Short fiber-reinforced plastic composites

Nishikawa M, Okabe T and Takeda N (2009) Effect of the microstructure on the fracture mode of short-fiber reinforced plastic composites, J Solid Mech Mater Eng 3 998-1009. 

The main stream of wood fiber PP composites is short fiber reinforced, suitable for typical thermoplastic processing. The main steps of this technology are (1) pre-mixing, (2) plastic transformation of the melt (typically sheet extrusion), and (3) thermoforming (vacuum- or pressureforming) of the sheet. 

Sims et al. [197] have pointed out that a redraft of ISO 527 tensile testing for plastics has resulted in two complementary parts for composites Part 4 based on ISO 3268 [199] covers isotropic and orthotropic materials, and Part 5 covers unidirectional materials. There is a need to harmonize these two methods into a new Part 5. Inputs were included from ISO, ASTM, CRAG, and EN aerospace methods. The remaining three parts are Part 1—general principles. Part 2—plastics and molding materials (including short fiber-reinforced materials), and Part 3—films. ISO DIS 527-5 has in parallel been voted as a CEN standard (EN 527-5) and should, with Part 4, replace EN61 [212] and possibly two aerospace EN standards [34,42,132,160,163-165,199-213]. 

Santrach, D. (1982) Industrial Application and Properties of Short Glass Fiber-Reinforced Plastics, Polymer Composites, 3(4), 239-43. 

In Table 4.12, the composite structure is stated for processing and testing of eight different glass fiber reinforced plastic laminates (EP, UP, VE). Their dynamic properties are listed in Table 4.13 [148]. With fiber contents (p ranging from 0.22 to 0.66%, tensile-fracture stresses (short-term) between 80 and 750 N/mm are achieved at fracture strains of 0.88 and 3.47%. 

Creep tendency in glass and carbon fibers is very low, in aramid fibers it is higher. In combination with organic matrices or adhesives, their viscoelastic behavior determines creep tendency in the composite. In comparative relaxation tests up to 1000 h at approx. 50% short-term strength, carbon fiber reinforced plastics indicated virtually no creep, glass fiber reinforced plastics exhibited low creep (approximately twice as much as pre-tensioned steel, while aramid fiber reinforced plastics showed four to five times as much creep [1011]. 

Reinforcing fibers for plastics are used in several ways. They can be wrapped around polymer tubes, laminated between polymer surfaces, laminated to the surface, woven into complex shapes containing polymer as an adhesive matrix, extruded as long or short fibers into polymer composites, and blended with polymers to make carpets with fiber reinforced backings. This discussion is limited to mostly short... 

S. Mohanty, and S. K. Nayak, Short Bamboo Fiber-reinforced HDPE Composites Influence of Fiber Content and Modification on Strength of the Composite. /. of Reinforced Plastics and Composites 29 (14), 2199-210 (2010). 

Extensive reviews on short fibers-reinforced elastomers have been published by Goettler and Shen, ° and more recently by Rajeev. Table 7.11 is a list of selected published works on natural fiber-filled rubber composites, sorted by rubber type. Only vulcanizable rubbers were considered in preparing the table thermoplastic rubber and rubber-plastics blends were omitted. As can be seen most grades of conventional elastomers have been considered with quite a large variety of natural fibers. Natural Rubber, SBR, and EPDM compounds have received much attention, as expected with respect to their industrial importance. A bonding system is us in most cases, with resin types (i.e. resorcinol-formaldehyde, resorcinol-hexamethylenetetramine, sil-ica-resorcinol-hexamethylenetetramine) the most frequent ones. 

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