|Chemical and Physical Phenomena
Resulting from Rubber Milling
Professor Emeritus,Kyoto Institute of Technology,Kyoto,Japan
Nippon Gomu Kyokaishi,(2003),76(6), 186-191 General Review in Japanese.
Rubber technology for operating milling and mixing with ease and a higher effeciency plays an important role in manufacturing rubber products.The milling patterns classified by Tokita and White are compared qualitatively with the time-temperature correspondence principle under a consideration of molecular structure of rubber.
Some chemical reactions of rubber attributed to mastication were outlined concerning "cold"and"hot"mastications.At the hot mastication SBR crosslinks predominantly to produce macrogels,contrary to degradation of NR.The macrogels induce poor processability and lowering of the mechanical properties.Some protection methods are cited.
Dispersive mixing of reinforcing filler is concerned with the size reduction of agglomerated particles produced by interparticle forces.Lowering the interparticle forces of ppt-silica and increasing its affinity toward rubber molecules are attainable by using bis(3-triethoxysilyl propyl)-tetrasulfane(TESPT).
The ease of the filler incorporation mainly depends on the milling patterns,whereas the filler dispersion proceeds by mechanical shear as shown in "Onion Model"proposed by Shiga and his coworkers.The stress for destroying the aggromerates are evaluated from the equation developed by Rumpf.The mechanisms of carbon gel formation and Carbon scorch phenomenon caused by mixing are also discussed.
Mechanochemical Reaction,Autoxidation,Macrogel,Critical Separation Distance,Agglomerate