Preparation And Conductive Properties Of Titanate Coupling Agent Treated Cu-Sn Alloy/Functionalized CNT/HDPE Composites

In this study, Cu-Sn alloy and CNTs were chosen as conductive fillers to prepare HDPEbased conductive composite materials by Ball milling and hot-pressing, wherein Cu-Sn alloyand CNTs were treated and functionalized by titanate coupling agent and PE-g-MAH,respectively, for well dispersion in HDPE matrices. In order to understand the conductive andmechanical properties, a series of fourier transform infrared spectrum, thermal, morphologicaland vicat softening temperature analyses were studied.The results showed that the room temperature volume resistivity values decreased as theincrease of the contents of Cu-Sn alloy in CuSn/HDPE composite materials. When the contentof Cu-Sn alloy reached 70wt%, the room temperature volume resistivity values(≤102 cm)and PTC intensity(≥104) reached or closed to the requirement of PTC materials. As thecontents of Cu-Sn alloy continued to increase, the Cu-Sn alloy conductive path in HDPEmatrix was mainly formed by the contact of conductive fillers, the conductive properties ofcomposite materials are owing to the characteristic of Cu-Sn alloy, so as the contents ofCu-Sn alloy continue to increase, the room temperature volume resistivity will not decreaseany more.After using titanate coupling agent treated Cu-Sn alloy filled with HDPE matrix, theconductive properties were improved compared with the CuSn/HDPE composite materials.This is atrributed to the coupling agent could enhance the interface compatibility between theinorganic Cu-Sn alloy and the organic polymer matrix. Therefore, the volume resistivitydecreased and the PTC intensity increased. However, surplus titanata coupling agent wouldblock the conductive properties of the Cu-Sn alloy, so in this study, we choose that the weightratio of titanate coupling agent to Cu-Sn alloy is 1.0%.This paper also study the ternary system conductive composite materials using titanatecoupling agent treated Cu-Sn alloy and functionalized carbon nanotubes filled with HDPEmatrix. The results showed that the conductive properties and PTC strength of titanatecoupling agent treated Cu-Sn alloy/functionalized CNTs/HDPE composite specimens weresignificantly better than those of Cu-Sn alloy/HDPE composite specimen without modification. When the content of functionalized CNT was 2.0wt%, only 53.0wt% of Cn-Snalloy, the composite material could show good conductive properties and high PTC intensity.The results of DSC analysis showed that titanate coupling agent treated Cu-Sn alloy andfunctionalized CNT can affect the melting temperature and the degree of crystallization of thecomposite materials. Impact properties and vicat softening temperature test showed thattitanate coupling agent and carbon nanotubes were benefit for the mechanical properties andprocessing properties of the composite materials, especially after adding functionalized CNT,the impact properties were improved greatly. The ternary system of titanate coupling agenttreated Cu-Sn alloy/functionalized CNT/HDPE composite materials could expand theapplication of polymer matrix/metal conductive composites, and have a deep researchmeaning.