Abstract:Abstract. In a novel binder system, carnauba wax was considered to replace the synthetic backbone polymers (polyolefins) enhancing the environmental sustainability of Ceramic Injection Molding (CIM) technology. The paper presents comparison of the rheological performance and thermal behavior of the aluminum oxide CIM feedstocks based on a binder containing carnauba wax with those consisting of a commercial binder. Further, acrawax (N, N'-Ethylene Bis-stearamide) has been considered as another possible substitu… Show more
“…The wettability trend is as follow: EGMA-3 (66.9°) > E40-3 (73.3°) > C–O (94.3°). The low contact angle of the binder is critical to ensure sufficient wetting of the metallic powder, subsequently promoting appropriate mixing and moulding of metal powders [36]. Figure 5 Contact angle of the POM-based binder system with different compatibiliser compositions.…”
Owing to the different characteristics of each of the multiple polymers, obtaining a homogenous metal injection moulding (MIM) feedstock blend is challenging. Therefore, studying interactions between the polymeric components is vital for achieving suitable MIM feedstocks. We report on the effects of different compatibilisers -EGMA and E40on the interactions in polyoxymethylene (POM) and polypropylene (PP) blends. We measured contact angles and performed Fourier transform infrared spectroscopy and atomic force microscopy analyses to identify the suitable compatibiliser that yields a feedstock with excellent properties. It was found that the binder system based on EGMA-3 demonstrates the lowest contact angle and best miscibility for the POM/PP blends compared to E40. This enhanced interaction lies in the chemistry of EGMA, having an active site that reduces the interfacial tension between the components of the POM/PP blend. Subsequently, this creates a positive interaction between the polymers and metal powders, ensuring good adhesion within the feedstock.
“…The wettability trend is as follow: EGMA-3 (66.9°) > E40-3 (73.3°) > C–O (94.3°). The low contact angle of the binder is critical to ensure sufficient wetting of the metallic powder, subsequently promoting appropriate mixing and moulding of metal powders [36]. Figure 5 Contact angle of the POM-based binder system with different compatibiliser compositions.…”
Owing to the different characteristics of each of the multiple polymers, obtaining a homogenous metal injection moulding (MIM) feedstock blend is challenging. Therefore, studying interactions between the polymeric components is vital for achieving suitable MIM feedstocks. We report on the effects of different compatibilisers -EGMA and E40on the interactions in polyoxymethylene (POM) and polypropylene (PP) blends. We measured contact angles and performed Fourier transform infrared spectroscopy and atomic force microscopy analyses to identify the suitable compatibiliser that yields a feedstock with excellent properties. It was found that the binder system based on EGMA-3 demonstrates the lowest contact angle and best miscibility for the POM/PP blends compared to E40. This enhanced interaction lies in the chemistry of EGMA, having an active site that reduces the interfacial tension between the components of the POM/PP blend. Subsequently, this creates a positive interaction between the polymers and metal powders, ensuring good adhesion within the feedstock.
“…It is essential that the variety of possible combinations of the dispersed filler and the polymer mixture of binders leads, both quantitatively and qualitatively, to a significant difference in the properties of feedstocks, which determine the technological modes of their processing and, to a large extent, the quality of the final product-parts mass-produced by the PIM method. Polyoxymethylene (POM), polyolefins in the form of polypropylene (PP) and polyethylene (PE), ethylene vinyl acetate (EVA), polystyrene (PS), polyethylene glycol (PEG), polymethyl methacrylate (PMMA), and other polymers and oligomers are the main components of binders [3][4][5]. However, the most industrially demanded types of polymer binders in PIM technology are polyoxymethylene-based compositions and wax-polyolefin mixtures [3][4][5].…”
Section: Introductionmentioning
confidence: 99%
“…Polyoxymethylene (POM), polyolefins in the form of polypropylene (PP) and polyethylene (PE), ethylene vinyl acetate (EVA), polystyrene (PS), polyethylene glycol (PEG), polymethyl methacrylate (PMMA), and other polymers and oligomers are the main components of binders [3][4][5]. However, the most industrially demanded types of polymer binders in PIM technology are polyoxymethylene-based compositions and wax-polyolefin mixtures [3][4][5]. Despite a large number of research and experimental and technological works devoted to different compositions of polymer binders for PIM technology, the actual task is still a comparative analysis of the properties of different binders to determine their advantages and disadvantages and to optimize the compositions used.…”
Despite the large number of studies devoted to different compositions of polymer binders for PIM technology, the actual task is still a comparative analysis of the properties of different types of binders to determine their advantages and disadvantages and optimize the compositions used. In this regard, this study aims at the identification and comparative analysis of the rheological properties of the most demanded feedstocks with binders based on polyoxymethylene and a wax–polyolefin mixture under the condition of using identical steel powder filler. The rate of change in the volume fraction of the liquid phase of the binder in the compared feedstocks with temperature change was determined by the calculation–experimental method. As shown, the temperature dependence of the viscosity of feedstocks with a binder based on a polymer blend depends on factors with variable power, i.e., the viscosity change with temperature occurs by different mechanisms with their relaxation spectra. Thus, the principle of temperature–time superposition for feedstocks with multicomponent binders is not applicable, and the study of the viscosity of such materials should involve a wide range of shear rates and temperatures using experimental methods. Capillary rheometry was used to measure the flow curves of feedstocks based on polyoxymethylene and wax–polyolefin binders. The analysis of flow curves of feedstocks showed that feedstocks with a binder of solution–thermal type of debinding have significantly lower viscosity, which is an advantage for molding thin-walled products. However, their difference of 1.5 times sensitivity to the shear rate gradient leads to their lower resistance to “jets” and liquation of components because of shear rate gradients when molding products with elements of different cross-sectional areas.
“…In addition, Hausnerova [ 36 ] reviewed the different binder systems for PIM feedstocks. It is suggested that polypropylene (PP) provides higher mechanical properties than other backbone polymers.…”
The current study presents the effect of the backbone as an important binder component on the mechanical, rheological, and thermal properties of Aluminium (Al) alloy feedstocks. A thermoplastic elastomer (TPE) main binder component was blended with either polypropylene (PP), grafted-maleic anhydride-PP (PPMA), or grafted-maleic anhydride-PPwax (PPMAwax) plus PP, as the backbone. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were performed to investigate the thermal properties of binder systems and feedstocks. Fourier-transform infrared (FTIR) spectroscopy was used to study the chemical interaction between the binder and the Al alloy. After making feedstock filaments, tensile tests, scanning electron microscopy (SEM), and fused filament fabrication (FFF) printing were done. The results showed that although the PP printability was acceptable, the best mechanical properties and printed quality can be achieved by PPMA. TGA test showed that all binder systems in the feedstocks could be removed completely around 500 °C. From FTIR, the possibility of chemical reactions between Al alloy particles and maleic anhydride groups on the grafted PP backbone could explain the better dispersion of the mixture and higher mechanical properties. Tensile strength in PP samples was 3.4 MPa which was improved 1.8 times using PPMA as the backbone.
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