Coupling agents

A thermoset composition comprising a dispersion of a particulate solid into a thermosetting resin in the presence of a coupling agent comprising monomeric units a, b, c, d, and e according to formula I:

• wherein, independently for each molecule of the coupling agent:
• R1 is H or CH3;
• R2 is H, a C1 to C20 alkyl group, a C6 to C10 aryl group, a C7 to C14 alkaryl group, or a C4 to C6 cycloalkyl group;
• R3 is H or CH3;
• R4 is a C1 to C20 alkyl group, —C—O—R12—, or —(C═O)—O—C—R12—, wherein R12 is a C1 to C20 alkyl group;
• R5 is H or CH3;
• R6 is —C—O— or —(C═O)—O—C—;
• R7 is a C1 to C20 alkyl group;
• R8 is H or CH3;
• R9 is a C1 to C20 alkyl group, —C—O—R14—, or —(C═O)—O—C—R14—, wherein R14 is a C1 to C20 alkyl group;
• R10 is H or CH3;
• R11 is a C1 to C20 alkyl group, —C—O—R15—, or —(C═O)—O—C—R15—, wherein R15 is a C1 to C20 alkyl group;
• POL1 is a polymer comprising at least one of a polyether or a polyester, wherein the polymer has a theoretical-number-average molecular weight of from 200 to 3,000;
• POL2 is a polymer comprising at least one of a polyether or a polyester, wherein the polymer has a theoretical-number-average molecular weight of from 200 to 3,000;
• X is S, O, NH, or —O—(C═O)—;
• a is an integer from 1 to 500;
• b is an integer from 1 to 500;
• c is 0, or an integer from 1 to 100;
• d is 0, or an integer from 1 to 100;
• and
• e is 0, or an integer from 1 to 100;
• with the proviso that if d is greater than 0, e is 0, and if e is greater than 0, d is 0.