Determination ofx from Swelling

A necessary preliminary to obtaining reliable values of the interaction parameter X from swelling measurements is the determination of the degree of crosslinking of the network, that is, the crosslinked polymer must be calibrated before use. A 

For equilibrium swelling in cyclohexanone, calculating as above from Eq. (3.135) 4 2m - 0.0521. Rearranging Eq. (3.132) gives  

A necessary preliminary to obtaining reliable values of the interaction parameter a from swelling measurements is the determination of the degree of crosshnking of the network, that is, the crosslinked polymer must be calibrated before use. A method used is to determine the volume fraction of polymer present in the swollen gel when a sample of the crosslinked polymer has swelled to equilibrium in an excess of a solvent in which the a value is known for the polymer. The relation between the ratio of initial to nal weight and the volume fraction is given by 

Problem 3.24 Osmotic pressure measurements at 25°C for poly(vinyl chloride) in dioxane solution yielded 

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