Hybrid composites collagen

In this chapter, we discussed possible methods for the formation of electrically conducting biocomposites using proteinaceous sohd biomasses arising from leather industries as wastes. The proteinaceous collagen wastes were blended with natural polymers (chitosan or GG) and different fillers such as GrC and nanotubes (ie, BCNTs and FWCNTs) to form hybrid-conducting biocomposite films. The formed biocomposife films were found fo exhibit promising mechanical, thermal, and electrical properties. The thermal properties of both of the hybrid composite materials increase moderately with the increase in the addition of nanocarbons. The mechanical... 

Figure 33.8 Typical composition of cartilage Stiff chains of collagens (CG), soft chains of hyaluronan (HA), and a smaller molecular group composed of protein and glycosaminoglucans (Agrican AG) form a hybrid mesh structure. See Ref. [29].

Collagen/chitosan composite hydrogels as comeal implants stabilized by EDC and NHS or a hybrid of poly (ethylene glycol) dibuty-raldehyde (PEG-DBA)/ EDC/NHS... 

Performance improvement of polysulfone ultrafiltration membrane has been achieved by blending with PANI-NFs [457]. Conducting blends of nanostruetured PANI and PANI-clay nanocomposites with ethylene vinyl acetate as host matrix have been prepared [458]. A new conducting hybrid biocompatible composite material of PANI-NFs well dispersed in a collagen matrix was fabricated with various PANI-NFs/eoUagen ratios [459]. PANI-NFs doped by protonic acids can be efficiently dispersed in vinylidene fluoride-trifluoroethylene copolymers [460]. Fabrication of MWCNTs/PANI-NF nanocomposites via electrostatic adsorption in aqueous colloids has been reported [143]. A PANI-NFs/ carbon paste electrode was prepared via dopping PANI-NFs into the carbon paste [461]. 

Collagen-chi tosan composite stabilized by either a simple carbodiimide crosslinker or a hybrid cross-linking system... 

In addition, the thermal stability of the developed nanobiocomposite films was found to increase steadily with an increase in the weight percentage of BCNTs and FWCNTs, which can be attributed to the incorporation of XCNTs, which have superior temperature stability. The surface morphology of the collagen-GG hybrid nanobiocomposite film shows a fairly uniform and smooth surface. However, the addition of XCNTs in the composite films interrupts the formation of the smooth surface because XCNTs are neither soluble nor completely dispersible in biopolymeric aqueous solutions. ... 

The thermal stability of the nanobiocomposites also increases as the proportion of GrC increases. This increase in thermal stability is also primarily due to the incorporation of GrC in biocomposite films. Scanning electron microscopic images of the broken biocomposite samples after tensile testing are shown in Fig. 3.5. The presence of GrC is seen on the fracture surfaces of the hybrid films, which are covered with several layers of biopolymers. It is evident that the collagen-chitosan/GrC composite films break typically at the place where the content of GrC is high. 

This leads to the formation of an artificial structure consisting of resin-impregnated collagen fibers, and which has been called the hybrid layer (Nakabayashi et al. 1982). The hybrid layer is strong, and is also sufficiently hydrophobic to allow the polymer phase of composite resins to bond to it. Its depth varies with length of the infiltration step, and has been reported to lie between 2.1 and 4.1 pm (Nakabayashi and Saimi 1996). 

---