Polytechnic University of Valencia

About: Polytechnic University of Valencia is a education organization based out in Valencia, Spain. It is known for research contribution in the topics: Catalysis & Population. The organization has 16282 authors who have published 40162 publications receiving 850234 citations.

Combined Effect of Poly(hydroxybutyrate) and Plasticizers on Polylactic acid Properties for Film Intended for Food Packaging

Abstract: Poly(lactic acid) PLA, and poly(hydroxybutyrate) PHB, blends were processed as films and characterized for their use in food packaging. PLA was blended with PHB to enhance the crystallinity. Therefore, PHB addition strongly increased oxygen barrier while decreased the wettability. Two different environmentally-friendly plasticizers, poly(ethylene glycol) (PEG) and acetyl(tributyl citrate) (ATBC), were added to these blends to increase their processing performance, while improving their ductile properties. ATBC showed higher plasticizer efficiency than PEG directly related to the similarity solubility parameters between ATBC and both biopolymers. Moreover, ATBC was more efficiently retained to the polymer matrix during processing than PEG. PLA–PHB–ATBC blends were homogeneous and transparent blends that showed promising performance for the preparation of films by a ready industrial process technology for food packaging applications, showing slightly amber color, improved elongation at break, enhanced oxygen barrier and decreased wettability.

Elastic analog of graphene: Dirac cones and edge states for flexural waves in thin plates

Abstract: An elastic analog of graphene is introduced and analyzed. The system consists of a honeycomb arrangement of spring-mass resonators attached to a thin elastic layer, and the propagation properties of flexural waves along it is studied. The band-structure calculation shows the presence of Dirac points near the $K$ point of the Brillouin zone. Analytical expressions are found for both Dirac frequency and velocity as a function of the resonator's parameters. Finally, the bounded modes of infinitely long ribbons of this honeycomb arrangement are analyzed. The presence of edge states, which are studied using multiple scattering theory, is shown. It is concluded that these structures can be used to control the propagation of flexural waves in thin plates.