DETERMINATION OF PEAK BASE-LINE FOR SEMICRYSTALLINE POLYMERS

To determine heats of fusion a base line is necessary. A DSC measures the heat flux into a sample, which is the sum of a part based on the exess enthalpie and another resulting from the heat capacity, which is the base line. The temperature dependences of these two parts describe the complex changes in morphology during the melting process. A method for determination of the heat capacity part of the sample is proposed. It is based on an one dimensional three phase layer stack model. First results on different polyethylenes are represented.