Author: haroonkhan

Plastics are basically organic substances which may be natural or synthetic resins in origin with or without moulding compounds. Synthetic resins are phenol, formaldehyde, cellulose, vinyl, alkyd, etc. The moulding compounds are catalysts, filters, hardeners, lubricants, pigments, plasticisers, solvents, etc.

1. Conventional Types Based on composition and properties, the conventional glass may be classified as soda lime or crown glass, flint glass, and Pyrex or heat-resistant glass. (i) Soda Lime or Crown Glass The composition by weight, in general, is sand 75 parts, lime 12.5 parts, soda 12.5 parts, alumina 1 part and waste glass…

Properties of glass are mainly governed by the factors such as composition of constituents, state of the surface, thermal treatment, dimensions of the object, etc. Glass has been popular and useful due to the following properties:

The main constituents of glass are silica, sodium or potassium carbonate, lime, manganese dioxide, cullet and colouring materials. 1. Silica Silica is the principal constituent of glass. Silica alone when fused at a very high temperature would give a good glass on cooling. However, it is essential to add some quantity of alkaline materials along…

Glass may be defined as a hard, brittle and transparent or translucent material. Technically glass is any substance or combination of substances which has solidified from the liquid state without crystallisation.

Tar is the viscous liquid produced when natural organic materials such as coal, petroleum, wood, etc., are carbonised. Depending on the material from which tar is obtained, it is called as wood tar or coal tar. Coal tar is used mostly for road work because of its superior quality. Road tar is produced by undergoing…

Bitumen is a hydrocarbon material of either natural or pyrogenous origin, found in gaseous, liquid, semi-solid or solid form. It is a complex organic material which is completely soluble in carbon disulphide. It occurs either naturally or may be obtained during the distillation of petroleum. Bitumen consists of colloidal hydrocarbon materials of asphalte nets, resins…

Bituminous materials may be broadly classified as bitumen and tar.

Following are the properties of gypsum plaster: