| Because of its excellent comprehensive performance,Hevea rubber was widely used in aerospace,transportation,national defense science and technology,medical treatment,industry and other fields.In order to solve the current shortage of Hevea rubber and ensure the sustainable development of rubber industry,it was urgent to find alternative and renewable Hevea rubber resources.TKS was one of the numerous contains rubber plants,its rubber mainly exist in the roots of latex tube,the structure of the rubber for cis polyisoprene,because of its short growth cycle and great production,planting was not restricted by regional conditions and climate conditions,extract gel contains no allergic protein,so TKS was expected to become the second rubber source.In this paper,Koksaghyz root was used as raw material,three kinds of rubber were extracted by the alkali method,acid method and solvent method,and the products and extraction methods were analyzed.Then the content of metal ions,impurity,nitrogen,ash,water soluble matter,volatile matter and acetone soluble matter in the extract glue was determined,and its composition and structure were analyzed by infrared spectroscopy,nuclear magnetic resonance spectroscopy,gel permeation analysis,paramagnetic cross-linking density meter and other instruments.The molecular weight,glass transition temperature,thermal stability,P0,PRI,Mooney viscosity and mechanical properties of three kinds of dandelion extract adhesives were determined by GPC,DSC,TG,rapid plastometer,Mooney viscometer and tensile testing machine.The results showed that among the three extraction methods,the alkali method had low extraction difficulty,few extraction steps,short extraction time and high yield(3.85%).However,the extraction rubber had the lowest purity(93.77%)and the highest impurity content(6.5%).Therefore,it was necessary to improve the subsequent process to improve the purity of the extracted rubber.Solvent extraction process has the highest rubber purity(98.23%)and the lowest impurity(2%)of the three,although the operation is complex,time-consuming and the yield is the lowest.Contents of nitrogen,ash,volatile matter,water soluble matter and acetone soluble matter of TKS extract rubber were not different from those of Hevea rubber.The average particle size of TKS latex was 343 nm,which was similar to that of Hevea rubber.It was Zeta potential was-38.2 m V,and its stability was general.The Mn of the alkali method extraction rubber was 38.24×104,Mw was 58.39×104,Mz was57.09×104,acid method extraction rubber was 36.86×104,Mw was 62.92×104,Mz was61.69×104,solvent method extraction rubber was 18.83×104,Mw was 29.94×104,Mzwas 42.97×104,Hevea rubber was 51.59×104,Mw was 154.62×104,Mz was249.33×104.Crosslinking densities of alkali method,acid method,solvent method and Hevea rubber were 1.53,1.62,1.08 and 1.87,respectively.In general,the composition and structure of TKS rubber are similar to that of Hevea rubber.The molecular weight and crosslinking density of TKS rubber were lower than that of Hevea rubber,but the content of total metal ions was much higher than that of Hevea rubber.The initial plasticity and Mooney viscosity of dandelion rubber were much lower than that of Hevea rubber,whereas PRI was the opposite.The glass transition temperatures of the alkali method,acid method,solvent method and Hevea rubber were-58.67?,-60.03?,-58.46?and-60.33?,respectively.The thermal stability of TKS rubber was higher than that of Hevea rubber,and the thermal stability of alkali extraction rubber was improved significantly.Finally,in terms of mechanical properties,the stress of alkali method extraction,acid method extraction and Hevea rubber was obviously higher than that of solvent extraction,while the elongation at break of alkali method extraction and acid method extraction was very low. |
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