Synthesis And Functional Study Of Polyurethane With Comb Structure

The molecular structure of polyurethane plays an important role in its properties and functions.The introduction of high density hydrogen bond can improve the tensile strength of polyurethane,and the introduction of large conjugated aromatic ring can give fluorescence.However,there are few researches on polyurethane materials with comb structure,especially in the field of functional research.Silicone has a very low glass transition temperature（T_g）and is often used to make low temperature damping materials.Long chain alkanes have excellent crystallization ability and have important applications in the field of polymer based phase change energy storage.The introduction of organosilicon and long-chain alkane into polyurethane as side chains is expected to enrich the types of comb polyurethane materials and expand the research on the functionalization of these materials,especially in the field of low temperature damping and phase change energy storage.Based on this idea,a series of polyurethane with comb structure were synthesized by using organosilicon and long alkane as side chains respectively.Specifically speaking,the main work of this paper has the following three parts:1.A long-chain coupling agent was obtained by grafting 3-mercaptopropyltrimethoxy-silane（KH590）into HTPB by mercapto click chemistry.Then the mono-hydroxy-silicone oil was grafted onto the synthesized long chain coupling agent,and finally isocyanate was added to solidified to obtain an organosilicon as a comb chain polyurethane material.This strategy broadens the low temperature damping performance of the material,and the damping temperature range is expanded from 14 to 80℃2.The single ended hydrogen-containing silicone oil was synthesized and reacted with HTPB by silane addition,then isocyanate was added for curing.Polyurethane material with comb structure is also obtained.The results show that with the increase of graft amount of organosilicon,the thermal stability of the material increases and the initial decomposition temperature T₁₀ increases.Most importantly,the combed polyurethane also exhibits ice resistance,with a minimum ice shear force of 40 k Pa.Then PU-Si-20 was used as the supporting material to encapsulate the methyl silicone oil.By virtue of the van der Waals force between the comb structure and the methyl silicone oil,the stable silicone oil-filled comb polyurethane material was obtained.This strategy improves the damping performance of the material at low temperature,with the damping temperature range reaching 133℃and the damping factor（tanδ）reaching 0.98.Silicone oil filled comb polyurethane material also has excellent anti-icing properties,the lowest ice shear force reached 16 k Pa.3.By clicking chemistry,octadecyl mercaptan（ODT）was graft to the side chain of polyurethane to form a combed polyurethane solid-solid phase change material with hydrogen bond fixation.The introduction of hydrogen bonds allows the material to maintain a stable shape at 50℃.Compared with the three dimensional network formed by covalent bond,the hydrogen bond three dimensional network makes the material have very good recyclability.It is worth noting that the maximum values ofΔHm andΔHc are 98 J/g and-101 J/g respectively.At the same time,the material also exhibits superhydrophobicity,with static water contact Angle up to 152.9°.