Structural Modification And Properties Research Of Foamable Phenolic Resin

As a new generation of thermal insulation and fireproof materials,phenolic foam has developed rapidly,and its low density,low flammability and low toxicity have been widely used in construction,defense,aviation,energy and other fields.From the research reports on the foamable phenolic resin at home and abroad,it can be seen that the research and modification of the foamable phenolic resin molecular structure has gradually become the main research direction for optimizing the performance of phenolic foam.Aiming at the weak link in the molecular structure of the expandable phenolic resin,the targeted improvement of its performance has become the preferred means of modifying the phenolic foam.This paper focuses on the structural modification of foamable phenolic resin and the foam properties of its preparation,modification of phenolic foam toughness,free formaldehyde content and heat resistance.Resin structure modification using 3-pentadecyl-phenol,acetoacetic ester-terminated polyether,urea and 1,4-bis(methoxymethyl)-benzene as modifiers,and the structure,gel time,free formaldehyde content and solid content of the modified resin were analyzed and tested,the mechanical properties,cell structure,water absorption and heat resistance of the modified phenolic foam were tested.The experimental results show that the spatial network of phenolic resin modified by 3-pentadecyl-phenol is more regular.When the amount of 3-pentadecyl-phenol added is 15% of the total amount of phenol,the toughness of phenolic foam is increased by 400%.The compressive strength is up to 0.21 Mpa and the bending strength is up to 0.32 Mpa.Acetoacetic ester-terminated polyether introduces a polyether polyol structure into the modified resin.When the amount of phenol is 14%,the toughness of the modified foam is more than three times higher than normal foam,and the bending strength is the largest up to 0.26 MPa,the compressive strength reaches a maximum of 0.188 Mpa.When the amount of urea added is 15% of the amount of phenol,the free formaldehyde content is the lowest,which can be up to 0.006%,but the performance is best at 9%.When the amount of 1,4-bis(methoxymethyl)-benzene added is 15% of phenol,the modified foam has the best heat resistance,the limiting oxygen index is up to 39.1%.At a weight loss of 5%,the modified phenolic foam is increased 50 ° C than the ordinary phenolic foam.