GRAFTING OF POLYESTERS FROM CARBON WHISKER SURFACE - COPOLYMERIZATIONOF EPOXIDES WITH CYCLIC ACID ANHYDRIDES INITIATED BY COOK GROUPS INTRODUCED ONTO THE SURFACE

To modify the surface of carbon whisker (vapor-grown carbon fiber) the grafting of polyesters by use of potassium carboxylate (COOK) groups introduced onto the surface was investigated. The introduction of COOK groups onto the carbon whisker was achieved by the treatment of surfa ce carboxyl groups with KOH aqueous solution. Untreated carbon whisker has no ability to initiate the polymerization. It was found that the anionic ring-opening alternating copolymerization of epoxides with cyc lic acid anhydrides is successfully initiated by COOK groups on the ca rbon whisker surface. The corresponding polyester was grafted onto the surface based on the propagation of polymer from COOK groups introduc ed on the surface. The percentage of grafting of the polyester from st yrene oxide and phthalic anhydride was determined to be 91.0%. The pol ymerization rate and percentage of grafting increased upon addition of crown ether. Furthermore, the rate of polymerization increased with i ncreasing the dielectric constant of the solvent, but the percentage o f grafting decreased. Polyester-grafted carbon whisker was found to gi ve a stable colloidal dispersion in a good solvent for the grafted pol ymer. (C) 1993 John Wiley & Sons, Inc.