A study on the toughening of PVC/Starch blends by MBS core/shell particles

PVC/starch blends were made using cellulose acetate as a compatibilizer with the starch amount varying from 5 to 25 phr. In the first stage, the influence of cellulose acetate content on the mechanical properties of blends was investigated with the aid of Izod impact strength and standard tensile testing measurements. It was found that a small amount of cellulose acetate can enhance the mechanical properties of PVC/starch blends significantly. The results showed that adding 0.15 phr cellulose acetate leads to best results in blends containing 5 phr starch. During the second stage, the compatibilized blends with 25 phr starch and 0.75 phr cellulose acetate were toughened using Methyl Methacrylate Butadiene Styrene (MBS) core/shell particles. The amount of MBS particles varied from 5 to 20 phr. As expected, increasing the content of MBS in the blends resulted in higher impact strength and elongation at break and at the same time lower tensile strength and modulus. The effect of temperature on impact strength of toughened blends confirmed the existence of a Brittle Ductile Transition (BDT) above 50 °C for those blends containing 25 phr starch and 20 phr MBS. The Transmission Electron Microscopy (TEM) was used to study the influence of starch on the dispersion of MBS particles in the latter blend

Keywords:

PVC , Starch , Cellulose acetate , biodegradation , MBS , toughening