The effect of magnetic field and ionizing radiation on the mechanical properties of polymer blends consisting of high density polyethylene （HDPE） and acrylonitrile-butadiene rubber （NBR） has been investigated. The...The effect of magnetic field and ionizing radiation on the mechanical properties of polymer blends consisting of high density polyethylene （HDPE） and acrylonitrile-butadiene rubber （NBR） has been investigated. The purpose of the work was to create HDPE/NBR blend composites of significantly different compositions （with an excess of HDPE, intermediate ones, and with an excess of NBR） and to investigate the role of composition on mechanical deformation properties under the influence of magnetic field. The investigation has importance from the engineering viewpoint, since thermoplastic composite materials have been used as structural elements in thermonuclear and engineering fields, like wires, insulation materials and others, which are frequently subjected to mechanical loadings under the effect of magnetic field greater than 1 T. One part of the blends has been irradiated with 5 MeV accelerated electrons up to absorbed dose D equal to 150 kGy. Unirradiated and the radiation modified blends have been exposed to a constant magnetic field with induction B equal to 1.0 T, 1.5 T and 1.7 T. It is found that the action of magnetic field decreases the elastic modulus of unirradiated materials. Decrement of elastic modulus is reduced with increase of the content of NBR in composites. It is also found that preliminary irradiation noticeably decreases the effect of magnetic field. Data of the influence of the magnetic field, radiation cross-linking, and the ratio of the components on the creep are also obtained.展开更多
This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE （High density polyethylene） industry. This polymer is part...This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE （High density polyethylene） industry. This polymer is partially crystalline, having amorphous phases and crystalline phases, HDPE type is harder and tougher than other polyethylenes, having a wide range of applications that depend almost exclusively on the processes for obtaining final products. After the process, waste from the manufacture of these products are discarded daily as they are not found effective ways to use this material. In this study we seek to use this ＂factory floor＂ to act as filler in a polyurethane matrix derived from the castor oil, which is a natural biodegradable. The residue loads were separated according to the process that originated in this way have been the A residue from the process of cork and the B residue derived from the extrusion process. Specimens in mass proportions of 10%, 20% and 30% polyethylene both loads were prepared and their thermal properties were mediated, these being the thermal conductivity （k）, specific heat （c） and thermal diffusivity （~）. By adding such fillers to castor polyurethane matrix, different behaviors were observed, because of the residue contributed to a reduction in conductivity and specific heat of the composite material. Since the residue B on average 47% higher than residue, caused an increase in these same properties as before the spaces filled with air only into the polyurethane are now filled with polyethylene grains. We can see then that the particle size of the HDPE waste has a direct influence on the improvement of the thermal properties of the analyzed composite material.展开更多
Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3...Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3-amino-1,2,4-triazole C2H4N4(ATz) were crystallized into NaN5 and two novel energetic coordination polymers(CPs),(NaN5)5[(CH6-N3)N5](N5)3–(1) and(NaN5)2(C2H4N4)(2) were prepared respectively via a self-assembly process. The crystal structure reveals the co-existence of the chelating pentazole anion and organic component in the solid state. In polymer 1, Na+and N5– were coordinated to form a cage structure in which guanidine cation [C(NH2)3]+ was trapped;for polymer 2, a mixedligand system was observed;N5 – and ATz coordinate separately with Na+and form two independent but interweaved nets. In this way, coordination polymer has been successfully utilized to modify specific properties of energetic materials through crystallization. Benefiting from the coordination and weak interactions, the decomposition temperatures of both polymers increase from 111°C(1D structure [Na(H2 O)(N5)]?2 H2 O) to 118.4 and 126.5°C respectively. Moreover, no crystallized H2 O was generated in products to afford the anhydrous compounds of pentazole salts with high heats of formation( >800 kJ mol–1). Compared to traditional energetic materials, the advantage in heats of formation is still obvious for the cyclo-N5– based CPs, which highlights cyclo-N5– as a promising energetic precursor for high energy density materials(HEDMs).展开更多
文摘The effect of magnetic field and ionizing radiation on the mechanical properties of polymer blends consisting of high density polyethylene （HDPE） and acrylonitrile-butadiene rubber （NBR） has been investigated. The purpose of the work was to create HDPE/NBR blend composites of significantly different compositions （with an excess of HDPE, intermediate ones, and with an excess of NBR） and to investigate the role of composition on mechanical deformation properties under the influence of magnetic field. The investigation has importance from the engineering viewpoint, since thermoplastic composite materials have been used as structural elements in thermonuclear and engineering fields, like wires, insulation materials and others, which are frequently subjected to mechanical loadings under the effect of magnetic field greater than 1 T. One part of the blends has been irradiated with 5 MeV accelerated electrons up to absorbed dose D equal to 150 kGy. Unirradiated and the radiation modified blends have been exposed to a constant magnetic field with induction B equal to 1.0 T, 1.5 T and 1.7 T. It is found that the action of magnetic field decreases the elastic modulus of unirradiated materials. Decrement of elastic modulus is reduced with increase of the content of NBR in composites. It is also found that preliminary irradiation noticeably decreases the effect of magnetic field. Data of the influence of the magnetic field, radiation cross-linking, and the ratio of the components on the creep are also obtained.
文摘This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE （High density polyethylene） industry. This polymer is partially crystalline, having amorphous phases and crystalline phases, HDPE type is harder and tougher than other polyethylenes, having a wide range of applications that depend almost exclusively on the processes for obtaining final products. After the process, waste from the manufacture of these products are discarded daily as they are not found effective ways to use this material. In this study we seek to use this ＂factory floor＂ to act as filler in a polyurethane matrix derived from the castor oil, which is a natural biodegradable. The residue loads were separated according to the process that originated in this way have been the A residue from the process of cork and the B residue derived from the extrusion process. Specimens in mass proportions of 10%, 20% and 30% polyethylene both loads were prepared and their thermal properties were mediated, these being the thermal conductivity （k）, specific heat （c） and thermal diffusivity （~）. By adding such fillers to castor polyurethane matrix, different behaviors were observed, because of the residue contributed to a reduction in conductivity and specific heat of the composite material. Since the residue B on average 47% higher than residue, caused an increase in these same properties as before the spaces filled with air only into the polyurethane are now filled with polyethylene grains. We can see then that the particle size of the HDPE waste has a direct influence on the improvement of the thermal properties of the analyzed composite material.
基金financially supported by the National Natural Science Foundation of China (11702141, 21771108, and U1530101)
文摘Coordination to form polymer is emerging as a new technology for modifying or enhancing the properties of the existed energetic substances in energetic materials area. In this work, guanidine cation CN3 H6+ (Gu) and 3-amino-1,2,4-triazole C2H4N4(ATz) were crystallized into NaN5 and two novel energetic coordination polymers(CPs),(NaN5)5[(CH6-N3)N5](N5)3–(1) and(NaN5)2(C2H4N4)(2) were prepared respectively via a self-assembly process. The crystal structure reveals the co-existence of the chelating pentazole anion and organic component in the solid state. In polymer 1, Na+and N5– were coordinated to form a cage structure in which guanidine cation [C(NH2)3]+ was trapped;for polymer 2, a mixedligand system was observed;N5 – and ATz coordinate separately with Na+and form two independent but interweaved nets. In this way, coordination polymer has been successfully utilized to modify specific properties of energetic materials through crystallization. Benefiting from the coordination and weak interactions, the decomposition temperatures of both polymers increase from 111°C(1D structure [Na(H2 O)(N5)]?2 H2 O) to 118.4 and 126.5°C respectively. Moreover, no crystallized H2 O was generated in products to afford the anhydrous compounds of pentazole salts with high heats of formation( >800 kJ mol–1). Compared to traditional energetic materials, the advantage in heats of formation is still obvious for the cyclo-N5– based CPs, which highlights cyclo-N5– as a promising energetic precursor for high energy density materials(HEDMs).
