Chemically modified natural rubber latex - poly(vinyl alcohol) blend membranes for organic dye release

Novel blend membranes were prepared from chemically modified natural rubber latex (NRL) and poly(vinyl alcohol) (PVA) for release application. Chemical modification of NRL was done by grafting (dimethylaminoethyl methacrylate) (DMAEMA) onto NR particles by using a redox initiator system viz; cumene hydroperoxide/tetraethylenepentamine (CHP/TEPA), followed by dialysis for purification. The grafting was confirmed by dynamic light scattering (DLS), fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance spectroscopy (NMR). The grafted NRL was subsequently blended with PVA to make uniform membranes by solvent casting at 60 ± 2 °C. The blend membranes were characterised by FT-IR spectroscopy, X-ray diffractometry (XRD) and thermogravimetry (TGA). Moisture uptake, swelling and water contact angle experiments showed an increased hydrophilicity when the PVA content in the blend membranes was increased. Scanning electron microscopic investigations indicated the formation of pores in the membranes after a leaching cycle. The potential of the membrane for the use in the release application was tested with model organic dyes rhodamine B, methyl orange and fluorescein. Results from the release study indicate that the membranes can be used for the release of cationic dyes.