Synthesis and characterization of butadiene-1,3 and octene-1 copolymer prepared by a Ziegler-Natta catalyst based on neodymium
The aim of this work is to evaluate the influence of octene-1 incorporation in the polybutadiene chain on the polymerization reaction and polymer characteristics. Thus, copolymerization of butadiene-1,3 with octene-1 using a Ziegler-Natta ternary catalyst based on neodymium was performed. The weight ratios of butadiene-1,3/α-olefin 100/0, 99/1, 97/3, 95/5, 90/10, 80/20 and 70/30 were evaluated. The copolymers were characterized by size exclusion chromatography (SEC), infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). The results showed that the degradation temperature (Tmax) was not affected by the addition of alpha-olefin, while the thermal behavior has undergone significant changes. The polymer microstructure was not influenced by the increasing of octene-1 content. However, a tendency to molecular mass increase was observed with the increasing of octene-1 content. It was also observed a trend in reduction of the polymerization conversion as the octene-1 content increased.
Well-Defined Comb, Star−Comb, and Comb-on-Comb Polybutadienes by Anionic Polymerization and the Macromonomer Strategy
Stryrenic macromonomers of polybutadienes (sMMB) were synthesized by selective reaction of living polybutadienes with the silyl chloride group of 4-(chlorodimethylsilyl)styrene. Anionic copolymerization of sMMBs with butadiene, in the presence of a randomizer (potassium 2,3-dimethyl-3-pentoxide randomizer), led to living random comb polybutadienes (PBCs). Taking advantage of the living character of the PBCs, a number of well-defined comb, star−comb, and comb-on-comb polybutadienes were synthesized by using high-vacuum techniques. All samples prepared were characterized by size exclusion chromatography (SEC) with DRI detector and SEC with two-angle laser light scattering detector (SEC-TALLS).
Low Molecular Weight Ethylene/Propylene Copolymers. Effect of Process Parameters on Copolymerization with Homogeneous Cp2ZrCl2 Catalyst
In ethylene/propylene copolymerizations with cyclopentadienylzirconium dichloride (Cp 2 -ZrCl 2 )/methylaluminoxane (MAO) catalyst, correlations were found between polymerization temperature (-15°C to +55°C), catalyst activity, and viscosity average molecular weight. As the polymerization temperature increased, the activity of the catalyst increased and the viscosity average molecular weight of the copolymer product decreased. The activity of the catalyst was higher than that reported earlier, even with the differences in polymerization condition taken into account. Changing the solvent from heptane to toluene and no effect on the viscosity average molecular weight of the product