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Polylactic acid resins are some of the most largely used bioplastics, some characteristics still limit their use, such as in mixing with other polymers or inclusion of additives. Currently, additive manufacturing technologies are enlarging their application sectors because they allow more rational use of raw materials, limiting both production waste and onerous post-processing stages. In this framework, polylactic acid resins, particularly favoured by their slow crystallization rate and the large availability, are some of the most used to obtain commercial filaments for fused deposition modeling. This research is then focused on the processability of the compounds, based on a commercial PLA resin, additivated with 1, 3, and 5 wt% of food flour wastes. The comparison of the performance of the products obtained with conventional and innovative technologies, respectively compression molding and FDM, is the key point of this study. Mechanical and morphological properties, obtained by the two technologies, were evaluated for neat and additivated resins. Preliminary results emphasize that, through compression molded, it was possible to obtain homogeneous components and the natural infilled used acts as reinforcement improving mechanical performances. For the additive technology, the samples obtained show a lower mechanical behavior due to the technological issues of 3d printing. [ABSTRACT FROM AUTHOR]

Composite laminates based on a commercial thermoplastic polyurethane (TPU) grade and reinforced by woven glass fibers were prepared by film stacking and compression molding procedures and subjected to static and dynamic mechanical tests, at ambient and low temperatures. The results were interpreted taking into account that preliminary analysis of TPU based laminates showed a fiber volume fraction equal to 53%, 56% and 48% for plates involving 10, 16 and 22 lamina, respectively. Flexural tests, performed so far only at room temperature (RT), revealed that the intermediate thickness laminates offer the highest performances, probably for their higher volumetric fraction of reinforcement. Impact results collected, instead, also at low temperatures (-25°C and -50°C) indicated that no delamination is verified all over the considered range of impact temperatures and thickness of plates. On the contrary crack propagation phenomena are enhanced by increasing the thickness of impacted samples and/or reducing the impact temperature. [ABSTRACT FROM AUTHOR]

The purpose of this work is to evaluate the influence of the manufacturing technology on the mechanical behaviour of composite laminates from commingled fabrics consisting of glass and polypropylene fibers. In this regard, non-isothermal and isothermal moulding technologies were used for manufacturing flat laminates with different thicknesses and stacking sequences. The laminates were characterized by flex and impact tests up to complete penetration; the data of penetration energy were also used to estimate the goodness of fit of a prediction model present in literature. The results obtained from the mechanical tests show the effectiveness of the isothermal moulding technology compared to the non-isothermal one, which is extremely important considering that the preheating phase is avoided with the first technology, saving on equipment and processing times. [ABSTRACT FROM AUTHOR]