Copolymerization of n‐Butyl Methacrylate and D‐Limonene

Abstract

The bulk free radical copolymerization of n‐butyl methacrylate (BMA) and D‐limonene is carried out at 80 °C using benzoyl peroxide (BPO) as initiator. Low conversion experiments are conducted to estimate the copolymer reactivity ratios while full conversion runs are performed to verify the estimates and to achieve high monomer conversions. Reactivity ratios of r1 = 6.0957 and r2 = 0.0459 (1 = BMA, 2 = D‐limonene) are obtained using a nonlinear, error‐in‐variables method with the RREVM computer program. Full conversions and reasonably high molecular weights are achieved at high BMA feed concentrations. Achieving high conversion is limited by a degradative chain transfer mechanism due to the D‐limonene.

Copolymerization of Limonene with n‐Butyl Acrylate

“…Limonene contains more than one allylic hydrogen (see Figure (a)), and these can all become reactive sites for degradative chain transfer. Even though the highly substituted tertiary allylic radical usually presents the highest stability, in the case of limonene, the formation of a primary allylic radical would be more likely due to reduced steric hindrance and is believed to be the dominant species generated during the chain transfer reaction . Since these allylic radicals are not prone to propagate, they either terminate with each other or more likely (because of limonene's bulkiness), with propagating chain radicals to yield polymer chains ending with a Lim' unit.…”

“…In all cases, the polymerization rates were greatly reduced due to the presence of limonene. More recently, the bulk copolymerization of limonene with BMA and 2‐ethyl hexyl acrylate was investigated …”

Computational Package for Copolymerization Reactivity Ratio Estimation: Improved Access to the Error-in-Variables-Model

“…Many reactivity ratio estimation studies (including [18,[21][22][23]) have used the Tidwell-Mortimer (T-M) criterion for design of experiments to select the feed compositions at which to run copolymerizations for reactivity ratio estimation. In most cases, two optimal feed compositions (according to T-M) are used and replicated four times each.…”

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

“…One family of bio‐derived materials, terpenes (e.g., α ‐pinene, β ‐pinene, d ‐limonene), are of particular interest but give rise to a degradative chain transfer mechanism due to the presence of allylic C‐H bonds in their molecular structure. This has impeded efforts to homopolymerize these monomers via free radical techniques . Since the alpha C‐H bond connected to the double bond is extremely weak, it tends to be abstracted via chain transfer and results in a highly stable allylic radical, which is no longer able to react, and will decrease propagating radical concentration .…”