Study On PU Nano-composites And PU/PS IPN

The ordered and micro-phase structures of the molecular of PU materials are decided directly by its synthesis technology, composition and other materials compounded with it, and they will influence the possessive properties of PU materials. In this paper, general studies on PU have been carried out by the methods of controlling the prepolymerize technology, taking off dissociative TDI from prepolymer through decompress boiling distilling technology, polymerized in-situ with nano-particles and interpenetrated with PS, The relationship between properties and structure of PU/OMT , PU/SiO2 nano-composites and PU/PS IPNs were characterized by FTIR, DMTA, TEM andTGA.The results indicated: The mechanical properties of PU prepared by added EG in a two-step process in prepolymerization technology were better than that of one-step process, its Tg shifted 6 towards high temperatures; The tan peak of PU material at low temperature disappeared through decompress boiling distilling technology.General mechanical properties of PU/OMT and PU/SiO2 nano-composites achieved the optimal value as the nano-particles content at 2wt%, the tensile strength increased 110.0% and 157.5% respectively, the elongation at break increased 27.9% and 8.7% respectively, their Tg shifted 6.8 and 7 towards high temperatures respectively. The thermal stability and swelling resistance of PU/OMT nano-composites have been improved remarkably. With the add of dispersant CH-10B, the tensile strength and elongation at break of PU/SiO2 nano-composites increased 48.5% and 4.2% respectively. It can be known from the result of FTIR that the TDI has reacted with OMT. The results of TEM showed that the layers of OMT had been separated partly into alone fragment by in-situ polymerization of PU; the agglomerativenano-SiO2 particles in PU composite had been dispersed, but the disperse status became worse as the increase of its content.It has been studied that the effect of component, cross-linking agent PG and DVB and initiating agent BPO on mechanical properties of PU(based polyether)/PS IPNs. Its tensile strength showed a maximum when the weight of PU/PS was in the ratio of 75:25, PO content was in 14% and the DVB content was in 5%, the tensile strength increased 84.0% compared with the pristine PU. The maximum tensile strength of PU(based polyester)/PS IPNs increased 133.5% compared with the pristine PU, when PU/PS was in the ratio of 80:20.