A recent study published in the journal Smart materials in manufacturing focuses on producing smart, multifaceted and structurally robust nanocomposites by combining functionalized graphene nanoplatelets (F-GNP) with polyurea.
Study: Smart Multifunctional Elastomeric Nanocomposite Materials Containing Graphene Nanoplatelets. Image Credit: Saachka Pro/Shutterstock.com
Polyurea is an elastomeric material with remarkable mechanical characteristics. However, pure polyurea elastomers are often hampered by a lack of toughness and performance.
What are polyurea materials?
Polyurea is one of the most important materials for structural shock absorption. Its soft sections are mainly composed of long sequences of carbon, oligomeric polyols and other elastic sections with a wide range of conformations. Isocyanates and chain extenders are used as mechanical crosslinks and reinforcing phases in hard sections.
Polyurea has distinct viscoelastic characteristics which are significantly affected by pressure, heat and strain rates. Strong hydrogen bonding and complex internal structures contribute to its remarkable defensive characteristics.
Polyurea polymers are limited in some situations due to lack of practicality or low protective efficacy. The technique of nanocomposites could help solve these problems.
Functional conductive additives: the future of polymers
Functionalized polymer-based substances typically incorporate polymers with particular functional additives to generate new or significantly improved capabilities such as conductance, heat dissipation, barrier properties, and sensing, especially self-sensing, which is required for advanced information-based materials.
Fiber optics are often used to provide sensing capabilities to polymeric materials or concrete composites. This, in turn, causes defects in composites and requires the use of large-scale test equipment. Self-sensitive nanomaterials, which have appeared in recent years, should make it possible to overcome this constraint.
Under external stress, the matrix of conductive particles deforms and detaches, allowing the network to alter and the electrical resistance of the composites (the piezoresistive capacitance) to change.
Graphene Nanoplatelets (GNP) as Functional Additives
Metals (e.g. flakes or strands), conductive foams, MXenes, and activated carbon fillers like carbon black, nanotubes, and graphene nanoplatelets (GNP) are all good considerations for conductive additives .
Compounds based on metals have the disadvantage of being heavier due to their high fillers. Higher loads can result in decreased machinability and increased expense.
PNBs have gained popularity due to their superior electromechanical qualities. Efficient conducting networks can be constructed at low electrical percolation criteria due to their large aspect ratios. However, the homogeneous distribution of GNPs in polymeric materials remains a significant challenge.
Schematics for (a) the preparation of a polyurea/F-GNP nanocomposite and (b) the multichannel detection system. © Meng, Q. et al. (2022)
Current Research Highlights
While most of the previous polyurea research focused only on mechanical characteristics and capabilities, the present work focuses on the multifunctionality of polyurea nanomaterials.
Functionalized graphene nanoplatelets (F-GNP) were used as fiber reinforcements in this study to create multifaceted, self-sensing polyurea composite materials with improved mechanical performance.
Researchers investigated the effect of F-GNPs on the mechanical characteristics and impact strength of polyurea elastomers to see if nanocomposites could be widely used as protective substances.
Main results of the study
Polyurea nanocomposites, as a new type of multifunctional nanomaterials, not only provide continuous and safe stress sensing and temperature measurement properties, but also can monitor and identify their degradation progress, as shown by experiments. of impact and tearing at low speed.
The electrical conduction of all nanocomposites produced increased as the nanofiller concentration increased, and the electrical percolation limit was determined to be 1.05% by volume. The nanocomposite demonstrated remarkable sensitivity in the 0-5% strain region.
The results reveal that the standardized resistance of the nanocomposite changes with temperature and that its sensitivity varies between low and high temperature ranges. The nanocomposites showed good reliability and stability during cyclic strain measurements up to 9100 cycles and showed stable detection capability between 20°C and 80°C.
Future prospects and prospects
This study describes a simple and efficient method to produce high-efficiency and multi-faceted polyurea nanocomposites. These functionalities are realized by modifying, degrading and restoring the conductive system inside the nanomaterials.
The self-sensing ability of functionalized polyurea composites to correctly detect and identify blast damage and crack development as a new class of smart materials may open the door to many new industrial applications.
Reference
Meng, Q. et al. (2022). Smart multifunctional elastomeric nanocomposite materials containing graphene nanoplatelets. Smart materials in manufacturing. Available at: https://Researchers reveal the multifunctionality of polyurea nanocomposites
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