Practice question

Chemical polymerization of acrylamide and bisacrylamide requires free radical generation to initiate vinyl addition. Ammonium persulfate (APS) decomposes to produce sulfate free radicals that attack acrylamide double bonds, starting chain propagation. Tetramethylethylenediamine (TEMED) acts as a catalyst by accelerating APS decomposition and facilitating radical formation at room temperature, stabilizing the reaction and controlling gelation rate. Neither acts efficiently alone for rapid casting. Riboflavin initiates photochemical polymerization under UV light, not chemical initiation. Glycerol is a density agent. Thus APS-TEMED pair constitutes the standard chemical initiator system.