Márta Szesztay

New Thermoplastic Elastomers by Quasiliving Atom Transfer Free Radical Grafting

Controlled synthesis of a new thermoplastic elastomer (TPE), poly(isobutylene-g-styrene) (PIB-g-PSt) was achieved by quasiliving atom transfer radical polymerization (ATRP). A new commercially available butyl rubber containing bromobenzyl moieties was used as macroinitiator for ATRP of styrene catalyzed by CuBr/2,20-bipyridine complex. Both bulk and solution polymerization resulted in well-defined graft copolymers as indicated by analyses with 1H NMR and GPC. Phase separated morphology in these graft copolymers was found by DSC. Stress-strain analyses indicate high elongation and tensile strength for PIB-g-PSt grafts with certain composition. This new grafting process and the resulting TPE are candidates for several useful applications.

Poly(1,3,4-oxadiazole-amide-ester)s and Thin Films Made from Them

Aromatic poly(1,3,4-oxadiazole-amide-ester)s were prepared by polycondensation reaction of diacid chlorides containing preformed ester groups with aromatic diamines containing 1,3,4-oxadiazole units. These polymers were easily soluble in N-methylpyrrolidinone and were cast into flexible films from such solutions. The polymers showed high thermal stability with initial decomposition temperature being above 365 °C and glass transition temperature in the range of 215–260 °C. The weight average molecular weight was in the range of 91 000–257 000 and polydispersity is in the range of 1.64–5. The polymer films showed good mechanical properties with tensile strength in the range of 40–91 MPa, elastic modulus in the range of 2.22–3.98 GPa and elongation at break in the range of 1.85–7.37%.