Mats, strand

Fig. 10.1 SEM images of various appearances of the supramolecular structure of barnacle adhesive (a) thin sheet of densely arranged nanometer-sized adhesive globules on aluminum foil (b) sponge-like appearance of adhesive with the tendency to form strands on a self-polishing coating (c) web-like adhesive of loosely matted strands on a PDMS coating.

The general term for a reinforced plastic (by using cloth-mat-stranded fibres). 

A general term for a plastic that is reinforced with cloth, mats, strands, or any other fiber form. 

Another product is made with strands produced by flakers, having dimensions of about 0.8 x 13 x 300 mm (0.030 x 0.5 x 12 in.). The strands are dried and then coated with isocyanate adhesives. The strands are formed into mats with unidirectional orientation and pressed in a steam-through press. The large panels are then sawn into dimension lumber sizes. 

The second main ingredient ia reiaforced plastic is the reinforcement, eg, fibers of glass, carboa, boroa, mineral, cellulose, or polymers. Reinforcements can be configured ia many ways, such as coatiauous or chopped strands, milled fibers, rovings, tows, mats, braids, and woven fabrics. 

AH forms and compositions of reinforcements, ie, mats, woven roving, glass, carbon, and aramid, are commonly used with these processes. Special continuous glass strand mats with a thermoplastic binder aHow preforms to be made using thermoforming techniques. These processes are used for tmck and autobody components, medical equipment cabinets, transportation seating, and other parts needed in the intermediate volume range (1,000—10,000 parts/yr). 

Polypropylene sheet has been used most extensively however, thermoplastic polyester, polycarbonate, and nylon versions are available (see Elastomers, synthetic Polycarbonates). Continuous strand glass fiber mat is the typical reinforcement. The limited number of sheet suppHers reduces potential for competitive pricing. 

Fibrous Composites. These composites consist of fibers in a matrix. The fibers may be short or discontinuous and randomly arranged continuous filaments arranged parallel to each other in the form of woven rovings (coUections of bundles of continuous filaments) or braided (8). In the case of chopped strand mat the random arrangement is planar. In whisker (needle-shaped crystals or filaments of carbon and ceramics) reinforced materials the arrangement is usually three-dimensional and the resulting composites are macroscopically homogeneous. 

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.

Slime is a network of secreted strands (extracellular polymers) intermixed with bacteria, water, gases, and extraneous matter. Slime layers occlude surfaces—the biological mat tends to form on and stick to surfaces. Surface shielding is further accelerated by the gathering of dirt, silt, sand, and other materials into the layer. Slime layers produce a stagnant zone next to surfaces that retards convective oxygen transport and increases diffusion distances. These properties naturally promote oxygen concentration cell formation. 

This is a material produced from the impregnation of glass fibre-mat (fibreglass, which is in the form of dry sheet, is commonly known as chopped stranded mat (CSM)) or rovings, with a liquid and unsaturated polyester resin, which thickens chemically to a dry sheet form. The total mix is sandwiched between polyethylene films and then roller-pressed to impregnate and consolidate it. 

Chopped strand mat. This consists of chopped strands (bundles of glass filaments) about 2 in long bound togther by a resinous binder. This type of mat is used extensively in glass-reinforeed polyester struetures. 

Needle mat. This is similar to chopped strand mat except that the mat is held together by a loose stitching rather than a binder. 

A number of different binder materials are in use for chopped strand mat and include starch, polyvinyl acetate and polyesters. The binder used depends on the end use of the laminate and the method of fabrication. 

Furane resin-chopped strand mat laminates have tensile strengths in excess of 200001bf/in (140 MPa), a heat distortion temperature of about 218°C and good fire resistance. 

In order to get the best out of fibre reinforcement it is not uncommon to try to control within close limits the fibre content which will provide maximum stiffness for a fixed weight of matrix and fibres. In flexure it has been found that optimum stiffness is achieved when the volume fraction is 0.2 for chopped strand mat (CSM) and 0.37 for continuous fibre reinforcement. 

A very wide sheet of grp which is known to contain intrinsic defects 1 mm long, is subjected to a fluctuating stress which varies from 0 to 80 MN/m. How many cycles would the sheet be expected to withstand if it is made from (a) chopped strand mat (CSM) and (b) woven roving (WR) reinforcement. The crack growth parameters C and n, and the critical stress intensity factors, Kc, for these materials are... 

A sheet of chopped strand mat-reinforced polyester is 5 mm thick and 10 mm wide. If its modulus is 8 GN/m calculate its flexural stiffness when subjected to a point load of 200 N midway along a simply supported span of 300 mm. Compare this with the stiffness of a composite beam made up of two 2.5 mm thick layers of this reinforced material separated by a 10 mm thick core of foamed plastic with a modulus of 40 MN/m. ... 

Fabric, Cloth or Mat Woven strands of filament. The weave pattern used depends on the flexibility and balance of strength properties required in the warp and fill directions. Fig. 4.65 shows a plain weave in which the strength is uniform in both directions. The warp direction refers to the direction parallel to... 

Chopped Strand Mat This consists of strands of long chopped fibres deposited randomly in the form of a mat. The strands are held together by a resinous binder. 

This process is carried out at low pressure and at ambient temperature. The fiber is placed in the tool in the form of a mat and the resin is poured in. The mold is closed, and the resin spreads through the reinforcement thereby impregnating and fully wetting out the fiber strands. The process is done on an hydraulic press. Pressure levels required for molding are typically around 10 MPa. Gel coat can be applied to the mold faces before the molding operation commences. 

Chondroitin 6-sulfate, 4 706 Chondroitin sulfates, 20 456 Chopped strand mat (CSM), 26 751 Chopper pumps, 21 78 Chop-stx number, for boron hydrides, 4 183 Chorinated trisodium phosphate, 4 52 Christmas tree module design, 15 835 Chromacity diagrams, 7 313-315 Chromaphores, 19 379 Chromate coatings, 9 827 Chromate conversion coatings, 16 218 Chromated copper arsenate, 3 276 ... 

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