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The material parameters melt flow rate (MFR), density (D), notched impact strength (NIS) at –30°C, stress crack resistance [determined with the Full Notch Creep Test (FNCT)] and resistance to oxidative degradation (Ox) have been selected for a comparison of polyethylene grades in the European standard EN 15507. These parameters have a relationship with design type tests of packagings for the transport of dangerous goods.
This paper presents the results of additional investigations to determine the impact of the pre-storage time of jerricans with 55% nitric acid at 40°C and 23°C on the marginal drop heights in drop tests at –18°C, on the MFR and on the tensile properties. Jerricans made of different polyethylene grades were pre-stored with 55% nitric acid for 21, 42 and 84 days at 40°C and for six months at 23°C.
The tests showed that the NIS values at –30°C of polyethylene grades were not comparable with marginal drop heights determined in drop tests at –18°C.
Pre-damage with 55% nitric acid for 21 days at 40°C led to an increase in the marginal drop heights of the jerricans. Altering the test regulations by increasing pre-storage time with 55% nitric acid to 42 days would be an alternative.
The test results demonstrated clearly that pre-storage of the jerricans for six months at 23°C caused a higher increase in the MFR and lower marginal drop heights for the jerricans when compared with pre-stored jerricans for 21 days at 40°C.
The aim of this work was to study the interaction between high-density polyethylene (HDPE) grades as material for dangerous goods packagings and biofuels such as E85 and biodiesel. Jerricans made of two polyethylene (PE) grades were filled with these fuels and exposed to temperatures of 20°C and 40°C for 1 year. Tensile properties (tensile strength, breaking elongation and elasticity modulus) and melt flow rate (MFR) were determined once a month, and Fourier transform infrared (FTIR) spectroscopy was used to evaluate changes in the chemical structure.
Measurements of the MFR and tensile properties of the PE grades after 1 year of exposure to E85 showed only a slightly damaging influence. An increase in the peak of 1585 cm-1 (C=C) stretching vibrations is visible in the FTIR spectra after the immersion tests with E85. Therefore, packagings made of HDPE grades are suitable for the transport of E85.
An increase in the MFR with immersion time of the grades in biodiesel was measured, in particular, after 1 year of exposure. The elasticity modulus of the PE grades was reduced with immersion time. The FTIR spectra showed a broadening of the CO peak of 1740 cm-1 and the appearance of the hydroxyl group at 3500 cm-1. Both results are explained by secondary degradation products of the PE decomposition process caused by increasing unsaturated fatty acid content in the biodiesel. In light of the above mentioned, it was concluded that HDPE grades are not suitable as packaging materials for the transport of biodiesel.
The notched impact strength at -30 °C is one of the selected properties, together with the corresponding test method and tolerances, for a comparison of polyethylene grades of one design type in the procedural rule on suitability proof for alternative plastic resins used for packagings and intermediate bulk containers (IBCs) for the transport of dangerous goods.
The marginal drop heights determined with the drop test at -18 °C after pre-storage of the test samples with 55 % nitric acid at 40 °C only partly related to the notched impact strength at -30 °C. The Charpy method is only suitable for classifying the grade in relation to toughness behavior and using this classification for comparison with other grades. Notched impact strength can provide a qualitative indication if the test samples fail under shock forces.
Conditioning the design types with 55 % nitric acid for 21 days at 40 °C causes an increase in the marginal drop heights of the design types in drop tests at -18 °C when compared with design types without pre-storage. Post-crosslinking of the grades increases stiffness because of the acidic influence.
For the characterization and the comparison of polyethylene grades used for the manufacture of packaging and intermediate bulk container, the following parameters are required: melt flow rate (MFR), density (D), low-temperature notched impact strength, full notch creep test (FNCT) and increase of MFR by molecular degradation (resistance to oxidative degradation). The relationship between these material parameters determined on the basis of specimens prepared from compression-moulded sheets of polyethylene grades and the test behaviour of packaging has been investigated in several tests. The environmental stress crack resistance determined by FNCT represents the impacts from the stacking tests performed with standard liquid wetting solution (without pre-storage) and with normal butyl-acetate-saturated wetting solution (pre-storage with normal butyl acetate). Resistance to molecular degradation by the determination of MFR increase is related to the impacts in drop tests and stacking tests performed after pre-storage for 21 days with standard liquid 55% nitric acid at 40°C. The low-temperature impact strength is directly comparable with the impacts in drop tests at -18°C performed without pre-storage and after pre-storage with 55% nitric acid. A partly good relationship was found between the test results and the material parameters. Conditioning the design types with 55% nitric acid for 21 days causes an increase in the marginal drop heights of the design types in drop tests at -18°C when compared with design types without pre-storage. Post-cross-linking of the grades increases stiffness because of the acidic influence.
8iofuels including ethanol and biodiesel (fatty acid methyl ester) represent an important renewable fuel alternative to petroleum-derived transport fuels. lncreasing biofuels use would bring some benefits, such as a reduction in oil demands and greenhause gas emissions, and an improvement in air quality.
Biofuels including ethanol and biodiesel (FAME) represent a renewable fuel alternative to petroleum-derived transport fuels. The aim of this work was to study the interaction between high density polyethylene (HDPE) with permeation barriers in form of polyamide (PA) and fluorination, and biofuels such as E85 (fuel with 85 % ethanol), biodiesel and B10 (heating oil with 10 % biodiesel). 10 l jerrycans made of polyethylene with permeation barrier of PA were filled with E85 and biodiesel and exposed to temperatures of 20 °C and 40 °C for 5 years. Half of the 20 l jerrycans of HDPE for filling with B10 were fluorinated at the inner layer to prevent permeation before the exposure. Tensile properties were determined once a year, and FTIR-spectroscopy was used to evaluate possible changes.
The tensile properties tensile strength and breaking elongation of HDPE jerrycan cuttings with permeation barrier decreased, but not significantly, after immersion in E85, biodiesel and B10. The elasticity modulus of the polyethylene grades was especially reduced during exposure to E85.
The FTIR spectra of HDPE jerrycan cuttings with permeation barrier showed that immersion tests for five years with the test fuels at 20 °C and 40 °C did not lead to a decomposition of the permeation barriers.
Biofuels including ethanol and biodiesel (FAME) represent a renewable fuel alternative to petroleum-derived transport fuels. The aim of this work was to study the interaction between high density polyethylene (HDPE) with permeation barriers in form of polyamide (PA) and fluorination, and biofuels such as E85 (fuel with 85 % ethanol), biodiesel and B10 (heating oil with 10 % biodiesel). 10 l jerrycans made of polyethylene with permeation barrier of PA were filled with E85 and biodiesel and exposed to temperatures of 20 °C and 40 °C for 5 years. Half of the 20 l jerrycans of HDPE for filling with B10 were fluorinated at the inner layer to prevent permeation before the exposure. Tensile properties were determined once a year, and FTIR-spectroscopy was used to evaluate possible changes.
The tensile properties tensile strength and breaking elongation of HDPE jerrycan cuttings with permeation barrier decreased, but not significantly, after immersion in E85, biodiesel and B10. The elasticity modulus of the polyethylene grades was especially reduced during exposure to E85.
The FTIR spectra of HDPE jerrycan cuttings with permeation barrier showed that immersion tests for five years with the test fuels at 20 °C and 40 °C did not lead to a decomposition of the permeation barriers.
The aim of this work was to study the interaction between high density polyethylene (HDPE) grades as material for dangeraus goods packagings and biofuels such as E10 (fuel with 10% ethanol), E85 (fuel with 85% ethanol), biodiesei and 810 (heating oil with 10% biodiesel). Jerricans made of two polyethylene grades were filled with these fuels and exposed to temperatures of 20 oc and 40 oc for more than one year. Tensile properlies (tensile strength, breaking elongation and elasticity modulus) and Melt Flow Rate (MFR) were determined, and Fourier Transform Infrared Spectroscopy (FTIR) was used to evaluate changes in the chemical structure.
Measurements of the MFR and tensile properlies of the polyethylene grades after exposure to E1 0, E85 and 810 showed only a slightly damaging influence. A n increase in the peak of 1585 cm·1 for the (C=C) stretching vibrations was visible in the FTIR spectra after immersion tests with E85. A n increase in the MFR with the immersion time of the grades in biodiesei was measured - in parlicular, after one year of exposure. The elasticity modulus of the polyethylene grades was reduced with the immersion time too. The FTIR spectra showed a broadening of the C=O peak of 1740 cm·1 and the appearance of the hydroxyl group at 3500 cm·1.