Properties of textile fibres (Part 2).

Properties of textile fibres.

Esthetic factor.

Silk is an outstanding example with good esthetic properties. Filament acetate ranks next. Polyesters appear wool like and are most pleasing.

Example of esthetic.

Comfort.

Comfort of fibre is most important but little understood property. It is related to the structure of the fabric in determining it's ventilation and heat insulating characteristics and twisting properties. The comfort is not, however, depend on high moisture absorption in the fabric.

Crease resistance.
The polyester, nylon and acrylics are good in this respect. Cellulosics are not good in crease resistance, however they may be modified by resin finishes to give good crease resistance.

Example of crease.

Fabric stability.

The stability of shape and dimension of synthetic fibres are outstandingly good. Wool retain well shape in garments but shrinks on wet treatment. A phenomenon called pilling is important in synthetics. A nodule or pill is formed on rubbing the fibre as the surface raise and tangled. These pill wear off in wool but do not break away in polyesters and appears quite unsightly.

Example of pills.

Wear resistance.

No laboratory test is for abrasion of fibre in actual used. However there are two or more independent factors on which abrasion of fibre depends. Acetate rayon is abraded most easily, followed by viscose, cotton and wool, while the polyesters, acrylics and nylon are progressively better.

Example of wear.

Properties of textile fibres part 1

Comments

Determination of molecular weight of polymers by viscosity method.

Determination of molecular weight of polymers by viscosity method. It is a simple method for determining the molecular weight of polymers. Addition of polymers in the solvent increases the viscosity of the solvent, due to introduction of inhomogeneities by the polymers. If η₀ is the viscosity of the solvent and η is the viscosity of the solution at the same temperature, then the relative viscosity is given by Relative viscosity. Specific viscosity: It is defined as the relative increase in viscosity and is given as Specific viscosity. Reduced viscosity: It is defined as the relative increase in viscosity per unit concentration (C) of polymer and is given as Reduced viscosity. Intrinsic viscosity: The reduced viscosity is dependent on concentration (C). If a graph is plotted between reduced viscosity vs concentration then the extraplotation value when C=0 is called intrinsic viscosity. Intrinsic viscosity. Graph of reduced viscosity vs concentr

Determination of molecular weight by Light scattering method.

Determination of molecular weight by Light scattering method. Due to big size macromolecules in solution, turbidity is produced. The light rays get scattered, when pass through macromolecule solution due to turbidity. The turbidity T is given by Where I₀ is the intensity of incident light. Iₜ is the intensity of transmitted light after passing through a solution of length l. In case of proteins or higher polymers the turbidity is small and is determine from the intensity of light scattered at 90° to the beam. This can be done by using a simple photometer as shown in figure below. Turbidity increase with increase in concentration as well as molecular weight. The Turbidity is related to molecular weight by the equation given by Debye. Hc/T=1/M+2Bc Where B is second virial coefficient and H is a constant. If we plot a graph between Hc/T vs c we get a straight line with intercept 1/M. Thus This curve was plotted by Zimm, so is called Zimm's Curve. Thus the c

Polypropylene (PP)

Polypropylene (PP). Polypropylene (PP) is also known as polypropene. Polypropylene is made from the polymerisation of propylene gas in the presence of Zeiglar Natta catalyst or metallocene catalyst. Polypropylene. Thus propene (or propylene) is the monomer of polypropylene. Polypropylene is a highly flammable material. It is sensitive to microbial attacks, such as bacteria and mold. It exhibits excellent resistance to diluted and concentrated acids, alcohols and bases. Polypropylene is used to make lunch boxes, margarine containers, yogurt pots, syrup bottles etc. Disposable syringes is the most common medical application of polypropylene. Polypropylene rope and twine are very strong and moisture resistant very suitable for marine applications. Polypropylene, highly colorfast, is widely used in manufacturing carpets, rugs and mats. Uses of Polypropylene. Questions on polypropylene; Q1) What is polypropylene? Ans) Polypropylene is a polymer of propylen

Polymers

Search This Blog