Abstract: Cyclic polycarbonate oligomer compositions are polymerized with lactones in the presence of a catalyst for the polymerization of either. Usually, the lactone is first polymerized at a lower temperature, followed by the cyclic polycarbonate at a higher temperature.

Abstract: A block copolymer having a narrow molecular weight distribution is produced by reacting an acid anhydride with an epoxide to yield a polyester, which is further reacted with a lactone, using a catalyst system comprising an aluminum porphyrin complex and an organic quaternary salt under mild reaction conditions.

Abstract: An epoxy resin composition comprising (a) an epoxy resin, (b) a lactone obtained by decarboxylation condensation reaction of a saturated alicyclic 1,2-dicarboxylic acid anhydride, and if necessary (c) a curing agent for the epoxy resin and (d) a curing accelerator gives a cured article showing almost no or very slight curing shrinkage.

Abstract: Certain aryloxyphosphonium salts have been found to be effective as curing agents for various cationically polymerizable organic materials, such as epoxy resins, when incorporated into such materials. The materials are found to be moisture curable coating compositions.

Abstract: Lactic-glycolic copolymers having molecular weights of about 6000 to about 35000 are prepared by condensation of lactic acid and glycolic acid in the presence of readily removable strong acid ion-exchange resins.

Abstract: Aromatic onium salts, such as diaryliodonium salts, have been found to be effective thermal initiators for the polymerization of a variety of cationically polymerizable materials including epoxides, cyclic ethers, phenol formaldehyde resins, etc., when used in combination with various cocatalysts such as organic acids and copper salts.

Abstract: A novel process for polymerization or copolymerization of monomers is described, according to which the reaction is carried out in the presence of an anionic initiator and a macroheterocyclic complexing agent of formula ##STR1## in which: EACH R.sub.1 is a hydrogen atom, a hydrocarbon group or an alkoxycarbonyl group, or the two R.sub.1 together can form a group of the general formula: ##STR2## THAT IS TO SAY FORMING A THIRD BRIDGE BETWEEN THE TWO NITROGEN ATOMS IN THE MOLECULE, A is a hydrocarbon group,D is an oxygen or sulfur atom or a hydrocarbon group, with the proviso that at least two of the groups D are oxygen or sulfur atoms and that, if each R.sub.1 is hydrogen, a hydrocarbon group or an alkoxycarbonyl group, one of these two groups D is oxygen or sulfur and the other is oxygen,n and p are integers ranging from 1 to 3, andm is 2 or 3.