Synthesis And Properties Study Of Novel Phosphorous-nitrogen Synergistic Flame Retardant Curing Agent Of Epoxy Resin

Epoxy resin is one of the most important thermosetting resins widely applied toaviation engineering, electronic packaging, architectural engineering, food packagingand transportation for its low-cost，high production efficiency，and reasonablereliability characteristics. General epoxy resin is highly flammable and the LOI onlyhas19.8, therefore we need flame retardant epoxy resin in many fields. According tothe trend of developing halogen-free flame retardant and the damage to the epoxyresin from additive flame retardant, Prepare the reactive flame retardant epoxy resinhas gained a lot of attention from many scientists in recent years.9,10-dihydro-9-oxa-10-phosphahenanthrene-10oxide (DOPO) and itsderivatives have high thermal stability, so we select them to apply to improve theepoxy resin flame retardant property. First, we use two-step method to synthesis3，3’，5，5’-tetramethyl diphenyl-4，4’-diol epoxy resin (TMBP)，and characterize itsstructure with FT-IR，1H-NMR and DSC. Then, we use DOPO to prepare two typesof derivatives DDP and DBI as the curing agent of TMBP. Dynamic non-isothermalDSC is used to study TMBP curing conditions in order to define time and temperatureof DDP and DBI curing blends.In the fourth chapter，the thermal properties and flame retardant properties ofTMBP/DDS (non-phosphorous), TMBP/DDP (phosphorous) and TMBP/DBI(phosphorous-nitrogen synergistic) three curing epoxy resins are tested respectively. First, we use DMA to three types of curing epoxy resins of TMBP/DBI、TMBP/DDP、TMBP/DDS make a comprehensive study for thermal properties. According to theresult, TMBP/DDP has the lowest Tg which structure compose of lots of alkeneschain only has132°C. However, TMBP/DBI、TMBP/DDS have higher Tg185°C and192°C. TGA result shows, TMBP/DBI (phosphorous-nitrogen synergistic) possesses abetter thermal property because of curing agent DBI has a better thermal stability.Although DDP has a less thermal stability than DBI, it remains has a certain amountof char yield in800°C at air atmosphere. Then we use LOI to make a comprehensiveanalysis about three curing epoxy resins of TMBP/DBI、TMBP/DDP、TMBP/DDS.The results shows, phosphorous-nitrogen synergistic flame retardant epoxy resinTMBP/DBI possesses the highest LOI value34.2, and TMBP/DDP (phosphorous)curing epoxy resin has a lower LOI about32.4. TMBP/DDS (non-phosphorous) alsohas30.0, it results of the epoxy resin has a lot of biphenyl rigid structure. In summary,three curing epoxy resins of TMBP/DBI、TMBP/DDP、TMBP/DDS achieve flameretardant level.