Study On Preparation Of Biodegradable Polyurethane Based On Vanillin And Performance

Polyurethane is widely used for its excellent properties such as better stability,chemical resistance,abrasion resistance,resilience and mechanical properties,smaller compression variability,heat insulation,sound insulation,shock resistance,and anti-toxicity.Due to the huge demand for these materials,the output is increasing,and the consumption will also increase sharply.A large number of these materials are buried.Chemical recovery is the most effective way to recycle polyurethane materials.Chemical recycling refers to the process of complete depolymerization of the polymer into monomers.The regeneration process may involve various monomer/polymer purification steps in addition to different purification processes such as distillation,crystallization and additional chemical reactions.Because these materials cannot be used repeatedly or disassembled quickly,treatment of these materials can cause serious environmental problems.A conceptual strategy to convert these non-degradable polymers into degradable ones is the introduction of dynamic bonds(e.g.imine bonds)into their backbone.In this paper,we use polyurethane chain expanders containing imine bonds as an entry point for the purpose of polyurethane degradation.The research in this paper can be divided into the following two:A new polyurethane chain extender precursor,VV,was prepared by reacting vanillin with 1,2-dibromoethane,and then a new polyurethane chain extender,EVV,was prepared by reacting VV with ethanolamine;finally,a bio-based imine-containing degradable polyurethane based on vanillin was prepared by polymerizing EVV with polytetrahydrofuran ether diol(PTMEG)and 4,4'-diphenylmethane diisocyanate(MDI).Thermoplastic polyurethanes(PUIs)based on vanillin were prepared,and polyurethane resins with PTMEG,EVV and MDI ratios of 2:2:4,2:3:5,2:4:6,2:5:7 and 2:6:8 were prepared simultaneously.After testing,the results showed that: the mechanical properties of the vanillin-based bio-based imine-containing degradable TPUs showed an increase followed by a decrease with the introduction of the new polyurethane chain extender,and the highest tensile strength and elongation at break of the samples were 34.59 MPa and600.06%,respectively;and they had good thermal stability;in the degradation experiments,PUI-3 was degraded at 20? in 5% In the degradation experiments,the replacement decomposition of PUI-3 can be completed in the ethanol solution of ethylenediamine at20? for 4h,which has a fast decomposition rate.A novel polyurethane chain extender EVV was used to react with PTMEG,MDI,and butyl 4-hydroxyacrylate to prepare vanillin-based biodegradable photocurable polyurethane acrylate(PUA).Then PUA was mixed with reactive diluent butyl acrylate(BA)to prepare pre-cured polyurethane acrylates with reactive diluent content of 0,15%,30%,45% and 60%.Finally,the cured urethane acrylate resin was made by UV light.After testing,the results show that: with the increase of active diluent content mechanical properties followed by a decreasing trend,viscosity also decreased significantly,thermal stability slightly enhanced;water absorption test with the increase of active diluent content also showed a decreasing trend of water absorption,indicating that its crosslinking density has increased;degradation test samples at 40? 10% ethylenediamine in tetrahydrofuran solution can be decomposed in 3-15 days,still has Displacement degradation ability.The above results show that the introduction of imine-containing degradable polyurethane hard segment can effectively improve the degradation performance of polyurethane and make the application of biodegradable polyurethane in all aspects.As biodegradable polyurethane is still in the exploratory stage,this study has some reference significance in both basic research or practical applications.