5. In Situ Polymerization 3907 5.1. General Polymerization 3907 5.2. Photopolymerization 3910 5.3. Surface-Initiated Polymerization 3912 5.4. Other Methods 3913 6. Colloidal Nanocomposites 3913 6.1. Sol-Gel Process 3914 6.2. In Situ Polymerization 3916 6.2.1. Emulsion Polymerization 3917 6.2.2. Emulsifier-Free Emulsion Polymerization 3919 6.2.3. Miniemulsion Polymerization 3920 6.2.4. Dispersion Polymerization 3921 6.2.5. Other Polymerization Methods 3923 6.2.6. Conducting Nanocomposites 3924 6.3. Self Assembly 3926 7. Other Preparative Methods 3926 8. Characterization and Properties 3928 8.1. Chemical Structure 3928 8.2. Microstructure and Morphology 3929 8.3. Mechanical Properties 3933 8.3.1. Tensile, Impact, and Flexural Properties 3933 8.3.2. Hardness 3936 8.3.3. Fracture Toughness 3937 8.3.4. Friction and Wear Properties 3937 8.4. Thermal Properties 3938 8.5. Flame-Retardant Properties 3941 8.6. Optical Properties 3942 8.7. Gas Transport Properties 3943 8.8. Rheological Properties 3945 8.9. Electrical Properties 3945 8.10. Other Characterization Techniques 3946 9. Applications 3947 9.1. Coatings 3947 9.2. Proton Exchange Membranes 3948 9.3. Pervaporation Membranes 3948 9.4. Encapsulation of Organic Light-Emitting Devices 3948

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

Natural fibers today are a popular choice for applications in composite manufacturing. Based on the sustainability benefits, biofibers such as plant fibers are replacing synthetic fibers in composites. These fibers are used to manufacture several biocomposites. The chemical composition and properties of each of the fibers changes, which demands the detailed comparison of these fibers. The reinforcement potential of natural fibers and their properties have been described in numerous papers. Today, high performance biocomposites are produced from several years of research. Plant fibers, particularly bast and leaf, find applications in automotive industries. While most of the other fibers are explored in lab scales they have not yet found large-scale commercial applications. It is necessary to also consider other fibers such as ones made from seed (coir) and animals (chicken feather) as they are secondary or made from waste products. Few plant fibers such as bast fibers are often reviewed briefly but other p...

A Review of Natural Fibers Used in Biocomposites: Plant, Animal and Regenerated Cellulose Fibers

A review on new bio-based constituents for natural fiber-polymer composites

Manipulation and navigation of micro and nanoswimmers in different fluid environments can be achieved by chemicals, external fields, or even motile cells Many researchers have selected magnetic fields as the active external actuation source based on the advantageous features of this actuation strategy such as remote and spatiotemporal control, fuel-free, high degree of reconfigurability, programmability, recyclability, and versatility This review introduces fundamental concepts and advantages of magnetic micro/nanorobots (termed here as "MagRobots") as well as basic knowledge of magnetic fields and magnetic materials, setups for magnetic manipulation, magnetic field configurations, and symmetry-breaking strategies for effective movement These concepts are discussed to describe the interactions between micro/nanorobots and magnetic fields Actuation mechanisms of flagella-inspired MagRobots (ie, corkscrew-like motion and traveling-wave locomotion/ciliary stroke motion) and surface walkers (ie, surface-assisted motion), applications of magnetic fields in other propulsion approaches, and magnetic stimulation of micro/nanorobots beyond motion are provided followed by fabrication techniques for (quasi-)spherical, helical, flexible, wire-like, and biohybrid MagRobots Applications of MagRobots in targeted drug/gene delivery, cell manipulation, minimally invasive surgery, biopsy, biofilm disruption/eradication, imaging-guided delivery/therapy/surgery, pollution removal for environmental remediation, and (bio)sensing are also reviewed Finally, current challenges and future perspectives for the development of magnetically powered miniaturized motors are discussed

Magnetically Driven Micro and Nanorobots

Cracks, microcracks and fracture in polymer structures: Formation, detection, autonomic repair

/pdf/indirect-3d-and-4d-printing-of-soft-robotic-microstructures-3ylp3y1nst.pdf

Indirect 3D and 4D Printing of Soft Robotic Microstructures

Isotropic polypropylene-based composites, containing up to 60 wt.% of well dispersed wool fibres, were successfully prepared by melt blending in an internal batch mixer. The addition of a maleinized polypropylene compatibilizer was investigated in order to improve fibre/matrix adhesion. Morphology, thermal and mechanical properties of the ensuing composites were investigated focusing the attention on fibre length and their distribution as well as on fibre/matrix interaction. Data from mechanical analysis were compared with theoretical models and with the mechanical characteristics of a composite made of polypropylene with uncut aligned wool fibres.

Composites based on polypropylene and short wool fibres

Polypropylene (PP)-based composites containing 20 wt.% wool fibres were successfully prepared using a simple melt blending procedure. A blend of a commercial-grade PP and a maleinised PP was chosen as the matrix. To investigate the effects of modifying the fibre surface on the fibre/matrix adhesion, wool fibres were used as received, oxidised, or functionalised with a silane-based coupling agent, capable in principle of reacting with both the fibres and the polyolefinic matrix. The silanisation of the fibres and the consequent surface modifications were assessed using infrared spectroscopy and scanning electron microscopy. The resulting PP-based composites were thoroughly characterised in terms of their morphology, thermal stability and mechanical behaviour.

/pdf/wool-fibres-functionalised-with-a-silane-based-coupling-2quyhg9wjm.pdf

Wool fibres functionalised with a silane-based coupling agent for reinforced polypropylene composites

The experimental investigation herein described is aimed at understanding the effects of cellulose-based fibers on the mechanical properties of bituminous mastics for paving applications. Three bitumen (two of which modified with SBS polymers), a calcareous filler and four different types of fiber with varying content were used to prepare the investigated mastics. The filler to bitumen ratio was maintained constant. The laboratory investigations were focused on empirical tests (Needle Penetration and Ring and Ball – R&B – Temperature) and dynamic-mechanical tests, the latter performed in a wide range of temperatures. Results suggest that fibers improve the behavior of mastics for hot mix asphalts, particularly with respect to the prevention of rutting phenomena at high service temperatures.

/pdf/the-effects-of-fibers-on-the-performance-of-bituminous-171cf40qen.pdf

Claudia Marano

Papers

Indirect 3D and 4D Printing of Soft Robotic Microstructures

Composites based on polypropylene and short wool fibres

Wool fibres functionalised with a silane-based coupling agent for reinforced polypropylene composites

The effects of fibers on the performance of bituminous mastics for road pavements

The essential work of fracture in relation to J-integral