The Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) with integrated digital camera are techniques that are used in the present investigation, for the morphological characterization of a new composite material called “organic polymer concrete” in which microparticles added fibers and polyethylene terephthalate (PET) recycling mechanically (RM). Polymer concrete (PC) is a new composite material (MC) in the application considered as an alternative material of construction in which reinforcement particles are recycled polymers which have approximately the same dimensions in all directions. Therefore, the particles can be rods, spheres, chips and many other shapes whose appearance reasons are about 10 microns. These MC, the size, shape and distribution and the ratio and the modulus of the particles affect the properties of the material.
At present, the science and engineering of materials focuses on the development of new synthetic methods, new ways to identify and characterize materials, a description of its structure, synthesis and custom design and innovate to obtain new materials with desired properties and controllable [
In this research, paper presents the microscopic characterization of a new polymer concrete using as raw material polyethylene terephthalate (PET) recycling mechanically because it is considered a 100 percent recyclable plastic based on the emerging Mexican standard NMX-E-232-SCFI-1999 of the Ministry of Commerce and Industrial Development. Note that in our country (Mexico), PET plastic waste is the second most important for their consumption as disposable bottles and recyclable municipal solid waste. Besides, primary or mechanical recycling is a feasible process for the revaluation of recyclable waste such as PET [
The mixtures are combinations of polymers by mechanical means. Such combinations do not depend on chemical bonds, but typically require compatibilizers that prevent the segregation of components. In mixtures typically kept the best characteristics and in many cases the object is to find two or more components which, when mixed, produce synergistic improvement of the properties beyond those that are purely additive in their effect. The improvements sought are in the areas of impact resistance, weatherability, better low temperature performance and flame retardancy [
Some of the microscopy techniques which are used to characterize composite materials are optical microscopes with integrated digital camera, SEM (scanning electron microscope), AFM (atomic force electron microscope) DRx (XRD). In particular, spectroscopic techniques were used in this research for the morphological characterization of the new composite material RPET mechanically. Polymeric concrete was conducted with the following equipment: Optical Microscope and Scanning Electron Microscope (SEM).
The micrographs obtained in metallographic microscope can be expanded due to the inclusion of various auxiliary devices such as for observing the structural features that are not visible to normal conditions. Minimum and maximum amplification obtained with the microscope Olympus brand and model GX71 is 50× to 2000× (
The main parts of SEM are: Electron gun, light source, magnetic lenses (condenser, objective), scanning coils (directs the beam), 2 detectors (Rx, secondary electrons), columns, camera, vacuum system, software for 3D structure and organic samples, mapping of chemical elements in the sample, secondary electrons gives threedimensional images. The SEM, JEOL model VP 1450 (
faces of the samples. The high resolution on this computer to monitor rainfall inclusions, second phase particles with diameters of 1 - 2 microns. Images are formed by gathering or bouncing electrons are emitted from the surface of the sample when it is scanned by a beam of high energy electrons. The image formed is an extension of some detail of the sample, as would a light microscope. The difference lies, however, in the high resolution and depth of field you can achieve with the SEM; observation has two modes, one shows the signal produced by the secondary electrons and the other the signal produced by electrons scattered retro. The signal produced by secondary electrons is much more sensitive to topographical changes to changes in composition in a sample. Instead, retro scattered signal is much more sensitive to changes in composition and is very sensitive regarding topographic changes. For this reason, the secondary electron signal is used to examine the sample [
From the samples prepared by the method of evaporating gold-palladium (Au-Pd) through ionized plasma for surface coating of the polymeric material powder, in order to obtain driving inside the SEM chamber and observe morphologies present samples, for which we use a Sputter Coater Polaron evaporator brand, model SC7620 (
Raw Material: microfiber Particulates and mechanically recycled polyethylene terephthalate, polyester resin and calcium carbonate.
A homogeneous mixture is produced which contains polyester resin and calcium carbonate particulates and recycled polyethylene terephthalate microfibers mechanically conventional mill ratio (1:1:1) is poured into molds of HDPE into the desired shape (cube, cylinders, tablets) and allowed to dry at room temperature (26˚C to 32˚C) for about 6 hours.
The equipment used for the characterization of materials by microscopic analysis are:
It breaks the sample of CP with MR PET electric cutter diamond tipped, solid surface for approximately 1 cm2, which is observed in the MO.
Sample is crushed recycled PET polymer concrete mechanically vibrating mill until fine powders that are placed in a stainless steel sample holder on which is fixed graphite tape, then placed the sample holder with the powder an evaporator (sputtering) for about 6 minutes, where gas is flowed argon inert element and have vacuum in the evaporator chamber to prevent sample contamination. This sample preparation technique using a target of palladium gold which has the function fragments powder coating of the polymeric material by deposition, in order to obtain a sample metal (conductive) and subsequently can be observed in the SEM.
Optical Microscope Images. In Figures 4 and 5 are images that were obtained in the MO of the composite surface “Polymeric Concrete RM PET”.
Micrographs of scanning electron microscope (SEM). Were obtained in the SEM micrographs of the combination of materials used in the concrete samples obtained polymeric RPET and thus observe the structure of the materials which in combination form the CP.
To characterize the composite fractured fragment is a sample to observe the solid structure in its thickness.
In the images of Figures 4 and 5 which were obtained in the MO with a magnification of 10× and 20×, into an area of the sample surface are observed pores with a size of about 8 μm, and also shows the presence of pores larger than about 200 μm, this manual mixing because that is applied during the preparation of PET RM CP.
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In the photomicrographs of Figures 7 and 8 show crystal morphology particles with rod-shaped or elongated thin fibers and PET RM (a).
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different phases and grains larger than about 60 μ in some grains, type crystal morphologies (b) are staggered.
The authors are grateful to the support of the Centre for Research in Engineering and Applied Sciences at the Autonomous University of the State of Morelos.