We present a methodology to fabricate one-dimensional porous silicon (PSi) photonic crystals in the visible range by controlled etching and monitored by photoacoustics. Photoacoustic can record in-situ information about changes in the optical path and chemical reaction as well as in temperature, refractive index, and roughness during porous layers formation. Radiometry imaging can determine the carrier distribution of c-Si substrate that is a fundamental parameter to obtain high-quality PSi films. An electrochemical cell was calibrated through a series of single PSi layers that allows knowing the PA amplitude period, porosity, and roughness as a function of the current density. Optical properties of single layers were determined using the reflectance response in the UV-Vis range to solve the inverse problem through genetic algorithms. PhC structures were designed using the transfer matrix method and effective media approximation.Based on the growth kinetics of PSi single layers, those structures were fabricated by electrochemical etching monitored and controlled by in-situ photoacoustics.

No abstract

This paper is focused on the study of the waste car bumper samples and their transformation by re-extrusion-injection. Car bumpers are formed by crystalline phases of polypropylene (PP), talc, and amorphous ethylene propylene diene monomer (EPDM). The thermal, mechanical, and structural properties of the recycled material strongly depend on the process used for the extrusion and injection. The FWHM of the X-ray diffraction patterns was used to study the recrystallization phenomenon in PP, and the result had a direct correlation with the findings obtained by Differential Scanning Calorimetry (DSC). Remaining micro paint particles from the waste car bumpers involved in the recycled extrusion-injection process affect the mechanical properties, and their size and toughness could affect injection. Removal of these particles could improve the mechanical properties of recycled PP. Automotive parts based on polypropylene can be recycled for the automotive industry by the production of the same kind of products, and even for other field. It proposed a methodology and metrology to know the accurate chemical composition and its relationship with the properties of PP-based materials to find applications in different fields that allow to development of a circular economy framework.

This work focused studying waste car bumper samples and their processing by re-extrusion-injection. Car bumpers are composed of crystalline phases of polypropylene (PP), talc, and amorphous ethylene propylene diene monomer (EPDM). The recycled material's thermal, mechanical, and structural properties depend strongly on the process used for extrusion and injection and the crystalline phases formed during the heating process. The FWHM of the x-ray diffraction patterns was used to study the recrystallization phenomenon in PP, and the result was in direct correlation with the Differential Scanning Calorimetry (DSC) results. The remaining micro paint particles from the bumpers involved in the recycled extrusion-injection process affect the mechanical properties, and their size and toughness could affect the injection. Removing these particles could improve the mechanical properties of the recycled PP. Car parts based on polypropylene can be recycled for the automotive industry to produce the same type of products and even for other areas. A methodology and metrology can be developed to understand the chemical composition and its relationship with the properties of PP-based materials. This could lead to finding new applications in different fields and promote the development of a circular economy.

No abstract