Nuevas formulaciones sostenibles de compuestos termoplásticos
- Autores: Martí Hortós Lobera
- Directores de la Tesis: Jordi J. Bou Serra (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Ana Inés Fernández Renna (presid.), Montserrat García Alvarez (secret.), Fabiola Vilaseca Morera (voc.)
- Programa de doctorado: Programa de Doctorado en Polímeros y Biopolímeros por la Universidad Politécnica de Catalunya
- Materias:
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- Resumen
Due to the great and growing demand of plastics, the importance of the sustainability of these products is essential in order to preserve the environment. Conventional polymers come from fossil resources and, therefore, the production of this type of plastics actively contributes to the generation of carbon dioxide emissions, contributing negatively to the problem of climate change. Currently, the global concern about the environment has motivated the society to find alternatives to oil as a source of energy and as a raw material for many of the synthetic products. In recent years, considerable research efforts have been made to develop new plastic materials with low or no environmental impact.
Bioplastics in general, including polylactic acid (PLA), have the advantage of their sustainability (renewable origin, low carbon footprint and closed life cycle). But they also have some technical limitations that restrict their use in certain applications. Among them, its mechanical properties and its low resistance to impact that, together with its low glass transition temperature (around 60ºC), makes the PLA not suitable for certain applications. Consequently, one of the main objectives of this Doctoral Thesis has been to obtain a material based on PLA that performs final properties similar to those of a technical polymer, derived from petroleum, such as ABS.
For this purpose, the polylactic acid has been formulated with different additives to obtain a material with improved thermomechanical and impact properties. There are several formulation strategies to obtain a high performance material. Among them, the control and promotion of its crystallinity is a crucial aspect to industrially extend the use of PLA. Optimizing this process will be an important factor to obtain final properties (mechanical, thermal, optical, barrier, etc.) that make this polymer a material capable of competing technically with conventional polymers of fossil origin. Other ways to obtain a high performance material based on PLA, which have been studied in this Doctoral Thesis, have been the blend of PLA with other polymers such as polycarbonate, the annealing of the polymer material as post-treatment in order to increase the degree of crystallinity of the PLA and, also, the obtention of the stereocomplex of high molecular weight PLA.
On the other hand, polyvinyl chloride (PVC) is still one of the most widely produced thermoplastics. Traditionally PVC has been plasticized by the esters of phthalic acid. However, current legislation limits its use in some applications. Therefore, during the last years many research works have been dedicated to find plasticizers of renewable natural origin, sustainable, that present low volatility and that are an alternative to conventional plasticizers for PVC.
In this context, another objective of this Doctoral Thesis has been the development of plasticized PVC formulations by means of the use of bioplasticizers that are a sustainable alternative to phthalates from a technical and economic point of view. The plasticizing capacity of the PVC of the new plasticizers has been evaluated based on hardness tests, tensile properties, thermal stability, among others.
Finally, the environmental impact of some of the formulations selected among those described in this Doctoral Thesis has been evaluated. It has been found that most of them are more sustainable compared to thermoplastic compounds derived from petroleum for specific applications from different industrial sectors.
In this Doctoral Thesis, sustainable formulations of thermoplastic compounds have been developed, both from PLA and from bioplasticized PVC, successfully achieving the technical and sustainability requirements defined in the objectives.
