Preparation Of Polyester Polyol/Nanoparticle Foam Composites By Self-assembly

Polyurethane foam materials have excellent properties of heat insulation,thermal insulation,vibration isolation,sound absorption,etc.,and are widely used in the fields of construction,transportation,and daily necessities.In this thesis,we prepared polyurethane foam with high foam strength,small and uniform pore size and excellent thermal insulation properties by self-assembly of polyester polyol-nanoparticles at the water-oil interface to stabilize the emulsion and by regulating the pH of water phase,polyester polyol and nanoparticle concentration,etc.In this thesis,we have addressed the shortcomings of traditional polyurethane foaming technology such as high viscosity of foaming system and difficult to regulate foam pore size.The specific results are as follows.(1)Self-assembly studies on polyester polyol/silica nanoparticle systems showed that the equilibrium value of interfacial tension of polyester polyol toluene solution/silica nanoparticles in aqueous solution decreased with the increase of pH of the aqueous phase.The addition of potassium bromide facilitated the tight accumulation of polyester polyol/silica nanoparticles at the oil-water interface.The increase of the concentration of silica nanoparticles led to the decrease of the droplet size of the emulsion,the smaller pore diameter of the prepared polyurethane foam,the thinner cell wall,the lower density and strength of the foam,and the higher closed cell ratio.The introduction of silica nanoparticles can effectively avoid cell coalescence and collapse.When the concentration of polyester polyol increases,the pore diameter of the prepared foam decreases,the cell wall thickness has no obvious change,and the density of the foam decreases,but the hardness slightly increases,and the closed cell ratio increases.(2)Research on self-assembly of polyester polyol/cellulose nanocrystals shows that pH value has almost no effect on the self-assembly behavior of polyester polyol/cellulose nanocrystals under weak acidity and neutral conditions.Under alkaline conditions,as the pH value increases,the accumulation of cellulose nanocrystals at the oil-water interface becomes firm.During the preparation of lotion,the increase of the concentration of cellulose nanocrystals and polyester polyols led to the decrease of emulsion droplet size,the pore diameter of the prepared foam became smaller,the cell wall became thinner,the density decreased,the strength slightly decreased,and the cell closure ratio increased.The introduction of cellulose nanocrystals effectively avoided the cell coalescence and collapse of foam.The increase of polyisocyanate concentration and the addition of chain extender effectively improved the strength of foam,and the addition of chain extender made the cell change from open to closed.