| Hydroxyl-terminated polybutadiene(HTPB)is one of the most representative products of liquid rubber,which is widely used in aerospace propellant,tire,coating,adhesive,rubber runway and other fields.Isoprene and butadiene are both diolefin compounds,which also have great potential for development.With the continuous improvement of isoprene industry in recent years,it is inevitable to carry out research on new polyisoprene liquid rubber.In this study,4-functionality star-shaped hydroxyl-terminated polyisoprene(4HTPI-Si)liquid rubber was designed and synthesized by anionic method.it not only has the liquid properties of liquid rubber at room temperature and chemical thermosetting property,but also has high reactivity of polyol and compact molecular structure of star polymer.it is promising as modifier of HTPB and matrix material of new solid propellant.The specific research contents of this topic are as follows:With isoprene as monomer,self-made organic lithium initiator with protective group and tetrachlorosilane as coupling agent,anionic 4-arm star hydroxyl terminated polyisoprene liquid rubber was synthesized in Schlenk operation line,and characterized by FT-IR,~1H NMR,GPC and hydroxyl number measurement.The obtained 4HTPI-Si has cis-1,4 structure with content as high as 86.1%.Controllable and accurate synthesis with molecular weight between 1000 and 8000 was realized,and liquid rubber with 1,2 and 4 functionalities could be obtained by controlling the addition of ethylene oxide,hydrochloric acid and silicon tetrachloride in the synthesis process.The microstructure of 4HTPI-Si and commercial HTPB were compared and analyzed by NMR.The mixed polyurethane was synthesized by one-step method with4HTPI-Si and commercial HTPB in different proportions.With the increase of the proportion of 4HTPI-Si,the tensile strength of the mixed polyurethane increased to 281%of the original pure HTPB polyurethane,the elongation at break increased by 66.8%,and the curing reaction rate was obviously accelerated.The prepolymer polyurethane was synthesized with 4HTPI-Si,TDI and BDO system.The results showed that the comprehensive mechanical properties of the cured product were the best when the curing parameters were 1.1~1.2:1 and the amount of BDO was twice the molar amount of 4HTPI-Si.The influence of catalyst DBTHL on polyurethane synthesis process was also investigated.When the amount of catalyst DBTHL was 0.05～0.15w%4HTPI-Si,it could promote the polymerization.Combining with the pre-risk analysis method,the process risks in each stage of4HTPI-Si research process are analyzed one by one,the safety relationship between the behaviors of experimenters and them is found,the behaviors that may trigger risks in the process of liquid rubber synthesis are identified,and the behavior prevention regulations are formulated.This paper summarizes and analyzes the unsafe behavior of human beings in the environment of chemical laboratory.The index system of factors affecting behavior safety ability was established,and the behavior safety ability of laboratory personnel was evaluated by AHP and fuzzy comprehensive evaluation method,and the mathematical model of fuzzy comprehensive evaluation was established. |
