Design and Synthesis of Furan-based Thermosetting Resin and the Effect of Hydrogen Bonding Interaction on Their Performance

Author:Shen Zuo Bin

Supervisor:liu xiao qing

Database:Doctor

Degree Year:2018

Download:48

Pages:156

Size:14257K

Keyword:

2,5-Furandicarboxylicacid(2,5-FDCA)and its derivatives are important building block chemicals.And furan-based resins are promising bio-based materials,when faced with energy crisis and environmental pollution,due to their rigid groups-furan ring-improving thermal and mechanical performance of bio-based polymers.Meanwhile,polybenzoxazine is a thermosetting resin with excellent thermal property,applied in aerospace and electronic devices.Therefore it has important actual meaning and research value to design and synthesize furan-based polybenzoxazines.In this paper,furfurylamine,as a derivative of 2,5-FDCA,was exploited for design and synthesis of a furan-based polybenzoxazine at first.The chemical structures were confirmed with 1H NMR,13C NMR and FT-IR.And the curing behaviors,thermal mechanical properties and thermal stabilities were investigated by differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA)and thermogravimetric analysis(TGA),respectively.As a result,poly(BZ-F)is a thermosetting resin with good curing property and excellent thermal property(Tg=270℃),whose performance was influenced by hydrogen bonding interaction a lot.In order to further investigate the relation between hydrogen bonding interaction and the properties of polybenzoxazine,model benzoxazine precursors are designed for the comparision of their structures,curing behaviors,hydrogen bonding in the networks and thermal performance.The effect on the curing properties from hydrogen bonding has been revealed and it is confirmed that there is closely positive correlation between the thermal properties of polybenzoxazines and hydrogen bonding interaction.With the adjustment of hydrogen bonding,poly(o-AP-FBZ),whose Tg is 292℃,could be obtained.Then molecular dynamics simulation with gradually crosslinking method was used for constructing model polybenzoxazines:poly(o-AB-FBZ),poly(o-AF-FBZ),poly(o-AP-FBZ),poly(p-AB-FBZ),poly(p-AF-FBZ)and poly(p-AP-FBZ).And the model was reasonable,as the results from simulation were comparable with those from experiment.After comparing the hydrogen bonding interaction of poly(o-AB-FBZ),poly(o-AF-FBZ),poly(o-AP-FBZ),poly(p-AB-FBZ),poly(p-AF-FBZ)and poly(p-AP-FBZ),the relationship between the thermal properties of polybenzoxazines(Tg)and hydrogen bonding interaction in the networks was confirmed again.As for epoxy resin,model epoxy monomers:BOF,p-BOB and m-BOB were synthesized.After mixed with curing agent DFDA or DDM,Tg of p-BOB/DFDA,m-BOB/DFDA,BOF/DFDA,p-BOB/DDM,m-BOB/DDM and BOF/DDM were41℃,41℃,47℃,78℃,76℃ and 126℃,respectively,obtained from DSC and DMA.As the crosslinking density of the resins was similar,it could be concluded that hydrogen bonding had a great role in thermal performance of epoxy resin,which would be verified by FTIR.These results provide the guidance for synthesis of thermosetting resins with better thermal performance via changing hydrogen bonds.In the end,as the furan group has diene structure,which can be used to react with maleimide via Diels-Alder addition reaction,if maleimide had flexible chain segment,BOF could be modified into self-toughening furan-based epoxy monomer(DA-BOF).When the mole ratio of DA-BOF reached 50%,the cured DA-BOF 50%system showed the highest impact strength of 5 KJ m-2 together with the slightly decreased tensile strength of 63 MPa and modulus of 3250 MPa.Therefore,DA-BOF is a good toughening system with excellent performance,which provide a new scheme for modifying furan-based epoxy resins.