Preparation And Characteristic Of PU/Rigid Organic Particle Composites Materials

Polyurethane (PU) elastomer has fine comprehensive properties, such as good mechanical properties, high elasticity, splendid properties of the frication resistance, good oil resistance, the ozone (O3) resistance and so on. So it has been widely applied in many fields of civil industry, national defense, space flight, military affairs and physical education. In order to widen the realm of application and improve the properties, many researchers have been devoted to study on the modification of PU. With the nanometer technology rising, now preparation of PU/Inorganic composite has been an effective approach. The modifying effect is not perfect because of the poor dispersion of inorganic particle in polymer. It is easy to synthesis rigid organic particle, further more have good compatibility. The method of using rigid organic particles modifying PU is proposed in this paper for the first time. The PS particles and rigid organic particles with hydroxyl group were synthesized by seed emulsion polymerization method. The influencing factors of stability and particles size were discussed, and rigid organic particles was characterized by TEM and FTIR.The test results of TEM proved that the rigid organic particles were nano-particles.The spectral of FTIR showed that HEMA has polymerized on the surfaces of rigid organic particles. The testing result of titration indicated that the content of hydroxyl group on the surfaces of particles was 0.107%.The PU/rigid organic particles composites were prepared by the pre-polymerization method in two systems of PTMEG and PEA . The composites were characterized by mechanical properties measurement, solvent resistance measurement, DSC, DMA and SEM.The test results of mechanical properties showed that the mechanical properties of the PU/rigid organic particle composites was improved remarkably than pure PU. The mechanical properties of the composites contenting PS rigid organic particles were better than composites contenting rigid organic particles with hydroxyl in the PEA system, it was opposite in the PTMEG system. When the content of rigid organic particles is 1%～3%,the comprehensive mechanical properties of composites were better.The DMA results showed that the storage modulus of the PEU/PS composites have not obviously changed, but glass transition temperature (Tg) and loss modulus decreased. The results verified that rigid organic particles improve the micro-phase separation of PU.The DSC results indicated that the rigid organic particles lead to produce more crystalline grain in the hard segments of PU, and the new crystal morphology appeared and some crystal of hard segments imbedding into soft segments. That is to say, the force between rigid organic particles and hard segment of PU influences the micro-phase separation of PU.The solvent resistance property tests proved that the solvent resistance property of composite was worse than pure PU.The SEM photographs revealed that the rigid organic particles can uniformly disperse in the composite of PU/rigid organic particle.