One-pot Preparation Of Kevlar Chemically Modified Multi-walled Carbon Nanotubes And Their Application In Composites

With the concept of nanotechnology In the mid-20th century,carbon nanotubes?CNTs?as an excellent nanomaterial has always been the focus of researchers.With the excellent performance of CNTs,CNTs has been the most ideal material enhancer,many studies have shown that when CNTs are added as reinforcements to materials in a very small amount,the mechanical properties of the composites will be very high.However,the disadvantages of CNTs are also very obvious.Due to the strong interaction between the tubes and tubes of CNTs,CNTs are easily aggregated,and thus they can't exert the effect of CNTs as reinforcing agents perfectly.Therefore,how to weaken the interaction between CNTs becomes an urgent problem to be solved.In,this paper we use para-aramid?PPTA?as an important basis to weaken the interaction between CNTs,because of PPTA has a similar structure as CNTs and can be conjugated system with CNTs,so it will enhance the dispersion of CNTs.The performance of PPTA itself is also very special,so we hope to get a more excellent material.In this paper,the PPTA oligomers were grafted onto the surfaces of Carboxy carbon nanotubes?MWN Ts-COOH?and Amino carbon nanotubes?MWNTs-NH₂?to obtain PPTA-MWNTs.The effects of different ratios of PPTA on PPTA-MWNTs were studied.The characterization of the oligomers of PPTA succeeded in grafting onto the surface of CNTs by means of characterizations such as infrared and transmission.The results of transmission electron microscopy are the most obvious,after modification the wall of CNTs has changed significantly.When the PPTA reaction ratio increases,the thickness of the wall increases.The reaction ratio of PPTA At 10 o'clock the outside of the CNTs showed distinct non-walled filaments.The dispersibility test shows that the dispersibility of CNTs in NMP and other solvents is significantly improved.Therefore,it is proved that the method of modifying CNTs with PPTA oligomers is feasible and can effectively improve the ability of CNTs to be evenly distributed in the solvent.In this paper,the PPTA-MWNTs as reinforcing agent was add to polyvinyl chloride?PVC?as the matrix,and comparie the different PPTA reaction ratio in polyvinyl chloride.The PPTA-MWNTs were added to PVC with different weight ratios and the films were mechanically analyzed.The Young's modulus?E?,tensile strength?TB?,and fracture strain?EB?of PVC films with PPTA-MWNTs increased by44.4%,79.4%,and 203.6%,respectively,compared to the corresponding values of pure PVC film.With CNTs as the reinforcing agent,the E,TB,and EB of the membrane increased by 29.7%,41.6%,and 104.2%,respectively,compared to the corresponding values of the pure PVC film.This fully demonstrates that the CNTs chemically grafted with PPTA oligomers are more capable of exerting CNTs as reinforcing agents.The performance of PPTA itself is also very stable and excellent,but the manufacturing technique is very strict,so the modification of PPTA fiber can only adopt the method of post-modification.In this paper,the swelling method was used to modify PPTA fiber.The advantages of this method are very obvious.It can be enhanced without changing the production process of PPTA.It plays an important role in promoting and using PPTA.In this paper,three different types of PPTA fibers were used for experiments,in which the E of the 529R fiber was improved,but the TB and EB were decreased with a larger reduction range.The increase of E in K129 fiber,TB slightly increased at a certain concentration,and TB decreased.The effect of K49 fiber is most obvious,and its E,TB and EB are all increasing.This is because there are differences in the synthetic raw materials of different types of fibers.The raw materials used in this article are the same as the synthetic raw materials of K49,so the enhancement effect of K49 is the most prominent.