|
The study of the composition and monomer sequence distribution of binary copolymers is often complicated because of the many definitions of representative properties for the sequence distribution, the numerous calculations required, and occasionally the abstract treatment of the statistical processes describing the copolymer formation. Copoly resolves these issues with a user-friendly, highly visual interface to perform all calculations. Using Microsoft Excel and Word, Copoly is compatible with Windows and Mac OS. In Copoly the students enter up to five independent data parameters using the Data Input Window, and immediately see the results. To obtain diagrams for a copolymerization obeying a second-order Markovian process, the fraction of one monomer, ƒA, and the reactivity ratios, rA, rB, rA´ and rB´ need to be entered; for a first-order Markovian process only the first three of these are required. For a Bernoullian- or zeroth-order Markovian process only ƒA and rA are required. The results are displayed on separate sheets labeled: 1. Copolymerization Diagrams, 2. Dyads and Triads, 3. Sequence Length Distribution, 4. Simulated Copolymer Design, and 5. Summary. 
Figure 1. Copoly, showing an excerpt of sheet 2. Dyads and Triads, and the Data Input Window.
Sheets 1–4 show side-by-side views of three diagrams for potentially all three of the Markovian process orders. In the Summary sheet, the four types of diagrams presented in sheets 1–4 are shown together, being calculated for a second-order process, which depending on the input data, may simplify to a first- or zeroth-order Markovian process as subsets. In addition, there are three supplements to the Excel worksheet integrated as Word files. In Supplement 1 all applied equations are given in their conventional notation, which are easier to comprehend than the Excel formula bar. Supplement 2 presents 20 selected cases with input data and comments. Supplement 3 provides further instructions. Students can learn to interpret the distributions of n-ads (for example, triads) and sequence lengths in combination with a simulated copolymer design, and ascertain how these key copolymer properties are related. They find that copolymerizations with tendencies to alternation or block formation do not necessarily lead to copolymers with easily recognizable patterns. Furthermore they can determine how to obtain a desired copolymer composition and monomer sequence distribution based on adjustments of the feed composition and the reactivity ratios. This tool can be used as a homework assignment or for self-tutoring. Accompanying documentation describes the theoretical background and provides information on how to effectively use this program.
|
Citation
