Study On The Preparation And Properties Of Poly(Butylene Succinate)-based Thermoplastic Poly(Ester-urethane)Elastomers

Based on the background of white pollution and the depletion of petroleum resources,we provided a new method for the preparation of poly(butylene succinate)-based thermoplastic poly(ester-urethane)elastomers(TEUEs)with excellent thermal and mechanical properties.In these thermoplastic elastomers,biodegradable poly(butylene succinate)was used as the hard segment(HS),and polyesters with different structures were introduced as soft segments(SSs)to make the copolymers exhibit microscopic micro-phase separation.The effect of different HS/SS ratios and SS lengths on the crystallinity,thermal properties and mechanical properties of TEUEs was systematically studied.The details were described as follows:1.Firstly,a hydroxyl terminated PBS prepolymer(HO-PBS-OH)was synthesized,and its molecular weight(Mdet=1641.39)was determined by phthalic anhydride pyridine titration.Then,two flexible hydroxyl terminated poly(neopentyl sebacate)prepolymers(HO-PND-OHs)(Mdet=1167.78 and Mdet=2044.95)with pendant methyl groups were synthesized.A series of PBS-based TEUEs with pendant methyl groups and different HS/SS ratios were prepared by a chain extension of HO-PBS-OH and HO-PND-OHs with diphenylmethane diisocyanate(MDI).The effect of SS length on the properties of TEUEs was studied.Long alkane chains and pendant methyl groups in SSs make SSs show relatively high hydrophobicity and easily show phase separation between the crystallized phases and amorphous phases.DMTA test showed that when the SS content was more than 30%,two tan?peaks can be observed,i.e.two glass transition temperatures.TEUEs with high content of PBS showed quite well phase separation.The increase of SS length is helpful to the crystallization of elastomers.The highest tensile strength and elongation at break of TEUEs were 64.27MPa and 1668.94%,and the resilience was up to 90.18%.2.Based on the work in the previous section,the hydroxyl terminated linear poly(propylene sebacate)prepolymer(HO-PPD-OH)(Mdet=1486.98)with long alkane chain was synthesized.A series of linear PBS-based TEUEs were prepared through a chain extension of the HO-PBS-OH and HO-PPD-OH with MDI.The intrinsic viscosity of TEUEs measured by Ubbelohde viscometer was about 1dL/g.The structures of TEUEs detected by FT-IR and 1HNMR were consistent with the expected.DSC and DMTA tests proved the phase separation of TEUEs.DSC and XRD tests verified that HS/SS ratios determined whether the HSs and SSs were crystallized or not.TGA tests showed that TEUEs had good thermal stability.The linear polyester SS can make the TEUEs chain more regular,and the intermolecular force between the SS and HS is stronger.The tensile strength and elongation at break of TEUEs are up to 69.14MPa and 1817.97%,and the resilience was up to 95.45%.