Hydroxyphenyl-terminated polysiloxane, polysiloxane-polycarbonate copolymer comprising the same as repeated unit with excellent transparency and improved flame retardancy, and method for preparing the copolymer

A polysiloxane-polycarbonate copolymer comprising, as repeating units, a hydroxylphenyl-terminated polysiloxane represented by the following chemical formula 1-1 or the following chemical formula 1-2;

• and a polycarbonate block:
• wherein:
• in the above chemical formulas 1-1 and 1-2,
• each R1 independently represents hydrogen atom, a hydrocarbon group having 1 to 13 carbon atoms or hydroxy group;
• each R2 independently represents a hydrocarbon group having 1 to 13 carbon atoms or hydroxy group;
• each R3 independently represents an alkylene group having 2 to 8 carbon atoms;
• each R4 independently represents hydrogen atom, halogen atom, hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 10 carbon atoms;
• each of a and b independently represents an integer of 0 to 10, provided that at least one of a and b is not 0;
• and
• c represents an integer of 1 to 2.

A method for preparing a polysiloxane-polycarbonate copolymer, comprising the steps of:

• (1) reacting a hydroxylphenyl-terminated polysiloxane represented by the following chemical formula 1-1 or the following chemical formula 1-2 and an oligomeric polycarbonate under an interfacial reaction condition to form a polysiloxane-polycarbonate intermediate;
• and
• (2) polymerizing the intermediate by using a first polymerization catalyst:
• wherein:
• in the above chemical formulas 1-1 and 1-2,
• each R1 independently represents hydrogen atom, a hydrocarbon group having 1 to 13 carbon atoms or hydroxy group;
• each R2 independently represents a hydrocarbon group having 1 to 13 carbon atoms or hydroxy group;
• each R3 independently represents an alkylene group having 2 to 8 carbon atoms;
• each R4 independently represents hydrogen atom, halogen atom, hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 10 carbon atoms;
• each of a and b independently represents an integer of 0 to 10, provided that at least one of a and b is not 0;
• and
• c represents an integer of 1 to 2.