Synthetic polymers are human-made polymers, and are produced for a wide variety of applications. The structure of the polymers produced influences the properties of final product. One of the most common raw materials for polymer production is polyols.
Polyols are alcohols that have more than one hydroxyl group available for organic reactions. Hydroxyl groups are a type of chemical grouping where a hydrogen atom is bonded to an oxygen atom in an organic compound. Combining raw polyols with isocyanate, a highly reactive compound, produces polymers such as polyurethanes. Polyurethanes are used in a wide range of applications, from the production of spandex fibers to insulating foam.
A common use of polyurethane foam is in seating systems. These seating systems are implemented in a wide variety of applications, which include airplanes, car seats, and office chairs. Polyurethane seating is a preferred material in seating systems due to its ability to be readily formed into comfortable, ergonomic designs.
The purity of raw materials is essential for consistent polyurethane formulations. Polyols are hygroscopic, meaning that they readily absorb atmospheric moisture. Excess moisture in the polymerization reaction between polyols and isocyanates is undesirable as isocyanates react with water to produce carbon dioxide. The carbon dioxide acts as a foaming agent, significantly altering the final texture and density of the polyurethane. In order to ensure consistency, the water content of the raw polyols must be monitored to maintain uniformity between raw materials. Because loss on drying is not possible as most polyols will evaporate at high temperatures, the favored method for moisture analysis is Karl Fischer titration.
A company that produces seating systems contacted Hanna Instruments to improve their raw materials quality control protocol. The customer wanted to monitor the water content of their polyol resin in order to produce the desired density of the foam. Their ideal water content was 3% moisture by weight. Hanna suggested the Karl Fischer Volumetric Titrator - HI903.
The HI903 conforms to the apparatus specifications of ASTM D4672, the industry standard method for determining the water content of polyols. Since standardization of the titrant is performed daily, the customer appreciated the ability to update the standardized value used in the titration methods at the push of a button.
Because the customer has different polyol blends with different water contents, the customer appreciated that the titrator will automatically suggest ideal sample sizes based on the expected water content. The ability of the HI903 to interface with their analytical balance allowed the customer to easily and accurately accept the exact sample weight entered into the titration cell.
Additionally, the customer appreciated support from the applications and tech departments as they were not certain which chemicals and supplies would be necessary to perform their titrations. Hanna’s support enabled customer to confidently purchase the correct chemicals and all accessories for their application. Overall, The customer felt that the HI903 provided a high value based on its features and the level of support offered by Hanna.
