Surface tension:

Molecules of the liquid at the surface are in different situation than those in the interior of the liquid. Molecule lying inside the liquid (As shown in figure as 'A') is surrounded by other molecules and so attracted equally in all directions. Hence the net force of attraction acting on the molecule is zero. But a molecule lying at the surface (As shown in figure as 'C') is attracted downwards by the molecules lying in the bulk of the liquid. Thus a molecule lying at the surface experiences a net inward attraction. As a result of this inward pull on all molecules lying at the surface, the surface behaves as if it were under tension. This property of liquid is called surface tension. Unit of surface tension is Dyne per cm. 

Classifications of Chemical Auxiliaries: i) Permanent or Temporary auxiliaries 

ii) Nature of auxiliaries (Surface active/non surface active/soluble/dispersing or emulsifying) 

i) Permanent or Temporary auxiliaries: 

Chemicals which are never remain with textile materials and need to be removed after processing come under Temporary auxiliaries. Examples of these chemicals are sizing chemicals, enzymes, detergents, wetting agents, leveling agents, carriers, dispersing agents, thickeners etc.

In case of permanent auxiliaries the chemicals which permanently fix on the textiles like softeners, water proofing agent, flame retardant chemicals, water repellent chemicals, rot proofing agents, binders, dye fixing agents etc.

ii) Nature of auxiliaries (Surface active/non surface active/soluble/dispersing or emulsifying/Inorganic chemicals) 

a) Surface active agents are those which act on the surface first and then react with the textiles. These are detergents, softeners, wetting agents, water repellent agent, emulsifier, dispersing agents, dyeing assistant etc

b) Non surface active agents are those which mostly not react with the textiles and remain only on the surface. Examples of these are resin, cross linking agents, sizing chemicals, thickener, binder etc.

c) There are some chemical auxiliaries which have non surface active with small amount of surface active agents properties. These are wax emulsions, silicone emulsion, spin finish oils etc.

d) Inorganic chemicals are reducing agents, acids like acetic acid, buffers to maintain pH, bleaching agents, mordants, oxidizing agents, hydrolyzing agents etc

What is Textile Auxiliaries?

At various stages of textile wet processing different types of chemicals and auxiliaries are used. Though all are actually chemicals, in practice the materials without which a process cannot be complete are termed as “chemicals” and the other substances which facilitate or improve the performance of that process are termed as “auxiliaries”. 

Auxiliaries are those chemicals which help processing operation such as preparation, dyeing, printing or finishing to be carried out more effectively. Some of the cases these chemicals are essential if a given effect such as wash & wear, water repellent, flame retardant, aroma finish, anti odour, colour deepening etc. is to be obtained. 

Classifications of Chemical Auxiliaries:

These can be classifies in to two ways:

i)             Permanent or Temporary auxiliaries

ii)           Nature of auxiliaries (Surface active/non surface active/soluble/dispersing or emulsifying) 

 Inauguration of Fabric smoothness Tester developed at NITRA. It is ready for commercialization.

A new instrument to measure surface smoothness characteristics of fabric.

Difference between inherent flame retardant and treated fabric

Inherent FR fabrics are made of fibers in which the FR properties are in-inbuilt during the polymerization and can never be worn away or washed out. The actual structure of the fiber itself is non-flammable; therefore, the flame retardant property is permanent.

On the other hand treated FR fabrics are made by applying a flame-retardant chemical finish to a fabric or by adding a chemical treatment to the fibers before they are woven or knitted into the fabric. The chemicals form a strong bond with the polymer chain of fibre that is difficult to remove by washing when the recommended laundering instructions are followed accurately. The chemical treatment alters the molecular structure of the polymer.

INTERVIEW ON TEXTILES

INTERVIEW ON TEXTILES