Synthesis And Characterization Of Sapium Sebiferum Oil-based Polyurethane Nanocomposites By Biological And Chemical Methods

Polyurethane(PU)is potentially applied in a variety of fields,such as light industry,chemical industry,electronics,aerospace,construction and medical owing to its own unique chemical structure leading to thermal stability,wear resistance,high elastic and strength.But with the exhaustion of petrochemical resources,the increase of greenhouse effect,and the deterioration of environmental pollution,it is regarded to be very urgent to prepare PU materials with efficient,cheap and renewable resources.Sapium sebiferum oil(SSO)is a kind of unedible woody plant oil,and its fruit resource is abundant.Moreover,the fruit oil contains a large number of unsaturated double bonds.Therefore,SSO is one of the most suitable platform feedstock for PU production.Therefore,in this work,Sapium sebiferum polyol(SSP)were prepared via biological and chemical methods,and the PUs were also synthesized with isophorone diisocyanate(IPDI).Then,the modified nanosilica(SiO2),carbon nanotube(CNT)and graphene oxide(GO)were employed to modify and enhance the properties of the SSO-based PU matrix.The main researches and results were summarized below:1.Firstly,the basic physico-chemical properties and fatty acid profiles of SSO were determined.The results show that the oil was well suitable for deep processing into various derivatives.With the help of SAS 9.2 statistical software and further optimization via response surface method(RSM),the optimized conditions of the synthesis reaction for SSP have been obtained.They are molar ratio 9.9:1,catalyst dosage 0.43%(w/w),reaction time 1.8 h,and reaction temperature 48.5 °C.Under the optimal reaction conditions,the hydroxyl value of SSP attained 219 mg KOH/g.Then,the novel PU was subsequently prepared by reaction of the polyol with IPDI.Through characterization of the PU product,the results demonstrate that the glass transition temperature(Tg)and the initial decomposition temperature(IDT)are 56.6 °C and 293.1 °C,the temperatures of the maximum rate of weight loss(Tmaxs)are 330.8 °C and 405.7 °C,and the tensile strength and the elongation at break are 6.2 MPa and 185.1%,respectively.2.The polyols with high hydroxyl value were prepared by Candida rugosa lipase(CRL)hydrolysis of polyol-143 with hydroxyl value of 143 mg KOH/g.With the help of Box-Behnken design and further optimization via RSM,the optimized parameters of the hydrolysis reaction for the polyol have been obtained.They are molar ratio 2.2:1,reaction time 1.8 h,and reaction temperature 48.5 °C.Under the optimized reaction conditions,the hydroxyl value of the polyol product attained 211 mg KOH/g.Then,the novel PU was subsequently prepared by reaction of the polyol with IPDI.Through physico-chemicl characterization,the results demonstrate that Tg and IDT are 60.6 °C and 307.2 °C,Tmaxs are 356.7 °C and 443.1 °C,and the tensile strength,Young’s modulus and the elongation at break are 12.5 MPa,22.3 MPa and 168.3%,respectively.3.The nano-SiO2 particles were modified with 3-aminopropyltriethoxysilane(KH550)and analyzed by FTIR and TGA.Then,SSO-based PU/SiO2 nanocomposites with different content of nano-SiO2 were successfully synthesized via in situ polymerization method.Through characterization of the PU/SiO2 nanocomposites,the results indicate that nano-SiO2 particles with 3 wt% loading could be homogeneously dispersed in the PU matrix and have positive effect on improving the PU properties.Compared with the pure PU,Tg and IDT of the PU/SiO2 nanocomposites are respectively enhanced by 20.5 °C and 43.5 °C with 3 wt% of nano-SiO2 loading.Meanwhile,the tensile strength of the PU/SiO2 nanocompositesis increases to 270%,and the water and toluene resistance properties of PU/SiO2 nanocomposites are also significantly enhanced.4.Multi-walled carbon nanotubes(CNTs)were treated with a mixture of concentrated sulfuric and nitric acids(3:1 ratio by volume),and modified by ethylenediamine(EDA)to grafting –NH2 on the surface of CNTs.Then,the microstructure and the properties of the functionalized CNTs were characterized by FTIR,TGA,TEM and XPS.The SSO-based PU/CNT nanocomposites with 2 wt% of CNTs loading were successfully synthesized via in situ polymerization method.By characterization of the PU/SiO2 nanocomposites,the results show that amino-functionalized CNTs(CNT-NH2)could be homogeneously dispersed in the PU matrix,which significantly improves the thermal and mechanical properties of the PU composites.Compared with the pure PU,Tg and IDT of the PU/CNT nanocomposites(2 wt% CNT-NH2)are respectively enhanced by 17.1 °C and 32.5 °C.Meanwhile,295% improvement in the tensile strength,111.3% enhancement in Young’s modulus and 22.4% increment in the elongation at break of the nanocomposites are observed.5.The graphene oxide(GO)was prepared with the improved Hummers method and analyzed by FTIR,TEM,Raman and XRD.Then,using the polyol prepared by CRL hydrolysis with hydroxyl value of 211 mg KOH/g as raw materials,the SSO-based PU/GO nanocomposites with different content of GO were successfully synthesized via in situ polymerization method.By characterization of the nanocomposites,the results demonstrate that GO particles with 1 wt% loading could be homogeneously dispersed in the PU matrix,which significantly improve the PU properties.Compared with the pure PU,Tg and IDT of the PU/GO nanocomposites(1 wt% GO loading)are enhanced by 14.1 °C and 31.8 °C,respectively.Meanwhile,the tensile strength and Young’s modulus of the nanocomposites are improved by 126% and 102%.