Local mechanical properties of irradiated cross-linked HDPE

Using high doses of beta radiation for high-density polyethylene (HDPE) and its influence on the changes in the micromechanical properties of the surface layer has not been studied in detail so far. Specimens of HDPE were made with the injectionmoulding technology and irradiated with high doses of beta radiation (0, 132, 165 and 198) kGy. The changes in the micromechanical properties of the surface layer were evaluated using an ultra nano-hardness test. The results of the measurements showed a considerable increase in the micromechanical properties (indentation hardness, indentation elastic modulus) when high doses of beta radiation are used. The aim of this paper is to study the effect of ionizing radiation at different doses on the ultra nano-hardness of the surface layer of HDPE and compare these results with those for non-irradiated samples. The study was carried out due to the ever-growing use of this type of polymer HDPE.BGS, Biogeoscience Institute, University of Calgary; 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 FundTBU in Zlin [IGA/FT/2017/010]; Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under project CEBIA-Tech [CZ.1.05/2.1.00/03.0089

The Influence of runner system on production of injection molds

This experimental study describes the influence of runner system on rheological properties during the injection molding process. Economic effects on the amount of production are discussed as well. Autodesk Moldflow Synergy 2016 (Moldflow) was used for the study of the injection process. Three suggestions of the runner system, cold runner system, hot runner system and the combination of cold hot runner system have been promoted. These three variants underwent the rheological and economic analysis. As a result, recommendations for the application of the runner system for the required amount of production have been suggested.Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]; TBU in Zlin [IGA/FT/2016/010

Micro-hardness of PBT influenced by beta radiation

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. This research paper deals with the utilization of electron beam irradiated PBT on the micro-indentation test. Radiation doses of 66, 132 and 198 kGy were used for unfilled PBT with the 5% crosslinking agent (triallyl isocyanurate). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the PBT tested. The highest values of micro-mechanical properties were reached radiation dose of 132 kGy, when the micro-mechanical values increased by about 30%.TBU in Zlin [IGA/FT/2016/010]; Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089

Polymer fluidity influenced by type and amount of filler

Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of cavity surface roughness and technological parameters on the flow length of polymers into mold cavity. Application of the measurement results may have significant influence on the production of shaping parts of the injection molds especially in changing the so far used processes and substituting them by less costly production processes which might increase the competitiveness of the tool producers and shorten the time between product plan and its implementation. This research focused into the influence of technological parameters on filling of the injection mold cavity and the flow length respectively.Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]; TBU in Zlin [IGA/FT/2016/010

Mechanical properties and temperature stability of modified polybutylene terephthalate by beta rays

The presented article deals with the research of mechanical properties before and after temperature load and temperature stability of modified polybutylene terephthalate by radiation cross-linking. The mechanical properties were measured, at the ambient temperature, by the tensile test on samples which were non-irradiated and irradiated by different doses of the beta radiation and then were temperature loaded. Results demonstrate that PBT has higher values of tensile strength with the increased irradiation dose and it has decreased elongation at break sharply. The purpose of the article is to consider to what extent the irradiation process influences the resulting mechanical properties and temperature stability. The PBT tested showed significant improvement of temperature stability after irradiation. This behaviour leads to the expansion of these materials in the automotive and electrical industry.TBU in Zlin [IGA/FT/2016/010]; Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [L01303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIATech [CZ.1.05/2.1.00/03.0089]ERDF, European Regional Development Fund; CZ.1.05/2.1.00/03.0089, ERDF, European Regional Development Fun

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

This article deals with the measurement of the mechanical properties of a filled poly (butylene terephthalate) (PBT+35 % GF (glass fibres)) surface layer modified with beta radiation. Injection-moulded test bodies were subsequently irradiated with beta radiation using doses of (0, 33, 66 and 99) kGy. The measurement of the mechanical properties was realized with an ultra nano-hardness tester. The results of the measurements showed a considerable increase in the micromechanical properties (indentation hardness, indentation elastic modulus) when low doses of beta radiation were used. The aim of this paper is to study the effect of ionizing radiation at different doses on the ultra nano-hardness of the surface layer of poly (butylene terephthalate) (PBT) and compare these results with those for non-irradiated samples. The study was carried out due to the ever-growing use of this type of polymer, 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 FundTBU in Zlin [IGA/FT/2017/010]; Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under project CEBIA-Tech [CZ.1.05/2.1.00/03.0089

Effect of beta radiation on the quality of the bonded joint for difficult to bond polyolefins

Bonding is increasingly being used, and it is an ever-evolving method for creating unbreakable bonds. The strength of adhesive bonds determines, to a significant extent, the possible applications of this technology and is influenced by many factors. In addition to the type of adhesive used, the characteristics of the surface layers play a significant role; therefore, significant attention is paid to their adjustment and modification. Radiation crosslinking is one of the most important methods for modifying polymer properties. Currently, the most frequently used type of radiation for polymer crosslinking is beta minus (β-) radiation, which affects not only mechanical but also surface properties, chemical and temperature resistance, and surface layer characteristics of polymers. This study investigated the effect of β- radiation on the surface layer properties of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) and the effects of surface-layer modification on the ultimate tensile strength of bonded joints. Based on the results, we concluded that β- radiation significantly changes the properties of the tested surface layers, increases the surface energy, and improves the adhesiveness of bonds. Consequently, the final strength of the LDPE, HDPE, and PP bonds increases significantly. © 2019 by the authors.European Regional Development Fund under the project CEBIA-Tech Instrumentation [CZ.1.05/2.1.00/19.0376]; Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Programme [LO1303 (MSMT-7778/2014)