Quantitative Analysis, Rubber Extraction And Characterization Of Structure And Properties Of Taraxacum Kok-Saghyz

The natural rubber industry which depended on Hevea is beginning to suffer a bottleneck of development. The restriction of development is becoming more and more. So the Taraxacum kok-saghyz (TKS) is gradually into people's sight as a potential rubber-producing plant. Although TKS had been already known since the World War ?. During the Cold War, TKS had been has been widely studied in the Soviet Union, and even has been industrialized. But with the end of the Cold War and the disintegration of the Soviet Union, suddenly the world demand for natural rubber is greatly reduced. And with the synthetic rubber sprung up, natural rubber's prices and supply are gradually stability. So there is not necessary to study the rubber-producing plant to yield natural rubber as substitute for Hevea Brasiliensis. So the study of the TKS has stopped for decades. China also had studied the TKS for few years in the early years of the Republic, but even these preliminary research had stopped because above reason.Now we restart to study this kind of rubber-producing plant. The TKS is both old and new for us. And there is many thing should be done without much thing as reference. In this paper, according to the current situation of domestic TKS industry development, I study some issue that the current industry very concerned. The scope of the study is relatively broad, so we can have a preliminary watch into the future development of the field. My study may give some realizable direction for research and way to research.This paper is divided into four major parts:1, Exploration for TKS rubber content quantification method to solve the issue on development.2, Exploration for the extraction of TKS rubber according to the demand of industrialization.3, Exploration for the structure and properties of TKS rubber. 4, Exploration for the end group structure of TKS.TKS rubber content quantitative method:This paper uses the infrared quantitative analysis method, and do some transformation and optimization of the quantitative method according to the characteristics of domestic TKS impurities. It was found that the extraction of acetone and ethyl acetate have influenced on the quantification of TKS rubber content. It was also found that the molecular weight below 2780 of the external standard have no effect on the quantification. So we developed a method fit our TKS and make the systematic error 0.1mg/mL. Using the method, we found that rubber random exist in the root of TKS.The extraction method:For the shortcomings of current solvent extraction-precipitation method, we developed a new extraction method to adapt to the current TKS industrial development. This method own the advantage of easily recovered solvent, simple solvent system, and so on.The similarities and differences on structure and properties between TKS and NR:Through the study, In the infrared spectrum, nuclear magnetic spectrum and TGA and DSC spectrum, TKS rubber and NR rubber are similar. And in the molecular weight determination, TKS rubber molecular weight is Mn=49.1W and NR rubber molecular weight is reached Mn=57.1W, the former in the molecular weight is slightly lower than the latter. They all lower than the IR (Type:SKI-3S, Mn=60.3W). In the vulcanization properties and mechanical properties of both mixed rubber and pure rubber, the TKS is not as good as NR but is similar to the IR. Both TKS and IR did not appear strain-induced crystallization as NR rubber did.The structure analysis for Terminal groups of TKS:We divided the research into three steps. First step is transesterification, and then fractionation of molecular weight, finally make CNMR spectrum with low molecular weight TKS rubber. The molecular weight of the TKS rubber after the transesterification is similar to original one. But the TENR have lower molecular weight than NR. It is indicated that TKS rubber may not have the some structure as NR. In detail TKS rubber may not own the network structure with the ester cross link point. It may be the reason of poor mechanical properties of TKS rubber. When I make fractionation of molecular weight, I chose two methods. One is to pour poor solvent gradually into the good solvent solution to change the solvent solubility of the polymer thus gradually precipitated the polymer. Another is directly mixed good solvents and poor solvents with a ratio to extract low molecular rubber. Finally, we found that the later method can fit our demand, so we chose the later method as our method to make the fractionation. Then we got the CNMR spectrum of low molecular weight TKS rubber, and we haven't found the structure of terminal groups. But TKS rubber have the same spectrogram of NR. And there needs more work to do to explain why.