Novolac is a thermoplastic phenol-formaldehyde resin, which is typically used as a bonding agent in brake linings and abrasive grinding wheels. Other uses include electrical insulation, clutch facings, and a reinforcement agent and modifier for nitrile rubber. The polymer is primarily obtained using excess phenol and acid catalysts. Novolac resin is generally cured with hexamethylenetetramine or p-formaldehyde to form cross-linked structures. The resin used in this study was not cross-linked.