Dual cure sealants

A composition comprising:

• a polythiol, wherein the polythiol comprises a thiol-terminated polythioether prepolymer, wherein the thiol-terminated polythioether prepolymer comprises a moiety having the structure of Formula (2c):
• —S—R1—[S-A-S—R1-]n—S— (2c)
• wherein,
• n is an integer from 1 to 60;
• each R1 is independently selected from C2-10 alkanediyl, C6-8 cycloalkanediyl, C6-14 alkanecycloalkanediyl, C5-8 heterocycloalkanediyl, and —[(CHR3)p—X—]q(CHR3)—, wherein,
• p is an integer from 2 to 6;
• q is an integer from 1 to 5;
• r is an integer from 2 to 10;
• each R3 is independently selected from hydrogen and methyl;
• and
• each X is independently selected from O, S, and NR, wherein R is selected from hydrogen and methyl;
• and
• each A is independently a moiety derived from a polyvinyl ether of Formula (3) and a polyalkenyl polyfunctionalizing agent of Formula (4):
• CH2═CH—O—(R2—O)m—CH═CH2 (3)
• B(—R70—CH═CH2)z (4)
• wherein,
• m is an integer from 0 to 50;
• each R2 is independently selected from C1-10 alkanediyl, C6-8 cycloalkanediyl, C6-14 alkanecycloalkanediyl, and —RCHR)p—X—WCHR3),—, wherein p, q, r, R3, and X are as defined for R1;
• B represents a core of a z-valent, polyalkenyl polyfunctionalizing agent B(—R70—CH═CH2)z wherein,
• z is an integer from 3 to 6;
• and
• each R70 is independently selected from C1-10 alkanediyl, C1-10 heteroalkanediyl, substituted C1-10 alkanediyl, and substituted C1-10 heteroalkanediyl;
• a polyalkenyl, wherein the polyalkenyl comprises an alkenyl-terminated prepolymer, a polyalkenyl monomer, or a combination thereof;
• a metal complex;
• and
• an organic peroxide.