Onset of vulcanisation - point of t

Onset of vulcanisation - point of time at which compound first begins to stiffen, thus becoming incapable of flowing thermoplastically.Undervulcanisation - stage at which tensile stress increases a lot with vulcanisation time, but the degree of crosslinking is small, highly undervulcanised articles are of no technical value.Vulcanization optimum - fairly high degree of crosslinking, technical vulcanization optimum below highest point on curve, at maximum tensile stress, products already have relatively poor ageing properties.Plateau and overvulcanisation - tensile stress of most synthetic rubbers continue to rise slightly after vulcanisation optimum. With natural rubber, when vulcanisation optimum exceeded, crosslinking is reversed and this reversion causes mechanical properties to suffer.