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Effect of radiation cross-linking of PA on its thermomechanical properties
Mikel, David ; Tocháček, Jiří (referee) ; Jančář, Josef (advisor)
The influence of ionizing radiation on thermomechanical properties of polyamide reinforced by glass fibers was studied in this bachelor thesis. Ionizing radiation caused reduction of crystallinity, melting and crystallization temperature of polyamide. Tensile strength and tensile modulus increased due to irradiation, meanwhile elongation at break decreased. Notched and unnotched impact strength at laboratory and lower temperature increased with dose of radiation and after reaching the maximum it decreased for higher doses of radiation. Heat deflection temperature increased significantly with dose of radiation and after reaching the maximum it decreased for higher doses of radiation, too. Based on measured properties of investigated material was chosen optimal dose of radiation. Radiation rosslinking is an appropriate technology for increasing dimensional stability at elevated temperatures of polyamide reinforced by glass fibers.
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Corrosion resistance of PA and PC components
Mikel, David ; Pospíšil, Ladislav (referee) ; Jančář, Josef (advisor)
The influence of two lubricating and cleaning agents and diesel fuel on environmental stress cracking of polyamide reinforced by glass fibers and polycarbonate was studied in this master thesis. Testing of environmental stress cracking was performed by the method of critical bending deformation. Bergen elliptical strain jig was used for testing. The test liquids caused varying levels of environmental stress cracking of amorphous polycarbonate, but they did not cause environmental stress cracking of glass fiber reinforced polyamide. The test method used allows testing the resistance of both materials against environmental stress cracking of any liquid. The results can be used to design products that are expected to be exposed to corrosive liquids. Quantification of the influence of stress free corrosion on the static and impact properties of polycarbonate and glass fiber reinforced polyamide was performed by accelerated test. Specimens were exposed to test liquid and an elevated temperature of 70 °C. The mechanical properties of the tested materials were significantly affected by elevated temperature exposure. The yield strength of the polycarbonate has increased and the toughness has decreased due to physical aging. The tensile strength of glass fiber reinforced polyamide has increased due to a decrease of the moisture content of the material.
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Corrosion resistance of PA and PC components
Mikel, David ; Pospíšil, Ladislav (referee) ; Jančář, Josef (advisor)
The influence of two lubricating and cleaning agents and diesel fuel on environmental stress cracking of polyamide reinforced by glass fibers and polycarbonate was studied in this master thesis. Testing of environmental stress cracking was performed by the method of critical bending deformation. Bergen elliptical strain jig was used for testing. The test liquids caused varying levels of environmental stress cracking of amorphous polycarbonate, but they did not cause environmental stress cracking of glass fiber reinforced polyamide. The test method used allows testing the resistance of both materials against environmental stress cracking of any liquid. The results can be used to design products that are expected to be exposed to corrosive liquids. Quantification of the influence of stress free corrosion on the static and impact properties of polycarbonate and glass fiber reinforced polyamide was performed by accelerated test. Specimens were exposed to test liquid and an elevated temperature of 70 °C. The mechanical properties of the tested materials were significantly affected by elevated temperature exposure. The yield strength of the polycarbonate has increased and the toughness has decreased due to physical aging. The tensile strength of glass fiber reinforced polyamide has increased due to a decrease of the moisture content of the material.
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Effect of radiation cross-linking of PA on its thermomechanical properties
Mikel, David ; Tocháček, Jiří (referee) ; Jančář, Josef (advisor)
The influence of ionizing radiation on thermomechanical properties of polyamide reinforced by glass fibers was studied in this bachelor thesis. Ionizing radiation caused reduction of crystallinity, melting and crystallization temperature of polyamide. Tensile strength and tensile modulus increased due to irradiation, meanwhile elongation at break decreased. Notched and unnotched impact strength at laboratory and lower temperature increased with dose of radiation and after reaching the maximum it decreased for higher doses of radiation. Heat deflection temperature increased significantly with dose of radiation and after reaching the maximum it decreased for higher doses of radiation, too. Based on measured properties of investigated material was chosen optimal dose of radiation. Radiation rosslinking is an appropriate technology for increasing dimensional stability at elevated temperatures of polyamide reinforced by glass fibers.
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