PP FIBCs Durability and Aging Estimates
Polypropylene FIBC bags are frequently re-used and thus purchased second-hand. Shouldn’t the end-user be aware of the possible biodeteriorations, which, according to the studies of Hueck-van der Plas (Poland, 1971 - 1977) affect 2% of annual manufacturing of artificial and natural fibres. It would be even a more worrying reason to bother if one buys a used woven FIBC bag, that are naturally susceptible to attacks minimum by microorganisms with keratinolytic and proteolytic enzymes.
At the moment scientists recognise two aging types: Physical (migration and additives + solvent absorption and free polymers volume relaxation) and chemical (thermochemical (thermoxidation and anaerobic aging), photochemical and aging in the reactive agents environment). But in practise testing of PP FIBC bags aging durability in normal services conditions (no extra high or low temperatures, no acid environment, no extra load tensions) is a very challenging task that requires the so called accelerated aging method approach.
Defining of FIBC bags life time and endurance is estimated by the critical concentration of chain scissions. Tensile strength, percentage of elongations and loss of mass usually serve as the indication of the end of life. However, scientists often come to the conclusion that laboratory tests are not applicable to measure aging and durability degradation for FIBCs. Field reports say that if used under normal conditions, FIBC bags can re-used up to the moment when damage to the bag occurs (and even the damage is subject for a repair in many cases). However, in accordance with the standards FIBC bag can be re-used to store the same type of contents that was loaded earlier.