Preparation And Characterization Study On Polymer Blend Of Disentangled Ultra-high Molecular Weight Polyethylene And Linear Low Density Polyethylene

Polyolefin are widely used in industrial production.As a typical representative of polyolefin,ultra-high molecular weight polyethylene(UHMWPE)has many excellent properties,such as high strength,high modulus,wear resistance,ageing resistance,resistance to chemical corrosion,etc.Disentangled ultra-high molecular weight polyethylene(DUPE)with its low entanglement density not only retains the performance of traditional UHMWPE,but also improves the material processing properties under low temperature or by press molding.This topic is based on the melt blending technology to prepare polymer blend of DUPE and linear low density polyethylene(LLDPE)and then study the mechanical properties and mechanism of the blend.Firstly,we synthesized disentangled UHMWPE using a type of single-active-site transition metal catalyst named Fenokishi-Imin catalyst(FI catalyst).The microstructure,crystallization and rheological properties of the synthesized DUPE were studied by scanning electron microscope,gel permeation chromatography,differential scanning calorimetry and rheometer,respectively.The DUPE showed high crystallinity(about 75%)and narrow molecular weight distribution.Rheological tests showed that the polyethylene has much lower entanglement density than commercial ultra-high molecular weight polyethylene(CUPE)under the same test conditions.The preparation of DUPE and LLDPE blend was carried out through Haake torque rheometer and Haake micro extrusion equipment,and a specific adjustment scheme of the processing technology,including the use of different proportion and the change of the processing temperature,processing time has been made to explore the method of preparing high performance polyethylene blend materials.Mechanics performance test showed that the tensile properties of DUPE/LLDPE blend have a significant improvement.Polyethylene wax(WAX),as a kind of common material with low molecular weight and low viscosity,has been further used to prepare blending materials.The molecular chains of DUPE tended to swelling with the help of WAX under the actual processing conditions.Then the molecular chains of LLDPE easily penetrated into the matrix of DUPE.Eventually,three-phase blending material with improved blending features and great mechanical performance had been made.Experimental results showed that the tensile strength of the composite system has improved a lot and can be used to produce foaming material.