scholarly journals Determination of oxygen permeability of polyethylene and polypropylene nonwoven fabric foils

2013 ◽  
Vol 59 (No. 3) ◽  
pp. 105-113 ◽  
Author(s):  
Ľ. Kubík ◽  
S. Zeman

The paper deals with determination of oxygen permeability of the polyethylene and polypropylene foils applied in mulching and food packaging. The construction of the equipment of measurement of gas permeability through the foils is discussed. The design and construction of the equipment was realized with applying of the Standard STN EN 77 0333. The measurement of permeability of oxygen through the polyethylene Bralen 2-63 with 9% colored concentrate Maxithen HP 533041 – violet foil, Polyten®MLB black&white foil and black polypropylene nonwoven fabric foil were realized by means of the modified method.  

2014 ◽  
Vol 60 (No. 4) ◽  
pp. 172-179 ◽  
Author(s):  
Ľ. Kubík ◽  
S. Zeman

The paper deals with the determination of the oxygen permeability and mechanical properties of butter and curd aluminium paper foils Radaflex applied in the food packaging. Foil Radaflex is a paper foil covered by the aluminium layer. The measurement of the oxygen permeability was realized according to the Standard STN EN 77 0333. The measurement of mechanical properties was realized according to the Standard STN EN ISO 1924-2. Determination of moduli of elasticity in the longitudinal and transversal direction were provided and tensile properties as maximal elongations, maximal tensile forces, tensile strengths, tensile indexes and strain at breaks of the longitudinal and transversal specimens were evaluated. The permeability of pure oxygen through aluminium paper foils was studied. Aluminium paper foil was not permeable for the oxygen.


1970 ◽  
Vol 53 (1) ◽  
pp. 3-6
Author(s):  
R. Bruce Klemm ◽  
Mary E. Ambrose Klemm

Abstract The AOAC official method, 24.029–24.035, for the determination of fluorine in foods was modified slightly to o btain quantitative recoveries of fluorine from samples of fish protein concentrate (FPC). The most important alterations include the use of steam distillation, the addition of finely ground silica sand in the distillation, a decrease in the distillation temperature, and the utilization of direct titration. Recoveries of fluoride added to FPC before ashing, using this modified method, averaged 96.0 ± 3.0%. Our results are in agreement with those of several other analysts who used a variety of methods.


2021 ◽  
Vol 22 (8) ◽  
pp. 4018
Author(s):  
Anna Masek ◽  
Angelika Plota

In the field of polymer technology, a variety of mainly synthetic additives are used to stabilize the materials during processing. However, natural compounds of plant origin can be a green alternative to chemicals such as synthetic polyphenols. An analysis of the effect of hesperidin on the aging behavior of ethylene-norbornene copolymer was performed. The evaluation of changes in the tested samples was possible by applying the following tests: determination of the surface energy and OIT values, mechanical properties analysis, colour change measurements, FT-IR and TGA analyses. The obtained results proved that hesperidin can be effectively used as natural stabilizer for polymers. Furthermore, as a result of this compound addition to Topas-silica composites, their surface and physico-mechanical properties have been improved and the resistance to aging significantly increased. Additionally, hesperidin can act as a dye or colour indicator and only few scientific reports describe a possibility of using flavonoids to detect changes in products during their service life, e.g., in food packaging. In the available literature, there is no information about the potential use of hesperidin as a stabilizer for cycloolefin copolymers. Therefore, this approach may contribute not only to the current state of knowledge, but also presents an eco-friendly solution that can be a good alternative to synthetic stabilizers.


1967 ◽  
Vol 50 (5) ◽  
pp. 1102-1108
Author(s):  
Charles F Gordon ◽  
Richard J Schuckert ◽  
William E Bornak

Abstract A modified method for the determination of dithiocarbamate fungicide residues on crops is presented. A large representative subsample of the frozen crop is blended in ice-cold deaerated water and an aliquot of the homogenate is added to the analytical apparatus containing hot 5 0% sulfuric acid. Dithiocarbamates are decomposed to evolve CS2 which is removed by a continuous gentle air-sweep from the digestion flask. Variations in technique allow the analysis of dithiocarbamate fungicide residues in several ranges, 1-10, 10-200, and 200-1000 /ig maneb. Recoveries from a wide variety of crops averaged 70 to 103%. Certain crop types present low recoveries and/or high apparent control values, but modifications in the analytical procedure are successful in solving these problems.


Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 1973-1981
Author(s):  
C Telloli ◽  
A Rizzo ◽  
C Canducci ◽  
P Bartolomei

ABSTRACTThe ENEA Radiocarbon Laboratory (Bologna, Italy) has been operating since 1985; it is the oldest among such laboratories operating in Italy and has been active for about 30 years in the field of dating of different types of samples with the radiocarbon (14C) liquid scintillation method. This study shows the detailed procedure for radiocarbon analysis on bioplastic materials by means of the synthesis of benzene, which includes CO2 production and purification, synthesis of acetylene, and synthesis and collection of benzene. The changes made to the original design of the synthesis procedures and the operational parameters adopted to optimize the combustion of the plastic materials are described. The measurement of 14C activity was performed using the liquid scintillation counting technique by a QuantulusTM 1220 low-background counter. The δ13C content was compared with the percentage of 14C concentration for the characterization of the bio content in plastic used in the food packaging.


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