| The PU/EP LIPN was prepared using toluene diisocyanates (TDI), polypropylene glycol (PPG 3010) and epoxy resin (E-44) as the main materials in this paper. The chemical structure of the product was characterized by FT-IR. The result showed that respective networks of PU and EP have formed and lack of chemical bonds between PU and EP. TEM suggested that the emulsion particles of LIPN were not core-shell structure and the average particle size of LIPN and PU blank emulsion sample were around 110nm. The particle size analysis showed that both LIPN products and PU blank samples had nano-scale emulsion particles and narrow particle size distribution. The results showed two components of PU and EP coexisted on the same particle. The glass transition temperatures (Tg) of LIPN, PU and EP were investigated by DMA. The results indicated that two components of PU and EP have formed the interpenetrating polymer networks. The result was also well in the accordance with DSC analysis. The LIPN structure was also characterized by shear modulus of products by Davies equation. The experiment results showed that none core-shell structure, molecular scale interpenetrating and homogeneous LIPN was successfully synthesized by a new way of polymerization reaction, and the EP content could adjust randomly at range 5～50%. The properties of the PU/EP LIPN were measured in this experiment. The water resistance, solvent resistance, chemical resistance, thermo oxidative stability, mechanical property and hardness all showed obvious synergistic effect of IPN. The results showed these properties of LIPN had been obviously enhanced with the increase of the amount of epoxy resin. Although the properties of the LIPN were very excellent, the storage stability of the LIPN was reduced with the increasing of the EP content. The mechanism remains uncertain, and further studies are needed.
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