Blends microfibrillar

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. 

Covas, J. A., O. S. Cameiro, and J. M. Maia. 2001. Monitoring the evolution of morphology of polymer blends upon manufacturing of microfibrillar reinforced composites. International Journal of Polymeric Materials 50 445-A67. 

What happens during the cold drawing First of all, the character of the 3-D structure arising in the molten blend is completely preserved. The only change which takes place is the conversion of the microfibrillar 3-D network into nanofib-rillar 3-D network (Figure 9.10b). With the progress of cold drawing, the sizes of... 

Evstatiev, M. and Fakirov, S. (1992) Microfibrillar reinforcement of polymer blends. Polymer, 33, 877-880. 

S. (1996) Morphology of microfibrillar reinforced composites from polymer blends. Polymer, 37, 4455-4463. 

A fibrillar polymer-polymer composite consists of an isotropic matrix polymer with fibrils of a second polymer dispersed within it. The idea was developed by Fakirov et al. [40] with the knowledge that drawing of polymers with good molecular orientation enhances their mechanical properties. Depending on the fibril diameters, such composites are referred to as microfibrillar composites (MFCs) or nanofihrillar composites (MFCs). For simplicity, MFCs are discussed because the manufacturing process is essentially the same. One method of creating MFCs is to produce a blend of the two selected polymers in the form of a continuous wire. 

Fakirov, S., Evstatiev, M., and Schultz, J.M. (1993) Microfibrillar reinforced composite fi om drawn polyfethylene terephthalate)/nylon-6 blend. Polymer,... 

Microfibrillar reinforced composites—new materials fi om polymer blends. Adv. Mater., 6, 395—398. 

Lei Y, Wu Q. Wood plastic composites based on microfibrillar blends of high density polyeth-ylene/poly (ethylene terephthalate). Bioresour Technol 2012 101 (10) 3665-3671. 

ABSTRACT. Chemical interactions (additional condensation and transreactions) on the interfaces of condensation polymers (nylons and polyesters) are discussed. In addition to the recently discovered phenomenon of chemical healing, a new type of composites from polymer blends - the microfibrillar reinforced ones are introduced. It is demonstrated that interfacial chemical Interactions result in the formation of a new interphase representing a copolymer of the blended components and playing the role of selfcompatibilizer. 

The described phenomena are of particular importance for incompatible blends of condensation polymers as far as interfaces are available. This is demonstrated on the recently discovered [ ] microfibrillar reinforced composites. 

On the basis of the above considerations, one can conclude that by following the approach described a new type of composites - microfibrillar reinforced ones can be obtained from all thermoplastic polymers. Using blends of condensation polymers, a strong self-compatibillzing effect can be achieved due to Interfaclal chemical interactions. Opportunities are also available for continuous controllable changes of the chemical composition and crystallization ability of the matrix. The formation of an interphase drastically Improves the mechanical integrity of drawn blends. 

Our first paper on MFCs was submitted to Polymer (M. Evstatiev and S. Fakirov, Microfibrillar reinforcement of polymer blends ) on July 12, 1991 and published in May 1992 Polymer, Volume 33, Issue 4, 1992, pages 877-880) [8]. It was based on the results... 

Microfibrillar composites from blends of condensation polymers... 

Special attention was paid to the structure-property relationships of blends involving polyolefins, especially PP and PE, as lower-melting components acting as matrices in MFCs, and PET as the higher-melting component, forming the microfibrillar reinforcing elements [45]. 

Sarkissova M, Harrats C, Groeninckx G and Thomas S (2004) Design and characterisation of microfibrillar reinforced composite materials based on PET/PA12 blends. Compos Part A 35 489-499. 

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. 

Jayanarayanan K, Thomas S and Joseph K (2008) Morphology, static and dynamic mechanical properties of in situ microfibrillar composites based on polypropylene/poly(ethylene terephthalate) blends. Compos Part A 39 164-175. 

Jayanarayanan K, Bhagawan S S, Thomas S and Joseph K (2008) Morphology development and non isothermal crystallization behaviour of drawn blends and microfibrillar composites from PP and PET, Polym Bull 60 525-532. 

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. 

Denchev Z, Dencheva N, Funari S S and Stribeck N (2010) Nanostructure and mechanical properties studied during dynamical straining of microfibrillar reinforced HDPE/PA blends, J Polym Sci Part B Polym Phys 48 237-250. 

Fakirov S, Evstatiev M, Friedrich K (2000) From polymer blends to microfibrillar reinforced composites, in Polymer Blends. Vol 2 Performance (Eds. Paul D R and Bucknall C B) John Wiley Sons, New York, pp. 455-475. 

Evstatiev M, Fakirov and Friedrich K (2000) Microfibrillar reinforced composite another approach to polymer blends processing, in Structure Development during Polymer Processing (Eds. Cunha A and Fakirov S) Kluwer Academic Pubhshers, Dordrecht, Netherlands, pp. 311-325. 

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