Good day to my steemit friends, I really appreciate the time devoted to reading my post and also for upvoting it.

Today I will talk about diapers and their absorbent materials, the types and the reason for difference in degree of absorption will also be discussed.

There are so many brands of diapers in the market and people do select or make their choice mainly on the bases of the degree of absorption. Other factors can also influence the choice of diaper brand but I will focus mainly on the absorption capacity.

Recently, I had an unpleasant experience with a particular brand of diaper. It happened that my wife had a gift of a pack of diaper from a family friend which is different from the brand she usually uses for our 4 months baby. We are very glad to receive such a gift at a right time we are in need of diaper because we have a few diapers remaining. When we started using the diapers, the first urine released inside the diaper run out through the baby's crotch and legs, exactly as when water falls on waterproof pants. When we removed the diaper from the baby buttock, the diaper was so dry, it was so glaring that the diaper failed to absorb the urine. Due to this occurrence, I decided to find out what could have happened that caused a diaper that should be an absorbent material into a waterproof.

Image taken by me

Hope you find this article useful

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Diapers And Their Absorbing Properties

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A few years back before the advent of diapers, nursing mothers and caregivers made use of a locally made nappy to serve the purpose of a diaper being used now. The locally made nappy is usually made with a thick cloth (100% cotton), which could be fashioned into a wearable under wares for babies, It involves systematic folding of the cloth to suit the main purpose for which it is made. The local nappy is made with a piece of cloth that can reasonably absorb water content which allows babies to defecate and urinate comfortably. The nappy can be washed, dried and made ready for subsequent use.

Due to the stress of laundry and their relatively poor absorbency, nursing mothers and caregivers will prefer disposable diapers. I remember those days when my mother was nursing my junior ones, she usually washes thrice in a day so as to keep the nappy clean for consequent use which can be so tedious sometimes. A rubber pant is always worn over the nappy to prevent linkage of excretion products like urine.

To solve the stress faced by nursing mothers and caregivers due to nappy laundry and the problem of poor absorbance of the nappy gave birth to the recent invention of diapers.

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What are Diapers?

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Image created by me

A diaper is a pant-like wearable underwear designed to retain and hold moisture content of excretion, it allows the person or baby wearing it to conveniently defecate and urinate inside it. It is made up of materials with high absorbency, which is usually worn under the cloth to prevent soiling the environment with excretory products. Diapers are categorized as cloth diapers and disposable diapers based on the absorbent materials used.

Cloth diapers are made from materials that could be washed and reused for many times, such materials include; cotton, microfiber, hemp, bamboo, or plastic fibers e.t.c. Several layers of these materials are put together to make a cloth diaper. Disposable diapers are made up of chemicals as the absorbent material. Initially made disposable diapers were extremely bulky because they were made from absorbing materials such as cotton fibers, cellulose wadding, wood pulp fluff, or fluff cellulose.

All types and forms of diapers contain elastic edge to ensure that the diaper fits the baby's legs in a slightly tight manner to avoid linkage from the crotch area. The top area of the diaper is made up of a permeable material to ensure that the moisture gets to the absorbent material and never come back to the wearer's buttock, that is why the baby buttock is dry even though the diaper is wet. The back side of a diaper is an impermeable bottom sheet which prevents the absorbed moisture from the absorbent pad from staining the outer cloth of the individual wearing the diaper. The absorbent pad or materials is usually embedded in the core of the diaper.

Diapers come is various forms and sizes. Sizes for babies and infants range from Nini (size 2), midi (size 3) to maxi (size 4) while diaper sizes for adults range from small, medium to big size.

By User:Ritchey - Own work, Public Domain,Superabsorbent Polymer

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Absorbent Materials

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The main function of a diaper is to absorb and retain body fluid or moisture of excretion. Diaper absorbing material is made by the process of polymerization and crosslinking reaction of parent compound of sodium polyacrylate known as acrylic acid. Acrylic acid is produced by the oxidation of Propylene when it is allowed to pass through acrolein (unsaturated aldehyde).

The combination of the chemicals in a suitable chemical reactor and temperature produces a colorless liquid or solid crystal absorbent material known as superabsorbent polymers. it is also referred to as a hydrophilic or water lover because its weight can actually increase to 15 time its original weight when deep in water depending on the degree of cross-linking.

Cross-linking is the process by polymer molecules chemically interconnect to one another to form a long chain or rope-like molecules. The process of cross-linking results in a non-soluble gel network capable to absorb water content. The strength of the gel formed depends on the intensity of crosslinking. During the process of crosslinking, it is very important to control the degree at which molecules engage in cross-linking so that the desired gel strength is achieved. The gel strength of the polymer must not be too high and must be too low.

If the gel strength is too high, the polymer of such diaper will have a reduced absorbent capacity, thereby causing the diaper to absorb little water content, which caused urine to rush out of the diaper, just like the experience I just shared. If the gel strength is too low, the diaper absorbs moisture too quickly and cause a sudden gel of polymer which blocks water from reaching the inner part of the absorbent material.

Image created by me

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Conclusion

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For a diaper to perform its function of absorption thoroughly, all the four major components of a diaper (the front permeable materials, the back impermeable bottom sheet, the absorbent pad or material, Elastic edge Bands and Adhesive strips) must be of high quality and must be placed rightly in position. Production of Acrylic acid is by the oxidation of Propylene in intermediate with acrolein to achieve better crosslinking is expensive, so manufacturers tend to reduce cost by going through an alternative process, which in turns leads to the production of low absorbent diapers.

Diaper was an innovation to solve a post-war problem of unavailability of cotton in which Marion Donovan made the diaper with a shower curtain and layers of tissue paper as the absorbent material. Many adjustments have been made to previous diapers made to increase its convenience and also the absorbency. Diapers are not made only for babies or infants, it can be worn by various individuals including adult, a patient that is movement constraint, people with mental disability, old aged people e.t.c

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References

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1. https://en.wikipedia.org/wiki/Diaper
2. https://study.com/academy/lesson/what-is-acrolein-used-for.html
3. http://www.madehow.com/Volume-3/Disposable-Diaper.html
4. https://www.babygearlab.com/expert-advice/what-is-inside-those-disposable-diapers
5. http://www.chemistryislife.com/the-chemistry-of-baby-diapers
6. http://www.chemistryexplained.com/Di-Fa/Disposable-Diapers.html