Explanation and Discussion of Binary Copolymer Composition Equations

Introduction: The description of copolymer composition is a crucial topic in polymer science courses. However, it is regrettable that current polymer science textbooks fail to sufficiently clarify the copolymer composition equations, posing a significant teaching challenge for course instructors. Methods: This study employs the kinetic method and the Markov chain method to mathematically and rigorously formulate two different equations that describe the relationship between the copolymer composition and the molar ratio of two monomers in a copolymerization reaction, one of which is the well-known Mayo-Lewis equation. Results: We prepared 11 sets of figures to evaluate the reliability and accuracy of the two equations. Despite significant formal differences, the equations were found to describe essentially equivalent phenomena, thereby validating the Mayo-Lewis equation as a reliable approximation of the underlying phenomenon. These explanations were then presented to a class of students majoring in materials chemistry. Discussion: The survey results regarding teaching effectiveness showed that over 70% of the students surveyed believed that these explanations improved the rationality of the steady-state assumption, the validity of the copolymer composition equations, the memorability of the equations, and their understanding of the mechanism of binary free radical copolymerization. Conclusion: Hence, these explanations address deficiencies in current textbooks and improve the students’ comprehension of the topic.