Preparation And Properties Of Aminosilanized Epoxy Soybean Oil-based Waterborne Polyurethan

Global goberments explicitly limited the emissions of volatile organic compounds(VOCs),low-VOCs waterborne polyurethanes(WPU)technologies are becoming more and more valued in the industry.The shortages of petrochemical raw materials are becoming increasingly serious,and environmentally friendly sustainable plant-based WPU are increasingly studied.Plant oils containing natural reaction sites would be used as raw materia ls for the preparations of WPU.General approachs to obtain polyol products containing hydroxyl groups is epoxiding double-bonds in unsaturated fatty acid chains of plant oil,and followed a ring-opening reaction of the epoxy groups using nucleophilic reagents,such as amines,acids or alcohols.Polyol products for the preparations of WPU could be obtained by ring-opening epoxy reaction between epoxidized plant oil and alcohol or acid.The amine groups reacted with the epoxy groups in epoxidized plant oil through ring-opening reaction and simultaneous1y reacted with ester groups through trans-amidification reaction,and finally obtained complex amino reaction products,which could synthesize solvent based polyurethanes(PU)through reaction with polyisocyanates.However,few literatures show that amino epoxidized vegetable oils could be used to prepare WPU at present.In order to apply amino epoxidized vegetable oil to the preparations of environmentally friendly WPU.In this paper,we synthesized an aminosilane epoxidized soybean oil(AESO),and the two types of WPU were prepared from AESO raw material The effects of AESO content on the properties of WPU emulsion and its cured films in two systems were studied.In addition Nano-SiO2/WPU emulsions were synthesized by the physical blending of colloidal silica and AESO-based WPU,and the efect of nano SiO2 on the properties of blend emulsion and its curing film was studied.The works of this paper were as followed:(1)AESO was prepared by reactions between 3-aminopropyltriethoxysilane(APTES)and epoxidized soybean oil(ESO).FTIR and 1H NMR characterized the structure of AESO,and APTES successfully participated in the ring-opening reaction and trans-amidification reaction.(2)Aminosilane epoxidized soybean oil-based waterborne Polyurethanes(AWPU)were synthesized by a one-step reaction method from isophorone diisocyanate(IPDI),dimethylolpropionic acid(DMPA),AESO as polyol.ART-FTIR analyzed the chemical structure of AWPU films.The effects of AESO content on the physicochemical properties of the emulsions and its cured films were studied.Ethoxysilane groups in AESO hydrolyzed in water and then formed crosslinked structure.As the content of AESO increased,the particle size of the emulsions gradually increased.The gel rate,water contact angle,water resistance,salt resistance,acid resistance,and weak alkali resistance of the cured films were enhanced.Thermogravimetric analysis(TGA)showed that the thermal stability of the cured films increased with the increase of the AESO content,and differential scanning calorimetry(DSC)indicated the glass transition temperature(Tg)of the cured films first increased and then decreased.(3)A series of bio-based WPU were synthesized by polytetrahydrofuran diol(PTMEG2000),IPDI,DMPA,AESO as the chain extender.ART-FTIR analyzed the chemical structure of WPU films.The effect of the content of AESO on the properties of WPU emulsions and its cured films was studied.The addition ofAESO could increase the degree of crosslink ing of the system As the content of AESO increases,the particle size of the emulsions tended to increase,and the viscosity of the emulsions gradually decreased.The gel content,water contact angle,water resistance,salt resistance,and acid resistance of the obtained cured films were enhanced.Due to the ester structure of the vegetable oil of AESO,the alkali resistance of the cured films showed the opposite trend.Similarly,the thermal stability and tensile strength of the cured films are also improved with the increase of the AESO content.(4)A series of Nano-SiO2/WPU emulsions were synthesized by the physical blending of colloidal silica and AESO-based WPU.The interaction of colloidal silica and WPU enhanced the properties of nanocomposite films.With the increase of the content of silica,the particle size of the blending emulsions firstly decreased and then increased,and viscosity of emulsions increased.The nanocorrposite films has increased gel content,acid resistance,salt resistance and alkali resistance.Due to the hydrophilic nature of silica,the contact angle and water resistance of the films firstly increased and then decreased.With the increase of silica content,the tensile strength and hardness of the films increased,and the adhesion showed the opposite trend.