Preparation And Properties Of Degradable Bio-based Thermoplastic Vulcanizates

Thermoplastic Vulcanizate(Thermoplastic Vulcanizate,TPV)is a kind of thermoplastic elastomer that combines the plasticity of plastic and the high elasticity and toughness of rubber,and has the characteristics of simple process,low energy consumption,and high production efficiency.In recent years,the environmental pollution caused by the excessive use of petrochemical resources has attracted the attention of scientific researchers.Therefore,the use of bio-based polymers to prepare a thermoplastic vulcanizate(TPV)with the characteristics of degradability,low toxicity and reproducible processing is in line with the concept of sustainable scientific development and circular economy.From the perspective of the source of raw materials,both components of bio-based thermoplastic vulcanizates(TPV)are derived from renewable resources,which can reduce dependence on petroleum from the perspective of product recycling.It can be recycled and reused and has a certain degree of biodegradability.Therefore,this paper firstly used polycaprolactone(PCL)to enhance bio-based polyester elastomer(BEE)to prepare a bio-based vulcanizate with a certain strength.Then a new type of bio-based thermoplastic vulcanizate was prepared using as two components of polycaprolactone and bio-based polyester elastomer(BEE),and bio-based thermoplastic vulcanizates with good compatibility,degradability and low toxicity were prepared.In this paper,firstly,aiming at the problem of poor mechanical properties of bio-based engineering elastomers(BEE),polycaprolactone(PCL)is used as the reinforcing phase of bio-based polyester elastomers(BEE)to prepare BEE/ PCL vulcanizate.Through dynamic thermomechanical properties(DMA),scanning electron microscope(SEM),differential scanning calorimetry(DSC),X-ray diffraction(XRD),mechanical testing,etc.,the vulcanization characteristics and compatibility of BEE/PCL vulcanizates,microscopic phase state,thermal properties,crystallization properties,and mechanical properties were characterized.It was found that the BEE/PCL vulcanizate has only one glass transition temperature,indicating that it is a thermodynamically compatible,however the SEM results show that the BEE/PCL vulcanizate is a microscopic phase separation.With the increase of PCL content,the crystallinity of BEE/PCL vulcanizates gradually increases.The tensile strength slightly increases,and the elongation at break first increases and then decreases.When the mass ratio of BEE to PCL is 8:2,the mechanical properties of BEE/PCL vulcanizates are better,the tensile strength is 5.1 MPa,and the elongation at break is 292%.Bio-based polyester elastomer(BEE)and polycaprolactone(PCL)as the two components of the thermoplastic vulcanizate,and dicumyl peroxide(DCP)as the initiator.A dynamic vulcanization method is used to prepare a new type of bio-based thermoplastic vulcanizate(BEE/PCL TPV).Through DMA,atomic force microscope(AFM),DSC,XRD,rotational rheometer(DHR),rubber processing analyzer(RPA)and cytotoxicity,the compatibility and rheology of different rubber-plastic ratios to BEE/PCL TPV were studied.Performance,in vitro biocompatibility,mechanical properties and other aspects.It was found that the BEE/PCL TPV did not change significantly with the increase in the ratio of rubber to plastic.However,the tensile strength,elongation at break,permanent deformation and hardness of BEE/PCL TPV all show a downward trend,while its elasticity gradually increases.The tensile strength of BEE/PCL TPV ranged from 6 to 20 MPa,and the elongation at break ranged from 295% to 593%.The dynamic thermal analysis test shows that BEE/PCL TPV has only one glass transition temperature.From a macro point of view,the two components have a good thermodynamic compatibility.The rheological performance test shows that BEE/PCL TPV has good processing performance.In vitro cytotoxicity tests and cell adhesion and proliferation experiments show that the cytotoxicity level of BEE/PCL TPV is level 1,its surface cells grow well and intact,and the material exhibits good biocompatibility.