Microfibrillar preparation

AMINO ACID COMPOSITION (EXPRESSED AS RESIDUES PER 1000 TOTAL RESIDUES) OF TYPICAL MATURE ELASTIN, MATRIX COLLAGEN AND MICROFIBRILLAR PROTEIN PREPARATIONS. 

A new type of composite material starting from polymer blends has been developed. Due to the fact that the reinforcing elements are the basic morphological entities of oriented polymers, the microfibrils, these new composites have been named microfibrillar-reinforced composites (MFC) (Evstatiev Fakirov, 1992). MFC, however, clearly differ from traditional composite systems. Since the microfibrils are not available as a separate component, the classical approach to composite preparation is inappropriate for MFC mannfactnring. 

Lyoo, W. S., Ha, W. S., Preparation of Syndiotacticity rich High Molecular Weight Polyfvinyl alcohol) Microfibrillar Fiber by Photoinitiated Bulk Polymerization and Saponification, J. Polym. Sci., Part A Polym. Chem. 1997, 35, 55 67. 

Figure 9.4 SEM micrographs of (a) PET microfibrils coated with collagen (microfibrillar biohybrid matrices) and (b) scaffolds from PET nanofibrillar knitted fabrics prepared...

Kimble, L.D., Fakirov, S, and Bhattacharyya, D. (2014) Poly(L-lactic acid)/poly(glycolic acid) microfibrillar polymer-polymer composites preparation and viscoelastic properties. 30th International Conference of the Polymer Processing Society, Cleveland, OH, 8-12 June, 2014,... 

Li W J, Schlarb A K and Evstatiev M (2009) Study of PET/PP/TiOj Microfibrillar-structured composites. Part 1 Preparation, morphology, and dynamic mechanical analysis of fibriUized blends, J Appl Polym Sci 113 1471-1479. 

Dencheva N, Oliveira M J, Carneiro O S, Pouzada A S and Denchev Z (2010) Preparation, structural development, and mechanical properties of microfibrillar composite materials based on polyethylene/polyamide 6 oriented blends, J Appl Polym Sci 115 2918-2939. 

From this view, the authors have used a new approach called melt extrusion-hot stretching-quenching to prepare two categories of CPC (isotropic and anisotropic CPC) based on in situ microfibril reinforced polymer-polymer composites. This chapter briefly describes our recent work on several conductive in situ microfibrillar reinforced composites via hot stretching. 

Figure 13.1. The preparation procedures of the electrically conductive in situ microfibrillar composites...

Preparation, Mechanical Properties and Structural Characterization of Microfibrillar Composites Based on Polyethylene/Polyamide Blends... 

In this work, the studies focused on the effect of draw ratio employed during cold drawing on the morphology development of the PP/PET microfibrillar blends and composites prepared at a fixed blend composition of 85/15. The tensile properties of MFCs prepared at different hot stretch ratios were reported recently [17,18]. However, the effect... 

Scheme 15.1. Scheme of the experimental setup for microfibrillar blends and composites preparation... 

Figure 17.20. SEM micrographs of microfibrillar and/or nanoporous scaffolds of (a) PHB filament spun on commercial equipment as PVA/PHB blend (80/20 by wt) and washed with water for removal of PVA, (b) PHB spun as PVA/PHB (90/10 by wt) blend and washed with water for removal of PVA, (c) PCL prepared in a similar way, and (d) PGA extruded as PP/PGA (80/20 by wt) blend and extracted with boiling xylene for removal of PP...

Figures 14.2, 14.13-14.15, 14.20-14.23, 14.26-14.29 and Tables 14.6, 14.8 and 14.10 are from Journal of Applied Polymer Science, Vol. 115, 2010, Authors Dencheva N, Oliveira M J Carneiro O S, Pouzada A S and Denchev Z, Title Preparation, structural development, and mechanical properties of microfibrillar composite materials based on PE/PA6 oriented blends, pp. 2918-2932, Copyright (2009), with permission from Wiley Periodicals, Inc.

In addition, we have recently described a procedure for controlling the morphologies of electronically conductive polymers (32). This procedure involves the electrochemical growth of the conductive polymer at an electrode surface which has been masked with a microporous polymer membrane. The pores in this membrane act as templates for the nascent electronically conductive polymer. Because the template membrane contains linear cylindrical pores, cylindrical conductive polymer fibrils are obtained (32). We will show in this manuscript that microfibrillar polypyrrole films prepared via this approach can support higher rates of charge-transport than conventional polypyrrole. 

---