Structures and compositions of copolymers

Abstract

Although studies on reactions of model radicals with olefins are becoming of increasing importance, most understanding of copolymerization has come from studies on copolymer composition and monomer unit sequence distribution information. A number of models for copolymerization have resulted from such studies. For most copolymerization systems the terminal model provides an adequate representation, but more complicated models which allow for the effects of penultimate units on radical reactivity, for reversibility of propagation steps and for participation of monomer complexes in copolymerization processes must be considered in some cases. Modeling of such copolymerization systems is considerably simplified by computer‐oriented approaches such as matrix–multiplication, Monte Carlo simulation and CSMP or ACSL programming. Recent studies on solvent effects in copolymerizations involving polar monomers indicate that partitioning of monomers between solvent and growing polymer radicals is a very significant phenomenon.

Copolymerization of Partly Incompatible Monomers: An Insight from Computer Simulations

“…The former value gives us some information about the ensemble of chains in general, while the latter values are often used to characterize the chain sequences. 29 Results are presented in Fig. 2.…”

Polymerization-Induced Microphase Separation with Long-Range Order in Melts of Gradient Copolymers

“…As it was expected, the results obtained from the DPD simulations at χ = 0 and KM are in good agreement; the differences observed in the transition region (which is smoother for the DPD simulation results) are most probably related to the chain polydispersity (even though the obtained dispersity value Ð of 1.012–1.013 is rather small, see the graphical chain representations in Figure 1 (right)) as well as the simplified growth process in the KM where all the chains grow simultaneously. At χ = 1, we see slight deviations from the KM data in the region of the styrene block; this can explained by the presence of the bootstrap effect [ 43 ], when the growing polymer chain due to the presence of the incompatibility between monomers of different types controls its own environment.…”

High temperature copolymerization of styrene/ethyl acrylate: Reactivity ratio estimation in bulk and solution

“…This may be due to preferential solvation of styrene sequences by p-xylene. Hence, local comonomer concentrations are affected by this (as previously discussed and illustrated by Harwood 15 with his "bootstrap" model, and by Maxwell et al 16 with their "solvent-polymer complex" effect). In general, p-xylene has a smaller molecular size than m-xylene, and more chances to form hydrogen bonds with styrenic segments.…”