Application Of Polyurethane/Phosphate Ester In Fire Retardant Polypropylene

The halogen flame-retardants are washout because of the repolution. The intumescent flame-retardants(IFR) containing phosphorus is most effective. The inorganic fire retardant is non-toxic and low-smoked. So IFR and brucite(MH) were used as flame-retardants. But in the preaparation of fire retadant polypropylene, both of the IFR and the inorganic fire retadant are not compatble with polypropylene(PP). Thermoplastic polyurethane (TPU) and phosphate ester acid were used as compatibilizing and coupling agent in fire tetardant PP.1. TPU is a high toughness polymer, which has the special structure of soft and hard segments, and could be as carbinizing agent in IFR. TPU could be used as the compatilizer of the PP/IFR system, because its soft organic segment makes it compatible with PP, and its polar group can react with IFR or the intermolecular forces exists. Mechanical test results indicated that tensile strength of PP/IFR/TPU =70/30/3 increased by 9.8% than the PP/IFR binary, and the self-extinguishing time shortened from 45s to 25s. When PP/IFR/TPU was 70/30/4, the impact strength increased by 49.8% than PP/IFR binary. SEM indicated that TPU compatilizer enhanced the interfacial adhesion of PP and IFR, and the compatibility was obviously improved. The rheology analysis showed that the viscosity of the blends declined and then increased again, which illustrated the forces between PP and IFR were influenced by TPU. TPU is an effective compatillizer for intumscent flame-retardant PP with the experiences.2. TPU is a polar polymer. When its content increases in blends, it became incompatible with PP. EPP was chosen as the compatilizer on the PP/TPU blends. SEM showed that as EPP content increased, the fractured surface of blends became rough, and the average size of the islands decreased greatly. POM suggested that EPP made TPU dispersed into PP matrix uniformly and PP crystallized on the TPU surface preferably. The variation of TPU/PP/EPP apparent viscosity implied the reaction between TPU and EPP. DSC measurement illustrated the reaction of EPP and TPU. It is confirmed with the experiment that EPP is an effective compatilizer to TPU/PP blends.3. MH is an inorganic flame-retardant that was added over 50% to meet the need of fire retardant in fire retardant material. Large amount of filler destroyed the mechanical...