Polymer composition and sequence distribution

The peptide sequence in a protein can now be determined with automated equipment. A standard reference on this technique is the Handbook of Protein Sequence Analysis. However, many synthetic copolymers cannot be taken apart with such precision they must be analyzed as intact chains. Consider an AB copolymer. The composition can be specified by the mole fraction = 1 - Xg. While some synthetic copolymers have an identical sequence distribution for each chain, most chains are characterized by sequence probability distributions, One example of a unique sequence distribu- 

Polypropylene has been studied in great detail, and the stereotactic composition and sequence have been measured by NMR spectroscopy. The following section presents the essential principles of NMR spectroscopy needed to understand the interpretation of the spectra of polypropylene. The technical details are based on the book Chain Structure and Conformation of Macromolecules  

---

FRP leads to the formation of statistical copolymers, where the arrangement of monomers within the chains is dictated purely by kinetic factors. The most common treatment of free-radical copolymerization kinetics assumes that radical reactivity depends only on the identity of the terminal unit on the growing chain. The assumption provides a good representation of polymer composition and sequence distribution, but not necessarily polymerization rate, as discussed later. This terminal model is widely used to model free-radical copolymerization according to the set of mechanisms in Scheme 3.11. 

---