Analytical review of some relevant methods and devices for the determination of the specific volume on thermoplastic polymers under processing conditions

This article reviews some of the most representative methods and devices to measure the specific volume in polymeric materials found in literature. Each method is described and a comparison between the experimental conditions and typical injection molding processing conditions is discussed. In general, the main difficulty with specific volume measurements is determination of the temperature distribution through sample thickness, particularly when achieving typical processing conditions is intended. Therefore, the necessity of developing a new device which allows direct measurements of pressure and temperature at various positions along the sample thickness in order to calculate the cooling condition was identified.