This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

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Cellulose nanomaterials review: structure, properties and nanocomposites

Unperturbed dimensions of stereoregular polymers.- Reinforcement of rubber by carbon black.- Transformations of phenolic antioxidants and the role of their products in the long-term properties of polyolefins.

Properties of polymers

A review on dynamic mechanical properties of natural fibre reinforced polymer composites

Mechanical metamaterials associated with stiffness, rigidity and compressibility: a brief review

High-porosity aerogels of high specific surface area prepared from nanofibrillated cellulose (NFC)

Deformation mechanisms and energy absorption of polystyrene foams for protective helmets

This paper investigates complex composite cellular structures featuring a chiral topology with the ability to undergo large overall displacements with limited straining of its components. Numerical analyses are performed to exploit such properties in the design of a morphing airfoil. The advantages associated with the use of composites are investigated by comparing the numerical results with those obtained with a metallic structure. A manufacturing process is then developed to assemble the considered structural configurations using composite materials. The novel process developed is described as applied to the manufacturing of macro chiral components that are tested to evaluate their ability to undergo large deformations. Finally, detailed numerical models of the manufactured structures are presented as a possible approach to evaluate the strength of the proposed configuration.

Composite chiral structures for morphing airfoils: Numerical analyses and development of a manufacturing process

A simple technique for the production of continuous fiber reinforced thermoplastic by fused deposition modeling, which involves a common 3D printer with quite limited modifications, is presented. An adequate setting of processing parameters and deposition path allows to obtain components with well-enhanced mechanical characteristics compared to conventional 3D printed items. The most relevant problems related to the simultaneous feeding of fibers and polymer are discussed. The properties of obtained aramid fiber reinforced polylactic acid (PLA) in terms of impregnation quality and of mechanical response are measured.

Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic

The development of polymers that can repair damage autonomously would be useful to improve the lifetime of polymeric materials. To date, limited attention has been dedicated to developing elastomers with autonomic self-healing ability, which can recover damages without need for an external or internal source of healing agents. This work investigates the self-healing behavior of epoxidized natural rubber (ENR) with two different epoxidation levels (25 and 50 mol % epoxidation) and of the corresponding unfunctionalized rubber, cis-1,4-polyisoprene (PISP). A self-adhesion assisted self-healing behavior was revealed by T-peel tests on slightly vulcanized rubbers. A higher epoxidation level was found to enhance self-healing. Self-healing of rubbers following ballistic damages was also investigated. A pressurized air flow test setup was used to evaluate the self-healing of ballistic damages in rubbers. Microscope (OM, SEM, and TEM) analyses were carried out to provide further evidence of healing in the impact z...

Autonomic Self-Healing in Epoxidized Natural Rubber

The use of natural fiber reinforcements for the production of ecofriendly composites has arisen considerable interest both in thermoplastic and thermoset based materials. In the latter case, the matrix is often an epoxy based polymer, which allows remarkable performance, but that cannot be considered eco-friendly since it is non-biodegradable and is produced from non-renewable sources. This strongly impairs the environmental friendly character of the resulting composite material. The aim of this work was to study the characteristics and performance of a thermoset bioepoxy resin, which is partly based on natural components, to be used in hemp reinforced laminates. The permeability of the hemp fabric as well as the rheological and thermal behavior of the resin were studied in view of their fabrication by resin infusion techniques. The results showed that laminated composites could be easily obtained with a vacuum assisted resin transfer molding process. Static, dynamic and vibration-damping tests were performed to evaluate limits and potentials of such biocomposites.

Luca Di Landro

Papers

Deformation mechanisms and energy absorption of polystyrene foams for protective helmets

Composite chiral structures for morphing airfoils: Numerical analyses and development of a manufacturing process

Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic

Autonomic Self-Healing in Epoxidized Natural Rubber

Composites with hemp reinforcement and bio-based epoxy matrix