Preparation and stabilization of fluoropolymer dispersions

A method comprising polymerizing at least one fluorinated olefinic monomer in an aqueous emulsion polymerization in the presence of a carbosilane surfactant having at least one hydrophobic part, wherein the hydrophobic part has at least one silicon atom, and having at least one hydrophilic part, wherein the carbosilane is selected from those having the general formula (I):

• Q-P—(OCnH2n)x—O-T (I)
• wherein Q is selected from R3Si— and R3Si—(R′—Si(R)2)a—R′—Si(R″)2—;
• each R is independently selected from an aliphatic group having from 1 to 18 carbon atoms, a cycloaliphatic group having from 6 to 12 carbon atoms, and an aromatic group having from 6 to 12 carbon atoms;
• R′is an alkylene group having from 1 to 14 carbon atoms;
• R″ is R when a ≠0 and is selected from R and R3SiR′ when a=0;
• the value of a is from 0 to 2;
• P is selected from an alkylene group having from 1 to 18 carbon atoms and AR′″, wherein A is an alkylene group having from 1 to 18 carbon atoms and R′″ is a functional group selected from —NHC(O)—, —NHC(O)(CH2)n-1—, —NHC(O)C(O)—, —NHC(O)(CH2)vC(O)—, —OC(O)—, —OC(O)(CH2)n-1—, —OC(O)C(O)—, —OC(O)(CH2)vC(O)—, —OCH2CH(OH)CH2OC(O)(CH2)n-1—, and —OCH2CH(OH)CH2OC(O)(CH2)vC(O)—;
• where v is from 1 to 12;
• T is selected from H, a alkyl radical having from 1 to 10 carbon atoms, and an acyl radical having from 1 to 4 carbon atoms;
• x is from 1 to 200 and n is from 1 to 6.

A method comprising polymerizing at least one fluorinated olefinic monomer in an aqueous emulsion polymerization in the presence of a carbosilane surfactant having at least one hydrophobic part, wherein the hydrophobic part has at least one silicon atom, and having at least one hydrophilic part, wherein the carbosilane is selected from those having the general formula (II):

• Q′-(P—(OCnH2n)x—O-T)2 (II)
• wherein Q′ is —SiR2—X—SiR2—, X is selected from a linear alkylene group, a branched alkylene group, a cycloalkylene group, a linear alkylene group bearing one or more oxygen containing groups, a branched alkylene group bearing one or more oxygen containing groups, and a cycloalkylene group bearing one or more oxygen containing groups;
• P is selected from an alkylene group having from 1 to 18 carbon atoms and AR′″, wherein A is an alkylene group having from 1 to 18 carbon atoms and R′″ is a functional group selected from —NHC(O)—, —NHC(O)(CH2)n-1—, —NHC(O)C(O)—, —NHC(O)(CH2)vC(O)—, —OC(O)—, —OC(O)(CH2)n-1—, —OC(O)C(O)—, —OC(O)(CH2)vC(O)—, —OCH2CH(OH)CH2OC(O)(CH2)n-1—, and —OCH2CH(OH)CH2OC(O)(CH2)vC(O)—;
• where v is from 1 to 12;
• T is selected from H, a alkyl radical having from 1 to 10 carbon atoms, and an acyl radical having from 1 to 4 carbon atoms;
• x is from 1 to 200 and n is from 1 to 6.