Polyacrylonitrile (PAN) polymers with low polydispersity index (PDI) and carbon fibers made therefrom

A method for synthesizing a polyacrylonitrile (PAN) polymer with a narrow molecular weight distribution, the method comprising:

• a) combining acrylonitrile (AN) monomer with a solvent, at least one co-monomer, and a thiocarbonylthio compound to form a solution;
• b) heating the solution to a temperature within the range of 40° C. 85° C.;
• and
• c) adding an initiator to the heated solution to affect polymerization reaction, thereby forming a polymer solution comprising polyacrylonitrile (PAN) polymer,
• wherein polymerization is affected by controlled/living radical polymerization, in which the thiocarbonylthio compound functions as a Reversible Addition/Fragmentation Chain Transfer (RAFT) agent,
• wherein the thiocarbonylthio compound is selected from the following structures:
• where Z1 is selected from:
• —CH2—(CH2)10—CH3;
• —(CH2)n—CH3, n=0-20;
• —C(CH3)m—COOH, m=1-2;
• —C(CH3)m—COOCH3, m=1-2;
• —C(CH3)m—COOC2H5, m=1-2;
• R1 is selected from:
• R′1 is selected from:
• —CN;
• x=0-1;
• R″1 is selected from:
• H;
• —CH3;
• —(CH2)m—COOH, m=1-2;
• R′″1 is H or —CH3
• where Z2 is selected from:
• R is selected from:
• F, Cl, CN, OCH3;
• R2 is selected from:
• R′2 is selected from:
• —CN;
• x=0-1;
• —C(CH3)m—COOCH3, m=1-2;
• —C(CH3)m—COOC2H5, m=1-2;
• R″2 is selected from:
• H;
• —CH3;
• —(CH2)m—COOH, m=1-2;
• R′″2 is H or —CH3
• where Z3 is selected from:
• —CH2—(CH2)10—CH3;
• —(CH2)y—CH3, y=1-20;
• R3 is selected from:
• —CH2—(CH2)10—CH3;
• —(CH2)y—CH3, y=1-20,
• wherein the PAN polymer has a polydispersity index (PDI) of about 2 or less and a molecular weight within the range of 60 kg/mole to 500 kg/mole.