Synthesis And Properties Of Thermolplastic Elastomer Crosslinked By Hydrogen Bond And Ionic Bond Hybridization

Thermoplastic elastomer(TPE)is a kind of special elastomer which has rubber like elasticity at room temperature and can be plasticized when the temperature rises.Because of repeated thermoplastic processing,solved the traditional vulcanized rubber materials difficult to recycle,TPE had received more attention of researchers.The ionic bond crosslinked thermoplastic elastomer had the characteristics of high strength,high toughness,high permanent deformation,high hysteresis and high temperature resistance.And hydrogen-bonded cross-linked thermoplastic elastomers exhibited low permanent and low hysteresis effects at low strain,high strength,high tear resistance and high elongation at high strain.Therefore,combined the two types of thermoplastic elastomer crosslinking system in one crosslinked system to prepare a thermoplastic elastomer of excellent performance material was very important.(1)β-alanine grafted ion bonds crosslinked ⅡR TPECarboxylation of butyl rubber(grade IIR-301)macromolecules was carried out by alder-ene reaction under the catalysis of vinyl aluminum trichloride with pentafluorophenol propionate.Then P-alanine t-butyl ester was grafted onto the butyl rubber macromolecule using the amidation reaction of the amino group with the propiolate carboxyl group.And finally,used different amount and kind of the metal compound neutralized the carboxyl group resulting in hybrid crosslinked TPE.Studies had shown that the material had two transition temperatures around 0℃ and about 60 ℃,and a significant rubber platform could be observed between the two temperatures.The glass transition temperature rised from-69℃ to-62℃,due to the cross-linking of ionic and hydrogen bonds in the system.The TPE enters a viscous state at 60 ℃,indicated that it could be thermoplastic processed at temperatures above 60℃.The results showed that TPE had the best mechanical properties neutralized by 4 phr ZnO,its tensile strength was 8.65MPa,the elongation at break was 1704%,the tensile permanent deformation was 110%and the compression set was 72%.(2)P-alanine dimer grafted ion-bonded cross-linked ⅡR TPEFirstly,we protected β-alanine amino group with boc and carboxy group with benzyl alcohol,inorder to prepare β-alanine dimer by amide coupling.Then we removed the protection of amino group and carboxyl group for the next reaction.Carboxylation of butyl rubber(grade IIR-301)macromolecules was carried out by alder-ene reaction under the catalysis of vinyl aluminum trichloride with pentafluorophenol propionate.Then P-alanine dimer was grafted onto the butyl rubber macromolecule using the amidation reaction of the amino group with the propiolate carboxyl group.And finally,used different amount and kind of the metal compound neutralized the carboxyl group resulting in hybrid crosslinked TPE.Studies had shown that the material had two transition temperatures around 0℃ and about 60℃,and a significant rubber platform could be observed between the two temperatures.The glass transition temperature rised from-69℃ to-62 ℃,due to the cross-linking of ionic and hydrogen bonds in the system.The TPE enters a viscous state at 60℃,indicated that it could be thermoplastic processed at temperatures above 60℃.The results showed that TPE had the best mechanical properties neutralized by 4 phr ZnO,its tensile strength was 10.98 MPa,tensile elongation was 1515%,tensile permanent deformation was 96%and compression set was 80%.The different types of metal oxides were effective for ⅡR TPE.The TPE neutralized with ZnO and MgO had good physical and mechanical properties,tensile strength of about 10MPa,however,neutralized with Al2O3,the TPE was a soft and weak elastomer,Its tensile strength was only 2.3MPa.