Investigation Of Regenerated Phenolic Resins

Thermosetted phenolic resins were successfullly recycled,ground and reused as an effective component in phenolic resins to prepare regenerated phenolic(i.e.PFwRPFxy)specimens with acceptable mechanical stengths and other required properties.More than 80%of the ground powders of recycled phenolic resins are between 200 to 400 mesh;while nearly 15%of the recycled ground powders are between 400 and 800 mesh after jet milling processes.The required mechanical stremgths improved significantly after addition of proper amounts of 1,4-butanediol(BDO)during the reaction injection processes of BDO modified regenerated phenolic specimens(i.e.PFwRPFxyBDO).Tensile,impact strength and specific gravity values of PFwRPFxy specimns reduced significantly as the contents of recycled ground powders increated;while their water absorption and shrinkage percentages increased significantly with the increase in contents of recycled ground powders.It is worth noting that tensile,impact strength and specific gravity values of PFwRPFxyBDOz specimens improved to a maximal value,respectively,after addition of an optimal amounts of BDO modifier during their reaction injection processes.Moreover,the tensile,impact strength and specific gravity values of each PFwRPFxyBDOz series specimens improved further as the sizes of the recycled ground powders reduced.In fact,the tensile and impact strengths of the best prepared PFwRPFxyBDOz specimen are more than 95%of those of the freash phenolic specimens without additon of any recycled phenolic resins.Fourier transform infrared spectroscopy and Solid-state 13C nuclear magnetic resonance analyses of the phenolic resins,ground powders of recycled phenolic resins,PFwRPFxy and PFwRPFxyBDOz specimens were performed to understand the interesting mechanical and other properties found for PF_wRPFxyBDO_z specimens.