• International Journal of Technology (IJTech)
  • Vol 11, No 1 (2020)

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

Tuti Indah Sari, Asep Handaya Saputra, Setijo Bismo, Dadi R. Maspanger

Corresponding email: ty_indahsari@yahoo.co.id

Cite this article as:
Indah Sari, T., Handaya Saputra, A., Bismo, S., R. Maspanger, D., 2020. Deproteinized Natural Rubber Grafted with Polyacrylonitrile (PAN)/Polystirene (PS) and Degradation of its Mechanical Properties by Dimethyl Ether. International Journal of Technology. Volume 11(1), pp. 15-25

Tuti Indah Sari Department of Chemical Engineering, Faculty of Engineering, Sriwijaya University, Kampus Indralaya, Indralaya 30662, Indonesia
Asep Handaya Saputra Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia
Setijo Bismo Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia
Dadi R. Maspanger Indonesian Rubber Research Institute, Jl. Salak Bogor 16151, Indonesia
Email to Corresponding Author


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.

Acrylonitrile; Deproteinized natural rubber; Dimethyl ether; Styrene


Dimethyl ether (DME) is an alternative fuel with several advantages over other fuels, such as higher oxygen content, a higher cetane number than diesel oil, and a low boiling point. It is also non-toxic, non-teratogenic, non-mutagenic, and non-carcinogenic (Semelsberger et al., 2006; Arcoumanis et al., 2008; Li and Zhou, 2008). However, its chemical properties are different from those of LPG, which has moderate polarity and high gas permeability to organic compounds such as plastics and rubber; DME swells easilyand dissolves organic compounds (Nishimoto, 2011). It can also attack some sealing  dissolves organic compounds (Nishimoto, 2011). It can also attack some sealing materials and plastic components because of its low viscosity (Arcoumanis et al., 2008). Previous studies have made use of the immersion method through the use of swelling and mechanical properties as parameters to test for resistance in DME (Li and Zhou, 2008; Wu et al., 2008; Saputra et al., 2016; Sari et al., 2017; Saputra et al., 2018). According to research conducted by Li and Zhou (2008), immersion of rubber in a mixture of DME/diesel at 20/80 w/w produces a corroded rubber seal.

       Furthermore, natural rubber grafted with acrylonitrile (AN) and styrene (ST) has the potential to be used as a seal for the storage of DME. It has excellent properties such as good elasticity, high tensile strength (TS), and good adhesion to metal. Polyacrylonitrile (PAN) is a non-solvent material with hydrocarbons, chlorinated hydrocarbons ketones, diethyl ether, and acetonitrile (Mark, 2009). The presence of PAN could increases its insolubility and resistance to organic solvents (Nataraj et al., 2012). ST has also been observed to be a good co-monomer for the stability of the graft-copolymerization process (Prasassarakich et al., 2001; Angnanon et al., 2011; Sari et al., 2015). According to studies conducted by Prasassarakich et al. (2001), the oil and solvent resistance of Natural Rubber can be improved by graft copolymerization using AN. Increases in TS and oil resistance were observed with an increase in the percentage grafting efficiency (GE) of AN monomer (Prukkaewkanjana et al., 2014); these results were also reported by Angnanon et al. (2011).

The objective of the present study was to obtain a copolymer of DPNR-g-PAN/PS with a high resistance to DME gas. This is important because resistance is the potency needed by natural rubber to survive the diffusion or corrosion caused by the DME. According to research conducted by Sari et al. (2017), the copolymer is expected to reduce the degradation of rubber because of the action of DME. The characteristics of the copolymer were determined using Fourier transform infrared spectroscopy (FTIR). The mechanical properties measured included TS, elongation at break (EB), and hardness, while the resistance test parameters included swelling, shrinking, and changes in mechanical properties after immersion. A surface morphology test was also performed using a scanning electron microscope (SEM) analysis.


The present study focused on the production and resistance testing of a DPNR-g-PAN/PS copolymer in DME with the influence of AN monomer and ST monomer. The presence of AN and ST increases the mechanical properties of DPNR and DPNR-g-PAN/PS. It was found that the lowest percent swelling was attain with the highest of composition of AN, while the lowest percent of shrinking was attain at the highest of composition of ST. This condition requires the advance optimization of the AN/ST composition for swelling and shrinking test. The FTIR spectrum of DPNR degraded more than that of DPNR-g-PAN/PS spectrum and the morphology of DPNR-g-PAN/PS experienced a slight shrinking effect while that of DPNR underwent a huge shrinking effect.



The authors wish to express their gratitude to the Research Laboratory of Chemical Engineering FT-UI and the Rubber Research Center Bogor for their support in this research.


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