Deproteinized Natural Rubber Grafted with Polyacrylonitrile (PAN)/Polystirene (PS) and Degradation of its Mechanical Properties by Dimethyl Ether

Abstract

Dimethyl ether (DME) is a clean fuel that has moderate polarity, swells easily, and dissolves organic compounds. It has the ability to attack some sealing materials and plastic components because of its low viscosity. The modification of deproteinized natural rubber with acrylonitrile (AN) monomer and styrene (ST) monomer by an emulsion copolymerization process can be used to obtain DPNR-g-PAN/PS copolymers. This process uses a stirred reactor with T = 65oC, P = 1 atm, initiator potassium persulfate (K2S2O8), and an emulsifier sodium dodecyl sulfate (SDS). The copolymer DPNR-g-PAN/PS can be used to seal storage for DME because it is expected to reduce the degradation of rubber due to the presence of DME. The parameters that were used in testing for the resistance of DPNR included swelling, shrinking, the infrared spectrum obtained through Fourier transform infra-red spectroscopy (FTIR), and changes in the mechanical properties of DPNR after immersion. The results of this research revealed that the presence of AN and ST can improve the mechanical properties of DPNR. They also showed that an increase in the concentration of AN decreased the swelling and increased the shrinking of rubber. However, an increase in the concentration of ST was found to increase the swelling and decrease the shrinking of rubber. From the results of the FTIR spectrum, DPNR was indicated to be more degraded compared to DPNR-g-PAN/PS after immersion with DME. The surface morphology test, which was carried out with a scanning electron microscope (SEM), showed that DPNR-g-PAN/PS experienced a slight shrinking effect in its morphology while DPNR underwent a huge shrinking effect.

Keywords

• acrylonitrile
• deproteinized natural rubber
• dimethyl ether
• styrene