Polymer Melt Intercalation in Organically-Modified Layered Silicates:  Model Predictions and Experiment

Abstract

The effect of silicate functionalization, anneal temperature, polymer molecular weight, and constituent interactions on polymer melt intercalation of a variety of styrene-derivative polymers in alkylammonium-functionalized silicates is examined. Hybrid formation requires an optimal interlayer structure for the organically-modified layered silicate (OLS), with respect to the number per host area and size of the alkylammonium chains, as well as the presence of polar interactions between the OLS and polymer. From these observations and the qualitative predictions of the mean-field lattice-based model of polymer melt intercalation (preceding paper in this issue), general guidelines may be established for selecting potentially compatible polymer−OLS systems. The interlayer structure of the OLS should be optimized to maximize the configurational freedom of the functionalizing chains upon layer separation while maximizing potential interaction sites with the surface. The most successful polymers for intercalation exhibited polar character or contained Lewis-acid/base groups.

The mechanical properties and fracture behaviour of epoxy-inorganic micro- and nano-composites

“…This allows more interaction to occur between the epoxy and the silicate and will provide an additional stiffening effect. The observed effect 20 of the more exfoliated nano-composites giving higher modulus values has been predicted by Sheng et al [64] and by Luo and Daniel [12].…”

“…An increase in the measured spacing between the silicate platelets is assumed to indicate an intercalated morphology. Note that it is difficult to discern accurately the degree of order of the silicate platelets using WAXS alone [19,20]. Although a specific type of surface-treated silicate may form an exfoliated structure at low percentage inclusion in a polymer matrix, when large concentrations are used the silicate may have insufficient room to exfoliate fully, and hence a more intercalated structure may be formed.…”

“…This morphology is typically described as 'particulate' (or conventional), 'intercalated' or 'exfoliated', as identified by wide-angle X-ray scattering (WAXS) [19,20]. These microstructures are shown schematically in Figure 1.…”

PP‐based nanocomposites with various intercalant types and intercalant coverages

“…Currently, there are three different main approaches to the preparation of PP-based PNCs: the solution process [5][6][7], in-situ polymerization [8 -10], and melt compounding [11][12][13][14][15][16]. In fact, melt compounding has proved to be an excellent technique because of its ease, versatility, and benign character, with respect to the environment.…”

Desenvolvimento de nanocompósitos polipropileno/argila bentonita brasileira: I tratamento da argila e influência de compatibilizantes polares nas propriedades mecânicas

“…Os nanocompósitos são materiais nos qual a fase dispersa apresenta pelo menos uma dimensão de ordem nanométrica [2] . A utilização de nanocargas permite o melhoramento das propriedades de barreira, estabilidades térmica e dimensional, retardância de chama e propriedades mecânicas com emprego de baixos teores de carga (até 5% em massa) o que os diferencia dos compósitos tradicionais que utilizam até 40% em peso [3][4][5][6] . Os nanocompósitos políme-ro/argila tiveram maior importância de aplicação industrial a partir do desenvolvimento por um grupo de pesquisadores da Toyota [3] .…”