Nanofiber mixed polymer

PAN blends changed with different amount of PANA of the mixed polymers. The morphologies of electrospun nanofibers are presented in Fig. 6.24a-d. According to the SEM images, the diameters of the PANA/PAN nanofibers are dependent on initially added PANA concentrations. The diameter of PANA/PAN fibers was smaller than for pure PAN fibers. The average nanofiber diameter decreased from 113 23 nm for pure PAN fibers to 105 23 nm for PANA/PAN (10 w/v %), 102 20 nm for PANA/PAN (15 w/v %), and 94 16 nm for PANA/PAN (20 w/v %), as shown in Table 6.6. 

Composites of carbon nanofibers and thermoplastic polyurethanes with shape memory properties prepared by chaotic mixing. Polym. Eng. Sd., 49,... 

Techniques to produce multiscale biomaterial scaffolds with designer geometries are the need of the hour to provide improved biomimetic properties for functional tissue replacements. While micrometer fibers generate an open pore stnicture, nanofibers support cell adhesion and facilitate cell-cell interactions. This was further proven by cell penetration studies, which showed superior ingrowth of cells into hierarchical structures. Mixed bimodal scaffolds of two different polymers are another promising approach, because they exhibit hierarchical pore/ surface systems and combine the beneficial properties of both polymers at two different scales. Vaiious 3D micro- and nanoscale multiscale scaffolds have been fabricated through various techniques and were found to have the potential to essentially recreate natural bone, cardiac, neural, and vascular tissues. 

The above polyolefin copolymers have also been used to prepare conventional composites and nanocomposites. However, similar to the case of polymer blends, not too many studies have been reported thus far. Recently, Kelarakis et al. (49) have mixed 10 wt% of surface-modified carbon nanofiber (MCNF) with propylene-ethylene random copolymer (propylene 84.3%). The MCNF acted as a nucleating agent for crystallization of the a-form of PP in the matrix. During deformation at room temperature, strain-induced crystallization took place, while the transformation from the 7-phase to a-phase also occurred for both unfilled and 10 wt% MCNF-filled samples. The tensile strength of the filled material was consistently higher than that of pure copolymer. These results are illustrated in Fig. 8.27. 

HGURE 4.4 Electrical properties of polymer composites. (A) The electrical conductivity of the PS/graphene composite as a function of graphene volume fraction. (B) The electrical conductivity of directly mixing (DM) CNT/PANI and CNT/ PANI nanofibers with different CNT contents in the directions being parallel and perpendicular to the fiber axis. 

To determine the activity of a single drug in different polymer matrices, the prepared polymer solutions are mixed with 1.5 wt% of each drag alone and electrospun into nanofibers. Then 5-mm circular sections of nanofibers are... 

It has been noted that the polymer of meta- and orfho-substituted anilines is essentially identical (Figure 7.49) [176]. However, there are some differences between these two identical polymers, such as conductivity, solubility, and thermal stability [174,176,177,184,185]. With the success of the rapidly mixed reactions for making polyaniKne nanofibers, we are able to reveal the basic morphologies of substituted polyanilines and compare the effect of substituent positions on the polymer morphology. 

Blending is the simplest and easiest method anployed to functionalize a polymer. This is a physical approach with the addition of blending ligand molecules into the polymer solution and then electrospinning the polymer solution. No chemical bonding or attachment is involved between the polymer material and the modified species (Figure 8.3). It is a simple mixing of two or more materials that has been proven to be an effective method for polymer nanofiber modification. Nevertheless, blend molecules are susceptible to detachment and the technique is neither reproducible nor controllable. 

Jimenez, G. and Jana, S.C. (2007) Polymer composites of oxidized carbon nanofibers prepared by chaotic mixing. Onbon, 45, 2079. 

---