Kinetics and Mechanism of Copolymerization of Linalool with Acrylonitrile

Abstract

Linalool (LIN) and acrylonitrile (AN) were copolymerized by benzoyl peroxide (BPO) in xylene at 75°C for 60 min. The system follows ideal kinetics with bimolecular termination and results in the formation of an alternating copolymer as evidenced from the values of reactivity ratios as r₁(AN)=0.011 and r₂(LIN)=0.017. The overall activation energy is 35.2 kJ/mol. The FTIR spectrum of the copolymer shows the presence of the band at 3467 cm⁻¹ due to hydroxy group of LIN and at 2240 cm⁻¹ due to a cyanide group of AN. The ¹H-NMR spectrum shows peaks at 7.0–7.7 δ due to alcoholic group of LIN. ¹³C-NMR spectrum of copolymer has peaks at δ ppm=116–120 of –CN, and δ ppm=75–77 of –C–OH. The TGA and DSC studies show that the copolymer is highly stable thermally and has glass transition temperature (Tg)=50°C. The mechanism of copolymerization has been elucidated. This paper also reports the measurement of Mark Houwink constants in THF at 25°C by means of GPC as α=0.50 and K=2.24×10⁻³ dl/g.

Keywords:

• Copolymerization
• Linalool
• Acrylonitrile
• Mark Houwink constants
• Reactivity ratio

Acknowledgment

The authors thank Dr. K. P. Singh, Director, H.B.T.I., Kanpur, for providing the necessary facilities. One of the authors thanks DST, New Delhi, for the sanction of the research project “Synthesis and Characterization of Copolymers of Terpenes with Vinyl Monomers” (SP-S 1-H-26-2000).