Study On Preparation, Structure And Performance Of Reclaimed Rubber

At present, the reclaimed rubber industry in our county universal have many problems such as great labor intensity, high energy consumption, serious environmental pollution and so on. It has important practical significance to study on waste rubber resource which the natural resource has been decreased and shortage of energy nowadays. In order to obtain the reclamation of waste tread rubber which has the properties of high performance, easy processability and environmental protection, attempts have been made to correlate the changes in the process conditions, softener, tackifying resin and reinforcing resin.When research on reclamation of40mesh and60mesh by different temperature mixing process, the result reveals that the former have the high sol content, small crosslinking density and low Mooney viscosity.This shows that former’s crosslinking network has more completely destroyed in the process of powder reclamation.The difference of performance between their properties is small.So, considering the fannacial factors, we can also choose the latter in the industrial production.In the process, the production temperature shall not be lower than150℃or more than180℃.When the temperature increased, the damage of crosslinking network are enhanced.While the rubber powder which has the60orders sizing qrid can get a good comprehensive performance in165℃,in order to achieve the comprehensive performance of the best value, the temperature of the rubber powder which has the40orders sizing qrid are as high as170℃.As the increase of reclamation time, damage increased in the rubber crosslinking network structure, meanwhile the proportion of the main chain rupture also increases. We can get the reclaimed rubber with the best comprehensive performance when the reclamation time is25min.When the different temperature conditions in the heat preservation process, it was found that crosslinking network destruction is poorer below the150"C.The proportion will increase when the tempereature up to200℃in the reclamation process.In addition, the content of oxygen has great influence on the results.The SEM analysis showed that the reclamation incomplete parts exist widely in the reclaimed rubber in forms of the "defects".This struture are easy to become the stress midpoint and destroyed under the press.Based on the morphology observation and reclamation process characteristic of fracture, it can be inferred that in the rubber’s reclamation process, the molecular chain turned from space stereo mesh structure into linear structure, branched-chain structure, small network structure of the molecular chain and the broken network structure of large molecules group.Except the amylose structure, the others are lead to the high Mooney viscosity in the reclaimed rubber.For the dynamic performance, in the condition of less strain, reclaimed rubber has a higher loss factor because of the huge rigid difference between the completely parts and not completely parts.Along with the increase of strain,"soft hard" gap between the two parts shrinks and the the loss factor becomes smaller.After vulcanization, the crosslinking density difference between the two kinds of structure also shrinks and the loss factor will not be the first decline which appeared totally different in the mixing rubber.The SEM analysis showed that the surface of this kind of vulcanizate’s pull section is smooth and the stress concentration phenomenon is weak.By research of different concentration and species of softener, As the increase of reclaim softener, damage increased in the rubber crosslinking network structure。 Wood tar as a softener makes reclaimed rubber have high mechanical performance but poor processing performance.Aromatic oil and naphthenic oil amount of about10phr can get a good overall performance.Shea pectin will consume the curing agent, impact on cured rubber performance.Biological oils and fats are not used alone as reclaimed softener.Through using different softener in the reclaimed rubber, the RPA study found that wood tar makes the internal "soft hard" parts combined more closely and the loss factor won’t appear the reduce phenomenon at first.Due to involved in the curing, the shea pectin can be reduce the bonding effect of the completely part and not completely part in the regeneration process, and also can be cause the relatively coarse cross section.Proved by experiments:the tackifying resin(coumarone resin) and reinforcing resin(VPN1132) can effectively improve the tensile properties of reclaimed rubber.Found by SEM, the coumarone resin can effectively increase the internal bonding effect of reclaimed rubber, which reduces stress concentration in the recured rubber tensile process.