Preparation And Performance Study Of Poly(10-hydroxy-2-decenoate)and Its Cross-linked Film

In recent years,due to the tight supply of fossil energy such as oil and the increasingly serious environmental problems,people have started to seek new polymers that are green and ecologically compatible.Bio-based polyesters prepared from bio-based resources have received widespread attention for being green,biocompatible and in line with the concept of sustainable development.Unsaturated polyester is a linear polymer compound containing repeating ester and unsaturated bonds,with notable mechanical properties,quickly molding speed,convenient processing and excessive chemical stability,has grow to be one of the most broadly used thermosetting materials.In this thesis,a bio-based unsaturated polyester was prepared,and the cured cross-linked film of unsaturated polyester was successfully prepared by self-cross-linking and light-curing reactions using the molecular structure characteristics of polyester.The research in this thesis is based on the high-purity 10-hydroxy-2-decenoic acid(10-HDA)prepared by microbial fermentation method in the early stage of the group.Firstly,a class of bio-based unsaturated polyester poly(10-hydroxy-2-decenoate)(PHDA)was synthesized by melting polycondensation method using bio-based 10-HDA as raw material and by optimizing the conditions of 10-HDA melting polycondensation reaction.The molecular structure,chemical composition,molecular weight and diploma of polymerization of the homopolymer PHDA had been investigated in element by using~1H-NMR,FTIR and GPC,the results show that PHDA can retain double bonds at the polycondensation temperature below 190°C.When the polycondensation temperature is170°C,the heavy average molecular weight(M_w)of PHDA can reach 4.182×10~4(±0.324%)g/mol and the number average molecular weight(M_n)reaches 1.588×10~4(±1.737%)g/mol;The crystallization behavior and apparent morphology of PHDA were measured and scanned by XRD and SEM,and the thermal and rheological properties of PHDA were investigated by DSC,rotational rheometer and in addition to the antibacterial properties of PHDA.The results show that the physical properties of PHDA are related to the polymerization conditions and depend largely on the polymerization temperature,and the inhibition test showed that PHDA has some inhibitory effect on E.coli and Staphylococcus aureus.Secondly,PHDA with high relative molecular weight and high performance was selected as raw material,and PHDA was cross-linked and cured by high temperature method and chemical modification to obtain the corresponding polyester cross-linked films P(PHDA)and P(PHDA-NCO).The crystalline properties,thermal properties,microscopic morphology,mechanical properties and degradation properties of P(PHDA)and P(PHDA-NCO)were investigated by a series of instrumental characterization.The test results of the two cross-linked films showed that the cross-linked film of poly(10-hydroxy-2-decenoate)had good thermal stability and comparable tensile properties compared with existing bio-based plastics,and its mechanical residences have been proper with tensile power up to 29.3 MPa and elongation at damage up to 331.0%;degradation performance studies showed that P(PHDA)had some stability in soil and P(PHDA-NCO)can be selectively degraded by bovine pancreatic lipase and glutathione.The structural changes of P(PHDA-NCO)during aging were analyzed and found that with the increase of aging time,the occurrence of chain breakage is accompanied by the generation of new cross-linked bonds,which is manifested by the gradual increase of tensile strength.Finally,the biological properties of P(PHDA)and P(PHDA-NCO)were preliminarily investigated by in vitro cellular assays.Different concentrations of P(PHDA)and P(PHDA-NCO)extracts were prepared and cultured with mouse epithelioid fibroblasts(L929)for 24h for cytotoxicity experiments;cuttings of certain sizes of P(PHDA)and P(PHDA-NCO)and mouse epithelial fibroblasts(L929)in contact culture for cell proliferation assay.The experimental results showed that mouse epithelioid fibroblasts(L929)grew well in different concentrations of P(PHDA)and P(PHDA-NCO)extracts,and the cell viability reached the maximum when the concentration of the extracts of both materials was 100%,with the P(PHDA)group being 0.028%higher than the blank control group.By cell proliferation assay,it was found that mouse epithelial-like fibroblasts(L929)reached the maximum cell viability when they were cultured in contact with the two materials for 48 h.At this time,the cell viability of P(PHDA)group was 0.29%higher than that of the blank control,and that of P(PHDA-NCO)group was0.34%higher than that of the blank control.The results of cytotoxicity assay and cell proliferation assay indicated that the two cross-linked membrane materials had good biosafety and biocompatibility.In conclusion,poly(10-hydroxy-2-decenoate)(PHDA)is a bio-based polymer with excellent performance and processability,and has the workable to exchange common petrochemical resources.