Last year, the Raw Material department at AGS Technology purchased a Differential Scanning Calorimeter (DSC) to assist in characterizing regrind material. A DSC measures the difference of heat flow between an empty sample pan and a sample pan using a small quantity of plastic. Using this technique, AGS can determine the precise melting point (for semi-crystalline polymers) and glass transition-softening point (for amorphous polymers). These data points appear as peaks on a graph. Since all polymers have a unique melting point, using a DSC we can positively identify the sample type (eg. PA6, PA66, PP, ABS, PC, etc…). If there is more than one peak, that means there is more than one polymer present in the sample, and from the size of the peaks we can also determine the percentage of each polymer. Used in conjunction with a battery of mechanical property tests, the DCS provides an analytical method to help verify incoming regrind material. To keep up with the high volumes of regrind materials that AGS processes every day, AGS ordered its DSC with a carousel to allow for pre-loading multiple samples that can be tested “lights out”. This new DSC capability continues to build on AGS Technology’s commitment to characterize every lot of regrind and always allocate it to its highest end use.
The chart above is sectioned into two parts for two different material samples from a potential supplier, best described as:
Top section: DSC thermogram shows Nylon 6 contaminated with 18.6% of High-temperature Nylon 6. This would be a problem for AGS and would be rejected at this early stage of sampling.
Bottom section: DSC thermogram on a supplier sample shows there is 99.6% Nylon 66 along with 0.6% PP. This slight amount of PP is attributed to black color concentrate carrier which is typical for this material. This is acceptable to be used in production.