Mark McCourt

Recycling of polymeric fraction of cable waste by rotational moulding

This study focuses on the mechanical recycling of polymeric waste that is produced in considerable amount from the cable industry. Every year large amounts of cables become waste; wires recycling has traditionally focused on metal recovery, while the polymer cover has just been considered as a residue, being landfilled or incinerated. Nowadays, increasingly restrictive regulations and concern about environment make necessary to reduce landfilling as much as possible. Main novelty of the study is that the material used in the research is a post-consumer material and the entire residual material is used, without a previous purification, in contrast with similar studies. Characterization of this residue was performed by thermal analysis, showing that the material is mainly made up of a heavy fraction (84% of the residue), which is not able to melt, fact what makes recycling more difficult. Once characterized, the material was ground, blended with virgin polyethylene and reprocessed by rotational moulding. The influence of the amount of residue and parts structure (1, 2 and 3 layers) was assessed, studying the mechanical behaviour of obtained parts (tensile, flexural and impact properties). It has been found that although mechanical properties get reduced with the increased amount of residue, up to a 35% of residue can be used without an important decrease in mechanical properties. On the other hand, the use of multiple layers in the mouldings allowed obtaining a better external appearance without compromising the mechanical properties.

The effect of internal mould water spray cooling on rotationally moulded polyethylene parts

The conventional method of cooling during the rotational moulding process is through the use of forced air. During the cooling phase of a typical rotomoulding cycle, large volumes of high velocity room temperature air are forced across the outside of the rotating rotomoulding tool to encourage cooling of the metal mould and molten polymer. Since no cooling is applied to the inside of the mould, the inner surface of the polymer (polyethylene) cools more slowly and will have a tendency to be more crystalline and the polyethylene will have a higher density in this region. The side that cools more quickly (in contact with the inside mould wall) will be less crystalline, and will therefore have a lower density. The major consequence of this difference in crystallinity will be a buildup of internal stresses producing warpage and excessive shrinkage of the part with subsequent increased levels of scrap. Therefore excessive cooling on the outside of the mould should be avoided. One consequence of this effect is t...

Banana Fiber Processing for the Production of Technical Textiles to Reinforce Polymeric Matrices

Banana fibers have been extracted by mechanical means from banana tree pseudostems, as a strategy to reevaluate banana crops residues. Extracted long fibers are cut to 45 mm length and then immersed into an enzymatic bath for their refining. Conditions of enzymatic treatment have been optimized to produce a textile grade of banana fibers, which have then been characterized. This fiber has then been transformed into yarns and woven to produce a technical textile with different textile structures. Woven material was then used to produce a composite by compression molding, using polypropylene (PP) as polymeric matrix.

Multilayered glass fibre-reinforced composites in rotational moulding

The potential of multiple layer fibre‐reinforced mouldings is of growing interest to the rotational moulding industry because of their cost/performance ratio. The particular problem that arises when using reinforcements in this process relate to the fact that the process is low shear and good mixing of resin and reinforcement is not optimum under those conditions. There is also a problem of the larger/heavier reinforcing agents segregating out of the powder to lay up on the inner part surface. In this study, short glass fibres were incorporated and distributed into a polymer matrix to produce fibre‐reinforced polymer composites using the rotational moulding process and characterised in terms of morphology and mechanical properties.