A Comparison of Various Methods for the Preparation of Polystyrene and Poly(methyl methacrylate) Clay Nanocomposites

Abstract

Polymer-clay nanocomposites of styrene and methyl methacrylate have been prepared by bulk, solution, suspension, and emulsion polymerization as well as by melt blending. Two different organic modifications of montmorillonite have been used: one contains a styryl monomer on the ammonium ion while the other has no double bond. The organic modification as well as the mode of preparation determines if the material will be exfoliated or intercalated. Exfoliation is more likely to occur if the ammonium ion contains a double bond which can participate in the polymerization reaction, but the mere presence of this double bond is not sufficient to always produce an exfoliated system. Solution polymerization always produced intercalated systems. Neither thermogravimetric analysis nor the tensile modulus can be used to evaluate the type of nanocomposite that has been formed.

Morphological memory of polymeric bodies

“…All the examined bodies had the hierarchical microrelief available for the morphological characterization, wherein this microrelief was similar to that presented in the publications on polystyrene (e.g., in [21][22][23]) and other polymers (e.g., [24][25][26]). …”

Nano-Scale Reinforcing and Toughening Thermoplastics: Processing, Structure and Mechanical Properties

“…In situ polymerization is a challenging one, as it allows us to adjust the chemistry to optimize the affinity between filler and the resulting polymer. Different types of polymerization methods have been used to prepare polymer nanocomposites, such as solution, suspension or emulsion, and free radical polymerizations (Akelah & Moet, 1996;Wang et al, 2002;Chen et al, 2000;Zhou et al, 2001). This variety to prepare polymer nanocomposites by in situ polymerization was mostly explored with clays.…”

The effects of intralayer metal composition of layered double hydroxides on glass transition, dispersion, thermal and fire properties of their PMMA nanocomposites

“…The various LDH additives all increase the molecular weight of the PMMA composites compared to that prepared in the absence of an LDH; CaAl gives the highest Mw, about twice that in the absence of an LDH, but MgAl and NiAl are only a little larger than pristine PMMA. These results should be compared to reported data where the influence of additive type on PMMA prepared by bulk polymerization was observed: the molecular weight of PMMA extracted from PMMA VB-16 (VB-16 is an organically modified MMT, a cationic clay) was almost double the molecular weight of pristine PMMA and PMMACloisite 10A prepared by bulk polymerization under similar conditions [4]. Wang et al, on the other hand, reported a slight decrease in both the weight average molecular weight (Mw), the number average molecular weight (Mn) and an increase in the polydispersity index of the disordered-exfoliated PMMA-undecenoate LDH nanocomposites prepared by bulk polymerization [17].…”

“…Clay/polymer nanocomposites often have properties that are dramatically different from those of the polymer alone with unique improvements in mechanical strength [4], thermal stability [5], flammability [6] and gas permeability [7]. The compatibility of the clay between the polymer and the clay is crucial for the formation of well-dispersed nanocomposites [6].…”