Miroslav Maňas

Mechanical properties of irradiated polyamide under thermal stress

It was found in this study, that radiation crosslinking has a positive effect on the mechanical properties of selected type polyamide. In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. The main purpose of this paper has been to determine the effect of radiation crosslinking on the tensile strength and elongation of PA 66 (filled with 30 % glass fibers). These properties were examined in dependence on the dosage of the ionizing electron beam radiation (non-irradiated samples and those irradiated by dosage 66 and 132 kGy were compared) and on the test temperature (23, 50, 80, and 110 oC). Radiation cross-linking of PA 66 results in increased mechanical strength, and decreased of elongation. As an addition, the increased surface microhardness of polyamide was found.

Local mechanical properties of irradiated cross-linked filled poly (butylene terephthalate) (PBT)

MEYS, Ministry of Education, Youth and Science; MSMT-7778/2014, National Landcare Programme; LO1303, National Landcare Programme; CEBIA-Tech, ERDF, European Regional Development Fund; CZ.1.05/2.1.00/03.0089, ERDF, European Regional Development Fund

Effect of Beta Irradiation on Mechanical Properties of Surface Layer of Injection Moulded High Density Polyethylene (HDPE)

TBU in Zlin - resources of specific university research and Technology Agency of the Czech Republic [IGA/FT/2015/006, TA03010724 AV]; Ministry of Education of the Czech Republic [MSMT-7778/2014]; European Regional Development Fund under the Project CEBIA-Tech [CZ.1.05/2.1.00/03.0089.]

Micro-Hardness of Irradiated Polyamide

The influence of beta radiation on the changes in the structure and selected properties (mechanical and thermal) was proved. Using high doses of beta radiation for glass fiber filled polyamide (PA) and its influence on the changes of micromechanical properties of surface layer has not been studied in detail so far. The specimens of glass fiber filled PA were made by injection moulding technology and irradiated by low doses of beta radiation (0, 132, 165 and 198 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using WAXS and instrumented microhardness test. The results of the measurements showed change some in micromechanical properties (indentation hardness) when high doses of beta radiation are used.

Effect of Recycled Particle Size to Micro-Hardness Properties of Styrene Acrylonitrile

The aim of this research paper is to study the effect of particle size of recycled material on the micro harness. Valuation of recycled material effect takes place in several mixtures of materials. These mixtures differ in particle size, which are made during grinding of plastic waste, from large particles similar to the original material to dust particles. The recycled material is always the same as is the original material. Tested material is styrene acrylonitrile SAN. Testing is performed at ambient temperature of 23°C. After the first recycling there is a change of hardness; which decrease mostly in mixture with the smallest particles.

The Behaviour of Cross-Linking Filled PP to 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 behaviour. The aim of the experiments was to study the influence of different doses of Beta radiation to the structure and micro-mechanical properties of polypropylene filled by 30% glass fiber (PP+GF). Hard surface layers of PP+GF can be formed by radiation cross-linking by β – radiation with doses of 33, 66 and 99 kGy. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the PP+GF tested. Micro-mechanical properties increased with increasing value of the dose of irradiation material (increase about 49%). The changes were examined and confirmed by X-ray diffraction.