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The mechanical properties of PE
by：CSSSLD
2021-02-03
PE under greenhouse to acid, alkali and salt solution, even under the high concentration of injection molding processing PE also had no significant effect.
But the sulfuric acid and nitric acid and other antioxidants will slow erosion of PE.
Temperature, oxidation is more significant.
PE does not dissolve in any solvent at room temperature, but the solubility parameter of similar solvent can make its swelling.
Gradually with the increase of temperature, crystallization of PE are destroyed, macromolecule and enhanced the role of the solvent, when reaching a certain temperature after PE soluble in fat hydrocarbon, aromatic hydrocarbon, halogenated hydrocarbon, etc.
But even under the high temperature PE still does not dissolve in water, glycerin, fatty alcohol, acetone, ether and vegetable oil.
PE after heated, with temperature rise, gradually melting crystallization part, amorphous part. Obviously, the melting point and crystallinity and crystal morphology. Melting point of about 125 - when the HDPE The melting point of 137 ℃, LDPE is about 105 - 120℃。 Tg of PE with relative molecular mass, the degree of crystallinity and branched vary, and on the basis of different test methods have bigger difference, it is generally believed in - 50 ℃.
the transmittance of nonpolar medium is greater than medium polarity of transmittance, the transmittance of organic medium is greater than the transmittance of inorganic medium. With LDPE plastic bottles containing different liquid will be different degree of loss, therefore, LDPE plastic container is not suitable for long-term storage of liquid, especially chemical and oil substances, not only easy to damage, but also may be due to the expansion deformation of the container. PE is polar crystalline polymer, it has excellent chemical stability.
the catalytic temperature of PE about - 60 - - 70 ℃, with the increase of relative molecular mass brittle temperature is reduced, the brittle temperature below - such as ultra-high molecular weight polyethylene 140℃。 Lower Tg and Tb has excellent cold resistance, PE in still has good low temperature toughness. But the temperature is not high, the use of PE force even small load the deformation temperature is low. In general, continuous use of LDPE temperature below 60 ℃, HDPE under 80 ℃.
PE heat capacity, thermal conductivity, linear expansion coefficient of little change with temperature rise. But PE heat capacity is larger than most thermoplastics, linear expansion coefficient is bigger also, should be given attention to in the processing. The permeability of polymer material caused by dissolve and spread two process. Gas dissolved in plastic material first and then spread to the lower side of the gaseous substances concentration, and evaporation.
PE ability of resistance to environmental stress cracking by relative molecular mass and its distribution and branched degree of influence is very big. With the improvement of relative molecular mass, narrow distribution, branched degree increased, the degree of crystallinity decreased, environment stress cracking resistance of PE ability enhancement. Visible, in terms of environmental stress cracking resistance, LDPE HDPE. Linear structure highly crystalline HDPE is sensitive to environmental stress cracking, under the effect of ambient medium easy to brittle cracking, long-term contact with chemical reagents and the bad environment of products such as buried should choose varieties of HDPE with high relative molecular mass, the macromolecular crosslinking between PE and can greatly improve its resistance to environmental stress cracking.
the molecular structure of the material, thickness and the chemical properties of diffusion medium and concentration, and environmental factors such as temperature will affect the amount of gas through. Injection molding processing plant permeability decreases with the increase of the density of PE, HDPE permeability is far lower than LDPE. PE film packaging is not suitable for long time to keep the items of fragrance, but suitable for moisture to prevent moisture loss of goods or packing. All kinds of medium permeability of PE in the relationship between the solubility of PE is very large.
more excellent articles: the structure of the polyethylene, click directly.
http://www。 csssld。 cn//html/2017/Info_0919/678。 HTML
changshu smoothly da plastic products factory website: http://www. csssld。 Cn /
more wonderful articles, immediately search: changshu da plastic products factory smoothly
PE after heated, with temperature rise, gradually melting crystallization part, amorphous part. Obviously, the melting point and crystallinity and crystal morphology. Melting point of about 125 - when the HDPE The melting point of 137 ℃, LDPE is about 105 - 120℃。 Tg of PE with relative molecular mass, the degree of crystallinity and branched vary, and on the basis of different test methods have bigger difference, it is generally believed in - 50 ℃.
the transmittance of nonpolar medium is greater than medium polarity of transmittance, the transmittance of organic medium is greater than the transmittance of inorganic medium. With LDPE plastic bottles containing different liquid will be different degree of loss, therefore, LDPE plastic container is not suitable for long-term storage of liquid, especially chemical and oil substances, not only easy to damage, but also may be due to the expansion deformation of the container. PE is polar crystalline polymer, it has excellent chemical stability.
the catalytic temperature of PE about - 60 - - 70 ℃, with the increase of relative molecular mass brittle temperature is reduced, the brittle temperature below - such as ultra-high molecular weight polyethylene 140℃。 Lower Tg and Tb has excellent cold resistance, PE in still has good low temperature toughness. But the temperature is not high, the use of PE force even small load the deformation temperature is low. In general, continuous use of LDPE temperature below 60 ℃, HDPE under 80 ℃.
PE heat capacity, thermal conductivity, linear expansion coefficient of little change with temperature rise. But PE heat capacity is larger than most thermoplastics, linear expansion coefficient is bigger also, should be given attention to in the processing. The permeability of polymer material caused by dissolve and spread two process. Gas dissolved in plastic material first and then spread to the lower side of the gaseous substances concentration, and evaporation.
PE ability of resistance to environmental stress cracking by relative molecular mass and its distribution and branched degree of influence is very big. With the improvement of relative molecular mass, narrow distribution, branched degree increased, the degree of crystallinity decreased, environment stress cracking resistance of PE ability enhancement. Visible, in terms of environmental stress cracking resistance, LDPE HDPE. Linear structure highly crystalline HDPE is sensitive to environmental stress cracking, under the effect of ambient medium easy to brittle cracking, long-term contact with chemical reagents and the bad environment of products such as buried should choose varieties of HDPE with high relative molecular mass, the macromolecular crosslinking between PE and can greatly improve its resistance to environmental stress cracking.
the molecular structure of the material, thickness and the chemical properties of diffusion medium and concentration, and environmental factors such as temperature will affect the amount of gas through. Injection molding processing plant permeability decreases with the increase of the density of PE, HDPE permeability is far lower than LDPE. PE film packaging is not suitable for long time to keep the items of fragrance, but suitable for moisture to prevent moisture loss of goods or packing. All kinds of medium permeability of PE in the relationship between the solubility of PE is very large.
more excellent articles: the structure of the polyethylene, click directly.
http://www。 csssld。 cn//html/2017/Info_0919/678。 HTML
changshu smoothly da plastic products factory website: http://www. csssld。 Cn /
more wonderful articles, immediately search: changshu da plastic products factory smoothly
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