SWELLING OF GRAFTPOLYMER

Abstract

The Flory's theory on swelling of network high polymer was applied on the network graft polymer.
The model used to derive the equation of swelling was constructed under the following assumptions:
1) Backbone polymer chains are crosslinked and branch polymer chains are deposited in the network of backbone polymer.
2) Heat of mixing for graft polymer and solvent is assumed to be of van Laar type.
3) Graft polymer being swollen, network chains are deformed entropicaly.
The derived equation is as follows:
where χ₁: parameter expressing the energy of interaction between solvent and graft polymer
P: moles of branch chains
υe: moles of chains between the network junctions in the backbone polymer network
f: number of backbone chains crosslinked at one crosslinkage
υp: volume fraction of graft-polymer at swollen state
υ_ν0: volume fraction of backbone polymer chains at non-swollen state
V₀: volume of graft polymer at non-swollen state
V₁: mole volume of solvent
M: primary molecular weight of backbone polymer
M_c: molecular weight per cross-linked unit of backbone polymer
ρ_ν: density of backbone polymer
These equations are modified further for crystalline graft-polymer.