The copolymerization of propylene with higher, linear alpha-olefins

Propylene was copolymerized with the linear alpha -olefins 1-octene, 1-dece ne, 1-tetradecene, and 1-octadecene. The metallocene catalyst Me2Si(2-Me-Be nz[e]Ind)(2)ZrCl2, in conjunction with methylalumoxane as a cocatalyst, was used to synthesize the copolymers. The copolymers were characterized by C- 13 and H-1 NMR with a solvent mixture of 1,2,4-trichlorobenzene (TCB) and b enzene-d(6) (9/1) at 100 degreesC. Thermal analyses were carried out to det ermine the melting and crystallization temperatures, whereas the molecular weights and molecular weight distributions were determined by gel permeatio n chromatography with TCB at 140 degreesC. Glass-transition temperatures we re determined with dynamic mechanical analysis. Relationships among the com onomer type and amount of incorporation and the melting/crystallization tem peratures, glass-transition temperature, crystallinity, and molecular weigh t were established. Moreover, up to 3.5% of the comonomer was incorporated, and there was a decrease in the molecular weight with increased comonomer content. Also, the melting and crystallization temperatures decreased as th e comonomer content increased, but this relationship was independent of the comonomer type. In contrast, the values for the glass-transition temperatu re also decreased with increased comonomer content, but the extent of the d ecrease was dependent on the comonomer type. (C) 2000 John Wiley & Sons, In c.