Theoretical investigation on the polyaddition of A2 and CB2 monomers with non-equal reactivity

✍ Scribed by Zhiping Zhou; Zhengwei Jia; Deyue Yan

• Book ID: 104088029
• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 447 KB
• Volume: 50
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2009.09.027

✦ Synopsis

Taking account of the difference of reactivities between C and B group, the evolution of the monomers and the various structural units formed from the polyaddition of A 2 and CB 2 monomers was investigated by the kinetic mechanism. The calculated results theoretically explain the experimental data observed in our previous works very well, if the reactivity ratio of C to B groups is 200. The critical conversion of gelation for the A 2 þ CB 2 type polymerization depends on the reactivity ratio. The lower the ratio, the earlier the gelation appears. Compared with the A 2 þ B 3 type polymerization, the disappearance of gelation for the A 2 þ CB 2 type polymerization should attribute to the much higher reactivity of C group than that of B one. The analytical expression of the degree of branching was derived as well. If the reactivity of C group is much higher than that of B group and the substitution effect is neglected, the value of the degree of branching for the hyperbranched polymers obtained is equal to the value of conversion of B groups and it may exceed 0.5, with the feed ratio of monomers varying from 1 to 3/2.