Water absorption is the amount of water the material takes to achieve the desired consistency and create a quality end product. For example, it is the optimal amount of water that can be added to a dough before it becomes too sticky to handle.
Some polymers have a natural tendency to absorb water. Indeed, superabsorbent polymers are preferred in medicine, construction and similar advanced applications. But at the same time, the absorptive capacity of thermoplastics leads to various changes in their processing properties. Moisture or water absorption is the capacity of a plastic or polymer to absorb moisture from its surroundings. The absorbed moisture acts as a plasticizer, reducing the glass transition temperature and the strength of the plastic, but this is a reversible effect. However, the absorbed water can also lead to irreversible degradation of the polymer structure.
Some of the known effects are: changes in size and mass caused by water absorption (eg swelling), extraction of water-soluble components or changes in mechanical (eg flexibility, tensile strength, impact strength) and electrical performance.
The main standard applied in water absorption tests is the following standard published by the American Society for Testing and Materials (ASTM): ASTM D570-98 Standard test method for water absorption of plastics. This standard describes a test method for determining the relative absorption rate of water by plastics when immersed in water. This test method is intended to be applied for testing all types of plastics, including cast, hot molded and cold molded resin products, and homogeneous and laminated plastics in rod and tubular form, and sheets with a thickness of 0,13 mm or more.
In accordance with this test method, the samples for the water absorption test are dried in an oven for a certain time and temperature and then placed in a device to cool. After cooling, the samples are weighed. The material is then kept in water at agreed conditions, usually 23 degrees Celsius, for 24 hours or until equilibrium is reached. The samples are removed, dried with a lint-free cloth and weighed.
Our organization also provides water absorption testing services with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.
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