The influence of fillers and degree of vulcanization on the mechanical properties of hard rubber polyblends

✍ Scribed by T. H. Meltzer; W. J. Dermody

• Publisher: John Wiley and Sons
• Year: 1964
• Tongue: English
• Weight: 673 KB
• Volume: 8
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1964.070080218

✦ Synopsis

Hard rubber polyblends, made from SBR-butyl rubber mixtures vulcanized with sulfur, show several consistent patterns of behavior in response to recipe modifications or changes in degree of vulcanization. Tg increases with degree of vulcanization, reinforcing fillers raise the modulus, and reversion is encountered upon overcure as in SBIt hard rubber. The dual or stepwise transition from glassy to rubbery modulus behavior which characterizes polyblends is clearly distinguishable in all of the mixtures. The level of the polyblend modulus plateau between glassy and rubbery behavior is dependent on the proportion of butyl in the blend. The range of temperatures spanned by the polyblend modulus plateau is dependent on the degree of vulcanization of the hard rubber portion of the blend. Hard rubber dust suppresses the characteristic stepwise transition of the polyblend in proportion to the amount of dust added. The changes in the other mechanical properties investigated are consistent with the changes in modulus. The impact resistance of the polyblend appears to be effectively limited by the impact resistance of the hard rubber portion a t all degrees of vulcanization.