Preparation of UV reactive montmorillonite and characterization of its nanocomposites with poly(vinyl alcohol)

A cation‐exchanged montmorillonite clay is prepared as filler material with high dispersibility, that should act as Fe³⁺‐donor for photochemical crosslinking of PVA/Fe³⁺‐MMT materials with filler contents of up to 50 wt % with regard to the polymer matrix. Hence, no organic photoinitiators and hazardous compounds are utilized. This material may be considered environmentally benign and could be applied in the field of food packaging or for biomedical applications. Upon UV exposure of liquid PVA/Fe³⁺‐MMT dispersion samples, a significant change of the refractive index is determined and the absorption at 360 nm decreased. This indicates the transition of Fe³⁺ to Fe²⁺, which initiates a radical crosslinking mechanism. A homogenous distribution and parallel orientation of the modified clay particles is revealed by SEM measurements. The solubility behavior of the PVA/Fe³⁺‐MMT composite materials in deionized water, changes considerably due to the high filler content and UV‐induced crosslinking, resulting in gel contents exceeding 90 wt %. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013