phenol formaldehyde resins - a synthetic resin having the properties of thermosets or thermosets.Such resins are oligomeric or liquid substances, obtained by polycondensation of formaldehyde with phenol in an acidic or alkaline medium (resol, novolac resin or bakelite).This further affects the final product properties.
properties of phenol-formaldehyde resins
phenol-formaldehyde resins (formula [-C6H3 (OH) -CH2-] n) has a high electrical insulation, good corrosion and mechanical stability.Perfectly soluble in aromatic and aliphatic hydrocarbons, ketones and chlorinated solvents.Also it dissolved in polar solutions and aqueous alkali solutions.After curing phenol-formaldehyde resins are transformed into polymers gustosshitye microheterogeneous amorphous structure.
Where phenol-formaldehyde resin is used?
- in the production of plastics: hardened resin called resite solidified in the presence of sulfonic acid oil - karbolit, in the presence of lactic acid - neoleykoritami;
- in the manufacture of varnishes, adhesives, synthetic, bearings, brake linings, billiard balls;
- from karbolit (cured phenol-formaldehyde resin) manufactured housing multimers some Soviet models;
- as the substance is used as a binder for the production of filled molding composition with different fillers (wood flour, glass fiber, cellulose), chipboard and fibreboard, casting and impregnating compositions (for fiber-filled and woven materials, plywood) adhesives.
formaldehyde resin: Preparation and ecology
formaldehyde and phenol, used in the manufacture of phenol-formaldehyde resins, are toxic and flammable substances.Phenol-formaldehyde resin has a negative impact on the human body: causes of eczema and dermatitis.Moreover, formaldehyde also has carcinogenic properties.
Bakelite - a product of hardening phenol-formaldehyde resin in the presence of a catalyst.This material is of great importance in various spheres of human life.Bakelite bad conductor of heat, but shows good resistance to mechanical damage: shock, shock, friction or pressure.Treatable in a special lathe.It is a good insulator.The diluted alkali, acid and water it does not apply, except for concentrated sulfuric or nitric acids.Resistant to 300 degrees, at a higher temperature combustion occurs.
originally created to be a substitute for shellac - a special resin produced in the nature of tropical lacquer scale insects.
Phenoplasts.Application
Phenoplasts - a plastic which is obtained by solidification formaldehyde resins at elevated temperatures in combination with any carrier.Currently, this material is unbeatable in its properties.Using phenoplasts made:
- material intended for the manufacture of printed circuit boards - getinaks;
- material to create a structural material - PCB;
- cheap items for board games - checkers, dominoes, chess;
- some elements of kitchen utensils: pens for gas cookers, kettles and knives, pots and pans;
- Bakelite phenolic adhesive;
- electrical products - sockets, plugs, electric meters, switches, relays, housings of electric motors, junction boxes, magnetic actuators, etc .;
- parts for mechanical engineering, for example, steps for escalators, various tips and handles;
- jewelry, souvenirs, stationery, some details of the hours.
