SynopsisThe texture and the pore size distribution of a set of styrene divinylbenzene copolymers, prepared by suspension polymerization with various compositions and various amounts of ethyl-2-hexanoic acid as diluent, have been studied using nitrogen adsorption-desorption isotherms, mercury porosimetry, and scanning-electron microscopy. It appears that pore volume and surface area may be well predicted in a large range of conditions (divinylbenzene contents between 20 and 60%, ethyl-2-hexanoic acid contents between 35% and 60%). In this range of conditions there are three structures: the elementary nuclei are spherical particles of about 100-200 8, in diameter. They are organized in microspheres of about 500-1000 A, and the microspheres form aggregates (2500-5000 8,) more or less separated by large holes. The smaller pores (<40 8,) are in the microspheres, between the nuclei; they are present only if the amount of divinylbenzene is high enough. Intermediate pores (40-500 A) are, in the aggregates, between the microspheres, although the larger pores between the aggregates range from about 500 8, t o more than 10,000 A, depending on the amount of diluent.

Macroporous styrene-divinylbenzene resins are studied using precipitating agents as diluents. A definition of the macroporous domain is given, based on homogeneous properties and structures. The existence of this macroporous domain is proved to be a general feature of the macroporous resins field. The position of this domain is specified for 4 different diluents. The evolution of the texture of the resins, according to their position inside or outside the macroporous domain is analyzed and discussed. RESUME:Les resines macroporeuses styrene-divinylbenzene preparees en presence d'agents reticulants comme porogenes ont ete etudiees. Une definition du domaine macroporeux est donnee en se fondant sur l'homogeneite des proprietes et des structures. L'existence de ce domaine macroporeux apparait comme un des traits caracteristiques des resines macroporeuses. La position de ce domaine est donnee pour 4 porogenes differents. L'evolution de la texture des resines est analysee et discutee en fonction de leur localisation a I'interieur ou a l'exterieur du domaine macroporeux.