THE SYNTHESIS AND CHARACTERIZATION OF NOVEL CARBOXYL TELECHELIC MICROSPHERES

A series of novel carboxyl telechelic microspheres (CTMs) with differe nt length of oligo-caprolactone telechelic chains are readily prepared via a three-step approach involving: (1) the hydrolytic oligomerizati on of epsilon-caprolactone, (2) the esterification of oligo-caprolacto ne with maleic anhydride, and (3) the suspension polymerization of mal eic acid polycaprolactone ester acid (MAPCLA) with divinylbenzene. The CTMs, which are water swellable, spherical, and porous, contain carbo xyl functionalities of 1.0 to 4.2 mEq/g (dry), which are found to be l ower swelling change (during conversion of ionic form) and higher exch ange efficiencies than those of the Emerk. IV resin. The intermediate products, oligo-caprolacton, and MAPCLA are characterized by the acid- base titration, hydroxyl value titration, and infrared and H-1 nuclear magnetic resonance analysis, respectively. The morphology and porous of CTMs are also tested by scanning electron microscopy and Brunauer-E mett-Teller technology. The effects of the length of the telechelic ch ains and the degree of crosslinking (divinylbenzene), as well as the a mount of porogen (toluene), on the physical and chemical parameters of the CTMs are also described. (C) 1998 John Wiley & Sons, Inc.