Abstract: A composition for foaming polyester which includes a carbonate or bicarbonate salt and water intermixed with a finely divided solid free flow agent such as synthetic amorphous silica. The free flow agent is added in an amount sufficient to absorb all of the water and render the composition a free flowing powder. The composition is readily mixable with an unsaturated polyester resin media. A source of acid in the mixture liberates gas from the carbonate or bicarbonate, and good foam structures having small uniform cells are obtained.

Abstract: Novel processes and compositions are provided for the preparation of foamed, cross-linked polyethylene utilizing di(alkylperoxy)acetylene cross-linking/blowing agents. The novel compositions include esters of thiodipropionic acid as activators.

Abstract: A composition for foaming polyester which includes a carbonate or bicarbonate salt and water intermixed with a finely divided solid free flow agent such a synthetic amorphous silica. The free flow agent is added in an amount sufficient to absorb all of the water and render the composition a free flowing powder. The composition is readily mixable with an unsaturated polyester resin media. A source of acid in the mixture liberates gas from the carbonate or bicarbonate, and good foam structures having small uniform cells are obtained.

Abstract: A composition for preparing polymeric articles comprising: (a) an acrylic polymerizable component such as monomeric and polymeric aliphatic acrylate and methacrylate esters having a Brookfield viscosity of about 0.1-400 poise and about 5-60% by weight of solids; (b) copper and tin polymerization promoters providing in the composition about 0.05-4 ppm of Cu.sup.+2 and about 10-300 ppm of Sn.sup.+2 ; (c) about 5.times.10.sup.-6 to 1.times.10.sup.-4 mole/gm of the composition of a primary mercaptan chain transfer agent; and (d) sufficient peroxyester initiator to provide about 0.02-0.3% by weight of active oxygen in the composition. The composition is highly efficient at room temperature and provides excellent optical quality polymers while permitting a wide choice of peroxyesters as the initiator.

Abstract: Di(acylperoxy)-bis-carbonates of the formula: ##STR1## wherein each R is selected from alkyl and aryl of up to about 20 carbon atoms. The new molecules have exceptional thermal stability, which facilitates storage at ambient temperatures. They have utility in initiating the polymerization of ethylenically unsaturated monomers and for curing polymers such as unsaturated polyester resins.

Abstract: A novel method of making foamed, crosslinked low density polyethylene utilizing as dual crosslinking/blowing agents, organic peroxides of the formula: ##STR1## where each R is a t-alkyl group bonded through its tertiary carbon atom and having 4-8 carbon atoms; and R' is an alkyl group of 1-6 carbon atoms.