Needled mat

Fukuta [8,9], in Japan, has developed a similar type of process using fluid jets to create fiber entanglement in place of needles. 

Milled carbon fibers are typically 30-3000 pm long, averaging about 300 pm with a mean LjD ratio of 30. 

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

There are several ways in that GMT materials can be manufactured, with various forms of reinforcement providing different properties (Table 4.8 and Figure 4.4). Continuous strand mats impregnated with a TP melt have only limited flow capabilities and cannot be used for deep-draw moldings, products with variations in wall thickness, or with ribs or bosses. Better flow properties are obtained when the sheet is reinforced with needled mats, which are usually produced as part of the main production process. 

Notes Melt temperature 180-22OC (endless mat) 190-22CW (other types). Mold temperature 20-70°C (endless mat) 40-90 C (other types). Molding pressure 50-150 bar (endless mat), 50-200 bar (20% needled mat),... 

The reinforcement used is generally a combination of uni directional roving and random mat (continuous filament mat). This combination provides a reasonably optimised set of properties in the longitudinal and the transverse directions respectively. Other reinforcement types may be used, including woven roving, chopped strand mat (nonsoluble binder), needled mat and multi-axial non-woven. 

These factors dictate the type of reinforcement which can be used. Continuous filament mat and needle mat (both glass fibre) are most common, but woven roving and multi-axial (glass, carbon, etc.) can also be used. 

Strands from forming packages chopped and collected in a random pattern with additional binder applied and cured some needled mat produced with no extra binder required. 

Matrax, Thermoplastic olefinic elastomers, M.A. Industries Inc., Polymer Div. Matrimid, High-temperature matrix resins, Ciba Specialty Chemicals, Performance Polymers MatVantage SMC, Needled mat for SMC, PPG Industries, Inc., Fiber Glass Maxi-Clean, Granulated melamine mold cleaning media, Maxi-Blast, Inc. 

Thermoplastic resins are generally reinforced with short fibres (for use with injection moulding and not considered in this book), with long fibres (thermoplastic sheet compound, Chapter 5) or with glass mat (i.e. glass mat thermoplastics or GMT). Polypropylene is the resin most used as the matrix for GMT and the reinforcement is usually a random mat, primarily chopped strand but it may be continuous filament or needled mat. 

Figure 12.1 Barcol hardness histogram. The dotted column is for a cast resin the others are for a needle mat fabric / phenolic resin (Mayer).

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. 

The general reaction procedure and apparatus used are exactly as described in Procedure 2. Ammonia (465 ml) is distilled into a 2-liter reaction flask and to this is added 165mlofisopropylalcoholandasolutionof30g(0.195 mole) of 17/ -estradiol 3-methyl ether (mp 118.5-120°) in 180 ml of tetrahydrofuran. The steroid is only partially soluble in the mixture. A 5 g portion of sodium (26 g, 1.13 g-atoms total) is added to the stirred mixture and the solid dissolves in the light blue solution within several min. As additional metal is added, the mixture becomes dark blue and a solid (matted needles) separates. Stirring is inefficient for a few minutes until the mass of crystals breaks down. All of the sodium is consumed after 1 hr and 120 ml of methanol is then added to the mixture with care. The product is isolated as in Procedure 4h 2. After being air-dried, the solid weighs 32.5 g (ca. 100% for a monohydrate). A sample of the material is dried for analysis and analyzed as described in Procedure 2 enol ether, 91% unreduced aromatics, 0.3%. The crude product may be crystallized from acetone-water or preferably from hexane. 

According to the submitter, further purification can be effected by sublimation the material is placed in the bottom of a Pyrex desiccator which is then evacuated and placed on a steam bath overnight. The mat of interwoven needles can be removed easily. One crystallization from benzene gives 37-40 g. (47-49%) of needles melting at 103-104°. 

Selenodi-j8-naphthylamine separates from benzene as yellowish-green, matted needles, M.pt. 245° C., from nitrobenzene as greenish prisms, and from alcohol in tablets. Its concentrated sulphuric acid solution is blue-green. Addition of ferric chloride to its alcoholic solution gives a moss-green coloration. Nitric acid yields a yellow nitro-compound. 

The slant was inoculated with ATCC 23342 and incubated for 6 days at 30°C. The culture does not normally sporulate on this medium, and it is necessary to macerate the mycelial mat with a flattened, sharpened, inoculating needle in order to increase the number of potential growth centers. The macerated mature culture was covered with sterile distilled water and scraped carefully with a sterile rod to obtain a mycelial suspension. 

Caffeine occurs as a white powder or as white, glistening needles, usually matted together. It may be compacted or compressed into free-flowing granules or pellets. It is odorless and has a bitter taste. Caffeine is anhydrous or contains one molecule of water of hydration. Its solutions are neutral to litmus. The hydrate is efflorescent in air, and 1 g is soluble in about 50 mL of water, in 75 mL of alcohol, in about 6 mL of chloroform, and in 600 mL of ether. 

All mass spectrometric analyses were carried out on a triple quadrupole mass spectrometer (TSQ-700) from Finnigan-MAT (San Jose, CA) equipp with an electrospray ion source (ESI) operating at atmospheric pressure. Mass spectra were recorded in the positive ion mode. The electrospray needle was operated at a differential of 3-4 kV, the conversion dynode was set to -15 V. The drying gas was nitrogen and the temperature was set to about 200 °C. A sheath flow of 2-methoxyethanol was delivered with 2 pJ/min and the nitrogen sheath gas was set at 50 psi. Samples were directly introduced into the source with a flow rate of 2 p.l/min. Scans were continuously taken every three seconds. 

This is insoluble in alkali, but with concentrated hydrochloric add yields colourless matted needles of CiaHi4N2AsCl,2HCl, i.e. the chloro-arsine dihydrochloride. This salt is readily soluble in water alkali repredpitates the oxide, and warming with hydrogen peroxide gives the acid. 

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