Shrinkage grease

Test specimens were prepared by melting bright sulfur containing various amounts of sand to approximately 145 °C. The slurry was then hand-mixed and poured into greased metal molds. To eliminate concavity resulting from nonuniform shrinkage, extra sulfur mixture was poured into each mold. On cooling, the excess material was easily... 

SAN copolymers are linear, amorphous materials with improved heat resistance over pure polystyrene. The polymer is transparent but may have a yellow color as the acrylonitrile content increases. The addition of a polar monomer, acrylonitrile, to tbe backbone gives these polymers better resistance to oils, greases, and hydrocarbons when compared to polystyrene. Glass-reinforced grades of SAN are available for applications requiring higher modulus combined with lower mold shrinkage and lower coefficient of thermal expansion. ... 

The most thorough studies of syneresis have been performed by Vysotskii and colleagues [55-57] using silica gel made by neutralization of sodium silicate with acid. The sol was cast into greased cylindrical tubes and the gel point (tg) was roughly determined from the rate of fall of spheres dropped into the tube. Then the tube was sealed and shrinkage of the gel was observed with a cathetometer. The kinetics of shrinkage are shown in Fig. 12 there... 

Clear and rigid with exceptional surface gloss more temperature resistant, less brittle than PS resistant to oils and grease low mould shrinkage (0.4 to 0.7%) better ESCR than PS can be solvent or hot bonded and ultrasonic welded. 

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