Preparation And Performance Analysis Of Graphene Modified Polyurethane Vibration Isolator

China is a large marine country.In the development of marine resources,submarine cables,cable restrainers,marine isolators and other scenes urgently need materials with good wear resistance,water resistance,low temperature resistance,shock absorption and noise reduction.Polyurethane as the ’ fifth plastic ’ its material strength and excellent water resistance and damping properties,is a good shock absorber material for vibration isolator.However,the mechanical properties and damping dissipation of graphene modified polyurethane isolator have not been studied in current research.In this dissertation,graphene modified casting polyurethane composites were synthesized by introducing different concentrations of graphene into polyurethane prepolymer in the prepolymerization stage by in-situ polymerization,and their mechanical properties and vibration damping properties were tested.The synthesis conditions of composite materials were explored through experiments,and the crosslinking degree,static / dynamic mechanical properties,microphase separation and damping dissipation attenuation of graphene modified polyurethane composite system were studied and discussed through swelling balance test,electronic universal tensile machine,dynamic thermal analyzer and drop ball test.Firstly,the synthesis route and experimental conditions of composite materials with polytetrahydrofuran(PTMG)as soft segment,2,4-toluene diisocyanate(TDI)as hard segment,3,3’-dichloro-4,4’-diaminodiphenyl methane(MOCA)as chain extender,graphene nanosheets(GNs)and silane coupling agent modified graphene oxide(AGO)as modified medium were studied in this dissertation.Secondly,the swelling ratio,tensile properties and dynamic mechanical properties of graphene modified polyurethane vibration isolator with different solubility gradient were tested.Experiments show that both GNs and AGO can improve the crosslinking density of the system to a certain extent,and both show a trend of increasing first and then decreasing.With the increase of GNs content,the tensile properties of the material increase first and then decrease,but the elongation at break shows an opposite trend.When the tensile strength is strong,the toughness is insufficient and the elongation at break is small.With the addition of AGO,the tensile properties of the composites increased first and then decreased.In terms of dynamic mechanical properties test and microphase separation,with the increase of GNs content,the storage modulus,loss modulus and loss factor did not show a consistent trend.The storage modulus and loss modulus increase first and then decrease,while the peak loss factor increases first and then decreases and then increases.With the increase of AGO content,the storage modulus and loss modulus of the composites reached the peak at 0.6 wt % and then decreased to lower than that of the blank group,while the loss factor reached the peak at 0.3 wt % and then decreased to lower than that of the blank group.Finally,the damping coefficient and attenuation of graphene modified polyurethane isolator at different frequencies were quantified by the drop ball test.The results show that GNs group and AGO group can increase the damping coefficient tanδ in each frequency band,and the high frequency band is about 3 times of the low frequency band.The peak voltage and tanδ of GNs group showed a continuous downward trend,while those of AGO group showed a trend of first decreasing,then increasing and then decreasing.Combined with the cross-linking density,tensile stress and microphase separation degree,the optimal addition concentrations of 0.3 wt % AGO and 0.6 wt % GNs were obtained.