Vojtech Senkerik

Behavior of Recycled Polypropylene with Glass Fibers at Different Temperature and their Charpy Impact and Hardness Properties

The aim of this paper is to investigate the behavior of the recycled polymer containing the filler. The recycled polymer under investigation is polypropylene with a glass fiber filler. During grinding of plastic waste particles are formed which have a different size, shape and surface, from larger pieces to dust particles. Several recycled mixtures were made, all from original material. Samples with different particle size of recycled material were subsequently tested by mechanical testing. Included tests were Charpy impact test and Shore hardness test. Testing was conducted at different temperatures; ambient 23 °C and increased temperatures 60 ° and 100 °C. The results show a very large effect on Charpy properties and a lesser influence on the hardness of these mixtures. Mixture of smallest dust particles indicates larges change of measured properties.

Study of Tensile Properties of Recycled Polypropylene with Glass Fibers at Different Temperature

This research paper studies the influence of preparation method of recycled polymer material with glass fibers on the tensile properties of the final product. The recycled material was made from polypropylene, which originally contained 30 % of glass fibers. It was divided into fractions using size of the crushed particles. These fractions ranged from large particles, similar to the original material, to small dust particles. Measurements were performed at various temperatures. It was found that the mixture of dust particles showed a large decrease in measured properties. It is mainly due to shortening of the large glass fibers, so that it no longer fulfills its function as reinforcing filler. Conversely, mixture with larger particles did not show a significant decrease in properties compared to the original material.

Effect of Particle Size of Recycled Polyamide 6 to Impact Toughness and Hardness

This work aims to investigate the effect of recycled material and effect of particle size on the mechanical properties of the recycled material. Tested material is polyamide 6. Every manufacture of any plastic parts produces certain amount of waste, such as defective injects or cold runner system from injection molding technology. When size of this material is reduced, particles of different sizes are made. From large particles similar to the original granulate material, to dust particles. This size variation can cause problems during subsequent processing. These particles of different size have distinct melting rate. To determine behavior of recycled material at room temperature. Impact toughness and hardness tests are performed.

Mechanical Properties of Rubber Samples

This article demonstrates what influence has a change in production technology on mechanical properties of rubber testing samples. It compares two basic production technologies compression molding and injection molding. The aim of this research is to show and evaluate to what extent the properties (tensile strength, extension, tear strength and microhardness) are influenced by the used production technology and to quantify this potential difference on the basis of standard tests. The mechanical tension test according the standard ISO 37, the test determining tear strength according to the standard ISO 34-1 and the instrumented microhardness test (DSI) according to the standard ISO 6507-1.

Surface Properties of Crosslinking Polyamide Measured by Micro-Indentation Test

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behavior. This paper studies the effect of different doses of ionizing beta radiation on the micro-mechanical properties of commercially available polyamide. The measured results indicate, that electron beam irradiation is very effective tool for improvement of surface properties of PA6. In terms of micro-mechanical properties, the values of micro-hardness of surface layer increased by 24% at radiation dose of 132 kGy, stiffness of surface micro layer by 26% (132 kGy) as a result of different loads (0.5N and 2N). Improvement of micro-mechanical properties of radiated polyamide has a great significance also for industry. The modified polyamide shifts to the group of materials that have considerably better properties. Its micro-mechanical properties make polyamide ideal for a wide application in areas where higher resistance to wear, creep are required. Commonly manufactured PA6 can hardly fulfil these criteria.

EFFECT OF LENGTH OF GLASS FIBERS IN RECYCLED POLYPROPYLENE ON MECHANICAL PROPERTIES

This article investigates the effect of recycled material particle size on the resulting mechanical properties of products. The product material was polypropylene with glass fibers. Recycled material was prepared by mechanical way of recyclation, then it was categorized by sieve analysis to different size of particles. After preparation, the samples were subjugated to mechanical tests. The samples were subjected to the Charpy impact test, the hardness of Shore D test. Testing was conducted at ambient temperatures. The effect of reprocessing of the material is mainly represented by fiber shortening. As a result, considerable reduction of mechanical properties can be observed.

THE BEHAVIOUR OF CROSS-LINKING FILLED PBT MEASURED BY NANO-HARDNESS

Radiation crosslinking of filled PBT is a well-recognized modification of improving basic material characteristics. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. The specimens of 30% glass fiber filled PBT were made by injection moulding technology and irradiated by doses of beta radiation (0, 33, 66 and 99 kGy). The change of nanomechanical properties is greatly manifested mainly in the surface layer of the modified PBT where a significant growth of nano-mechanical values can be observed. Indentation modulus increased from 1.1 to 1.8 GPa (increasing about 64%) and indentation hardness increased from 56 to 85 MPa (increasing about 52%).The results of the measurements showed considerable increase in nano-mechanical properties (indentation hardness, indentation elastic modulus, indentation creep) when beta radiation are used.

The Behaviour of Cross-Linking Filled PA66 by Micro-Indentation Test

The process of radiation crosslinking helps to improve some mechanical properties of polymer materials. Micro-mechanical changes in the surface layer of glass-fiber filled PA 66 modified by beta radiation were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The specimens were prepared by injection technology and subjected to radiation doses of 0, 33, 66 nad 99 kGy. The change of micro-mechanical properties is greatly manifested mainly in the surface layer of the modified polypropylene where a significant growth of micro-hardness values can be observed. Indentation modulus increased from 1.8 to 3.0 GPa (increasing about 66%) and indentation hardness increased from 87 to 157 MPa (increasing about 80%). This research paper studies the influence of the dose of irradiation on the micro-mechanical properties of semi-crystalline polyamide 66 filled by 30% glass fiber at room temperature. The study is carried out due to the ever-growing employment of this type of polymer.

The Effect of Technology on Micromechanical Properties of Rubber

The aim of this article is to demonstrate to what extent there is an impact on the micromechanical properties of a standardized testing sample made of rubber compound based on synthetic rubber EPDM and produced by injection molding in comparison with a sample produced by classic preparation (cutting off a compression molded plate). Measurement of the properties was carried out according to the instrumented test (DSI), in compliance with ISO 14577 on the measuring device micro-combi-tester.

The behaviour of recycled material with particles of various sizes of polyamide 6 to micro hardness

Every manufacture of any plastic parts produces some waste, such as defective injects or cold runner system from injection molding technology. This waste can be directly used several times. But when size of this material is reduced, particles of different sizes are made. From large particles similar to the original granulate material, to dust particles. This size variation can cause problems during subsequent processing. These particles of different size have distinct melting rate. That can cause an inhomogeneity of a melt and diverse structure of solidified polymer. This research paper studies the influence of the particle size of recycled polymeric material on the micro harness properties of semi-crystalline polyamide 6 at room temperature.