Search results
Results from the WOW.Com Content Network
The melting point for average commercial low-density polyethylene is typically 105 to 115 °C (221 to 239 °F). These temperatures vary strongly with the type of polyethylene, but the theoretical upper limit of melting of polyethylene is reported to be 144 to 146 °C (291 to 295 °F).
Linear polyethyleneimine is soluble in hot water, at low pH, in methanol, ethanol, or chloroform. It is insoluble in cold water, benzene, ethyl ether, and acetone. Linear polyethylenimine has a melting point of around 67 °C. [3] Both linear and branched polyethylneimine can be stored at room temperature.
Polyvinyl acetate is also the raw material to make other polymers like: Polyvinyl alcohol −[HOCHCH 2]−: Polyvinyl acetate is partially or completely hydrolysed to give polyvinyl alcohol. This reversible saponification and esterification reaction was a strong hint for Hermann Staudinger in the formulation of his theory of macromolecules. [12]
Polyvinyl alcohol (PVOH, PVA, or PVAl) is a water-soluble synthetic polymer. It has the idealized formula [CH 2 CH(OH)] n. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) adhesive formulations, in a variety of coatings, and 3D printing. It is colourless (white) and odorless.
One result of ionization is that the organic molecules disproportionate to form smaller hydrocarbon molecules as well as larger hydrocarbons molecules. This is reflected by increased evaporation loss, lowering of the flash and fire points, and increased viscosity. Other chemical reactions caused by radiation include oxidation and isomerization ...
The simple structure of the molecule also gives rise to surface and chemical properties that are rare in high-performance polymers. For example, the polar groups in most polymers easily bond to water. Because olefins have no such groups, UHMWPE does not absorb water readily, nor wet easily, which makes bonding it to other polymers difficult ...
General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to air and water vapor and has a relatively low melting point. [6] Polystyrene is one of the most widely used plastics, with the scale of its production being several million tonnes per year. [7]
The melting point of α-crystalline regions is given as 185 [15] [16] to 220 °C, [15] [17] the density as 0.936 to 0.946 g·cm −3. [ 18 ] [ 19 ] The β-modification is in comparison somewhat less ordered, as a result of which it forms faster [ 20 ] [ 21 ] and has a lower melting point of 170 to 200 °C.