Preparation of polyacrylonitrile with different molecular weights and high conversion yield in aqueous phase polymerization

Document Type : Original Article

Authors

1 assistance researcher, petrochemicals department Egyptian Petroleum Research Institute,

2 Egyptian Petroleum Research Institute

3 chemistry department, faculty of science, Ain Shams University, Cairo, Egypt,

4 Petrochemicals department, Egyptian Petroleum research Institute

5 petrochemicals department, Egyptian Petroleum Research Institute, Egypt

6 petrochemicals department Egyptian Petroleum Research Institute, Egypt

Abstract

Different molecular weights of polyacrylonitrile (PAN) homopolymers were prepared based on the process of aqueous phase precipitation polymerization of acrylonitrile. Aqueous phase precipitation polymerization system includes water as aqueous media, acrylonitrile as monomer, ammonium persulfate as initiator, and drops of HCl as the activator of polymerization process. The polymerization processes were investigated at different monomer and initiator ratios, and different pH. The results showed that molecular weight of prepared polyacrylonitrile increased up to with increasing the monomer ratio at optimized pH 2.25, and the conversion percent was decreased. However, with increasing initiator ratios the opposite trend was occurred, i.e. the molecular weight decreased and conversion percent increased. The optimized conditions for getting suitable molecular weight at high conversion (84%) were at pH 2.25, 90 g/L of monomer concentration, and 0.67 g/L of APS initiator at time 6 hr. The prepared polymers were investigated using XRD, FTIR, H1NMR, TGA, and DSC. XRD results showed that crystallinity of the prepared polymers was decreased with increasing its molecular weight, as well as, the higher molecular weight of prepared PAN has more thermal stability than lower molecular weight.

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Egyptian Journal of Chemistry
Volume 65, Issue 132 - Serial Number 13
Special Issue: Chemistry and Global Challenges (Part B)
December 2022
Pages 1347-1353

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History

  • Receive Date: 19 April 2022
  • Revise Date: 29 May 2022
  • Accept Date: 05 June 2022

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