Surface Treatment of Carbon Nanotubes and Its Effect on the Mechanical Properties of Polymer Composites

Materials and Reagents Multi-walled carbon nanotubes (CNTs) are approximately 100-150 nin in diameter, and are provided by the Department of Chemical Engineering of Hua University. The polyurethane (PU) hard segment is MDI, the soft segment is PTMG, Mn = 1000, and the chain extender is BD. Other reagents are domestically produced analytically pure products.

Composite material preparation and mechanical properties testing CNTs were treated with concentrated acid solution for 24 hours, diluted with pure water, filtered through a filter with a pore size of 丨OO nm, washed to neutrality, dispersed in a PU solution, and removed the solvent to obtain a composite material (CNT -PUC) containing carbon nanotubes in a ratio of 1% Cw/w). Another non-surface-treated CNT was blended with a polyurethane solution using a high pressure microfluidic method at a weight ratio of 2%, and the composite material (CNT-PUU) was obtained after removing the solvent. The above composite material was formulated into a 5% tetrahydrofuran solution and cast into a film in a glass dish and placed in a vacuum oven for 48 hours under a vacuum oven to remove the residual solvent. The film thickness was 0.15 mm and 0.03 mm. The mechanical property test data was obtained through a universal tensile machine. 2.5 Kg, tensile rate results and discussion Mechanical properties of the test results show that polyurethane and surface treated carbon nanotube composite tensile strength and elongation at break have been improved, and the elongation at break improved more Obviously, the maximum tensile strength increases by 7-30% and the elongation at break increases by 14-50%. For non-surface-treated carbon nanotubes, the mechanical properties of the composites with polyurethanes are also to a certain extent. It is improved, but compared with CNT-PUc, the increase in elongation at break of CNT-PUu is low. The experimental results show that the surface treatment on the one hand can overcome the agglomeration forces between the carbon nanotubes, enabling them to be more evenly dispersed into the polyurethane matrix, and on the other hand can enhance the interaction between the carbon nanotubes and the polyurethane molecules, so that the inorganic The phases and organic phases are more fully compounded. Due to the high aspect ratio at the nanometer scale, the carbon nanotubes simultaneously enhance and toughen the polyurethane matrix, and the toughening effect appears to be more pronounced in the composite ratio used.

Conclusion The surface treatment of carbon nanotubes to a certain extent is beneficial to increase the degree of dispersion in the polymer matrix and the interaction with macromolecules, so as to improve the mechanical properties of the polymer matrix; the introduction of carbon nanotubes to polyurethane The matrix has an increased M and double M effect.

AW Jing-Jian-Jian-Feng Xue from the Gold Funding Project 丨-I (027U391), teaching faculty excellent teachers to fund UAMHA △ overnight people