Synthesis And Properties Of PVA/Modified CB Composite Material

In this work, the oxidized carbon black and polyetheramine modified carbonblack (AC1830-OCB)are obtained by the way of oxidation carbon black and graftingof oxidized carbon black and polyetheramine. Poly(vinyl alcohol)(PVA)/AC1830-OCB composites were prepared by a casting method in which PVA wasused as polymer matrix and AC1830-OCB as reinforcement components. Thepolyetheramine modified carbon black were investigated by Fourier TransformInfrared Spectroscopy(FTIR), Thermogravimetric Analysis(TGA),DifferentialScanning Calorimetry(DSC) and Transmission Electron Microscope(TEM)Observation.The results show that grafting rate is about90%,and the modified carbonhas a core-shell structure.According to the TEM of the Observation of the AC1830-OCB/PVA composites,the dispersion of modified carbon black in the matrix of PVA is good when the masspercentage of modified carbon black is below3%.Otherwise with the increase ofcontent in PVA the dispersion is getting worse, and agglomeration appeared when thecontent exceeds3%. According to the characterization of morphology and structure ofAC1830-OCB/PVA composites, it revealed that modified carbon black plays a role ofheterogeneous nucleation, and it accelerates the rate of crystallization. Thecrystallization temperature, crystallinity, melting point， crystallization enthalpy,melting enthalpy are higher than that of pure PVA; The highest degree of crystalinityup to30.99%. Dynamic storage modulus improved and tensile strength improvedabout70%,it proved that modified carbon black improved the rigidity of PVA.Dielectric test show that the dielectric constant and dielectric loss tangent wereimproved, they were up to the highest when the content of modified carbon black was5%. Absorption rate experiments indicates that in the content of2%the rate is thelowest. Absorption rate is the lowest at the content of AC1830-OCB2%.The modification mechanism of AC1830-OCB/PVA composites has beendiscussed according to the above results. The surface of modified carbon black withgroups (ether oxygen and amine)can form hydrogen bonds between PVA andmodified carbon black. It enhanced the combination between two particles more closely, to share the load transmitted from the matrix, thus improving the mechanicalproperty and storage modulus of the composites. However, excessive addition ofAC1830-OCB particles leaded to reunite, weakening the interfacial bonding effect,which make the interfacial between the inorganic and organic phases debonding. Inthis case,when composites faced external forces, it unable to transmit from matrix toreinforcement particles, which resulted in decline of the mechanical property. Themodified carbon black play the role of a nucleating agent in the system affecting thecrystal growth process of PVA which improve the crystallinity and crystallinity rate.The surface effects plus increased dipole moments of polar groups in system leadedto a complex interface polarization,and it improved the dielectric constant as well asdielectric loss tangent of the composite. Modified carbon black make the free volumereduced,which hindered the entry of water and reduced the moisture of the material.