Characterization Of Intumescent Fire Retardant Polypropylene's Morphology And Performance

The ammonium polyphosphate (APP)- pentarytheritol(PT) - melamine(M) system was used extensively for a long time in the past. The main problem of preparation of [FR/PP composites is poor process and mechanical properties. Thermoanalysis and flow test results showed that PT 's melting point is near the same with the blend temperature of IFR/PP system, that made the processibility of IFR/PP system has problems; SEM and POM morphology analysis proved the incompatibility of IFR filler and PP matrix, these were the main reasons to made the performance of PP/IFR composite decreased. Compatibility of IFR with matrix PP were improved by tnicroencapsulated IFR or use carboxyl PP (EPP) as coupling agent, but the processibility can't solved completely. So replacing PT or change it's form is necessary.our work as follow:1. Spirocyclic pentaerythratol-di (phosphoric acid mono melamine salt), had high thermostability, intumescent properties, good prcessibility and fire retardance; here PT in form of spirocyclic phosphoric ester, SEM proved that because of incompatibility, the PP/IFR composite had poor mechanical properties.2. The phosphoric acid - pentaerythritol - melamine copolymer, PT in form of phosphoric ester, just the three main components of IFR coexist at suitable proportion, it has good flame retardancy. The results obtained from mechanical tests, SEM morphology analysis and Flow test showed that phosphate ester acid and functionalized PP such as meleated PP, a-Methylacrylic Acid grafted PP , especially EPP was true coupling agents for IFR/PP blends, but not changing the necessary flame retardancy. All result come from flame retardancy test, mechanical properties test, SEM morphology analysis, phosphorus dispersion of section plane of PP / IFR showed: if cortrol proper condition, can obtain PP/IFR that have good processibility and dispersed uniformity.3. SEM, POM morphology analysis and flow test results showed that nylon-6 replaced PT, EPP as coupling agent, can increased mechanical properties of PP/IFR composite; but polyamide is catenulate, at combustion temperature it dripping and the intercourse reaction not easy, went against the intumescent char forming, can't obtain UL 94 V-0 PP/IFR..4. Intumescent graphite and nano-clay cooperate with IFR, hopeful to increase fire retardance, meantime increase mechanical properties of PP/IFR composite, is the direction of fire retardant PP development.