Polyethylene Wax Modified by Organoclay Bentonite Used in the Lost-Wax Casting Process: Processing−Structure−Property Relationships

Abstract

In this paper, the influence of bentonite (BNT) on rheological properties, linear shrinkage, hardness, and structure of polyethylene wax (PE-wax) used in the lost-wax casting process are studied. Experiments were conducted with PE-wax with different contents of bentonite (from 0.1 to 5 wt.%). The structural changes of modified polyethylene wax were evaluated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The addition of bentonite in a concentration range between 0 and 0.8 wt.% into PE-wax caused a decrease of the linear shrinkage and the hardness of PE-wax/BNT blends. Modified polyethylene wax containing greater than 1 wt.% of the filler showed an increase in viscosity. The DSC-based investigations confirmed good miscibility and a uniform structure of PE-wax with BNT. Moreover, an increase in melting temperature onset and its enthalpy observed for filler PE-wax material showed an influence of bentonite on the crystalline structure of the polymeric matrix. SEM observations of the fractured surfaces confirmed the homogeneous structure of blends with contents up to 0.8 wt.% BNT. In the case of higher filler concentrations, the presence of more numerous and large clusters of filler in the polymer matrix was observed due to the increase in the viscosity of the PE-wax/BNT melt composition during mixing. The PE-wax blend with 0.4 wt.% BNT gives better results of reduced linear shrinkage and lower hardness than unmodified material. Lastly, a new developed material (PE-wax/0.4 BNT) was subjected to technological tests, consisting of the preparation of the mold and manufacture of a high-quality aluminum cast, using the lost-wax method.

Polyethylene/Polyamide Blends Made of Waste with Compatibilizer: Processing, Morphology, Rheological and Thermo-Mechanical Behavior

“…The ideal materials that meet both economic and environmental criteria that can be used in mechanical engineering are recycled polymer regranulates of various engineering plastics, i.e., polyethylene (PE), polyamide (PA), polypropylene (PP), and polyoxymethylene (POM) [ 11 , 12 ]. Polymer regranulates, as a rule, have reduced mechanical properties and thermal resistance, and many procedures can be used to improve these properties, such as mixing with virgin polymers; adding fibrous fillers, i.e., glass fibers, and natural fibers; and modifying with powder fillers such as basalt [ 13 ], talc [ 14 ], polysilsesqioxanes (POSS) [ 15 , 16 ], or montmorillonite (MMT) [ 17 ].…”

Optimization of Extrusion-Based 3D Printing Process Using Neural Networks for Sustainable Development

“…To date, a limited number of publications have investigated the use of ANNs in 3D printing parameter selection and optimization. Research on the sustainable characteristics of materials [ 66 ], including polymers used as 3D printing material [ 67 ], is ongoing, but the number of studies is so far small. We view our results as preliminary.…”

The overall crystallization behavior of polyethylene/wax blends as phase change materials for thermal energy storage: A mini review

“…Very few studies investigated the morphology of polyethylene/wax blends with the addition of inorganic fillers such as Copper (Cu) and bentonite (BNT), [49,52] and organic fillers such as Wood Flour, and/or expanded graphite (EG) [50,51] as a means to expand its practical applications. For LDPE/wax/Cu composites containing 40 vol% wax and 1 or 5 vol% Cu powder, a two-phase morphology was reported with the copper particles covered by the wax layer.…”