Hot-compacted polymers

Ward I M, Hine P J and Norris K (1992) Polymeric materials, British Patent GB 2253420. Ward I M and Hine P J (2004) The science and technology of hot compaction. Polymer 45 1413-1427. 

Ward IM, Hine PJ (2004) The science technology of hot compaction. Polymer 45 1413-1427 Wei W, Minullina R, Abdullayev E, Fakhrullin R, Mills D, Lvov Y (2014) Enhanced efficiency of antiseptics with sustained release from clay nanotubes. RSC Adv 4 488-494 White HM, Bassett DC (1998) On row structures, secondary nucleation and continuity in a-polypropylene. Polymer 39 3211-3218... 

Special processing forms, such as hot compacted polymers, coextruded multilayer polymers, electrospun nanofibers, and polymer foams... 

Composites with naturai particies or fibers such as wood, bamboo, sisal, jute, wheat straw, banana, or coconut form another group of polymer composites. They are considered with other biopoiymers in Section 8.2 in Part II. The so-called hot-compacted polymers can be considered as special fiber composites. The idea behind this is to make high-strength compositions starting from highly oriented anisotropic fibers or tapes of a singie poiymer, which are connected to woven mats and compacted with the technoiogy of hot compaction (see Section 9.2 in Part II). 

Ward and his coworkers investigated the interlayer adhesion in self-reinforced PP composites modified with different nano- and micron-sized particles [27-29]. They found that the introduction of a small amount of carbon nanofibers (CNFs) led to improved performance of polypropylene single-polymer composites obtained by hot compaction of oriented CNF/ PP tapes. The peel strength of a CNF/PP woven fabric composite was significantly increased. In addition, the authors pointed out that the drawn CNF/PP tapes showed substantial voiding around the fibers which were closed and sealed by the hot compaction process. As a result, the composite density increased to its initial value [27]. 

The micro- and nanofibrils isolated in a neat form after selective dissolution of the second blend component, even after preparation of fabrics or knitted articles from the blend yarn, can be used as a starting material for preparation of nanostructured single polymer composites. A PET nanofibrillar SPC prepared via hot compaction using one constituent shows a modulus competitive with that of the glass fiber/PE (40/60 by wt) composites. 

In this case study, the results of attempts to prepare nanofibrillar composite materials starting from nanofibrils are presented. This approach is based on (i) the concept of polymer/polymer NFCs produced by in situ formation using polymer blends, which have recently been manufactured by Fakirov et al. [33], (ii) on the opportunity to isolate aligned neat nanofibrils through selective dissolving of the second blend component, and (iii) subsequent consolidation via hot-compaction. 

Figure 19.8. SEM micrographs of (a) PET nanoflbrils prepared from PP/PET =80/20 (by wt) textile filaments via selective extraction of PP, (b) cryofracture of PET nanofibriUar single polymer composite prepared via hot-compaction of one constituent construct, (c) the surface of the hot-compacted composite (sample of (b)), and (d) the buUc of the hot-compacted composite, (sample of (b)), at higher magnification [71]...

PET nanoflbriUar SPCs (PET-NSPC) prepared by the one-constituent approach, PET single-poljnner nanoflbrillar composites (PET-NFC) prepared by the two-constituent approach [32], (aU averaged from five specimens), and PET single-polymer composite prepared by hot-compaction (PET-SPC) [63]... 

Hine P J, Ward I M, Abo El Maaty M I, Olley R H and Bassett D C (2000) The hot compaction of 2-dimensional woven melt spun high modulus polyethylene fibres, J Mater Sci 35 5091-5099. Jordan N D, Olley R H, Bassett D C, Hine P J and Ward IM (2002) The development of morphology during hot compaction of Tensylon high-modulus polyethylene tapes and woven cloths, Polymer 43 3397-3404. 

Rein D M, Vaykhansky L, Khalfin R L and Cohen Y (2002) Controlling the properties of singlepolymer composites by surface melting of the reinforcing fibers, Polym Adv Technol 13 1046-1054. Hine P J, Ey R H and Ward I M (2008) The use of interleaved films for optimising the production and properties of hot compacted, self reinforced polymer composites, Compos Sci Technol 68 1413-1421. 

Hine P J and Ward I M (2004) Hot compaction of woven poly(ethylene terephthalate) multifilaments, J Appl Polym Sci 91 2223-2233. 

Jenkins M J, Hine P J, Hay J N and Ward IM (2006) Mechanical and acoustic frequency responses in flat hot-compacted polyethylene and polypropylene panels, J Appl Polym Sci 99 2789-2796. 

Athough this subsection does not really fit with the title of this book chapter, it has been inserted for the sake of completeness of the SPC topic. SPC microcomposites were produced by hot compaction (oniwconstituent approach) while nanocomposites by film stacking (two-constituents) using the same polymer, namely, poly (methyl methacrylate) (PMMA). It has to be mentioned that amorphous/amorphous (reinforcement/matrix) SPCs are studied less than those containing a reinforcing phase of semicrystalline nature. This is due to a small difference in the stiffness and strength between the polymers that overtake the role of the matrix and reinforcement, respectively. 

Mine P J and Ward I M (2005) High stiffness and high impact strength polymer composites by hot compaction of oriented fibers and tapes, in Mechanical Properties of Polymers Based on Nanostructure and Morphology (Eds. Michler G H and Baltd-Calleja F J) CRC, Boca Raton, FL, pp. 683-727. 

Jebawi K, Sixou B, Seguela R, Vigier G and Chervin C (2006) Hot compaction of polyoxymeth-ylene. Part 1 Processing and mechanical evaluation. J Appl Polym Sci 102 1274-1284. 

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