Study On Glycidyl Methacrylate And Acrylic Acid Graft Modified Recycled Polyethylene

As the most important general-purpose plastic,high-density polyethylene(HDPE)has an extremely wide range of uses and is consumed at home and abroad.The long-term use of HDPE will inevitably occur in different degrees of degradation,oxidation and aging.Therefore,the recycling of HDPE has been a focus of attention of researchers.The traditional recycling methods mainly improve the mechanical properties and machinability of recycled high-density polyethylene(rHDPE)through physical blending and graft modification.However,the simple physical blend modification method is difficult to solve the problems of poor compatibility of the multiphase polymer,stress concentration of the blend,and poor mechanical properties,because the lower grafting rate makes the method of single component graft modification of rHDPE.It is difficult to achieve similar mechanical properties to the new resin.In view of the lower mechanical properties of rHDPE and the poor compatibility of modified blends,the following studies have been conducted in this paper:GMA was used as a graft modifier and AAc was used as a modified comonomer.Firstly,rHDPE and mPE were melt-grafted to prepare rHDPE-g-(GMA-co-AAc)(abbreviated as rH-g-G/A)and mPE-g-(GMA-co-AAc)(abbreviated as mPE-g-G/A),and then LDPE/HDPE was prepared by blending rH-gG/A with LDPE.G-(GMA-co-AAc)(abbreviated as L/rH-g-G/A)blend;mPE-gG/A as rHDPE/LDPE interface modifier,prepared rHDPE/LDPE/mPE-g-(GMA-co-AAc)(abbreviated rH/L/mPE-g-G/A)blend.The mechanical properties,rheological properties,crystallization behavior,and microscopic morphology of the two blends were measured by Universal Tensioner,Melt Indexer,Rotary Rheometer,Scanning Electron Microscope(SEM),X-ray Diffraction(XRD),and Differential Scanning.Calorimeters(DSC)were tested and characterized.In this study,the L/rH-g-G/A blends were prepared by grafting rHDPE with GMA and AAc in an attempt to improve the mechanical properties of the blends.As the concentration of AAc and GMA increased,the tensile strength of the blend first increased and then decreased.When the contents of GMA and AAc were 1.2% and 0.6%,respectively,the tensile strength increased from 17.26 MPa to 24.3 MPa,the elongation at break increased from 107% to 647% and the melt index was from 3.42 g/10 min.The min was reduced to 0.97 g/10 min.Dynamic rheological properties show that the temperature dependence of L/rH-g-G/A is also lower than that of rHDPE.Differential scanning calorimetry(DSC)analyzes the melting curve and the non-isothermal crystallization curve of the sample.The melting temperature of the blends increases,the crystallization temperature decreases and the peak area increases,indicating that the molecular chains are closely entangled and the activity of the molecular chains is reduced;the microscopic morphology of the samples is observed by scanning electron microscopy(SEM),and the modification is found.Before and after the blend,the brittle fracture to ductile fracture occurred.In this study,the mechanical properties of rH/L/mPE-g-G/A blends prepared by melt grafting show that compared with rHDPE/LDPE,the tensile strength of blends increases from 25.06 MPa to 34.51 MPa.The elongation increased from 784% to 1263%.The DSC results showed that the melting peaks of rH/L/mPE-g-G/A blends were approximately overlapped,indicating the existence of partial co-crystallization,indicating good compatibility between the two components.The rheological test shows that the phase angle slope of rH/L/mPE-g-G/A is close to 0,indicating that the elasticity of the blend becomes larger and the compatibility is improved;the X-ray diffractometer has a total of rH/L/mPE-g-G/A The crystal structure of the mixture was analyzed.Compared with rHDPE/LDPE,the thickness of the interfacial layer was increased,and the size of the dispersed phase LDPE was reduced,indicating that there was partial compatibility between the multiphase polymers.