Abstract
This study describes a simple, practical, inexpensive, improved, and efficient novel method for obtaining polyurea-polyurethane-multiwall carbon nanotubes (MWCNTs) nanocomposites with enhanced mechanical properties, and their experimental testing in a dynamic regime. SEM and micro-CT investigations validated the homogeneity of the nanocomposite films and uniform dispersion of the nanofiller inside the polymeric matrix. The experimental measurements (TGA, DSC, DMA, and tensile tests) revealed improved thermal and mechanical properties of these new materials. To demonstrate that these nanocomposites are suitable for ballistic protection, impact tests were performed on aluminum plates coated with the polyurea-polyurethane MWCNTs nanocomposites, using a Hopkinson bar set-up. The experimental testing in the dynamic regime of the polyurea- polyurethane-coated aluminum plates confirmed that the nanocomposite layers allow the metal plate to maintain its integrity at a maximum force value that is almost 200% higher than for the uncoated metallic specimens.
Highlights
Nowadays, war migrates from the battlefields towards less predictable areas
DMA analysis aimed to follow the evolution of storage (E′) and loss (E′′) modulus o synthesized nanocomposites to evaluate their potential to be used as coatings for the s DMA analysistuarimesetdhattonfeoeldloiwmptrhoevedvoblaultliostnicopfrostoecrtaigoen.(FEig)uarned9 illolussst(rEa”te)sma ocodmulpuasraotfive plot o the synthesizedE′naanndocEo′′mvaplouseistefsotrotheevablluaantke stahmeipr lpeo(tPeUnt)i,aalntod bfoerutsheednaasncoocaotminpgossfitoer wthheich displ structures that tnheeedbeismt pternosvieledtbeastllrisetsiuclptsro(PteUct-iNonC.3F).igure 9 illustrates a comparative plot of the E and E” values for the blank sample (PU), and for the nanocomposite which displayed the best tensile test results (PU-NC3)
Polyurea-polyurethane and multiwall carbon nanotubes (MWCNTs) nanocomposites were obtained to be used for ballistic protection applications through a facile synthesis approach involving MWCNTs pre-dispersed in a polyester polyol-based resin
Summary
War migrates from the battlefields towards less predictable areas. All existing ammunition types and improvised explosive devices represent serious threats. This product consists of a concentrate of MWCNTs pre-dispersed in a polyester-polyol system, which ensures a good dispersion in the polyurea matrix This simplified synthesis method could be more advantageous for coating extended areas specific for ballistic protection applications. To improve the response of the metallic structures to impulsive loadings, we decided to employ our previously synthesized polyurea matrix [17], which was obtained from poly (propylene glycol) bis(2-aminopropyl ether) with Mn ≈ 2000 Da, diphenylmethane-4,4 diisocyanate, and 4 -diaminodiphenylmethane as chain extender This polyurea possesses superior mechanical resistance, displaying a maximum quasi-static true stress of 33.76 MPa. Its unique set of properties established the premises for obtaining a performant nanocomposite with superior mechanical resistance (up to 40.84 MPa maximum quasi-static true stress) for ballistic protection applications. The novelty of this paper consists of both the straightforwardness of the polyurea coating fabrication method and the experimental set-up approach for the evaluation of the behavior of these materials at impact with a projectile
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