Preparation Of Phenolic Resin Modified By Nano-silica And Its Applied Research In Graphite Impregnation

Phenolic resin is an excellent thermosetting resin with good mechanical properties,tribological properties,flame retardance and heat-resistant quality,and it has been used in many fields,such as transportation,electronics,space and so on.However,with the rapid growth of phenolic resin applications,weakness of brittleness and oxidation have been major limiting factors in its applications.At the same time,these have promoted extensive research to improve its heat resistance,mechanical properties,et al.In-situ polymerization with nanomaterials is an effective way to modify polymer.On the one hand,nano particles can reach to polymer with its unique Structure and react with phenolic resin by its active functional groups,thus forming crosslinked network structuce.On the other hand,it can have a reinforcement positive as inorganic additives,which has improved the properties to some extent.In this paper,nano-silica with amino,epoxy,hydroxyl groups?RNS-A,RNS-E,DNS-0?have been added to modify phenolic resin and its effect on the properties of phenolic resin has been investigated.The major content are as follows:1.RNS-A/PF has been synthesized in the presence of phenolic,formaldehyde,RNS-A and catalyst via in-situ polymerization.Its structure has been examined by the FT-IR and Raman.The curing process is studied by DSC.Ti,Tp,Tf of the system were gained by extrapolation method which is 98.1?156.7?176.2?,separately.So temperature-rise period is 80?/3h,then rising at a heating rate of 10?/h from80?to 180?.Post curing temperature is set as 200?for 2h.Its heat resistance has been examined by thermo gravimetric analyzer?TG?.Results show that the addition of nano-silica has a positive effect on the themral stability.Heat resistance of RNS-A/PF increases by the addition of RNS-A from 1%to 4%.When the addition of RNS-A is 4%,T_5%,T_10%,char resident is 385.8?,454?,69.03%,respectively,which has been improved by 25?,37?,7%compared to phenolic resin.Its morphology performance has been investigated by SEM,EDS.Results show that nano-silica disperse in phenolic resin matrix uniformly,which can improve the property of phenolic resin.RNS-A/PF has been used in impregnated graphite specimens according to the procedures,and the compressive strength of graphite is improved from 25 MPa to 50 MPa.2.Firstly,DNS-0 was modified by coupling reagent KH-560.DNS-0/PF has been synthesized in the presence of phenolic,formaldehyde,DNS-0 and catalyst via in-situ polymerization.Its structure has been examined by the FT-IR and Raman.Its heat resistance has been examined by thermo gravimetric analyzer?TGA?.Results show that the addition of nano-silica has a positive effect on the themral stability.When the addition of DNS-0 is 2%,T_5%,T_10%,char resident is 400?,461?,69.41%,respectively,which has been improved by 39?,43?,7%compared to phenolic resin.Its morphology performance has been investigated by SEM,EDS.Results show that nano-silica disperse in phenolic resin matrix uniformly,which can improve the property of phenolic resin.DNS-0/PF has been used in impregnated graphite specimens according to the procedures,and the compressive strength of graphite is improved from 25 MPa to 44 MPa.3.RNS-E/PF has been synthesized in the presence of phenolic,formaldehyde,RNS-E and catalyst via in-situ polymerization.Its structure has been examined by the FT-IR and Raman.Its heat resistance has been examined by thermo gravimetric analyzer?TGA?.Results show that the addition of nano-silica has a positive effect on the themral stability.When the addition of RNS-E is 1%,T_5%,T_10%,char resident is 397?,476?,71.59%,respectively,which has been improved by 36?,58?,10%compared to phenolic resin.Its morphology performance has been investigated by SEM,EDS.Results show that nano-silica disperse in phenolic resin matrix uniformly,which can improve the property of phenolic resin.RNS-E/PF has been used in impregnated graphite specimens according to the procedures,and the compressive strength of graphite is improved from 25 MPa to 53 MPa.