Silvia E. Barbosa

Influencia del Recubrimiento de las Fibras de Vidrio sobre la Efectividad de la Reacción de Copolimerización Propileno-Vidrio

The influence of fiber coatings on the effectiveness of the propylene-glass copolymerization reaction has been analyzed. The mechanical properties of fiber reinforced composites depend on the effective stress transfer fiber-matrix, which is possible if the adhesion between them is strong. An alternative method to improve the adhesion is the establishment of chemical links between matrix-fiber such as in situ polymerization. The study was carried out on sandwich composite of polypropylene and fiber glass, with and without acrylic coating. Adhesion is analyzed through its influence on the mechanical properties of the composites. The copolymerization reaction acts as an effective bonding agent, when it is carried out on uncoated fibers, making this proposal technological attractive.

PC-SAFT Equation: A Predictive Tool to Determine Experimental Conditions for Polymer Blend Demixing

Abstract The perturbed-chain statistical associating fluid theory equation of state (PC-SAFT) was applied to predict the phase behavior of polymer solutions in order to determine the pressure – temperature region for the high molecular weight polymer blend separation by using n-alkanes at high pressure and high temperature. The polymer blends selected were physical blends of polyethylene (PE)/polystyrene (PS), and polypropylene (PP)/PS. The miscibility and immiscibility region of each polymer in different alkanes (n-pentane, n-hexane, and n-heptane) was studied and from this analysis, the experimental conditions of the polymer blend demixing were predetermined. The results obtained were validated with experimental data indicating that the PC-SAFT equation is a good tool to predict experimental conditions for the processing windows of polymer blend separation.

Compatibilization of HIPS/ABS blends from WEEE by using Styrene-Butadiene Rubber (SBR)

The aim of this work is to develop compatibilization strategies for High Impact Polystyrene (HIPS)/ Acrylonitrile-Butadiene-Styrene (ABS) blends from WEEE in order to add value to these recycled plastics by improving their mechanical performance. Results from a screening study of HIPS/ABS blends compatibilization by the addition of Styrene-Butadiene Rubber (SBR) are presented. Two different weight proportion of HIPS/ABS physical blends were analyzed, 80/20 and 20/80, with three different concentration of SBR: 2, 10 and 20 wt%. Compatibilization efficiency was analyzed from an accurate thermal and mechanical analysis, by comparing each physical blend and corresponding compatibilized blends with SBR. Results were discussed relating glass transition changes with mechanical performance, both aspects were interpreted in terms of blend morphology. Phase and fillers dispersion and distribution as well as SBR amount and its interaction with each phase were accurate analyzed. Compatibilization of HIPS/ABS blends from WEEE with the addition of SBR is effective in blends with HIPS as main component. With the addition of 2 wt% of SBR, strength and toughness have notably increased respect to the corresponding physical blend, 244% and 186% respectively. From this screening study is possible to infer that SBR is a sustainable and efficient compatibilizer of HIPS rich blends allowing to obtain a final blend that can be used as a replacement material of separated resins from WEEE.

USE OF ACRYLONITRILE-BUTADIENE-STYRENE FROM WASTE ELECTRIC AND ELECTRONIC EQUIPMENT WITHOUT AN ACCURATE PREVIOUS SEPARATION

The aim of this work it to develop recycling strategies for Acrylonitrile-Butadiene-Styrene (ABS), coming from plastic WEEE stream, avoiding sorting by type. Self-compatibilization of ABS/HIPS blends, as well as the addition of Styrene-Butadiene-Styrene (SBS) as a compatibilizer to ABS/HIPS blends in order to improve mechanical properties, were studied. In this way, thermal behavior, mechanical performance and morphology of ABS/HIPS physical blends with two different proportions, 80/20 and 50/50, was analyzed comparatively with single ABS to assess self-compatibilization effectiveness. Obtained results indicate that ABS/HIPS self-compatibilization is effective. ABS can tolerate up to 50 wt% of HIPS conserving its properties with a slight improvement in ductility and strength. This allows a wider error in plastic sorting by type within plastic WEEE stream and consequently costs can be reduced. Same blends proportions with the addition of 2 wt% of SBS was also studied in comparison to their physical blends and single ABS. Mechanical properties of SBS-compatibilized blends were notably improved with respect to physical blends and consequently to ABS. Results are very promising for plastic WEEE recycling leading to a sustainable strategy that can promote the reuse of recycled ABS blended with other plastic WEEE instead of single ABS.

Composites and Nanocomposites Based on Starches. Effect of Mineral and Organic Fillers on Processing, Structure, and Final Properties of Starch

Composites development, by incorporating organic or mineral fillers to starch matrices, can be used to improve their final properties. Accordingly, composites of different starch matrices reinforced with organic fillers, as well as, with mineral particles are described in this chapter. In this sense, it was reported, among others, the use of cellulose fibers from different botanical origins and clays particles. Nowadays, both academic and industrial interest in nanoscale fillers is growing since a nanostructured composite could be developed from a polymeric matrix and layered mineral particles. Thus, in this chapter is also included the development of nanocomposites based on thermoplastic starch and talc nanoparticles from different geological origins and morphologies. Processing methods and structural and final properties of composites are described.