Abstract: A transparent, non elastomeric, high refractive index, impact resistant poly(thio)urethane/urea material comprising the reaction product of: a) at least one (?, ?)-diiso(thio)cyanate cycloaliphatic or aromatic polysulfide prepolymer, and b) at least one aromatic primary diamine, in an equivalent molar ratio amine function/iso(thio)cyanate function ranging from 0.5 to 2, wherein, said prepolymer and diamine are free from disulfide (—S—S—) linkage and wherein the (?, ?)-diiso(thio)cyanate polysulfide prepolymer is the reaction product of at least one cycloaliphatic or aromatic diiso(thio)cyanate and at least one (?, ?)-diol prepolymer.

Abstract: A transparent, non elastomeric, high refractive index, impact resistant poly(thio)urethane/urea material comprising the reaction product of: a) at least one (?, ?)-diiso(thio)cyanate cycloaliphatic or aromatic polysulfide prepolymer, and b) at least one aromatic primary diamine, in an equivalent molar ratio amine function/iso(thio)cyanate function ranging from 0.5 to 2, wherein, said prepolymer and diamine are free from disulfide (—S—S—) linkage and wherein the (?, ?)-diiso(thio)cyanate polysulfide prepolymer is the reaction product of at least one cycloaliphatic or aromatic diiso(thio)cyanate and at least one (?, ?)-diol prepolymer.

Abstract: A transparent, non elastomeric, high index, impact resistant polythiourethane/urea material comprising the reaction product of: a) at least one (?, ?)-diiso(thio)cyanate cycloaliphatic or aromatic prepolymer having a number average molecular weight ranging from 100 to 3000 gmol?1, and b) at least one primary diamine, in an equivalent molar ratio amine function/iso(thio)cyanate function from 0.5 to 2, preferably from 0.90 to 1.10, wherein, said prepolymer and diamine are free from disulfide (—S—S—) linkage and at least one of the prepolymer or the diamine contains one or more S atoms in its chain.

Abstract: A transparent, non elastomeric, high index, impact resistant polythiourethane/urea material comprising the reaction product of:

Abstract: A process for making a stabilized, liquid, diepisulfide based prepolymer having a viscosity at 25 C. ranging from 20 to 330000 centipoises which comprises polymerizing at room temperature a monomer composition comprising at least one diepisulfide monomer in the presence of at least one anionic polymerization initiator and at least one halogenated polymerization inhibitor and compositions made therefrom.

Abstract: The room temperature polymerizable composition comprises at least one polymerizable monomer having at least one episulfide functionality and an effective amount of at least one (alkoxyphenyl)phosphine polymerization catalyst.

Abstract: Polysiloxane sheet or tube polymers having pendant siloxane groups are prepared by contacting sheet or tube silicates with halogen endblocked halosiloxanes represented by the formula: ##STR1## where X is chlorine, fluorine, bromine, or iodine; R1 to R7 are alkyl groups with 1-6 carbon atoms, aryl groups, alkaryl groups, or aralkyl groups; in which one of the groups R1, R4, and R5 can additionally represent X; and n has a value of 2 to about 20.

Abstract: Method of making polysiloxanes by ring opening polymerization of dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane (D.sub.3), and cyclosiloxanes such as 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl) cyclotrisiloxane (F.sub.3) or 1,3,5,7-tetramethyl-1,3,5,7-tetrakis(3',3',3'-trifluoropropyl) cyclotetras iloxane (F.sub.4) in an acid-free system using electrophillic initiators. The reaction mixture is formed under anhydrous conditions and contains (i) the cyclosiloxanes, (ii) a Lewis base such as 2,6-di-tert-butylpyridine which serves as a co-catalyst and an acid scavenger, and optionally (iii) a salt of a strong acid such as tetrabutylammonium trifluoromethane sulfonate. The anhydrous mixture is contacted with a silyl ester of a strong acid such as triflic acid. The anhydrous reaction mixture is agitated at room temperature until a polysiloxane is formed.