Effect of monomer functionalization

Figure 2.12 Effect of monomer functionality on molecular structure ...

Sarkar, M.D., Gill, N.L., Whitehead, J.B., Crawford, G.P. Effect of monomer functionality on the morphology and performance of the holographic transmission gratings recorded on polymer dispersed liquid crystals. Macromolecules 36, 630-638 (2003)... 

We now turn to two of the problems we have sidestepped until now. In this section we consider the polymerization of reactants in which a stoichiometric imbalance exists in the numbers of reactive groups A and B. In the next section we shall consider the effect of monomers with a functionality greater than 2. 

Next let us examine the effect of monomers with functionality greater than 2 on step-growth polymers. 

Other commercially relevant monomers have also been modeled in this study, including acrylates, styrene, and vinyl chloride.55 Symmetrical a,dienes substituted with the appropriate pendant functional group are polymerized via ADMET and utilized to model ethylene-styrene, ethylene-vinyl chloride, and ethylene-methyl acrylate copolymers. Since these models have perfect microstructure repeat units, they are a useful tool to study the effects of the functionality on the physical properties of these industrially important materials. The polymers produced have molecular weights in the range of 20,000-60,000, well within the range necessary to possess similar properties to commercial high-molecular-weight material. 

Branched and crossiinked condensation polymers are produced when the reaction mixture includes tri-functional monomers as well as bi-functional ones. The incorporation of a single tri-functional monomer into a chain generates a branch point. As we increase the fraction of tri-functional monomers, branching becomes more prevalent and the resulting molecules more complex. When sufficient tri-functional monomers are present we create a three-dimensional crossiinked network. Figure 1.12 shows the general outline of the effects of tri-functional monomers on condensation polymers. 

Figure 1.12 General outline of the effects of tri-functional monomer content on condensation polymers...

In PE/aluminium laminates, which are used for packaging, the bond strength can be improved by surface oxidation of the polymer. An alternative to surface oxidation is to use copolymers of ethylene and monomers containing polar groups that can provide stronger bonds to metal thus increasing adhesion [24,25]. The effects of three functional groups in ethylene copolymers, namely EVS [polyethylene-co-vinyl trimethoxy silane], EBA [polyethylene-co-butyl acrylate], EAA [polyethylene-co-acrylic acid) on the adhesion was studied [25]. The interface in polymer/metal laminates has been analysed by FT-IR... 

Williams, H. L., Mas, E. M., Szalewicz, K., and Jeziorski, B., On the effectiveness of monomer-, dimer-, and bond-centered basis functions in calculations of intermolecular interaction energies, J. Chem. Phys. 103, 7374-7391 (1995). 

Table II. Effect of Monomer on the Distribution of Functional Groups in Plasma-Polymerized Fluorocarbon Films... 

Berthon-Fabry et al. have studied multiscale structure formation as a function of the concentration of monomers and of acid. The % mass ratio (percent of monomers to the total mass of the sol) was used as a controlling parameter for the effect of monomer concentration. Formulations with % mass ratio >35 and relatively low acid catalyst concentration (R/C > 50) gave homogenous monoliths. With a higher monomer % mass ratio (>55) and acid catalyst concentrations RjC < 1), a very viscous resin-like material was obtained. Varying the concentration of monomers and acid is an effective method to produce carbon aerogels with different morphologies [11, 37]. 

The effect of monomer packing in reaction rates was first determined decades ago studying reactions in mono-layers [39]. The rate of lactonization of y-hydroxystearic acid (HSA) was determined in substrate monolayers as a function of applied lateral pressure ( r). As n increases the film of HSA passes from an expanded to a condensed state and at the transition the rate of acid catalyzed lactonization of HSA decrease sharply. The rate decrease was attributed to a change in the accessibility factor related to the alteration of the fluidity of the monolayer, preventing the approach of hydroxyl and carboxylate groups [39]. 

Zhang Tingling, Kashima Miki, Zhang Mingzhi, et al. Effects of the functionality of epoxy monomer on the electro-optical properties of thermally-cured polymer dispersed liquid crystal films. RSCAdv. 2 no. 5 (2012) 2144-2148. 

Myrcene is an interesting diene (actually triene) monomer since it has an isolated double bond in its alkyl side chain. Thus, this monomer provides a unique opportunity to study the effects of internal ir-bond interactions in living anionic polymerizations and also to examine the effects of this functionality on the physical properties of poly(myrcene) and various block copolymers as reported herein. 

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