Preparation of Natural Rubber/EVA/Montmorillonite Nanocomposites by Latex Compounding

摘要

Nanocomposite materials of natural rubber (NR)/poly(ethylene-co-vinyl acetate) (EVA)/montmorillonite (MMT)nwere prepared by latex compounding without modifi cation of the MMT. EVA and MMT were well mixed atnroom temperature in the latex state and subsequently blended with NR latex at NR/EVA dry weight ratios ofn100/0, 90/10, 80/20, 70/30, 60/40 and 50/50. Where used, MMT was added at 4 parts per hundred of dry rubbernand EVA (phr). The homogeneous latex mixture was then cast into sheets on a glass mold, air dried for 2 daysnat room temperature and then in an oven at 70 °C for 6 h. It was subsequently cured at 110 °C for 2 h. Afterncuring, samples were examined for their structure and morphology by X-ray diffraction (XRD), scanning electronnmicroscopy (SEM) and transmission electron microscopy (TEM), whilst tensile properties were investigated usingna Universal Testing Machine. The XRD patterns and TEM images of the nanocomposites showed an exfoliatednstructure. The 90NR/10EVA/4MMT exhibited the highest tensile strength, with incorporation of MMT offeringna substantial improvement in tensile strength. SEM micrographs revealed that the MMT particles were wellndispersed in the polymer matrix. However, increasing the EVA content to 50 wt.% reduced the compatibilitynbetween NR and EVA.