Branislav Duleba

Evaluation of Process Wear of Selected Tool Steels for Injection Molds

The aim of this contribution is to test the suitability of selected types of tool steels used for manufacturing of injection molds. Experiments were realized by the simulation of adhesive wear using laboratory equipment Amsler, which allows the testing of grinding pairs. Evaluated grinding pairs consisted of tool steel and two types of roundels. Tested polymeric materials were based on pure PA6 and PBT filled with short glass fibers, prepared by mixing process in twin screw extruder. The wear of five types of tool steels were evaluated by weight decrease before and after the experiment, while changing the friction coefficient of grinding pairs, material of grinding pairs and sensing the roughness of steel before and after wear.

Preparation and Characterization of Polypropylene/MMT Nanocomposites

In this paper, study of preparation and testing of polymer nanocomposites (PNC) based on polypropylene matrix and montmorillonite nanofillers is described. Samples were prepared by twin-screw extrusion and injection molding to final shape. Changes of basic properties of these PNC ́s were tested and described in main part of this article.

Possibility of Increasing the Mechanical Strength of Carbon/Epoxy Composites by Addition of Carbon Nanotubes

The development of nanoparticle reinforced polymer composites is presently seen as one of the most promising approaches in the field of future engineering applications. The unique properties of at least some of these nanoparticles (e.g., CNTs or carbon black) and the possibility of combining them with conventional reinforcements (e.g., carbon-, glass-or aramid-fibers) has led to an intense research in the field of nanocomposites. This study presents mechanical properties of two carbon composites made from bisphenol A epoxy resin (E) and 3 layers of 160 g/m2 carbon cloth with twill (TC) and plain (PC) weave as a reference and three-composite system that consists from carbon fiber reinforced epoxy matrix and 1% of multi-wall carbon nanotubes dispersed in epoxy resin. Used hardener H507 was based on cycloaliphatic polyamine with absence of nonylphenol. Samples were also tempered at 80 oC (for 12hours) for improvement of their thermal resistance.

Effect of mechanical properties of metal powder-filled hybrid moulded products

Abstract The extensive research on polymer composites is motivated by the fact that it can result in obtaining new materials with enhanced properties. This research primarily focuses on investigating basic mechanical properties which determine the use of a particular composite material. This paper presents the results of tests investigating the mechanical properties, i.e. tensile strength, hardness and impact strength, of hybrid injection mouldings produced at constant processing parameters. We used five metal powder fillers: aluminium, zinc, tin, iron and copper powders, with their contents ranging from 2.5 wt% to 15 wt% relative to a polypropylene matrix composite material. The relationships were determined between different contents of the aforementioned metal powder fillers and Young’s modulus, maximum tensile stress, tensile stress at break, strains, Shore hardness and Charpy impact strength. The research also involved investigating mould shrinkage. Relevant conclusions were drawn.

Analysis of the Reason of Non-Homogeneity of Molded Part from Semi-Crystalline PPS

This study presents measurement and calculations of crystallization of PPS composite with 40 % of glass fibers on real molded part using differential scanning calorimeter and also FEM simulation of impact of injection mold temperature on the crystallization of same part. Analyzed part had circular shape and samples for testing were taken from 4 different locations marked “3, 6, 9, 12” depending on their position (marked like as at clock face), while location 3 was nearest to the mold intake.

Analysis of Short Glass Fiber Orientation in Injection Moulded Components

Fiber reinforced polymer composites are common materials used to produce parts for structural applications. The attractiveness of these materials is a result of the combined advantages of the fiber reinforcing effect and the high production rates achievable by technologies such as injection molding. The fiber orientation in short fiber reinforced thermoplastics depends on injection moulding technology parameters. The aim of this paper is to propose possibilities for comparing fiber orientation of the real sample and the result from simulation software.

Prediction and Verification of Compatibility of MMT Nanofiller in PA6 Matrix

This contribution deals about study of mechanical properties and compatibility between PA6 polymer as matrix and modified and unmodified montmorillonite clay nanofiller Cloisite. For this purposes in the first part of study the Hamaker constants, Adhesion work and B parameter for systems PA6/Cloisite 30B, PA6/Cloisite 93A and Pa6/Cloisite Na+ were calculated and compared. The second part of article consists of mechanical tests (tensile test, impact test) of moulded samples and Scanning Electron Microscope (SEM) study of these samples.

STUDY OF PP/CLOISITE MMT NANOCOMPOSITE PROPERTIES

Abstract This paper deals with the explanation of the preparation process for polymer nanocomposites. As a reference matrix, Mosten PND 33-301was used, filled with montmorillonitebased nanofillers (Cloisite 20A, Cloisite 3010). A twin-screw extruder and an injection molding machine were used for the preparation of material and samples, and the relevant parameters are described in the first part of the article. Changes in the basic properties of these PNCs were tested and described in the experimental part of this article. The structures of the materials were observed by SEM microscopy.