Lesson plan
Composition drift
Composition drift occurs during the process of free radical copolymerization causing variation in the instantaneous mole fraction of a monomer added to a copolymer, therefore altering the chemical composition of the copolymer over the period of conversion. The degree of composition drift is directly affected by the reactivity ratios of each monomer in the copolymer system. Both the Mayo-Lewis equation and plot of the equation make evident that as monomer conversion increases, the copolymer composition will drift as the preferences for monomers change due to the interaction between reactivity ratios and the instantaneous concentration of each monomer. Composition drift in some degree will occur unless the reactivity ratios for both monomers are equal to 1. In this case, each monomer prefers reaction with itself and the other monomer equally. This causes equal rates of consumption for copolymer formation and leads to random copolymerization.
Article summary
Composition drift occurs during the process of free radical copolymerization causing variation in the instantaneous mole fraction of a monomer added to a copolymer, therefore altering the chemical composition of the copolymer over the period of conversion. The degree of composition drift is directly affected by the reactivity ratios of each monomer in the copolymer system. Both the Mayo-Lewis equation and plot of the equation make evident that as monomer conversion increases, the copolymer composition will drift as the preferences for monomers change due to the interaction between reactivity ratios and the instantaneous concentration of each monomer. Composition drift in some degree will occur unless the reactivity ratios for both monomers are equal to 1. In this case, each monomer prefers reaction with itself and the other monomer equally. This causes equal rates of consumption for copolymer formation and leads to random copolymerization.
Key claims
No claims recorded.
Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
No sources recorded.
Key claims and bibliography are generated from the same tracked claims and sources as the article page.