PMMA/clay

Okamoto et al. [2000, 2001a] investigated the dispersed structures in PNC with PMMA or its copolymers (MMA with polar monomers) as the matrix. The PNC was prepared by in situ polymerization with 10 wt% of organically modified smectic clay, obtaining intercalated nanocomposites. The storage tensile modulus E and tan 5 of PMMA-clay and PMMA-intercalant were similar. However, when copolymers were used as the matrix, the E of PNC increased over the entire temperature range, but tan 5 peaks shifted to lower T. 

Ottewill RH, Schofield AB, Waters JA, Williams NSJ (1997) Preparation of core-shell polymer colloid particles by encapsirlation. Colloid Polym Sd 275 274-283 Okubo M, Lu Y, Wang Z (1999) Analysis of stepwise heterocoagulation for the preparation of soft core/hard shell composite polymer particles. Colloid Polym Sd 277 77-82 Xu Y, Brittain WJ, Xue C, Eby RK (2004) Effect of clay type on morphology and thermal stability of PMMA-clay nanocomposites prepared by heterocoagulation method. Polymer 45(ll) 3735-3746... 

Fis Fischer, B., Ziadeh, M., Pfaff, A., Breu, J., Altstadt, V. Impact of large aspect ratio, shear-stiff, mica-like clay on mechanical behaviour of PMMA/clay nanocomposites. Polymer 53 (2012) 3230-3237. 

Yeh, J. M., Liou, S. J., Lin, C. Y., Cheng, C. Y, Chang, Y. W, and Lee, K. B. 2002. Anticorrosively enhanced PMMA-clay nano-composite materials with quaternary alkylphosphonium salt as an intercalating agent. Chemistry of Materials 14 154-161. 

D.C. Lee, L.W. Jang, Preparation and characterization of PMMA-clay hybrid composite by emulsion polymerization,... 

Figure 1.9 TGA analysis of (I) linear PMMA-clay nanocomposite, (E) cross-linked PMMA-clay nanocomposite, and (III) pure PMMA. The lines are drawn at 50% mass loss for comparison. Reproduced from [34] with permission from Elsevier.

Figure 10.16 Curves of TGA and DTG (an insert image) as a function of temperature from PMMA and PMMA/clay nanocomposites. Reproduced from Ref. [7] with permission from Elsevier.

Fig. 5 DSC thermograms of (a) pure PMMA and (b-e) PMMA/clay nanocomposites with different clay contents (h) 0.62 wt%, (c) 2.33 wt%, (d) 4.13 wt%, and (c) 10.4 wt%. Reproduced with permission from [56]...

Recently, our group reported [56] DSC characterization of PMMA/clay nanocomposite prepared by in situ polymerization initiated with a Ni(acac>2 catalyst in combination with MAO (Fig. 5). The pure PMMA exhibits Tg of 124.28 C in contrast, the PMMA/clay nanocomposites exhibit an increasing endothermic trend at 127.0-133.18°C as an increasing amount of the clay is added. 

Recently, our group [103] used TEA-modified MMT to prepare exfoliated PMMA/clay nanocomposites by in situ polymerization using Ni(acac)2 catalyst. A schematic representation is given in Fig. 12. The PMMA/clay nanocomposites are found to retain over 80% transparency, which is important for optical applications. In addition, the tensile strength of nanocomposites is up to 70 MPa for 7.26 wt% clay content, and the tensile modulus shows a value 20% higher than that of neat PMMA. 

Cui L, Tarte NH, Woo SI (2008) Effects of modified clay on the morphology and properties of PMMA/clay nanocomposites synthesized by in situ polymerization. Macromolecules 41 (12) 4268 274... 

Zeng and Lee (2001) prepared PMMA/clay nanocomposites via in-situ bulk polymerization. The compatibility of the initiator and monomer with the clay surface was found to profoundly affect the clay dispersion. Furthermore, by using a nanoclay (MHABS) that was modified by a surfactant containing a polymerizable group (the chemical structure is shown in the top right of Figure 1.2), exfoliated PMMA/clay nanocomposites with excellent clay dispersion were synthesized. 

Wang et al. (2002) compared various in situ polymerization methods for the preparation of PMMA/clay nanocomposites. It was found that the particular preparative technique that is used has a large effect on the type of nanocomposites (in terms of nanoclay dispersion) that may be obtained. Solution polymerization of MMA only yields intercalated nanocomposites regardless of the presence of polymerizable double bond in the intergallery region. On the other hand, emulsion, suspension, and bulk polymerization can yield either exfoliated (with intergallery double bond) or intercalated (without double bond present) nanocomposites. 

FIGURE1.18 Dielectric constant of PMMA clay nanocomposite and nanocomposite foams with two kinds of nanoclays (CCLM A and ACLMA) at varions freqnencies nnder room temperature. Number in legend is the clay concentration (F) indicates foam. (Reprinted with permission from Yeh J. et ah, Materials Chemistry and Physics 2009, 115, 744-750. Copyright 2009, Elsevier.)... 

Fu J. and Naguib H. E., Effect of nanoclay on the mechanical properties of PMMA/clay nanocomposite foams. Journal of Cellular Plastics 2006,42, 325-342. 

Jo C., Fu J., and Naguib H. E., Constitute modeling for intercalated PMMA/clay nano composite foams. Polymer Engineering and Science 2006, 46, 1787-1796. 

Manninen A. R., Naguib H. E., Nawby A. V, Liao X., and Day M., The effect of clay content on PMMA-clay nanocomposites. Cellular Polymers 2005, 24, 49-70. 

Wang Y. and Guo J., Melt compounding of PMMA/clay nanocomposites with styrene-maleic anhydride copolymers Effect of copolymer type on thermal, mechanical and dielectric properties. Polymer Composited 2010, 31, 596-603. 

Yeh J., Chang K., Peng C., Lai M., Hung C., Hsu S., Hwang S., Lin H., and Lin H., Effect of dispersion capability of organoclay on cellular structure and physical properties of PMMA/clay nanocomposite foams. Materials Chemistry and Physics 2009, 115, 744-750. 

Figure 3.14 Scanning transmission X-ray microscopy images (30pm x 30pm) of PS/PMMA biends annealed at 190 °C for 14 hours (taken at 285.2 eV, the adsorption energy of PS, PS is dark) (a) PS/PMMA (30/70) (b) PS/PMMA/clay (27/63/10) (reprinted with permission of reference Si, M., Araki,T., Ade, H., Kilcoyne, A. L. D., Fisher, R., Sokolov, J. C. and Rafailovich, M. H., Macromolecules, [2006) 39, p.4793, copy right (2006) American Chemical Society)...

Microwave irradiation was applied for in situ polymerization of PMMA/clay (ClOA) layered nanocomposites. The polymerizations were carried out using a microwave reactor at 70 °C with 200W of irradiation power. An intercalated/exfo-liated stmcture was observed by both XRD and transmission electron microscopy (TEM) analyses. Thermogravimetry analysis (TGA) of pure PMMA and PMMA/clay nanocomposites... 

Transmission electron microscopy of PMMA/clay (5 wt%) nanocomposite. 

Permeability of H2O and O2 as a function of the MMT clay content in the PMMA/clay nanocomposite materials. 

Yeh J. M., Liou S. J., Lin C. Y, Cheng C. Y, Chang Y. W. etal., (2002), Anticorrosively Enhanced PMMA-Clay Nanocomposite Materials with Quaternary AUcylphosphonium Salt as an Intercalating Agent. Chem Mater, 14, 154-61. 

Contrary to what many people think, PLSNs are not a recent discovery. One of the earliest systematic studies of the interaction between a clay mineral and a macromolecule dates backs to 1949, when Bower described the absorption of DNA by montmorillonite. Even in the absence of X-ray diffraction (XRD) evidence, this finding implied insertion of the macromolecule in the lamellar structure of the silicate. In the case of synthetic polymers, Uskov found in 1960 that the softening point of polymethylmethacrylate derived by polymerisation of methylmethacrylate was raised by montmorillonite modified with octadecyl-ammonium, while in the following year Blumstein obtained a polymer inserted in the structure of a montmorillonite by polymerising a previously inserted vinyl monomer. In 1965 Blumstein first reported the improved thermal stability of a PMMA/clay nanocomposite. He showed that PMMA inserted between the lamellae of montmorillonite clay resisted thermal degradation under conditions that would otherwise completely degrade pure PMMA." ... 

Ryu, J.G., The effects of Power Ultrasonics Wave on in-situ Polymerization and Formation of PMMA-Clay Nanocomposites, ANTEC 2001 Conference Proceedings, Society of Plastics Engineers, Brookfield CT... 

---