Macronet Polyesters and Polyacrylates

Swelling data for macronet crosslinked polyesters were reported by Takahashi [144], His polymers were prepared by causing a mixture of propylene glycol and an equivalent amount of diacid (maleic anhydride plus succinic acid) to undergo 

The average number (k) of backbone carbon atoms between crosslinked junctions in such macronet structures is given by the ratio of the total number of atoms in the backbones of the crosslinked network divided by the total number of atoms that form crosslink junctions. Thus, in this macronet system, k is given by  

An approximately linear relationship of S as a function of k1/3 is also exhibited by hydrophilic macronet crosslinked polymers as indicated by the results deduced via a similar reconsideration of the swelling and molecular weight data reported by Refojo [145], who studied swelling of 2,3-dihydroxypropyl metha-crylate-co-tetraethylene glycol dimethacrylate polymers in water. 

The correlation of calculated S with calculated X113 (Fig. 19) show that all but one of the data points fall on the line given by  

The above results indicate that Eq. 14 may be general for liquid sorption by crosslinked polymer networks, i.e. the volume, S, of liquid sorbed per gram of crosslinked polymer increases linearly with the cube root of the average number, X, of backbone atoms in the segments between crosslink junctions. The constants 

---