# US 5,347,028 A · Highly functionalized polycyclosiloxanes and their polymerization into thermally reversible living rubbers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,028 A - Document ID: US5347028A - Status: Granted - Kind: A - Application number: 08/173,734 - Filed: 1993-12-23 - Granted: 1994-09-13 - Earliest claimed: 1992-07-16 - Assignees: Temple University of the Commonwealth System of Higher Education - Inventors: Mark A. Buese; Pao-Sun Chang - Web page: https://patentgrep.com/patent/US5347028A ## CPC - C08G 77/485: {containing less than 25 silicon atoms} - C07F 7/21: Cyclic compounds having at least one ring containing silicon, but no carbon in the ring - C08G 77/04: Polysiloxanes - C08G 77/08: characterised by the catalysts used - C08G 77/50: by carbon linkages - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS - C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22) ## Abstract A composition curable to a thermally reversible rubber comprises (i) a strong acid catalyst having a pK.sub.a of less than about -9, (ii) at least one polycyclosiloxane containing at least one polyfunctional siloxane unit, and (iii) at least one polysiloxane selected from the group consisting of a linear polydimethylsiloxane; a polydimethylcyclosiloxane containing from about 6 to about 50 silicon-oxygen bonds; a linear or cyclic block copolymer of polydimethylsiloxane and a non-siloxane organic polymer; and a linear or cyclic random copolymer of a siloxane of the formula Si(R)(R.sup.1)O wherein R and R.sup.1 are different and are selected from the group consisting of hydrogen, C.sub.1 -C.sub.18 hydrocarbon and C.sub.2 -C.sub.18 hydroxyalkyl, wherein the catalyst comprises from about 0.05 to about 0.5 wt % of the composition, and the concentration of polyfunctional siloxane units is at least about two times the catalyst concentration in the composition, but no more than about 0.27 molar. Novel compounds useful as the polycyclosiloxane component of the composition are also provided. ## Claims ### Claim 1 A polycyclosiloxane according to formula I, ##STR16## wherein R is oxygen, or C.sub.1 to C.sub.12 straight or branched chain alkylenyl, a is 2 to 20, and b is 2 to 4. ### Claim 2 (depends on 1) A polycyclosiloxane according to claim 1 wherein R is C.sub.2 to C.sub.8 alkylene, and a is 2 to 8. ### Claim 3 A polycyclosiloxane according to formula II, ##STR17## wherein R is oxygen, C.sub.1 to C.sub.12 straight or branched chain alkylenyl, a is 2 to 20, c is 1 to 3, and d is zero to 100, provided a may not be 3 when c is 1. ### Claim 4 (depends on 3) A polycyclosiloxane according to claim 3 wherein R is C.sub.2 to C.sub.8 alkylene, and a is 2 to 8. ### Claim 5 A polycyclosiloxane according to formula III, ##STR18## wherein R is oxygen, or C.sub.1 to C.sub.12 straight or branched chain alkylenyl, a is 2 to 20, c is 1 to 3, d is zero to 100 and e is 1 to 3. ### Claim 6 (depends on 5) A polycyclosiloxane according to claim 5 wherein R is C.sub.2 to C.sub.8 alkylene, and a is 2 to 8. ### Claim 7 A polycyclosiloxane according to formula IV, ##STR19## wherein R is oxygen, or C.sub.1 to C.sub.12 straight or branched chain alkylenyl, a is 2 to 20, f is 1 or 2, g is 1 to h, and h is 3 to 20, provided f and g are not both 1. ### Claim 8 (depends on 7) A polycyclosiloxane according to claim 7 wherein R is C.sub.2 to C.sub.8 alkylene, a is 2 to 8, and h is 3 to 8. ### Claim 9 A polycyclosiloxane according to formula V, ##STR20## wherein R is oxygen, or C.sub.1 to C.sub.12 straight or branched chain alkylenyl, a is 2 to 20, j is 1 to 2, m is 1 to 100, X is hydrogen, C.sub.1 to C.sub.12 straight or branched chain aklyl, C.sub.1 to C.sub.12 straight or branched chain alkoxy, phenyl vinyl or Z, wherein Z is a cyclic moiety according to formula (VII) ##STR21## where a and R are defined as above, provided: when X is Z: k is 1 to 100 and n is 1 to 100; when X is other than Z: k is 1 to 100 and n is 1 to 100, except that when k is 1 or 2, n must be greater than 2, and when n is 1 or 2, k must be greater than 2; Y is methyl or Z; p is 1 or 2; q is zero to r; r is 1 to 18; and t is zero to 100. ### Claim 10 (depends on 9) A polycyclosiloxane according to claim 9 wherein R is C.sub.2 to C.sub.8 alkylene, and a is 2 to 8. ### Claim 11 A polycyclosiloxane according to formula VI, ##STR22## wherein R is oxygen, or C.sub.1 to C.sub.12 straight or branched chain alkylenyl, a is 2 to 20, Y is methyl or Z, wherein Z is a cyclic moiety according to formula (VII) ##STR23## wherein a and R are defined as above, p is 1 or 2, q is zero to r, r is 1 to 18, and t is zero to 100, provided, that when p is one, R may not be CH.sub.2 or CH.sub.2 CH.sub.2. ### Claim 12 (depends on 11) A polycyclosiloxane according to claim 11 wherein R is C.sub.2 to C.sub.8 alkylene, and a is 2 to 8. ### Claim 13 (depends on 7) A polycyclosiloxane according to claim 7 having the formula VIII, wherein x is 1 or 2, and n is 1 to 100: ##STR24## ### Claim 14 (depends on 4) A polycyclosiloxane according to claim 4 which is 1,3-di(2-heptamethylcyclotetrasiloxane-yl-ethyl)-1,1,3,3-tetramethyldisilo xane. ### Claim 15 (depends on 8) A polycyclosiloxane according to claim 8 which is 1,3,5,7-tetra-(2-heptamethylcyclotetrasiloxane-yl-ethyl)-1,3,5,7-tetrameth ylcyclotetrasiloxane. ### Claim 16 (depends on 4) A polycyclosiloxane according to claim 4 which is 1,3,3,3-tetra-(2-heptamethylcyclotetrasiloxane-yl-ethyl)-1,3-dimethyldisil oxane. ### Claim 17 (depends on 2) A polycyclosiloxane according to claim 2 which is tris-(2-heptamethylcyclotetrasiloxane-yl-ethyl)-methylsilane. ### Claim 18 (depends on 6) A polycyclosiloxane according to claim 6 which is 1,3-di-(2-[tri-(2-heptamethylcyclotetrasiloxane-yl-ethyl)]-silylethyl)-1,1 ,3,3-tetramethyldisiloxane. ### Claim 19 (depends on 2) A polycyclosiloxane according to claim 2 which is tetrakis-(2-heptamethylcyclotetrasiloxane-yl-ethyl)silane. ### Claim 20 (depends on 1) A polycyclosiloxane according to claim 1 which is tetrakis-(2-heptamethylcyclotetrasiloxane-yl-oxy)silane.