Fiber composite, thermoplastic

Lyocell tibers have been explored in blends. Chang et al. [141] prepared Lyocell based blends. Poly(vinyl alcohol) (PVA), poly(vinyl alcohol-co-ethylene) (EVOH), and poly(acrylic acid-co-maleic acid) (PAM) were used as fillers in blends with lyocell produced through solution blending. The results showed that blends with PVA exhibit the best tensile properties. Thus, Lyocell fibers have recently been used as reinforcement for thermoplastic fiber composites. 

More recent developments that will soon see series production in the automotive industry will facilitate low-cost placement of local structural component reinforcement with C fiber bundles combined with process engineering using a thermoplastic matrix (PP, PA, PET, PQ in 30-second cycles (see also under processing of thermoplastic fiber composites in the LFT-D process). 

Considerable work has been done on the sisal fiber-reinforced epoxy composites. It is reported that the fractured cross sections of the sisal-epoxy composites, showed no epoxy resin in the fiber lumen. The total lumen area in the fiber cross-section was fotmd to be 15% and the total void content was about 17%. In sisal, total leaf mass contains only 2-4% sisal fibers other cells take care of the water distribution. Oksman et al. [9] studied the thermoplastic fiber composites and showed that lumen was filled with the polymer matrix. Fibers therefore have distribution channels between the single wood cells. It is possible that the absence of such channels in sisal, due to the different function of sisal fibers, is the reason for lack of polymer in the lumen. At several locations in the sisal fiber, a gap between the fiber and matrix can be observed. The gaps indicate weak fiber-matrix adhesion [9, 58, 59]. 

Kodokian G K A and Kinloch A J (1988) Surface pretreatment and adhesion of thermoplastic fiber-composites, J Mater Sci Lett 7 625-627. 

Self-reinforced thermoplastic fiber composite materials... 

Fig. 5. Interlaminar fracture toughness, for a number of thermosetting and thermoplastic composites (36,37). Open white bars represent glass-fiber composites shaded bars are for carbon fibers. The materials are A, polyester (unidirectional) B, vinyl ester (CSM = chopped strand mat) C, epoxy (R/BR1424) D, epoxy (T300/914) E, PPS F, PES and G, PEEK. To convert J/m to fdbf/in. multiply by 2100.

A number of amorphous thermoplastics are presently employed as matrices in long fiber composites, including polyethersulfone (PES), polysulfone (PSU), and polyetherimide (PEI). AH offer superior resistance to impact loading and higher interlaminar fracture toughnesses than do most epoxies. However, the amorphous nature of such polymers results in a lower solvent resistance, clearly a limitation if composites based on such polymers are to be used in aggressive environments. 

The lower thermal stability of natural fibers, up to 230°C, the thermal stability is only small, which limits the number of thermoplastics to be considered as matrix materials for natural fiber composites. Only those thermoplastics whose processing temperature does not exceed 230°C are usable for natural fiber reinforced composites. These are, most of all, polyolefines, such as polyethylene and polypropylene. Technical thermoplastics, such as poyamides, polyesters, and polycarbonates, require... 

Nando, G.B. and Gupta, B.R., Short fibre-thermoplastic elastomer composites, in Short Fiber—Polymer Composites, De, S.K. and White, J.R. (Eds.), Woodhead Publishing, Cambridge, 1996, Chapter 4. 

Table 15.2 Selected properties of 30% glass-fiber-reinforced (GFR) thermoplastic polyester composites [15-17]...

A technique for the characterization of polymer crystallinity as a bulk material or around the stiff fibers/particulates in composites is based on WAXS. The WAXS method is actually more of a bulk analytical tool than a surface technique, but it has been developed mainly for monitoring crystallinity in thermoplastics and fiber composites made therefrom. 

Ogata, N., Yasumoto, H., Yamasaki, K., Yu. H., Ogihara, T., Yanagawa, T., Yoshida, K. and Yamada, Y. (1992). Evaluation of interfacial properties between carbon fibers and semi-crystalline thermoplastic matrices in single fiber composites. J. Mater. Sci. 27, 5108-5112. 

Friedrich K. (1985). Microstructural efficiency and fracture toughness of short fiber/thermoplastic matrix composites. Composites Sci. Technol. 22, 43-74. 

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