Study On Toughing Phenolic Formaldehyde Foam

Phenolic foam is a thermal insulation material with advantages of flame retardant, non-toxic and dimensional stability when burning. It has high practical value in high-rise buildings, transportation, petroleum and chemical industry. At same time, its drawbacks are seriously restricted in production of application in reality,for example fragility, easily dregs. In this paper, the problem of phenolic foam toughened was studied, explore the ideal synthesis of the foam and the appropriate type and amount of toughener.The influence of synthesis process, reaction materials ratio, phenolic foam, catalyst, reaction temperature and reaction time to resin properties was studied. Summarized the optimal process of synthetic resins by research in resin solid content and viscosity. And based on that, phenolic foam was modified with several tougheners PVB, PBT, PEG, PVA, NBR(PNBR, LNBR) and faberglass(ECPZ-1, ECPB-1-3). The analyses showed that the free phenol, aldehyde content of the toughened phenolic foam was further reduced.TG-DTA results of the toughened phenolic foam showed that several toughener can improve the compression strength and bending strength of the foam in varying degrees and the thermal stability was not affected. The existence of the modified phenolic functional groups, mechanical properties, thermal properties were characterized by IR, universal testing machine and TGA testing. The results showed that mechanical properties, thermal stability and water absorption of the foam can achieve the standards.The better toughening effect was PBT, when the toughener volume was 2.5 phr. (accounting for the total mass of resin), compressive strength of the foam increased from the 0.105MPa to 0.336MPa, the tougheners on the foam has resulted in higher toughening effect; when the weight loss 44% at 802℃, the modified bubble has good heat resistance without lowering the thermal stability.The toughened foam structure was studied by SEM. Generally, the modified phenolic foam showed lower free phenol, formaldehyde content, higher toughness, excellent thermal stability and high rate of closed-cell structure.