Moisture, Moisture Relation, and testing are essential in any fabric. From MR testing, they can measure the moisture that’s present in the material. Fiber and yarn materials, which are affected by humidity content, can be from there. Moisture is an important factor to measure and control in testing surroundings.
Table of Contents
Absolute moisture is also used to calculate humidity content, which is important in fiber and yarn testing. The relative moisture indicates the equilibrium humidity content of the fiber or yarn under testing conditions, which is essential for homogenizing testing results.
Let’s know about them.
What is Moisture Relation?
Moisture Relation: Moisture Relation is the term used to describe the humidity in the atmosphere.
It is also defined as the quantum( weight) of water present in the unit volume of wettish air; it’s the factual viscosity of water vapor present in the atmosphere, which is expressed in terms of grains per boxy bottom( gr/ foot3) or grams per boxy cadence( g/ cm3). It’s the relation between moisture relation and moisture content.
What is Moisture Testing?
Testing is the way of controlling or the process to check or corroborate any material’s nature, kind, or character, hence the control of the degree of excellence.
Cloth testing assists cloth products in opting for colorful types of filaments and their metamorphosis into yarn, fabric, and finished goods similar to apparel.
What is Moisture regain and moisture content?
Moisture regain: Moisture regain is defined as the weight of water in a material expressed as a chance of the roaster dry weight. It’s the quantum of moisture that a fabric or yarn can absorb.
R = W/ D * 100%
Where, R = Moisture regain
W = Weight of water
D = The roaster sot of the material
The “ Roaster dry weight “ is the constant weight attained by drying at a temp of( 105+- 3)C.
Moisture Content: Moisture content is defined as the weight of water in a material expressed as a chance of the total weight of the material. It’s denoted by C.
Let, Oven dry weight of a material = D
Weight of water in this material = W
Moisture Content, C = W/ W + D * 100%
Relation between moisture regain and content
The relation between humidity recapture and humidity content
Let,
Humidity recapture, R =W/D×100 __________________________________ (1)
Humidity content, C= W/W+D × 100 _________________________________ (2)
From equation (1) we get,
D= W/R × 100
Putting the value of D in equation (2) we get,
C = W/W+W/R ×100 × 100
C = W×100/W (1+100/R)
C = 100/(1+100/R)
C = 100R / R+100____________________________________ (3)
Again, from equation (3) we get,
R = RC+100C / 100
R = RC/100 + C
C =R- RC/100
C =R (1 − C /100)
R = 100C / 100−C____________________________________ (4)
Equation (3) and (4) express the relation between Moisture regain and Moisture content.
Standard moisture regain of different fibers
The humidity absorbed by a particular weight sample is a standard atmosphere after treatment at 105 ± 3oC is called standard humidity recapture. The formula of Standard humidity content = ( wet weight-dry weight)/ dry weight X 100. Then are some standard humidity regains of different filaments.
| Fiber | Standard Moisture |
| Cotton | 8.5% |
| Silk | 11% |
| polyester | o.4% |
| Viscose | 11% |
| Nylon | 4% |
| Flax & Hamp | 12% |
| Cellulose Acelate | 6% |
| Acrylic | 1.5% |
| Sisal & Manila | 12% |
| Wool (carbonised) | 17% |
| Wool (scoured) | 16% |
| Jute | 8.5% |
Atmospheric conditions and relative humidity
The dimension of atmospheric conditions, specifically moisture, is generally expressed in relative moisture( RH). Relative moisture is the rate of the quantum of humidity in the air to the maximum quantum of humidity the air could hold at the same temperature, expressed as a chance.
There are colorful instruments used to measure moisture, and some common types include
1. Hygrometer: This is a general term for any instrument that measures moisture. There are different types of hygrometers, similar to psychrometers, hair hygrometers, and electronic hygrometers.
2. Psychrometer: It consists of two thermometers — one with a dry bulb and the other with a wet bulb. By comparing the temperatures recorded by these two thermometers, one can determine the relative moisture.
3. Hair Hygrometer: This type of hygrometer uses a pack of mortal or carnal hair to measure moisture. As the hair absorbs humidity from the air, it changes length, and this change is used to calculate relative moisture.
4. Electronic Hygrometer: These ultramodern biases use electronic detectors to measure moisture. Capacitive and resistive detectors are generally used. These detectors respond to changes in humidity content and convert the information into a digital or analog moisture reading.
5. Dew Point Hygrometer: This instrument measures the dew point temperature, which is the temperature at which air becomes logged with humidity and dew forms. The dew point is another parameter frequently used to express moisture conditions.
Absorption curve of various materials
Absorption curve It’s generally a wind that represents a graph that shows the immersion of the accouterments. It shows the relationship between the quantum of incident radiation and the quantum of radiation absorbed by the accouterments. There are numerous types of absorption curve like Line absorption curve.
Factors affecting the regain of textile materials
The factors that affect the regain of textile materials are as follows
1. Time
2. Relative moisture.
3. Temperature
4. Former history of the material
5. Type of the material.
1. Time: Material in equilibrium at specific relative moisture takes time to reach a new equilibrium, depending on its physical form and humidity escape. The British Standard recommends one hour for annulet yarn and three hours for Packages.
2. Relative moisture: The recapture of cloth material depends on the relative moisture of the atmosphere. Recapture is advanced at advanced relative moisture( RH).
3. Temperature: It has a negligible effect on recapture. For illustration, a change of °C may bring a change of 0.3 in the recapture of cotton.
4. The former history of the sample: The former history of the materials recapture is affected by the nature of the material and the atmospheric condition in which the material has been stored or reused. For illustration, blanched or trolled cotton will absorb further humidity than undressed material because the junking of contaminations helps in more immersion of humidity.
5. Type of accoutrements :
- Different filaments have different humidity recaptures.
- For illustration, silk has a recapture of 11 and nylon has only 4. The form of material is also important in case of recapture.
- For illustration, the recapture of yarn( woolen and worsted) is 18.25, and that of cloth( woolen and worsted) is 16.
- From the below wind, we can say that hair and viscose rayon show analogous immersion carves while nylon shows a low immersion property.
Effects of regain on fiber properties
Some properties that affect the fibers.
1. Dimension/ Physical properties
2. Mechanical properties
3. Electrical properties
4. Thermal properties
1. Dimension/ Physical properties:
The immersion of humidity affects the dimension of filaments in colorful ways. The lump is substantially transversal( Area lump) because water motes access between the resemblant molecular chains and ply their forces outwards.
The length of the fiber increases due to absorbed humidity, but in the case of fabrics, humidity absorption causes fabric loss.
So, lump = lump dimension − Sot dimension/ Sot dimension × 100
Dimension changes of some filaments due to immersion of humidity is tabulated below –
| Fiber | Transverse of area swelling% | Axial or Longitudinal % |
|---|---|---|
| Cotton | 21 | 1.1 |
| Wool | 25 | 1.2 |
| Silk | 19 | 1.3-1.7 |
| Viscose | 60 | 4-7 |
| Acelate | 8 | 0.3 |
| Nylon | 3.2 | 1.5 |
The advantage of swelling is to produce a leakproof fabric. Swelling plays a
great part in making further weave which prevents the penetration of water.
2. Mechanical properties:
The water motes in the fiber reduce the size of the holding forces the molecular chains together is a result of which filaments come weak. However, the strength of vegetable filaments similar to cotton and flax is increased by swelling.
Not only is maximum strength reduced, but the stress–strain wind assumes a different form.
Other mechanical materials affected by recapture include extensibility, crinkle recovery, inflexibility, etc.
3. Electrical properties:
MR affects the electrical resistance of the fiber greatly. The rate of the resistance at low regains and at grand recapture can be of the order of hundreds of thousands to one.
That’s why the design of humidity measures is grounded on the dimension of resistance values of fabrics.
High recapture doesn’t allow the form of stationary electricity on the fiber face.
Other electrical materials affected by the quantum of humidity in the material are the dielectric characteristics and the vulnerability of static Troubles.
4. Thermal properties:
When humidity is absorbed by cloth material, heat is generated. This heat is known as the heat of immersion. When the dry sample is fully bathed, the heat evolved, expressed in calories per gram of dry material is nominated as heat of wetting down.
Thermal goods play a vital part in the field of apparel. If a woolen jacket of 1 kg weight is passed from 18 ̊C and 45 R.H to an atmosphere of 5 ̊C and 95R.H, it’ll produce 100,000 calories of heat.vvGoods of recapture on fiber materials.
Conclusion
The presence of water vapor in the atmosphere is known as moisture. Hence, the more water evaporates in a given position, the further water vapor rises into the air, raising the moisture. Because temperature affects water to dematerialize briskly, hot regions are more sticky than cool places.
Reference
- https://www.sciencedirect.com/topics/engineering/standard-atmospheric-condition
- https://www.textilecalculations.com/standard-moisture-regain-and-moisture-content-of-fibers
- http://onedotshare.blogspot.com/2019/01/moisture-regain-and-moisture-content.html
- https://www.linkedin.com/pulse/calculating-moisture-regain-rate-textile-raw-materials-wendy-li
- https://www.numerade.com/ask/question/question2-a-psychrometer-is-a-device-used-to-measure-heat-transfer-rate-during-an-adiabatic-saturation-process-both-dry-bulb-and-wet-bulb-temperatures-during-an-adiabatic-saturation-process–13047
- https://sperdirect.com/blogs/news/humidity-control-monitoring-in-commercial-buildings
Hi, this is Taspia Binta Yousuf, A B.Sc. in Textile Engineering student at Textile Engineering College, Noakhali. My department is fabric Engineering.