Control Of Interface Strength Of Epoxy Resin/Clay Nanocomposites And Its Effect On Properties

In the past two decades,the research of polymer / clay nanocomposites has attracted extensive attention at home and abroad.It is well known that for traditional polymer matrix composites,a certain strength interface is built between the matrix and the reinforcement The force is the key to ensure that the stress can be effectively transmitted between the polymer matrix and the reinforcement to improve the performance of the material.This critical issue did not attract limited attention until recent years.Clay as a commonly used polymer reinforcement.Choosing the proper clay modifier is not only an effective method to improve its dispersion in the polymer matrix,but also a major means of constructing interfacial forces.This article uses epoxy resin（E-51）as the resin matrix.Organic modifiers with different chemical structures were constructed,and nanofillers（clay）were modified to prepare organic nanofillers with different structural characteristics,and different strength interface forces were constructed between the EP matrix and the nanofillers."Slurry compound method" A new preparation method can provide good dispersion and peeling effect of nano filler in EP matrix.Based on this,the effects of organic modifiers with special chemical structures on the interfacial forces between nanofillers and polymer matrix and the mechanism of macroscopic properties of composite materials were studied.The main findings are as follows:1.In order to build a strong interface force between the polymer matrix and the clay flake layer,and to explore the effect of the amount of curing agent on the mechanical properties of the reactive organic clay / epoxy resin nanocomposites.Two kinds of reactive clay organic modifiers were synthesized by reacting triglycidyl-p-aminophenol（TGPAP）with epoxy groups and bromo-n-butane（BB）and 2-bromoethanol（BE）,respectively:（Positive alkyl）double epoxy（4-epoxy ether）ammonium（TGPAPB）and bromide（2-hydroxyethyl）double epoxy（4-epoxy ether）ammonium（TGPAPE）.Two types of organically modified clays（B-clay and E-clay）with the same reactive functional group but slightly different compatibility with epoxy resin were obtained by modifying the clay with the above two modifiers.Two kinds of EP / clay nanocomposites were prepared by the "clay slurry composite method",and the effects of two reactive organic modifiers on the structure and properties of nanocomposites were explored.The results show that the E-clay with hydroxyl groups is evenly distributed in the epoxy resin matrix in the form of highly random peeling;B-clay forms a random peeling / intercalation hybrid structure.Both types of clay can build a strong interface force between the epoxy resin matrix and the clay sheet by participating in the curing reaction.By adjusting the amount of curing agent,the mechanical properties of the nanocomposite are further improved,and its tensile strength and modulus It can also be improved.When the clay mass fraction is 3%,the tensile strength of the two nanocomposites is increased by 76.47%（E-clay）and 52.51%（B-clay）respectively;the modulus is increased 258.87% and 236.92%.2.To further study the different interfacial strengths of organoclay sheet and epoxy resin matrix,the modifiers selected are similar in structure and have good compatibility with the polymer matrix.Three different interfacial strengths were constructed to explore their effects on the performance of nanocomposites.The polyetheramine M-600（JM600）and epichlorohydrin（ECP）ring-opening reaction was used to synthesize a polyether secondary amine with two hydroxyl groups（JMH）-NR₂（R:-CH₂-CH（OH）-CH₂Cl）;then ring-closing reaction with Na OH to synthesize a polyether secondary amine with two epoxy groups（JME）-NR₂（R:-CH₂-C₂H₃O₂）;then react with bromo-n-butane（BB）to synthesize one A variety of quaternary ammonium salts（JMB）-N⁺R₂YBr-（R:-CH₂-C₂H₃O₂,Y:-C₄H₉）.Choline chloride（CC）,JM600,JMH,and JMB were used to modify the clay to obtain four different types of organoclays: CC-clay,JM600-clay,JMH-clay,and JMB-clay."Clay slurry composite method " Preparation of 4 flexible epoxy resin / clay nanocomposites with different interface strengths.The results show that the stripping effect of CC-Clay,JM600-Clay and JMH-Clay in the matrix is worse,and it shows a mixed structure of intercalation and stripping.JM600-Clay,JMH-Clay and JMB-Clay contain ether bonds,which are well compatible with epoxy groups The dispersion effect is better than CC-Clay,JMB-Clay has better epoxy group dispersion effect,basically realizes random peeling,when the clay mass fraction is 3%,the tensile strength of the four nanocomposites is more The epoxy resin polymer was increased by 83.66%（CC-clay）,100.16%（JM600-clay）,120.51%（JMH-clay）,139.92%（JMB-clay）;the modulus was increased by 226.51%,246.19%,270.27%,281.17%.3.To further study the interface strength between the organoclay sheet and the epoxy resin matrix,compare the polyetheramine D230 system with the polyetheramine M-600 system.Under the same interface force,the organoclay and epoxy resin matrix have a good Compatibility,at the same time increase the number of active functional groups,build three different interface strengths,and explore its impact on the performance of nanocomposites.D230 and ECP ring-opening reaction to synthesize a polyether secondary amine（DH）₂ [-NR₂] with 4 hydroxyl groups（R:-CH₂-CH（OH）-CH₂Cl）;synthesis with Na OH ring-closure reaction with 4 Epoxy-based polyether secondary amine（DE）2 [-NR₂]（R:-CH₂-C₂H₃O₂）;then reacted with bromo-n-butane（BB）to synthesize a quaternary ammonium salt（DB）-N⁺R₂YBr-（R:-CH₂-C₂H₃O₂,Y:-C₄H₉）.D230,DH,and DB were used to modify the clay to obtain three types of organoclays with different structures: D230-clay,DH-clay,and DB-clay."Clay slurry composite method" prepared three kinds of flexible epoxy resins with different interface strengths Resin / clay nanocomposites.The results show that D230-clay,DH-clay and DB-clay are dispersed in the epoxy resin matrix in a random peeling form,which has a better dispersion effect than JM600 series.This difference originates from D230-clay,DH-clay,DB-Clay’s organic modifier has better compatibility with epoxy resin prepolymer and curing agent,so it is more conducive to its dispersion in the epoxy resin matrix and the formation of random peeling structure.The tensile strength of the three kinds of nanocomposites is increased by 81.53%（D230-clay）,125.11%（DH-clay）,180.17%（DB-clay）respectively;the modulus is increased 264.15%,268.19%,315.90%.