Polystyrene (PS), one of the most used polymers in everyday life, has a low recycling rate due to its inexpensive virgin resin. In order to make polystyrene waste (WPS) recycling advantageous, it is possible to change it chemically, introducing heteroatoms in the polymer chain thus transforming the waste into a material with more added value. In this work, sulfonation reactions of polystyrene waste (disposable cups and expanded polystyrene-EPS) with different degrees of sulfonation were carried out by homogeneous sulfonation using acetylsulfate as a sulfonating agent, originating polystyrene sulfonate (PSS). The characterization of the products was done using Fourier Transformed Infrared Spectroscopy (FTIR), solubility tests and inductively coupled plasma optical emission spectroscopy (ICP-OES). Infrared spectroscopy revealed that the reaction was efficient and all the starting materials tested were successfully sulfonated and transformed into PSS. There was no distinction between the residues tested, revealing that it's possible to carry the reaction without sorting the waste. EPS was chosen as the substrate for further reactions varying the degree of sulfonation. Solubility and ICP-OES tests have shown that, by changing the synthesis conditions, it is possible to achieve different degrees of products sulfonation. As a result of the studied reactions it was found that varying the degree of sufonation it is possible to use polystyrene residues to produce PSS for different applications.
This paper examines the use of active lock-in thermography and optical microscopy coupled with digital image processing as a production-time quality control tool for porcelain tile manufacturing. We demonstrate that it is possible to associate physical properties such as density, porosity and water absorption capacity with internal defects such as thermal delamination in ceramics. Defective and intact samples were subjected to active lock-in thermography and digital microscopy analysis on a workbench developed to simulate the conditions found in production lines. The images were collected and processed using morphological operators, image enhancement and thresholding to detect the presence of defects. These methods were compared with methods that analyze the physical properties of the materials to demonstrate that it is possible to detect the presence of defects.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.