Modelling Degradative Chain Transfer in d‐Limonene/2‐Ethylhexyl Acrylate Free‐Radical Copolymerization

Abstract

Summary: Degradative chain transfer plays a significant role in the free-radical copolymerization of d-limonene (LIM) and 2-ethylhexyl acrylate (EHA). This is due to d-limonene allylic radicals. A kinetic model was developed to account for degradative chain transfer. Experimental data at feed compositions (LIM/EHA, mol/ mol) of 40/60, 50/50, 30/70 were compared with model predictions. The model revealed the considerable effect of degradative chain transfer on conversion, copolymer composition and molecular weight. Moreover, it indicates that degradative chain transfer to d-limonene is not only conversion-dependent but also concentration-dependent.

An Experimental and Computational Approach on Controlled Radical Photopolymerization of Limonene

“…[26] Another important parameter that should be observed is the propagation kinetic rate constant for limonene radical polymerization. Literature shows the values of k p = 13 L mol −1 s −1 for the thermally-initiated radical copolymerization of limonene and 2-Ethylhexyl acrylate (80 °C), [45] which was 3.5 times lower than the respective parameter determined in this study at 40 °C (k p = 45 L mol −1 s −1 ). This is an important result, because although both values can be considered in a range close to the evaluated parameter, the trend is quite divergent, indicating that photopolymerization has advantages in terms of accelerating the polymerization rate.…”

Sustainable polymer reaction engineering: Are we there yet?

“…[97] As a monomer, limonene polymerizations result in only limited monomer conversion, but they can be copolymerized or used as a property modifier (eg, chain transfer agent). [97][98][99] The third route is to use natural polymers (eg, cellulose, [100][101][102][103][104][105] chitosan, [106][107][108][109] starch, [68,[110][111][112][113] lignin [69,[114][115][116][117] ) to develop materials. Usually, chemical or physical modification of the natural polymers is required.…”

“…[ 97 ] As a monomer, limonene polymerizations result in only limited monomer conversion, but they can be copolymerized or used as a property modifier (eg, chain transfer agent). [ 97–99 ]…”