Why should natural latex be pro-valcanization
The partiacal size of natural latex is about 0.5u , each partiacal contains a lot of molecules . Surfur , zinoxide , acceleratants , are insoluble in water , so only the molecules on partical surface can obtain vulcanizaters and get vaulcanization.
To solve the problem , in latex production, we need pro-valcanization : mix latex and vulcanizaters and keep stirring for 20-48hours at setting temperature .
About the pro-vulcanization , there are 2 theories in academic circle :
1. Trace vulcanizaters can be soluted in water , during pro-vulcanization, soluted vulcanizater molecules can permeate into rubber particals very slowly , after long time , most of the rubber colecules in the partical can touch vulcanizaters .
2. During pro-vulcanization , rubber particals and vulcanizater particals have chance to impact each other , the molecules on the surface can touch together . according to the theory of brownian motion, every molecule in rubber partical is keep moving , so after long time pro-vulcanizating , most of the molecule can touch vulcanizaters .
Myself accept 2nd theory more .
According to 2nd theory , we can conclude the influence factors of pro-vulcanization: time , temperature , sitrring speed .
Long time , more chance for molecules touching vulcanizaters ; high temperature , molecule has more energe to move faster ; stirring speed higher , particals touching chance is more .
Of cause , too high pro-vulcanization temp and stirring speed will weaken the stability of latex , too long time stirring will also weaken the latex ,so kow to control pro-vulcanization is very important .