| Functional inorganic nanoparticles can be widely used in functional finishing of textiles attributing to their excellent natures. However, their dispersion in organic media and polymer matrix were always poor due to their inherent hydrophilic and nanoscale features. This seriously weakens the efficiency of inorganic particles in the finished textile. The surface modification of inorganic particles with polymer chain was well considered as an effective way to improve their dispersion both in organic media and in polymer matrix.In this basic research, nanosilica (SiO2), being taked as a representative inorganic particles, was modified by 3-(trimethoxysilyl)propyl methacrylate (MPS) and then re-dispersed into monomer methyl methacrylate (MMA). After that, a series of silica/poly(methyl methacrylate) (SiO2/PMMA) composite materials were prepared via in-situ bulk polymerization and SiO2/PMMA composite latexs via in-situ miniemulsion polymerization. The application performances of SiO2/PMMA composite materials in melt mixing and SiO2/PMMA composite latexs in textile finishing were further studied. During the above processes, the key factor and mechanism to the dispersion of silica in MMA media, in PMMA matrix, in fiber interior and on fiber suface were systematically explored.Firstly, it was found from TEM, DLS, TGA and FTIR that the coupling modification of 3-(trimethoxysilyl)propyl methacrylate (MPS) on silica particles can effectively improve its lipophilic, its compatibility with monomer and its dispersion in monomer media. The appropriate amount of MPS is about 0.020.10 g·(g·SiO2)-1, in which MPS grafting amount and MPS grafting percent were perfect, and the modified silica particles can be dispersed in monomer media at primary particles size level. Thus, a series of MPS-SiO2/MMA dispersion with excellent silica dispersion and high silica content can be successfully prepared via MPS modification and media replacement processes.Secondly, series of MPS-SiO2/PMMA grafting composite materials were prepared via in-situ bulk polymerization, and the grafted SiO2 particles in composite were re-dispersed into target resin via melt mixing process. It was found from section-TEM that the dispersion and the re-dispersion of silica particles in polymer matrix were mainly related with the apparent coupling ratio of MPS on silica particles surface. When the apparent coupling ratio were in 28%, silica particles can be dispersed both in polymer and in resin matrix at the primary particles size level.Thirdly, the formation mechanism of grafting and crosslinking structure of MPS-SiO2/PA composites druing in-situ bulk polymerization were analyzed by soxhlet extraction, HF etching and by GPC. It was found that, in the case of lower silica content and lower MPS coupling ratio, the grafted PMMA were generally took as a simple grafted chains grafted on a simple silica partile, while in the case of higher silica content and higher MPS coupling ratio, a three-dimensional crosslinked structure with silica as crosslinked point was easily formed in the part and even in the whole composite. Therefore, the grafting and crosslinking structure of MPS-SiO2/PA composites can be effectivly controlled by adjusting the silica content and the coupling ratio of MPS on silica partiles.Finally, series of MPS-SiO2/P(BA+MMA) grafting composite latexes were prepared via in-situ miniemulsion polymerization, and used as finishing agent to finish cotton fabric via dip padding treatment process. It was found from the distribution experiment of MPS-SiO2 in water/monomer phases, the TEM images of MPS-SiO2/P(BA+MMA) composite latexes and the FE-SEM images of finished cotton fabric surface that, when the MPS coupling ratio is greater than 2%, silica particles can be homogeneously dispersed in the monomer phase, in the adhesive polymer latexes and then in the adhesive thin layer on the finished fiber surface.The above results are favourable for achieving the primary-particles-size-level-dispersion of functional inorganic particles in monomer medium, in polymer matrix, in fiber interior and on fiber surface. |
PDF Full Text Request