| Следующее: Low-molecular weight polyisobutene » |
ГОСТ 13303-86
Seven grades of high molecular weight polyisobutene are produced with different molecular masses. Technical data of the product is shown in the table:
| Properties | Values | ||||||
|---|---|---|---|---|---|---|---|
| P-80 | P-85 | P-100 | P-118 | P-155 | P-220 | P-225 | |
| Apperance | Rubber-like with colour ranging from white to grey | ||||||
| Staudinger molecular mass×103 | 71 … 94 | 59 … 104 | 104 … 131 | 106 … 159 | 153 … 206 | 170 … 243 | 221 … 260 | Staudinger Index (Io), cm3/g | 178 … 236 | 150 … 260 | 260 … 325 | 265 … 395 | 380 … 510 | 420 … 600 | 550 … 640 | Viscosity-Average molecular mass, Mv, (×103) | 619 … 965 | 476 … 1110 | 900 … 1564 | 1143 … 2112 | 1989 … 3128 | 2331 … 4017 | 3512 … 4435 | Number-Average molecular weight, Mn,(×103) | 161 … 217 | 134 … 241 | 192 … 305 | 246 … 376 | 361 … 493 | 401 … 586 | 535 … 628 |
| Ash mass content, %, max | 0,04 | ||||||
| Volatile matter at 105°C, %, max | 0,5 | ||||||
| Non-staining stabilizer content, %, max | 0,04 | ||||||
High molecular weight polyisobutene is a solid rubberlike substance; it retains its resilient and high elastic properties and belongs to "the elastomers" in contrast to such polyolefines as polyethylene, polypropylene, polybutene, which belong to "thermoelasticoplasts".
High molecular weight polyisobutene is a product of the method of low temperature polymerization with evaporating liquid ethylene and in presence of catalyst boron trifluoride and together with the process regulators.
Polymerization is performed on continuously moving line at temperature minus 100 °C. Heat removal is performed by means of liquid ethylene evaporation. Gas phase is sent to gasholder and is further recycled, purified for use
Polyisobutene is a saturated carbon-chain polymer. As such it is highly resistant to oxygen, ozone, and solutions of acids, alkalis and salts. The polymer doesn't swell or dissolve in oxygen containing polar solvents, but readily dissolved in aliphatic or aromatic hydrocarbons (passing through a swelling stage).
High molecular weight polyisobutene is an elastic rubber-like product, nearly colorless and free of odor or taste, density — 0.91 ...0.93 g/cm3.
When heated in air up to 100 °C over a long period of time polyisobutene becomes increasingly plastic, at 180...200 °C it can be shaped. At 350...400 °C thermal degradation occurs with evolution of oily gaseous products. Polyisobutene retains its resilient and elastic properties down to -55 °C, it remains practically unchanged after immersion in water or at elevated temperatures.
Being a non-polar substance of regular macromolecular structure, polyisobutene shows good dielectric properties. In common with other rubbers polyisobutene can be mixed with variable ingredients, thermoplastic polymers that fully reduce cold flow and improve dielectric properties.
The outstanding chemical stability of polyisobutene has won it a place in the forefront of rubbers used for corrosion protection of equipment, for manufacturing of seals, rubber things, insulating materials, adhesives, covers and many other products.
Polyisobutene is produced in bales of 25 ±1 kg or 30 ±1 kg which are packed in polyethylene film and then in metal or wooden containers, laid by polyethylene film, or it is packed into paper bags with 4-6 layers. Polyisobutene can be transported by any kind of covered transportation means. Polyisobutene is stored in closed warehouses at temperature 25 °C. Guaranteed period of storage — 2 years.
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