Synthesis Of New Surfactant And Its Modified Application In Nanocomposites

Due to the unique properties of the nanoparticles/polymer resin matrix compositematerials, which has become one of the hottest materials which focused by researcher at thepresent and in the future. It overcomes not only the defects in a single material andconventional composite material properties, so that the material has both advantages ofnanomaterials, such as rigidity and high stability, but also at the same time having theadvantage of polymer material, such as elasticity, dielectric properties, ductility, etc.. Thereby generating a number of excellent performances.The nano-particles have a great specific surface area and a high surface energy, it easilyagglomerated, which becomes the secondary particles, so that the size of the particles isbecome larger. Since the surface of the nano-particles with hydrophilic properties, it isdifficult to be uniformly dispersed in an organic medium at the same time, which results inpoor adhesion between the organic matrix and nanoparticles, this will easily result in theinterface defects. And if the nano-particles in the polymer matrix can not achieve veryuniform dispersion of nanoparticles many special properties will greatly restricted, and thusthe final integrated performance of the nanoparticles/polymer resin matrix composite wouldbe limited.In this experiment, a new type of anion surfactant was synthezied which has anunsaturated end group, and glycol chain segment （as hydrophilic group） and a long chainalkyl group （as hydrophobic group） on the molecular structure, IR,1H NMR, and otherinstruments were used to determine the molecular structure of the surface active agent.Using anionic surfactant to modified the surface of silica, calcium carbonate andtitanium dioxide nanoparticles, the modified nanoparticles mixed with an epoxy resin （EP）or poly methyl methacrylate （PMMA） to prepare nanocomposite by pouring fabircation,TGA DMA and DSC were used to characterized the thermal properties of the compositesamples which the nanoparticles modified by different content of the synthesized surfactant,as well the toughening property.The results showed that the interfacial adhesion between nanoparticles and matrix wasimproved by adding which could be observed by scanning electron microscope （SEM）, itcould find that the pounding fracture crack roughness and cracks was increased, pulling structure dense, the degree of plastic deformation of the matrix is more obvioused, themechanical properties of the composites such as strength and toughness were enhanced. Thereason is the nanoparticles inhibited of the surfactant chain movement and effectivelyimprove the toughness of the material.The thermal properties of the modified nanoparticles/polymer resin matrix compositessuch as the thermal decomposition temperature, the glass transition temperature and storagemodulus, were improved according to increase the amount of surfactant. When thesurfactant content is9%, the storage modulus of the SiO₂/EP sample at higher temperatureenhanced almost90%. This is mainly because the crosslinking density of the resin matrixwas increased by introduced the new type of anionic surfactant which synthesized in thispaper.