of abaca fibers improves the properties of the matrix. Slightly higher tensile strength results are obtained with the addition of the coupling agent. Among the two matrices used, BioPE shows slightly higher values than HDPE. In terms of tensile deformation, the values of the composites are worse than those of the matrices, although the increase of the fibre content results in an improvement of the deformation capacity, without reaching the capacities of the matrix. The analysis of the Young's modulus of the composite material, shows how it improves substantially with increasing abaca fiber content compared to the matrix, but the addition of MAPE has very little influence on the improvement or worsening of the values. When analysing the results of the flexural properties, a similar behaviour to that of the tensile properties is observed. Obtaining higher values of flexural strength of the composites with respect to the matrices, and slightly higher values with the addition of MAPE. The deformation behaviour is also similar to the tensile case, with a reduction of its capacities with respect to the matrix, but with a small increase in the properties of the composite with the addition of the coupling agent. To further analyse the mechanical properties, micromechanics models have been used to determine the intrinsic properties of the phases, both in tensile and flexural cases. Intrinsic strengths, intrinsic modulus and efficiency factors of the fibers and the matrix are determined by means of these models. The analysis of the properties of the flexural modulus, the results obtained in the impact tests, water absorption, thermal properties and acoustic properties are still pending. Is also pending the evaluation of the results obtained from the design of a possible application and the results obtained from the 3D simulation carried out. ​
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