Study On The Preparation And Tensile Response Properties Of Thermoplastic Polyurethane-based Antistatic Materials

Polyurethane is widely used in many fields such as daily life and transportation due to its excellent physical and mechanical properties,wide hardness range,high strength and elastic modulus.However,itself has electrical insulation property and can only be used as an insulating material,which limits its application in the fields of electronic communication and smart sensors.The research contents of this dissertation were as follows:（1）The traditional polyurethane was modified by adding PEG as a hydrophilic polymer.A series of thermoplastic polyurethane（TPU-x PEG2k）was prepared by bulk polymerization,and their structure was characterized by FT-IR.XRD,TG,and DSC test results showed that as the PEG content added,the polyurethane crystallinity increased,and the thermal stability,melting point,and molecular weight decreased.（2）The performance of the polyurethane was studied by water absorption test,tensile test and surface resistivity test.The results showed that PEG was beneficial to improve the moisture absorption capacity of polyurethane,the maximum water absorption was 82.8%,and TPU-0.4PEG2k had the highest elongation at break（1244.3%）in a series of polyurethanes prepared.Simply changing the content of PEG had almost no effect on the surface resistivity of polyurethane,but it showd a synergistic effect on reducing the surface resistivity of polyurethane when used in combination with ionic liquids.However,PEG did not have a"synergistic effect"with multi-walled carbon nanotubes（MWCNTs）.（3）1-butyl-3-methylimidazole trifluoromethanesulfonate（[C₄mim]CF₃SO₃）and MWCNTs was used as conductive fillers,a series of TPU-0.4PEG2k-based antistatic composites were prepared by in-situ polymerization.The structure and properties of the composite were characterized by XRD,TG,DSC,etc.The results showed that[C₄mim]CF₃SO₃ can destroy the crystalline structure of polyurethane,and MWCNTs increased the crystallinity of polyurethane;the addition of two conductive fillers improved the polyurethane’s thermal stability and melting temperature;[C₄mim]CF₃SO₃ hardly changed the light transmittance of the film,but the introduction of a small amount of MWCNTs significantly reduced the light transmittance of the film.（4）The surface resistivity and tensile response properties of composite materials were studied.As a result,both of[C₄mim]CF₃SO₃ and MWCNTs can reduce the surface resistivity of polyurethane.When the content was 2wt%,the two conductive fillers reduced the surface resistivity of TPU-0.4PEG2k by about four orders of magnitude and six orders of magnitude,respectively.And the combined use of the two synergistically improved the conductivity of polyurethane.When the strain was30%,the tensile strain gauge factors of TPU-0.4PEG2k/1[C₄mim]CF₃SO₃ and TPU-0.4PEG2k/1MWCNTs were 3.67 and 96.41,which indicated that compared with TPU-0.4PEG2k/1[C₄mim]CF₃SO₃,TPU-0.4PEG2k/1MWCNTs had higher tensile strain response sensitivity.In addition,when the content of conductive filler was the same,the strain response sensitivity of polyurethane-based composites increased with increasing strain.Under the same strain,the strain response sensitivity of the composite decreased with the increase of filler content.