Study On The Preparation Of Oil-based Polyol And The Modification Of Its Foams

With the growing shortage of petrochemical resources in the world,people are paying more and more attention on the development and utilization of renewable biomass resources.Researchers from all over the world constantly explore the use of renewable biomass resources as raw material to develop new green biomass materials.Vegetable oil from plant fruits,seeds,and grease,which is abundant in source in renewable resources,are widely distributed in nature.Oleic acid are the important component of oil.In this thesis,environmental polyurethane foams（PUFs）were synthesized by polyols which were synthesized from non-edible plant fatty acids—oleic acid.In the present work,a novel polyols was explored from oleic acid by epoxidation-ring opening and esterification.The structures of polyols were modified by dicarboxylic acid or anhydride,and the properties of oil-based polyols were improved.Reinforced PUFs by bamboo fiber were prepared,and the mechanical strength were enhanced.The oil-based foams were modified by flame retardant.The novel Mannich polyether polyols（TMP）were prepared by biomass pyrolysis tar,and the tar-oil-based foams were also prepared with the co-foaming technique.The major research content and result are as follows:1)The synthesis of oleic-base polyols（OAP）and the study on the foams structures and properties.OA-based polyols were synthesized using oleic acid as raw materials by epoxidation-ring opening and esterification reaction.The epoxidation technology was optimized.The effect of epoxidation conditions on epoxy value,iodine value,hydroxyl value and acid value were investigated.The proper reaction conditions are as followed: n（OA）: n（HCOOH）: n（H₂O₂）=1:0.5:1.5,reaction temperature and time 55℃ and 2h,1wt% H2SO4 as epoxidation catalyst,and ZnO was used as catalyst for the esterification.Catalyst can be reused more than four times.The epoxidation and ring opening kinetic mode was also established.The oil-based foams were prepared using OAP to replace petroleum base polyether polyols partially.The effect of OAP on the preparation,structure and properties of PUFs were inverstigated by FT-IR,TGA,DMA and SEM.The results showed that with the increase of OAP content,the thermal stability were improved.When the substitution amount reached to 80%,the mechanical strength could meet the performance requirements of thermal insulation foams,but coefficient of thermal conductivity was decreased for the increasing aperture ratio.2)the effect of branched modification on the properties oil-based pololsA series of novel polyester polyols based on different dicarboxylic acid or anhydride were synthesized by branched modification.The result showed that more primary hydroxyl groups and proper branched structure were introduced by carbonylation of fatty acid chains,which improved the reaction activity and storage stability of OAP.The effect of modifier on the foams structure and properties were also investigated.The phthalic anhydride modified oil-based polyols（PA-OAP）with appropriate hydroxyl value and viscosity was filtered,and proper optimum technological condition was determined.OAP is studied in detail and various properties of PA-OAP,and its structure was characterized.The properties and structures of OA and PA-OAP were compared in detail.The reaction kinetics of oil-based polyols and 4,4’-MDI was analyzed.The second order reaction kinetics model was established,the apparent activation energy of the cross-linking reaction was 35.87 kJ/mol and 45.97 kJ/mol,respectively.It demonstrated that PA-OAP possessed higher reactivity mathematical.Meanwhile,di-n-butyltin dilaurate showed better catalytic ability.Fitting process is conducted on TGA data according to Flynn-Wall-Ozawa dynamic method and Coast-Redfern dynamic method,and pyrogenation reaction dynamics model of oil-based PUFs was established.3)Preparation and properties of oil-base foams reinforced with bamboo fiberTo improve the mechanical properties and the biodegradability,meanwhile lower the cost,bamboo fiber was added to oil-based foams.Surface modification of BF by alkali could enhance the interfacial interaction between the reinforcing fibers and foam matrix,resulting in greater mechanical strength of the PUFs.Cellulose content,crystallinity and hydroxyl value of bamboo fiber were increased after modification.There were different effect of different particle size on mechanical properties.In this section,two size bamboo were used.With BF having particle sizes of 250–500 μm,the mechanical strength of composite foams increased,on the contrary to the negative effect of BF with sizes of 80¹80μm.The optimal addition of modified BF for reinforced PUFs was 5php.DMA and TGA results aslo revealed that alkali treatment can improve the interface between the matrix and fiber simultaneously increase the crosslink density,so does the thermal stability.4)Preparation of flame retardant oil-based PUFs and flame retardant mechanism researchIn this chapter,some flame retardant oil-based PUFs were prepared by one-step method.The effect of common flame retardants,such as DMMP,melamine,APP,DP,Al（OH）₃,Sb₂O₃ and TCCP on the LOI,mechanical properties,aperture ratio and thermal stability were determined,respectively.Flame retardants were combined,analyzed and evaluated.TG-IR and Py-GC/MS were employed to inverstigate the flame retardants thermal decomposition pyrolysis process so as to speculate the flame retardant mechanism.The results showed that Sb₂O₃ 和 DMMP had the best flame retardant efficiency according to LOI,but the introduction of DMMP caused the poor mechanical properties.The mixture of DMMP and APP was fit for oil-based PUFs with better fire resistance and mechanical properties.By analysis of pyrolysis gas product from TG-IR and Py-GC/MS,phosphonium flame retardant played the role in condensed phase in the initial stage of thermal decomposition,and possessed free radicals effect when phosphorus volatilized to the gas phase at high temperature.The release of CO₂ was restrained at the third stage in the absence of phosphorus.5)Preparation and properties of Tar-based Mannich polyether polyols and corresponding oil-tar based PUFsTar based Mannich polyols with different structures and properties were synthesized from pyrolytic tar,paraformaldehyde,diethanolamine and epoxypropane by Mannich reaction and polymerization reaction.The effect of substitution amount,PO amoun,eet al on the structure and properties of products and corresponding PUFs were discussed.The properties of oil-tar based PUFs were also studied.