General Approach to Nanocomposite Preparation

TLDR

Many polymers fail to form nanocomposites by simple melt mixing of clay and polymer. The method uses a small amount of swelling agent to swell clay layers, enabling any polymer—tested across 24 polymers differing in solubility, molecular weight, and polarity—to intercalate/exfoliate, with nanocomposite formation confirmed by shifts or disappearance of clay reflections in X‑ray diffraction. The approach yields several new nanocomposites, and adding 2 wt % swelling agent to polymers that only partially intercalate/exfoliate without it results in complete intercalation/exfoliation or a higher nanocomposite yield compared to clay–polymer mixtures.

Abstract

A novel approach to nanocomposite preparation utilizing a swelling agent, a monomer or polymer known to intercalate/exfoliate smectite clay, has allowed the preparation of several new nanocomposites. Present in small amounts, the swelling agent serves to swell the clay layers, allowing the organic matrix to be virtually any polymer. Twenty-four polymers are used in this study, varying in solubility parameter, molecular weight, and polarity. Many of these polymers do not yield a nanocomposite structure by simple melt mixing of the clay and polymer. Although some polymers are capable of partial intercalation or exfoliation without the addition of a swelling agent, addition of 2 wt % of this additive results in either complete intercalation/exfoliation or an increased percentage of nanocomposite formation, in comparison to the clay−polymer mix. The evidence of a nanocomposite structure is provided by a shift in, or the absence of, clay reflections in X-ray powder diffraction patterns.