Yellow index comparison of different polyethylene and polypropylene in pellets and plaque measured in two spectrophotometers color-view BYK-Gardner

Identifier:  TFG:303

Handle: https://hdl.handle.net/20.500.11797/TFG303

Authors:  Nadal Lozano, Joan Carles

Abstract:
The work is based on the comparison of the yellow index for high and low density polyethylene and polypropylene in pellets and plaque measured in two spectrophotometers color-view BYK-Gardner, called instruments 26006 and 26003. The measurements are performed both for intermediate products and final products. Two methods, compression and injection, have been used to obtain the plaques for the measurement. When measuring the yellow index of polymers the interday reproducibility was very good, which means that the polymers are stable over time. Results show that in the intermediate products, polypropylene homopolymers (PP) have the biggest difference between measurements from spectrophotometers of all polymers measured in pellets and plaque. However, for high density polyethylene (HDPE) and polypropylene heterophasic (PB) differences are lower. For final products, injection method to obtain the plaques provides very low differences between both instruments, but has the disadvantage of a longer time to obtain the plaques.