Preparation of impact-resistant functional polyurea coatings and effect of γ-ray irradiation on its microstructure and performance

Modeling of success factors of using PU coats in concrete construction projects

“…The model's validity is being demonstrated further because a greater impact will be produced if the polyurea coating is implemented in concrete construction projects. SE values are also less than 1, which justifies the overall path analysis of the formative construct and further gives evidence of the justification of hypotheses relative to each of the constructs [ 87 ]. t values also indicate acceptable statistics because they are not much greater but still greater than 1, while giving further evidence of validation of all the alternate hypotheses and indicating that the constructs are creating an impact on the latent variable.…”

Enhancement effect of polyurea coating on the impact resistance of aluminum foam

“…The coating was cut by an electric punching machine to obtain standard specimens for quasi‐static and dynamic compression experiments. With reference to standard ‘HG/T3843‐2008/ Vulcanized rubber‐Test method for short time static compression’, and in order to reduce the influence of inertia effect and end friction effect of polyurea under dynamic loading, 29,30 the dimension of polyurea specimen used in the compression tests was designed as the cylinder of φ19 × 10 mm.…”

“…The aluminum foam specimen was processed by wire cutting to reduce the damage to the hole wall of aluminum foam. The existing researches showed that the size effect can be ignored when the specimen size reached more than 5 times the cell size of aluminum foam, and the influence of end friction and inertia effect under dynamic loading can be reduced when the length‐diameter ratio of the specimen was between 0.5 and 1 30,31 . Combined with the existing test device, the aluminum foam specimen used in the test was designed as the cylinder of φ100 × 50 mm.…”

“…The existing researches showed that the size effect can be ignored when the specimen size reached more than 5 times the cell size of aluminum foam, and the influence of end friction and inertia effect under dynamic loading can be reduced when the length-diameter ratio of the specimen was between 0.5 and 1. 30,31 Combined with the existing test device, the aluminum foam specimen used in the test was designed as the cylinder of φ100 Â 50 mm. In the process of preparing polyurea-coated aluminum foam, in order to accurately control the thickness of polyurea coating, soft plastics was used to wrap the side of aluminum foam and reserve corresponding height, and transparent tape was used to wrap to avoid the side of aluminum foam being covered by polyurea during spraying.…”

A Shear-Stiffening Mouthguard with Excellent Shock Absorption Capability and Remoldability via a Dynamic Dual Network

“…Moreover, polyurea is a widely used polymer, which exhibits excellent impact resistance performance via abundant and strong hydrogen bonds. − Such urea-based polymers have attracted considerable attention from an industrial perspective in the field of protection and bullet proof and antiexplosion materials. − For example, He et al fabricated a bioinspired cellular ceramic structure/polyurea dual-phase architecture, whose energy-absorbing ability is 50.34 times that of a cellular ceramic structure without polyurea; Dragonshield BC (Specialty Polymers Inc., USA) is an ultrahigh-strength polyurea elastomer product, which is used as a coating material on armored vehicles to mitigate blast and protect soldiers from fragment injury; XS-350 (LINE-X, USA) is an aromatic spray polyurea elastomer product, which has been applied as a protective layer in boats, farm equipment, construction equipment, etc. , Therefore, polyurea provides a dynamic supramolecular network for mouthguards to possess shock absorption ability thereby suiting the current processing method.…”