Urethane elastomers, peroxide

Urethane elastomers suitable for peroxide vulcanization typically are prepared from a hydroxyl-group-terminated oligomeric adipate polyester and 4,4 -methylenediphenylisocyanate (MDI). A typical structural representation is as follows ... 

Peroxide Vulcanization of Urethane Elastomers. Urethane elastomers suitable for peroxide vulcanization are typically prepared from an hydroxyl-group-terminated oligo-... 

Three urethane-crosslinked polybutadiene elastomers (TB-1, TB-2, and TB-3) of varying crosslinking levels, along with a similarly crosslinked styrene-butadiene copolymer (HTSBR) and two polybutadiene polymers randomly crosslinked with dicumyl peroxide (PB-1 and PB-2), have been investigated to determine their viscoelastic behavior. Elsewhere, TB-1, TB-2, and TB-3 have been designated as HTPB-1, HTPB-2, and HTPB-3, respectively. 

Peroxides are vulcanizing agents for elastomers, which contain no sites for attack by other types of vulcanizing agents. They are useful for ethylene-propylene rubber (EPR), ethylene-vinyl acetate copolymers (EAM), certain millable urethane rubbers, and silicone mbbers. They generally are not useful for vulcanizing butyl rubber (poly[isobutylene-co-isoprene]) because of a tendency toward chain scission, rather than crosslinking, when the polymer is subjected to the action of peroxide. 

Uses Urethane-acrylic for radiation and peroxide cured structural adhesives, coatings (paper, PVC floor, wood), elastomers, electronics, screen inks... 

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