DENSITY-BASED ANALYSIS OF POLYMERS USING MAGNETIC LEVITATION DEVICE CONSTRUCTED BY MAGNET ARRAYS

Standard magnetic levitation (MagLev) device consists of two identical square permanent magnets with like poles facing each other. Limited by the size of the permanent magnet, standard MagLev device cannot levitate samples with large size. This paper proposed a novel MagLev device using magnet arrays, which can accommodate large-scale samples. Unlike magnet arrays in previous studies, all magnets employed herein face the same direction. The magnetic field generated by the magnet arrays is similar to that of the standard magnet. Within the magnetic field induced by the magnet arrays, the polymer can be levitated to an equilibrium position in a paramagnetic solution and the levitation height is related to its density. The equation correlating density and levitation height can be obtained according to the simulation results. Solutions of different concentrations were used to measure densities of a variety of polymers with an accuracy of ±0.0003 g/cm³. The non-destructive testing could also be used for plastic parts based on its posture (orientation) within the paramagnetic solution. The use of magnet arrays circumvents the trouble of manufacturing large magnets, realizes testing of polymers/parts with large sizes, and facilitates industrialization of magnetic levitation detection.