Study On Surface Treatment Of Inorganic Nanoparticles And Its Reinforcing & Toughening Polymer Materials

Inorganic nanoparticle is a particle with smaller characteristic latitudinal dimension than 1 00nm, being a substance between macroscopic solid and sub-stable immediate of molecule. It possesses small-dimension effect, quantum dimensional effect and surface effect. Polymer/nanoparticles nanocomposites become very active domain at present, displaying good exploitation and application foreground. But because of inorganic particles' smaller dimension, bigger specific surface area, higher interfacial energy, they agglomerate very easily, and consequently can't exert nanometric effect to full extent. Thus lowering the interfacial energy of nanoparticles, improving compatibility between nanoparticles and polymer, and weakening interfacial polarity of nanoparticles become the most important technological problems for surface modification of nanoparticles.In the paper, we use coupler KH570 to modify nanoparticles, bond coupler onto nanoparticles, and obtain alkylated nanoparticles; Then with the help of coupler on the surface of alkylated nanoparticles, we graft PMMA onto nanoparticles through in-situ polymerization of MMA monomer, and gain composited nanoparticles encapsulated by polymer, thereby nanoparticles are encapsulation modified.In our work, we select zero-dimensional nanomaterial (SiO2 and CaCO3) and one-dimensional nanomaterial(AT). After surface modification of these nanoparticles, we composite them with polymer (polypropylene, polyethylene and polyvinyl chloride) and prepare nanocomposites. The results show that:(1) FTIR and XPS analyses prove that coupler KH570 are bonded onto the surface of nanoparticles, and on this basis, PMMA are grafted onto the surface of nanoparticles, thus nanoparticles are encapsulated by polymer. Where coupler KH570 plays interconnecting role between nanoparticles and polymer.(2) DSC and XRD tests also reveal that: untreated nanoparticles and alkylated nanoparticles have no significant effect on the crystallization behavior of PP matrix, whereas composited naonparticles induce the formation P-form crystalline of PP, moreover, the content of P-form crystalline amounts to 69.3%. Nanoparticles, alkylated nanoparticles and composited nanoparticles have different influence on themicrocrystalline size of crystallizable polymer (i.e., PP and PE).(3) In comparison with nanoparticles, alkylated nanoparticles and composited nanoparticles evidently improve the mechanical properties of polymer matrix. In particular, addition of composited particles enhances the impact strength of PP by nearly 100%.(4) We use SEM to observe fractured morphology of composites, and TEM to observe dispersion and particle size of nanoparticles or composited nanoparticles in matrix. We also investigate dispersion property of composited nanoparticles in polymer matrix with the help of microtone.(5) We study the non-isothermal crystallization behavior of PP/AT composite by means of DSC compared with pristine PP. Moreover, we use DSC to examine the glass transition behavior of PVC/nanoparticles composites.