Automation of procedures to measure ash content for polyolefin and ryton poly(phenylene sulfide) resins



A robotic system was implemented to automate the polymer ash procedure performed in the Plastics Technical Center's Materials Evaluation Laboratory. The system automates ASTM Test Method D 5630: “Standard Test Method for Ash Content in Thermoplastics (Procedure B)” and Phillips Ryton poly(phenylene sulfide) (PPS) laboratory procedures “Determination of Ash of PPS Compounds” and “Ash Content of Polyphenylene Sulfide.” These procedures determine the ash content of the respective resins using a rapid, muffle furnace ashing technique. The robot system automates all aspects of the procedure, including taring the crucibles, inserting the samples into and retrieving the samples from the muffle furnace, weighing the crucibles, recording the weights, cooling the crucibles, calculating and reporting the results, and storing the data. Data generated on polyolefin (polyethylene and polypropylene) and Ryton poly(phenylene sulfide) samples show that the system generates data that are reproducible and equivalent to those obtained by manual application of the ASTM and Phillips procedures. The robot system has been successfully used to determine ash values ranging as low as 0.02 wt% for polyolefin resins and as high as 40+ wt% for PPS compounds. A comparison of results from the automated procedure to those obtained by the manual application of the procedure demonstrated that the robot provided equivalent values, with estimates of the precision that were at least as good as the manual procedure. Since its installation, the system has been used extensively, increasing the laboratory's testing capacity and providing labor savings of more than 0.5 human-years annually. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:296–304, 2000