| Nowadays,in order to reduce people’s dependence on non-renewable resources and curb the pollution caused to the environment,biodegradable materials have attracted extensive attention.Polybutanediol succinate(PBS)is a biodegradable polymer material with excellent properties,which has been used in medicine,agriculture,packaging and other fields.However,the low strength and poor toughness of PBS have limited its further application.In order to solve this practical problem,we synthesized a series of PBS copolyesters for PBS modification and systematically studied the structure and performance of the blend system.The main work is as follows:Start with succinic acid,1,4-butanediol as raw materials,tetrabutyl titanate as catalyst,synthesis of linear PBS by melt polycondensation method,and then to the same synthesis method with ethylene glycol(EG)and 1,3-propanediol(1,3-PG)and 1,5-butyl glycol(1,5-PTD)such as Moore instead of 1,4-butanediol synthesis of a series of PBS copolyesters:poly(butyl glycol succinic acid ester-co-succinic acid glycol ester)(PBSE);Poly(butanediol succinate-1,3-propylene glycol succinate)(PBSP);Poly(butanediol succinate-co-1,5-pentanediol succinate)(PBST).By ubbelohde viscometer,infrared spectrometer(FTIR),nuclear magnetic resonance spectrometer(~1H-NMR),thermo-gravimetric analyzer(TGA),differential scanning calorimetry(DSC),wide-angle X-ray diffraction(XRD),polarizing microscope(POM),mechanical property test,the introduction of the modified monomers,the PBS copolyesters of molecular weight,chemical structure,thermal properties and crystallization properties and the influence of blending after the performance.The results showed that(1)the molecular weight of PBS copolyester was between 3.49×10~4-5.05×10~4,and the introduction of diol had little effect on the molecular weight of PBS copolyester;(2)The introduction of modified diol did not change the chemical structure of PBS copolester,and the initial decomposition degree was above300°C;(3)The crystallinity of PBS copolyesters decreased by 16.7%,14.7%and 17.4%respectively with the increase of diol content,but the crystal shape remained unchanged;(4)After blending,as the chain length of dibasic alcohol increases,the crystallization temperature of the blends increases to 76.3°C,73.5°C and 81.6°C,respectively,when the modified co-polyester with the same content is added.The melting point changes little,and the crystallinity decreases by 6.9%,9.2%and 5.9%,respectively;(5)When the modified copolyesters with the same content were added,the impact strength of the blends increased by 1.2kJ/m~2,0.2kJ/m~2,and 1.8kJ/m2 respectively,but the tensile strength decreased by7.3Mpa,6.7Mpa,and 7.3Mpa,respectively.Secondly,a series of poly(butylene succinate-co-2,5-furadicarboxylic acid)(PBSF)were synthesized by using the same synthesis method.The molecular weight,chemical structure,thermal and crystallization properties of PBSF copolyesters with different content of FDCA were investigated.The results showed that(1)the molecular weight of the synthesized PBSF copolyester was between 2.61×10~4-4.81×10~4.With the increase of FDCA content,the molecular weight of the PBSF copolyester decreased;(2)with the increase of the content of FDCA,the components of FDCA in copolyester PBSF increased correspondingly,but the chemical structure did not change and the thermal stability was good;(3)The thermal properties and crystallinity of copolyester PBSF decreased by 13.8%with the increase of FDCA content,but the crystal structure remained unchanged;(4)Along with the increase of the content of FDCA in adding the same content of copolyesters PBSF,blend PBS/PBSF T_m rose to 3.2°C,T_C,ΔHc,ΔHm,Xc decreased,the crystal structure remains the same;(5)With the increase of FDCA content,when the same content of copolester PBSF was added,the gap impact strength of PBS/PBSF decreased by 2.2kJ/m~2and the tensile strength decreased by 6.3Mpa. |
