Wednesday, August 7, 2019


Fibre maturity:
The maturity of cotton fibre has a big concern to a cotton spinner. The maturity of cotton fibres plays a decisive role in resulting in yarn properties to be spun.
It is a significant characteristic of cotton fibres. The maturity of cotton fibre is an indicator that expresses "the degree of development of cotton fibre". The maturity of fibres tells us how much development has been taken place in the fibres. The cotton fibres do not have regular development within the sample or the fibres obtained from the same seed too. This difference among the maturity of various fibres appears because of the variations in the degree of the secondary thickening or deposition of cellulose in fibres.
In mature fibres, "the secondary wall's thickness is very high". In some fibres, the lumen gets invisible too.
In the immature fibres, due to some physiological reasons, the secondary deposition of cellulose has not taken sufficiently and in maximum fibres, the secondary thickening is practically got absent.

The presence of immature fibres appears as a defect in yarn, grey fabric, and processed fabric.  "Excessive neps" appear on the yarn surface if the cotton has immature fibres in it. The neps appearing in this yarn "influence the appearance of the fabric greatly".

The presence of an excessive degree of immature fibres in the yarn results in the form of "weight losses in processing". The balls of immature fibres appearing on the fabric surface require an "extra dose of caustic soda and hydrogen peroxide" to dissolve the same during processing. This extra dose of chemicals causes increases in the" processing cost".

 The presence of excessive immature fibres also "influences the gsm of finished fabric". Due to excessive weight loss occurring during dyeing,  the gsm is of the processed fabric decreased.
The presence of immature cotton fibres in the fabric also influences the "dyeing affinity" of the fabric. The immature fibres have very poor dyeing affinity. The colour of dyed fabric gets "uneven" if excessive immature fibres are present in the fabric.

Maturity ratio:

The 100 fibres are picked up from the comb sorter sample. The picked-up fibres are selected randomly. These fibres are treated with a caustic soda solution. The concentration of the solution is kept at 18 %. When the fibres get completely swollen. Each swollen fibre is examined with the help of a microscope having sufficient magnifying capability. 

Now the observations are recorded accurately. After completion of the observation process, the fibres are classified into different maturity groups depending upon the basis of the relative dimensions of wall thickness and lumen of the fibres. However, the procedures followed in different countries for sampling and classification differ in some respects. The swollen fibres are classed into three groups as follows
Normal fibres: Rod( round shape) like fibres with no convolution ( twist) and no continuous lumen are classified as “normal” fibres. 

Dead fibres: Convoluted (twisted) fibres having wall thickness one-fifth or less of the maximum ribbon width are classified as “Dead fibres ".

Thin-walled fibres: The fibres having maturity less than normal and greater than dead fibres are classified as thin-walled fibres.

"A combined index known as maturity ratio is used to express the results".
Maturity co-efficient:

Around 100 fibres from the comb sorter are spread across the glass slide (maturity slide) and the overlapping fibres are again separated with the help of a teasing needle. The free ends of the fibres are then held in the clamp on the second strip of the maturity slide which is adjustable to keep the fibres stretched to the desired limit. The fibres are then irrigated with 18 % NaOH solution. Now, these fibres are covered with a suitable cap. The prepared slide is examined with the help of a microscope. The observations are recorded precisely. Now the data are analysed and then the fibres are categorized into the following three groups:

About four to eight slides are prepared from each sample and are examined. The results are expressed as a percentage of matured, half-matured and immature fibres in a sample.  The maturity Coefficient of the cotton fibres sample is determined as below:

Please click on the below video link to watch the full article in Hindi:


No comments:

Post a Comment