Study On Synergistic Compatibilizing Effect Of Reactive Compatibilizer On GTR/HDPE Thermoplastic Vulcanizate

In this paper,the thermoplastic vulcanizate was prepared by dynamic vulcanization of ground tire rubber(GTR)and high density polyethylene(HDPE).The main components of GTR are natural rubber and styrene butadiene rubber,the surface of GTR has active functional groups such as hydroxyl group and carboxyl group.By adding three reactive compatibilizers(HY-2045,PE-g-MAH and GMA)to the phase interface of GTR and HDPE blends,a strong interaction was formed at the interface of the two phases,so as to prepare high-performance thermoplastic vulcanizate and realize the recycling of GTR.GTR/HDPE thermoplastic vulcanizate was prepared by the synergistic Compatibilization of PE-g-MAH and GMA with DCP as initiator.HDPE and HDPE in PE-g-MAH are compatible systems.MAH can react with hydroxyl groups on GTR surface to form ester;The carbon-carbon double bond on GMA can react with HDPE molecular chain,and the epoxy group can react with the carboxyl group on the surface of GTR to form ester;The two compatibilizers improved the interface between GTR and HDPE by using the hydroxyl and carboxyl groups on the surface of GTR.The effect of GMA content on the properties of GTR/HDPE thermoplastic vulcanizate was studied by mechanical properties test,FTIR,SEM and DSC.The results show that the tensile strength,tear strength and elongation at break of the thermoplastic vulcanizate prepared by adding 60 phr GTR,30 phr HDPE,10 phr PE-g-MAH,0.5 phr GMA and 0.4 phr DCP can reach 12.82 MPa,82.08 k N/m and 341.61 % respectively.Under the synergistic action of two compatibilizers,the interface of GTR/HDPE thermoplastic vulcanizate was well bonded.SEM showed that the two phases of GTR and HDPE were more evenly distributed,and a large number of white fibrous materials appeared in the cross section due to the formation of interface layer;DSC results show that increasing the content of GMA will reduce the crystallinity of the HDPE phase,affecting the mechanical properties of the thermoplastic vulcanizate.GTR/HDPE thermoplastic vulcanizate was prepared by the synergistic Compatibilization of PE-g-MAH and HY-2045 with DCP as initiator.HDPE and HDPE in PE-g-MAH are compatible systems.MAH can react with hydroxyl groups on GTR surface to form ester;HY-2045 can cross-link natural rubber without the action of catalyst.The methylol and phenolic hydroxyl groups on the molecular chain can form an oxa naphthalene ring and form a graft with HDPE by forming o-methylenequinone intermediate.The two compatibilizers improved the interface of GTR and HDPE by using the hydroxyl and natural rubber components of GTR respectively.Using gel content test,mechanical property test,SEM and DSC,under the premise of fixing the content of PE-g-MAH,the effect of HY-2045 content on the performance of GTR/HDPE thermoplastic vulcanizate was studied.The results show that the tensile strength,tear strength and elongation at break of the thermoplastic vulcanizate prepared by adding 60 phr GTR,30 phr HDPE,10 phr PE-g-MAH,4 phr HY-2045 and 0.4 phr DCP can reach 18.47 MPa,88.01 k N/m and 264.70 % respectively.Under the synergistic action of two compatibilizers,the interface of GTR/HDPE thermoplastic vulcanizate was well bonded.SEM shows that the cross section of the modified thermoplastic vulcanizate has a large plastic deformation,and a small amount or excessive compatibilizer will affect the formation of the interface layer;DSC results show that the change of melting enthalpy and crystallinity of the thermoplastic vulcanizate are less affected by the content change of HY-2045.GTR/HDPE thermoplastic vulcanizate was prepared by the synergistic Compatibilization of GMA and HY-2045 with DCP as initiator.The carbon-carbon double bond on GMA can react with HDPE molecular chain,and the epoxy group can react with the carboxyl group on the surface of GTR to form ester;HY-2045 can cross-link natural rubber without the action of catalyst.The methylol and phenolic hydroxyl groups on the molecular chain can form an oxa naphthalene ring and form a graft with HDPE by forming o-methylenequinone intermediate.The two compatibilizers improved the interface of GTR and HDPE by using the carboxyl group and natural rubber component of GTR respectively.Using gel content test,mechanical property test,SEM and DSC,under the premise of fixing the content of GMA,the effect of HY-2045 content on the performance of GTR/HDPE thermoplastic vulcanizate was studied.The results show that the tensile strength,tear strength and elongation at break of the thermoplastic vulcanizate prepared by adding 60 phr GTR,40 phr HDPE,0.75 phr GMA,3.5 phr HY-2045 and 0.4 phr DCP can reach 20.24 MPa,94.30 k N/m and 184.18 % respectively.Under the synergistic action of two compatibilizers,the interface of GTR/HDPE thermoplastic vulcanizate was well bonded.SEM showed that the cross section produced a lot of plastic deformation and a lot of white fibrous materials,and GTR and HDPE would form a stable interface layer;DSC showed that the synergistic Compatibilization of GMA and HY-2045 had no obvious effect on the crystallinity of the thermoplastic vulcanizate,and the changes of crystallinity and melting enthalpy did not change with the content of HY-2045.