Degradation of Fabrics

Common nappy issues such as ammonia, bacteria (stains and smells), fungi (mould), sun exposure and the use of acids, bases and undiluted bleaches can damage nappies. This information provides an overview of each and outlines how to avoid these issues, helping to preserve nappies.

Ammonia Damage

See the Ammonia page.

Bacterial Damage

Fecal matter is full of bacteria. Some of these bacteria have cellulolytic activity, meaning they can break down cellulose (plant/fabric) fibres (McAlister et al. 2006; Szostak-Kotowa 2004). Some examples of cellulolytic bacteria not present in faecal matter are Cytophaga (oral), Cellulomonas (upper GI tract), Cellvibrio (soil) and Sporocytophaga (soil).
Bacillus and Clostridium species are both found in fecal matter (Rajilic-Stojanovic & de Vosand 2014) and display cellulolytic activity (Szostak-Kotowa 2004). Bacillus species are particularly prevalent in infant faeces (Rajilic-Stojanovic & de Vosand 2014).
It is important to wash nappies effectively to prevent bacterial degradation of the fibres.
A combination of factors contribute to the removal of soil and bacteria from fabrics. These factors are sufficient quantities of effective detergent, use of enzyme detergents (the enzymes typically found in laundry products break down proteins and fats that bacteria are made from), sufficient wash temperature, (washing at 60 degrees is typically effective against most bacterial species) and sufficient agitation, which will enable more effective soil removal. Lovborg (2015) found that strong enzyme detergents (in this case, Ariel, which is similar to premium supermarket detergents such as Omo/Persil in AU/NZ) both kill and remove bacteria even at cooler wash temperatures, while weak plant-based detergents do not.

Fungal Damage

Fungi and moulds can cause rapid degradation of fabrics (Szostak-Kotowa 2004; McAlister et al. 2006). Unlike bacteria that break down fabrics from the outside in, fungi are particularly destructive as they break down fabrics from the inside out (Szostak-Kotowa 2004).
If nappies have visible mould, or smell of mould, be sure to treat it quickly. Dilute sodium hypochlorite is the most effective method against both mould and spores (Reynolds 2012).

Sun Damage

While fabric maintains its strength for long periods of time when kept dry and out of the weather, when exposed to the outdoors it can deteriorate rapidly (McAlister et al. 2006).
UV Degradation is not typically an issue for your inserts. Cotton fabric, for example, cannot absorb visible light or longer UV (UVA/UVB) wavelengths. Cotton is degraded by UVC (Germicidal) Radiation (McAlister et al. 2006). The good news for line dryers is that UVC radiation is absorbed by ozone in the upper atmosphere (Navy Environmental Health Center 1992) so the risk of UVC degradation is minimal. However, this means that the UV light reaching your washing line does not possess any germicidal properties, ie. the sun is not sanitising the nappies.
UV Degradation of dyes and polymers (such as the polyurethane layer of PUL in your nappies) is possible and much has been written about the topic in the literature. Keep nappy covers, pocket shells, AIOs etc out of the sun for maximum life.


The above photo illustrates UV degradation of a pocket shell; this damage occurred over the course of one day on the line in Brisbane.

Acids, Bases And Bleaches

The degree of degradation of cellulose fabrics is proportional to both the concentration and immersion time in these solutions. While Kraft et al. (2013) did not assess more than one chemical in each of these categories, the mechanism of action on the fabric can be considered equivalent within categories.
Do not use acids (vinegar) or bases (eg. sodium hydroxide). Undiluted bleaches should never be used. Concentrated (dilute) bleach soaks should only be performed following directions and never immersed for longer than recommended. The regular or extended-duration use of acids, bases and bleaches can compromise the degree of polymerization (strength) of cellulose fabrics.
With a good wash routine, there should be no need for ongoing troubleshooting.


Delamination occurs when the plastic backing on the Polyurethane Laminate (PUL) physically comes away from the fabric to which it was bonded. Delaminated PUL looks like a clear plastic sheet that has separated from the fabric. It does not necessarily render a nappy useless, but it could mean it is more susceptible to tearing and when it is torn it will leak.
There are two processes for lamination of PUL. Solvent lamination fuses the fabric and polyurethane film together, while hot melt uses heat activated glue to adhere the fabric and film. It is possible to re-laminate a delaminated nappy by using a tea towel and iron to heat the plastic and stick back onto the fabric but the solution is only temporary. Delaminated nappies can be used as swim nappies.
PUL is not waterproof, it is water resistant. When inserts are saturated moisture will seep through.
Common causes for delamination are; age, prolonged UV exposure, exposure to excessive heat (eg. 90 degree cycle in the washing machine), prolonged soaking or the PUL wasn’t of good quality to begin with.


Kraft, G., Kraft, M., Zeppetzauer, F., Weber, H., Mozdyniewicz, D and Roder, T (2013), Cellulose Degradation During Viscose Processing, Lenzinger Berichte 91 pp. 19 – 22

Navy Environmental Health Center (1992), UltraViolet Radiation Guide, available online from

McAlister, David D., Noelie R. Bertoniere, Phillip J. Wakelyn, Marie-Alice Rousselle, Barbara A. Triplett, Devron P. Thibodeaux, Alfred D. French, Lawrance Hunter, J. Vincent Edwards, and Jr., Wilton R. Goynes. Cotton Fiber Chemistry and Technology, edited by David D. McAlister, et al., CRC Press, 2006. ProQuest Ebook Central

Lovborg, C (2015), NappyLab Diaper Washing Experiments- Temperature and detergent as variables, available online

Szostak-Kotowa, J (2004), Biodeterioration of Textiles, International Biodeterioration & Biodegradation 53 pp. 165–170

Rajilic-Stojanovic, M & de Vosand, W (2014), The first 1000 cultured species of the human gastrointestinal microbiota, FEMS Microbiology Reviews 38 pp. 996–1047

Reynolds, K.A (2012), Occurrence of household mold and efficacy of sodium hypochlorite disinfectant, Journal of Occupational Environmental Hygiene 9(11) pp. 663-669.