Study on the Synthesis, UV Resistance and Mechanical Properties of Poly(methyl methacrylate)/Organic Modified Montmorillonite Nanocomposites

• Main Authors: Mei-Ju Lin, 林美汝
• Other Authors: Tsung-Yen Tsai
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/88953676966050177512

博士 === 中原大學 === 化學研究所 === 101 === The potential to improve the mechanical, thermal, and optical properties of poly(methyl methacrylate) (PMMA)/montmorillonite nanocomposites, prepared with clay containing an organic modifier, were investigated. Pristine sodium montmorillonite clay was modified by using (disodium cocoamphodipropionate, K2) and (cocamidopropylhydroxysultaine, C50), via ion exchange to enhance the compatibility between the clay platelets and the methyl methacrylate polymer matrix. The characteristics of modified clays were exhaustively identified by X-ray Diffraction (XRD) for the d-spacing of the montmorillonite layer, Fourier transform infrared (FTIR) for the organic modifier and function group of montmorillonite, and thermogravimetric analyzer (TGA) for the theoretical intercalation amount of the modified agent in the modified clay. Four types of modified clays of CL42-K2, CL120-K2, CL120-C50, and CL88-K2 were applied to prepare the PMMA/clay nanocomposites via solution polymerization. The dispersion morphology was characterized by XRD and transmission electron microscopy (TEM). The results show that SP-CL120-K2 and SP-CL88-K2 nanocomposites displayed exfoliated morphologies. Conversely, SP-CL120-C50 and SP-CL42-K2 nanocomposites displayed intercalated and partly exfoliated morphologies. The decomposition temperature (Td) of SP-CL120-K2-5% was increased 56℃ from 240℃ to 296℃. The glass transition temperature (Tg) of SP-CL88-K2-5% was increased 28℃ from 96℃ to 124℃. The PMMA/clay nanocomposites show a slight decline in transmissionin of the visible light region as clay content increased but maintain an optical transmission of approximately 87.4%. The UV resistance of SP-CL88-K2-5% was decreased 31% from 86.3% to 59.6%. The lowest gas permeability of SP-CL88-K2-3% was 0.3292 barrer, which was decreased 65% in permeability incomparison to the pristine polymer sample. The storage modulus of SP-CL88-K2-5% was increased 29% from 1315 MPa to 1700 MPa due to the exfoliated nanostructure. The pencil hardness of the pure PMMA film was found to be HB, but that of all the PMMA/clay nanocomposite films was at least in H standard. The hardness of SP-CL120-K2 and SP-CL88-K2 nanocomposites with 3 wt% clay loading was even up to 3H. There were three types of modified clays of CL42-K2, CL120-K2, and CL88-K2 was used to synthesize the PMMA/clay nanocomposites via emulsion polymerization. The XRD and TEM were employed to study the dispersion morphology of PMMA/clay nanocomposites. The result shows EP-CL42-K2 and EP-CL120-K2 nanocomposites displayed exfoliated morphologies. On the contrary, the EP-CL88-K2 nanocomposites displayed intercalated and partly exfoliated morphologies. The Td of EP-CL88-K2-3% was increased 12℃ from 294℃ to 306℃. The Tg of EP-CL120-K2-5% was increased 6℃ from 121℃ to 127℃. The PMMA/clay nanocomposites show a slight decline in transmissionin of the visible light region as clay content increased but keep an optical transmission of approximately 86.0%. The UV resistance of EP-CL120-K2-5% was decreased 30% from 83.9% to 58.7%. The lowest gas permeability of EP-CL120-K2-3% was 0.1885 barrer, which was 80% decrease in permeability incomparison to the pristine polymer sample. The storage modulus of EP-CL120-K2-5% was increased 64.6% from 1637 MPa to 2695 MPa due to the exfoliated nanostructure. The pencil hardness of the pure PMMA film was found to be H, and the hardness of EP-CL120-K2 and EP-CL88-K2 nanocomposites with 3 wt% clay loading was even up to 3H. Therefore, the performance of PMMA/clay nanocomposites have shown the great improvement in various properties.