Short glasses

Alternatively a mercury-sealed stirrer may be employed. Here again a short glass tube C is inserted through the cork of the flask to act as a collar for the stirrer. The tube C carries a short wide tube B which is either fused at its lower end to C, or is fixed to it by means of a cork as shown. The stirrer D carries a precisely similar tube E, the top of which however is now fixed to D the bore of the tube E allows it to fit easily within the annular space between the collar C and the tube B. Mercury... 

Mix 6 2 ml. (6 4 g.) of pure ethyl acetoacetate and 5 ml. of pure phenylhydrazine in an evaporating-basin of about 75 ml. capacity, add 0 5 ml. of acetic acid and then heat the mixture on a briskly boiling water-bath (preferably in a fume-cupboard) for I hour, occasionally stirring the mixture with a short glass rod. Then allow the heavy yellow syrup to cool somewhat, add 30-40 ml. of ether, and stir the mixture vigorously the syrup may now dissolve and the solution shortly afterwards deposit the crystalline pyrazolone, or at lower temperatures the syrup may solidify directly. Note. If the laboratory has been inoculated by previous preparations, the syrup may solidify whilst still on the water-bath in this case the solid product when cold must be chipped out of the basin, and ground in a mortar with the ether.) Now filter the product at the pump, and wash the solid material thoroughly with ether. Recrystallise the product from a small quantity of a mixture of equal volumes of water and ethanol. The methyl-phenyl-pyrazolone is obtained... 

A composite material for a car-repair kit consists of a random mixture of short glass fibres in a polyester matrix. Estimate the maximum toughness of the composite. You may assume that the volume fraction of glass is 30% the fibre diameter is 15 pm the fracture strength of the fibres is 1400 MPa and the shear strength of the matrix is 30 MPa. 

Chloro-1 -methyl-5-phenyl-s-trizolo[4,3-a]quinoline A stirred mixture of 6triethyl-orthoacetate (0.925 g,0.0057 mol) and xylene (100 ml) was refluxed, under nitrogen, for 2 hours 40 minutes. During this period the ethanol formed in the reaction was removed by distillation through a short,glass helix-packed column. The mixture was concentrated to dryness In vacuo and the residue was crystallized from methanol-ethyl acetate to give 1.28 g of 7-chloro-1-methyl-5-phenyl-s-triazolo[4,3-a]-quinoline (83.9% yield). The analytical sample was crystallized from methylene chloride methanol and had a melting point 252.5°-253.5°C. 

Fibrous fillers are now gaining more importance over particulate fillers due to the high performance in mechanical properties. The influence of fiber diameter on the tensile behavior of short glass fiber on polyimide was reported [95], At higher concentrations thick fibers seem to be more advantageous probably because of the... 

In investigations of the failure of fiber compositions (PETP — short glass fibers) [251] it was found that the main process responsible for composite failure under load is the rupture at the matrix-fiber interface. The author of [251] observed formation of microvoids in loaded samples, both at the interphases and in the bulk. The microvoids, or cavities) grow in size and become interconnected by microcracks, and this results in fiber separation from the binder. However, when the matrix-fiber bond is strong enough, the cavities appear mostly in the bulk of matrix, the failure of the specimen does not over-power cohesion and traces of polymer remain on the fibers. 

Thermoplastic RPs (RTPs), even with their relatively lower properties when compared to thermoset RPs (RTSs), consume about 55wt% of all RP products. Practically all of the RTPs are injection molded with very fast cycles using short glass fiber producing highly automated and high performance products. 

The usual process for processing TP-short glass fiber RPs is IM consuming about 55wt % of all RPs. Specially designed IMMs process TS-RPs with materials such as BMCs (bulk molding compounds). The other processes primarily use TS plastic matrices. 

First-generation polymer composites (e.g., fiberglass) used thermosetting epoxy polymers reinforced with randomly oriented short glass fibers. The filled epoxy resin could be cured into a permanent shape in a mold to give lightweight, moderately strong shapes. 

Liquid rubbers In order to improve the flexibihty of short glass fiber-reinforced epoxy composites, Kaynak et al. [53] modified the epoxy resin matrix with hydroxyl-terminated polybutadiene (HTPB) liquid mbber. A silane coupling agent was also used to improve the interfacial adhesion between glass fibers and epoxy matrix. However, Humpidge et al. [54] reported some unique processing problems for the resulting pasty mixmres when short textile fibers were incorporated in a hquid mbber medium. 

After the identification of the suitable compound bands, silica gel is scraped off the plates, placed in short glass columns, Pasteur pipettes, or sintered filter funnels, and fractions are recovered with such volatile solvents as ethyl acetate or dichloromethane. 

At this point 20-30 g. of short glass fiber or asbestos is added and the yeast is filtered out by suction. The filtrate is concentrated to a thick syrup under diminished pressure on a water bath, care being taken to keep the temperature below 40° (Note 3). The residue (about 200 cc.) is taken up in a mixture of 400 cc. of absolute alcohol and 100 cc. of dry ether (Note 4). The precipitate formed is removed by centrifuging, the supernatant liquid is decanted, and the residue is extracted with a mixture of 200 cc. of 98.5 per cent alcohol and 100 cc. of dry... 

If a centrifuge is not available, about 15 g. of short glass fiber or asbestos may be added to the solution, stirred with a mechanical stirrer for five minutes or thoroughly shaken, and filtered on a suction filter with similar results to those obtained by centrifuging. 

The measurements were carried out while increasing the temperature in 0.5 °C increments at intervals of 30 min., using an aqueous solution of the polymers in Pyrex tubes(5 ml volume). Each tube contained a short glass rod which was used to stir the solution after being filled with the polymer solution of 0.05 -2.5 wt %, each tube was evacuated and sealed. The warm up to 70 °C was carried out in a water bath. The cloud point was taken as the temperature at which phase separation was first noted it was compared with the temperature at which the solution first became clear again while cooling. 

The levelling bulb is closed with a rubber stopper carrying a short glass tube drawn out to a capillary. 

Tetraphenylhydrazine (5 g.) is dissolved in 40 c.c. of toluene in a small round-bottomed flask fitted with a two-holed cork. A delivery tube, which is connected to the apparatus just described and reaches to the bottom of the flask, passes through one hole, a short glass tube through the other. With the second wash-bottle disconnected from the rubber tube, and the latter closed by means of the clip, the dropping in of sulphuric acid is begun, and at the same... 

Fakirov, S. and Fakirova, C., Direct determination of the orientation of short glass fibers in an injection-molded polyethylene terephthalate) system, Polym. Composites, 6, 41 (1985). 

Fu SY, Lauke B, Mader E, Yue CY, Hu X. Tensile properties of short-glass-fiber- and short-carbon-fiber-reinforced polypropylene composites. Composites Part A Applied Science and Manufacturing. 2000 31(10) 1117-25. 

---