The market of polyethylene terephthalate (PET) bottles presents polymers of different types, which have been developed in order to provide the client with products with improved properties, mainly in respect of molar mass. In the case of PET, as well as in the recycling industry of this polymer, the test of intrinsic viscosity is widely used to determine molar mass. This study presents the results of intrinsic viscosity and density for PET bottles of soft-drinks, juices and soy-bean oils. Samples of each bottle were dissolved in 60-40 phenol-tetrachloroethane solution and flowed into a Cannon-Fenske viscometer at 30 °C to measure the relative viscosity, which was converted to intrinsic viscosity. The results have shown a change in the property, depending on the producer and volume. For the twenty-one samples analyzed, the viscosity varied from 0,70 to 0,79 dL/g. Therefore, a best bottle's selection can help the recyclers to provide best products, with small variation of molar mass. The values of density obtained showed little variation, which increase when the results are converted to crystallinity.
PET; recycling; intrinsic viscosity; molar mass; density
