production of ethylene butadiene coploymer
INTRODUCTION
1. INTRODUCTION
The copolymerization of ethylene with 1, 3-butadiene to give crystalline, homopolymer-free, high molecular weight, substantially linear copolymer is described. Butadiene polymerizes almost exclusively in a trans-1, 4 structure, ranging in content from zero to 50 mole-%. At relatively low content of butadiene monomeric units (≤30 mole-%) X-ray crystallinity is of polyethylene type with a slight variation of the structural parameters. At higher levels of butadiene monomeric units, crystallinity of trans-1, 4-polybutadiene is also observed. The products with little unsaturation (1–5 mole- %) melt at about 132°C and are able to crosslink with sulfur-based recipes.
The product of the reactivity ratios was evaluated. The catalyst system consists of vanadium tris (acetylacetonate),
Diethylaluminium chloride, and an acidic compound or its precursor. The nature and the amount of the acidic modifier regulate the polymerization rate as well as the molecular weight, composition, and long branching of the copolymer, So that a strict control of the catalyst system is required The behavior of the catalyst is tentatively explained by the polarity of the active carbon-vanadium bond, which depends on substituent’s and complexing agents.
HISTORY AND REGULATION OF PRODUCTION
2. HISTORY AND REGULATION OF PRODUCTION
Throughout the later 19th century many chemists attempted to determine the makeup of natural rubber, with the goal of reproducing it. In 1860, the British chemist Charles Greville Williams analyzed rubber by destructive distillation and obtained a large quantity of light oil which he termed isoprene. In 1873, the French chemist Georges Bouchardat found that isoprene, when heated with hydrochloric acid for several hours, produced a rubber-like
1. INTRODUCTION
The copolymerization of ethylene with 1, 3-butadiene to give crystalline, homopolymer-free, high molecular weight, substantially linear copolymer is described. Butadiene polymerizes almost exclusively in a trans-1, 4 structure, ranging in content from zero to 50 mole-%. At relatively low content of butadiene monomeric units (≤30 mole-%) X-ray crystallinity is of polyethylene type with a slight variation of the structural parameters. At higher levels of butadiene monomeric units, crystallinity of trans-1, 4-polybutadiene is also observed. The products with little unsaturation (1–5 mole- %) melt at about 132°C and are able to crosslink with sulfur-based recipes.
The product of the reactivity ratios was evaluated. The catalyst system consists of vanadium tris (acetylacetonate),
Diethylaluminium chloride, and an acidic compound or its precursor. The nature and the amount of the acidic modifier regulate the polymerization rate as well as the molecular weight, composition, and long branching of the copolymer, So that a strict control of the catalyst system is required The behavior of the catalyst is tentatively explained by the polarity of the active carbon-vanadium bond, which depends on substituent’s and complexing agents.
HISTORY AND REGULATION OF PRODUCTION
2. HISTORY AND REGULATION OF PRODUCTION
Throughout the later 19th century many chemists attempted to determine the makeup of natural rubber, with the goal of reproducing it. In 1860, the British chemist Charles Greville Williams analyzed rubber by destructive distillation and obtained a large quantity of light oil which he termed isoprene. In 1873, the French chemist Georges Bouchardat found that isoprene, when heated with hydrochloric acid for several hours, produced a rubber-like
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