Effect of temperature on sulfur prevulcanization of natural rubber latex

✍ Scribed by N. M. Claramma; N. M. Mathew

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 180 KB
• Volume: 65
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19970906)65:10<1913::aid-app8>3.0.co;2-i

✦ Synopsis

Sulfur prevulcanization of natural rubber latex was conducted at 60, 70, 80, and 90ЊC for different periods. The extent of crosslinking was assessed. Tensile properties, water absorption, leaching, and stress-relaxation characteristics of the films were also evaluated. The volume fraction of rubber (Vr), which is a measure of crosslink density of the films, showed a maximum when prevulcanization was conducted at 80ЊC for 2 h or at 90ЊC for 1 h. At lower temperatures, the rate of reaction was slow. At each temperature, tensile strength and elongation at break decreased when the prevulcanization time increased, whereas the modulus increased up to a maximum crosslinking and thereafter decreased. Water absorption and leaching were more rapid in prevulcanized film than in postvulcanized film. The rate of stress relaxation slightly increased as the extent of prevulcanization increased.