Synthesis And Properties Of Poly(10-hydroxydecanoate) And Its Crosslinked Film

In recent years,with the increasingly scarce petroleum resources and the increasingly serious environmental pollution,people begin to search for new polymers that can replace the traditional petroleum-based polymers.Biopolymer has been widely concerned and developed rapidly because of its advantages of sustainability,environmental friendliness and biocompatibility.As an important classification of bio-based polymers,the design and development of bio-based polyester and its composites are particularly important.Therefore,a series of novel bio-based polyesters and their crosslinked films with different molecular weights were designed and prepared in this paper.According to the properties,it can be used as polyethylene(PE)materials to replace some traditional petroleum-based polymers.As a new shape memory material,the crosslinking films also have good shape memory properties.First of all,a series of Poly(10-hydroxydecanoate)(PHDA)with different molecular weights were prepared by melting and polycondensation of decanoyl decanoic acid from ricinoleic acid.Through GPC,DSC,WAXD,POM,rheometer and tensile test,the effects of molecular weight on the thermal properties,crystallization behavior,crystal morphology,rheological behavior and mechanical properties of PHDA were studied in detail.The results show that the physical properties of PHDA depend greatly on the molecular weight.In particular,when the molecular weight increased to 55kg/mol,PHDA underwent brittleness-toughness transformation.With the increase of molecular weight,the elongation at break increases greatly,eventually exceeding 1400%.Its ultimate tensile strength is about20 MPa.Studies have shown that PHDA has mechanical properties similar to PE.Therefore,PHDA is an excellent bio-based polyester,which can replace some traditional petroleum-based materials in the field of packaging materials and other fields.Then a series of crosslinked films with different gel contents,different molecular weights of crosslinked precursors and different component contents were prepared by using low molecular weight poly(10-hydroxydecanoate)and polyethylene glycol(PEG)as raw materials through the crosslinking agent tri-HDI.The thermal,crystalline and mechanical properties of PHDA/PEG based crosslinked films were investigated by DSC,WAXD,TG and tensile tests.It is found that the gel content,molecular weight of the crosslinking precursor and component content all have great influence on the performance of the crosslinking film.The results show that the lower the gel content and the higher the molecular weight of the crosslinked precursor,the higher the melting temperature of the crosslinked films.With the increase of PEG component content,the melting temperature of PHDA segment and PEG segment increases.In the end,the double-shape memory effect of PHDA-based crosslinked films and the triple-shape memory effect of PHDA/PEG-based crosslinked films were investigated in detail from macroscopic to microscopic by “fold-unfold” method,“dynamic thermo-mechanical”method and “uniaxial stretching” method.The results show that both double and triple shape memory crosslinked films have good shape memory performance.The shape fixing rate is above 90%,the shape recovery rate can be as high as 95%,and the shape recovery time can be maintained within 10 s.More importantly,the thermal transition temperature of the material is regulated by chemical synthesis,so that the shape memory behavior occurs near the human body temperature,which greatly expands its application field.