Study On The Improvement Of The Comprehensive Properties Of Skim Rubber

Skim is a by-product which is obtained through centrifuge separate from fresh natural latex, skim rubber is prepared by skim, its copper ion and manganese ion content is much higher than that of natural rubber which is the most important reason for poor aging proprieties. Its poorly aging properties have hindered the application fields and storage properties of skim rubber, so improving the aging properties of skim rubber is very necessary.In this paper the author modified the skim by four methods:One, modified the skim by adding8-hydroxy quinoline (HQ) by emulsion blending; Two, modified the skim by adding HQ and two Antioxidants (Antioxidant264or Antioxidant SP-P) by emulsion blending; Three, concentrating the skim by using50,000-molecuIar weight column of hollow fiber (concentration the skim rubber from5%to about20%), then adding HQ to modifiy the skim which was treated by Hollow fiber column by emulsion blending; Four, adding HQ and two Antioxidants (Antioxidant264or Antioxidant SP-P) to modifiy the skim which was treated by Hollow fiber column by emulsion blending. Static mechanical properties, Aging properties, FTIR Analysis, Scanning electron microscope (SEM), Thermo gravimetric analysis, Rubber processing analysis, Dynamic mechanical properties, Metal content, Crosslink density were used to investigate properties of skim rubber before and after the modification.The results showed that:Mechanical properties analysis:the mechanical properties were improved by4kinds of modification methods. When HQ and antioxidant were0.75phr respectively, the mechanics properties exhibited a better performance. The excellent sample is0.75phr HQ/0.75phr antioxidant264modified the skim which was treated by Hollow fiber column, its tensile strength increased31.7%compared with skim rubber while tear strength increased21.58%. The thermal aging properties also has improved by4kinds of modification methods, While using HQ and antioxidant together the aging properties were much better compared to adding HQ alone. The excellent sample is0.75phr HQ/0.75phr antioxidant SP-P modified the skim which was treated by Hollow fiber column, its rate of change in tensile strength increased34.3%compared with skim rubber.FTIR analysis:Comparing the FTIR spectra before and after thermal aging, the carbon-carbon double bond is still there after modified by4kinds of modification methods while the Skim rubber’s carbon-carbon double bonds had already disappeared, it can certificated that the modification of skim rubber can enhance the aging properties.SEM analysis:HQ and two different antioxidants can uniformlydisperse inskimrubber matrix,no obviousstratification andholes existed, made the skim rubber exhibited excellent compatibility, which can explain the improvement of the static mechanical properties of skim rubber.Thermo gravimetric analysis:skim rubber exhibited good thermo-dynamic stability properties, thermal degradation activation energy increased by4kinds of modification methods. The excellent sample is0.75phr HQ/0.75phr antioxidant SP-P modified the skim which was treated by Hollow fiber column, its To increased1.33℃,Tｐ increased0.48℃, Tf increased34.48℃, thermal degradation activation energyincreased34.48KJ/mol.Rubber processing analysis:after skim rubber were modified, in the Strain sweeping scanning, with the strain increased, the elastic modulus (Ｇ) will be reduced, which showed Panye effect obviously, loss factor (TanS) will be increased; In the Temperature sweeping scanning, With the temperature increased, there will be a turning point at110℃, elastic modulus (G’) first decreased and then increased while loss factor (Tan8) will first increased and then decreased.Dynamic mechanical properties analysis:the molecules chains of skim rubber become rigidity after modified by4kinds of modification methods, which lead the glass transition temperature of skim rubber increased2-3℃as well as has less impact on tyre rolling resistance and wet skid resistance.Metal content analysis:the bivalent metal ion contents decreased by4kinds of modification methods. More precisely, the excellent sample is0.75phr HQ/0.75phr antioxidant264modified the skim which was treated by Hollow fiber column, the content of Cu2+decreased0.229ug/ml, the content of Mn2+decreased44.56ug/ml, the content of Fe2+decreased0.034ug/ml, the content of Co2+decreased1.692ug/ml. This results can be the explanation why the aging properties had improved.Crosslink density analysis:the molecular weight averages Mｃ decreased while Crosslink density increased after the skim rubber was modified by4kinds of modification methods. When adding0.75phr HQ to modified the skim which was treated by Hollow fiber column, the Mｃ decreased4697.21g/mol while crosslink density increased9.66mol/m3...