The Preparation Of Expansible Graphite And Its Flame Retardant Application In Rigid Polyurethane Foam

The rigid polyurethane foam (RPUF) is extensively used as structural materials because of their light weight, greater strength, strong adhesion, high strength, and environmental protection etc.Unfortunately, like the majority of organic materials, RPUF is combustible. Consequently, their use is particularly limited. Nowadays, more and more attention has been paid to improve its flame-retardant and high temperature resistance. Improved the high-temperature resistance mainly depends on the structural design; However, the flame retardancy of polyurethane foam mainly rely on adding efficient flame retardant and using structure modification technology introducing the nonflammable and temperature resistance structures to the polyurethane. The main contents of the paper are as follows:1. We studied the functionality, molecular weight, hydroxyl value of polyether and its mixture effect on the viscosity、compatibility、stability. We also studied the different structure of polyether polyols, catalyst, foaming agent, isocyanate index effect on foam process parameters, surface appearance, mechanical properties, the glass transition temperature.2. We synthesized a high volume expansion of the expandable graphite under the optimum reaction condition and formula.and modified RPUF with the expandable graphite (EG) and ammonium polyphosphate (APP). We analyzed the mechanical properties, oxygen index, flame retardant mechanism of composite materials. In addition, we also studied the thermal stability and synergistic flame retardant effect of the RPUF/APP/EG composite materials by scanning electron microscope (SEM), oxygen index test (OI) and Smoke density meter. We synthesized the rigid polyurethane foams with high flame retardant, high temperature resistant and high strength.3. A new system of chemical intumescent flame retardant was built which consisting of recycled phenolic foam powder(carbon source) and ammonium polyphosphate (APP) (acid source/gas source). We applied the r (PF) solely or together with APP as fillers into the RPUF, and investigated the effects on the performance of the foam by scanning electron microscope (SEM), oxygen index test (OI) and the dynamic mechanical analysis (DMA). The results showed that the active groups in PF could take part in reactions within the molding of polyurethane foam, which has contribution on both the interfacial compatibility as well as the compression strength of RPUF. However, it was observed that synergy of PF and APP exhibited excellent flame retardancy by the formation of expanded carbon layers.