Effects of polymerization conditions when making norbornene-ethylene copolymers using the metallocene catalyst ethylene bis (indenyl) zirconium dichloride and MAO to obtain high glass transition temperatures
✍ Scribed by Christer H. Bergström; Jukka V. Seppälä
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 128 KB
- Volume
- 63
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Using 70 mol % norbornene in the monomer mixture before polymerization, the influences of different polymerization conditions were studied. It was found that by increasing the temperature from 10 to 70ЊC, the yield increased and the molecular weight decreased; and when increasing the ethylene pressure from 2 to 6 atm, yield and molecular weight increased. The highest glass transition temperatures, however, were achieved at 30ЊC and 4 atm. Further improvements could be obtained by increasing the amount of catalyst or Al/Zr ratio. Using the conditions of 30ЊC, 4 atm, 4 mg catalyst, 3000 Al/Zr, 250 mL toluene solution, and 30 min, the amount of norbornene was increased from 31.1 to 90 g, resulting in an increase in the glass transition temperature from 98 to 155ЊC.