Synthesis Of Ionic Triblock Or Grafted Copolymer Composite Thermoplastic Elastomers And Their Structure-property Study

Polymer multiphase blending and copolymerization are the effective methods to obtain advanced functional materials,which involving the complex structural change and complex macrophase separation or microphase separation.The microphase separation morphology endows the material performing from gel to elastomers or even plastics.Grasping the relationship between microstructure and performance of functional materials and controling microstructure to obtain high performance materials are the focus of this research work.This study involves the relationships between structure and performance of elastomers and polymer interfacial diffusion dynamics,and the main research content includes the following four aspects:1.BAB type triblock copolymer elastomers(TBCPEs)with a hard middle block of poly(isobornyl acrylate)(PIBA)and two soft outer blocks containing n-butyl acrylate(BA)and 1-vinylimidazole(VI)were synthesized,and the microstructure-property correlations were analyzed in the case of varied molecular masses.The order-to-disorder transition(ODT)and the phase separation kinetics of these TBCPEs were tunable by adjusting the molecular mass of the blocks.In the case of soft-hard-soft block sequence,the entangled soft P(BA-co-VI)chains are only tethered at one end by the glassy PIBA microdomains.The considerable mechanical properties of TBCPEs could be also tuned by controlling of molecular mass.This easy synthesis and versatility render this approach general applicability through copolymerization of certain comonomers with very minor mass percentages for further development in advanced functionalized materials.2.We prepared the BAB triblock copolymers(TBCPEs)with metal-ligand cross-links in the soft end blocks.UV/vis titration and rheological measurements were undertaken to explore the changes of modulus and viscosity for coordinated TBCPEs(STBCPEs).With low mass percentage of poly(1-vinylimidazole)component,the STBCPEs were endowed with improved the modulus,tensile strength,extensibility and creep resistance by adding zinc chloride(ZnCl2).The dynamic nature of the metal-ligand bonds allows them to rupture and re-form which endows the STBCPEs with reversible recovery.Many biological and device applications in current stretchable elastomers can benefit from such architecture design with exhibited simultaneously improved tensile strength and elongation at break without losing extensibility.3.A biomass thermoplastic elastomer was synthesized using cellulose as main chain where grafted with butyl acrylate and imidazole soft segment through the reversible addition-fragmentation chain transfer(RAFT)polymerization.And anovel thermoplastic elastomer was formed by adding zinc ion.Experiment results show that cellulose chain rigidity and metal-ligand crosslinks can significantly improve the mechanical properties of thermoplastic elastomer.And metal-ligand crosslinked elastomers shows double or even triple temperature memory properties,making the cellulose elastomer to be applied to artificial muscle and brake.4.Polymer mutual diffusion behavior are often encountered in polymer welding,polymer blending and phase separation controling.Mutual diffusion behaviors are affected by many factors,such as molecular mass,molecular topology structure and compatibility between polymers.Simply and accurately studying polymer interface diffusion dynamics can provide powerful theoretical guidance for polymer blending.However,many spectroscopy studies concerning polymer diffusion need advanced technology as well as complex molecular markers.In this study,the mutual diffusion dynamics between PEO and PLA for the double-layer films was explored in details and the results were analyzed by using the Zhang-Lamnawar-Maazouz model.The effects of welding time,temperature and the Flory-Huggins parameter on the diffusion dynamics were investigated.In addition,the interfacial layer thickness for the PEO/PLA double-layer films could be obtained from the rheological measurements.The main innovations involved in this thesis:1)The microphase separation of TBCPEs with soft-hard-soft sequence was studied,and the ODT transformation,transformation kinetics,and microstructure performance relationship were studied in detail.2)By introducing functional monomer into TBCPEs system,the relationship between metal-ligand crosslinked network microstructure and mechanical properties was studied in detail.3)We report biomass-derived,shape-memory materials prepared via simple reactions,including "grafting from" RAFT chemistry.The work presented herein provides burgeoning opportunities to design metal-ligand crosslinked elastomer.4)Explore interface diffusion dynamics of PLA/PEO double films using rheological method,and obtain interface layer thickness using rheological theory.