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Chemistry LibreTexts

21.3: Laundry Auxiliaries- Softeners and Bleaches

  • Page ID
    152270
  • Learning Objectives

    • Describe a fabric softener and its use.
    • Describe bleaches and their use.

    A fabric softener (or conditioner) is a conditioner that is typically applied to laundry during the rinse cycle in a washing machine. In contrast to laundry detergents, fabric softeners may be regarded as a kind of after-treatment laundry aid.[1]

    Machine washing puts great mechanical stress on textiles, particularly natural fibers such as cotton and wool. The fibers at the fabric surface are squashed and frayed, and this condition hardens while drying the laundry in air, giving the laundry a harsh feel. Adding a liquid fabric softener to the final rinse (rinse-cycle softener) results in laundry that feels softer.[2][1]

    Fabric softeners coat the surface of a fabric with chemical compounds that are electrically charged, causing threads to "stand up" from the surface and thereby imparting a softer and fluffier texture. Cationic softeners, like those shown in Figure \(\PageIndex{1}\). bind by electrostatic attraction to the negatively charged groups on the surface of the fibers and neutralize their charge. The long aliphatic chains then line up towards the outside of the fiber, imparting lubricity.

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    Figure \(\PageIndex{1}\) Cationic surfactants in fabric softeners. Source: Wikipedia

    Fabric softeners impart antistatic properties to fabrics, and thus prevent the build-up of electrostatic charges on synthetic fibers, which in turn eliminates fabric cling during handling and wearing, crackling noises, and dust attraction. Also, fabric softeners make fabrics easier to iron and help reduce wrinkles in garments. In addition, they reduce drying times so that energy is saved when softened laundry is tumble-dried. Last but not least, they can also impart a pleasant fragrance to the laundry.[1]

    Risks

    As with soaps and detergents, fabric softeners may cause irritant dermatitis.[5] Manufacturers produce some fabric softeners without dyes and perfumes to reduce the risk of skin irritation. Fabric softener overuse may make clothes more flammable, due to the fat-based nature of most softeners. Some deaths have been attributed to this phenomenon,[6] and fabric softener makers recommend not using them on clothes labeled as flame-resistant.[citation needed]

    Laundry Bleaches: Whiter Whites

    Bleach is the generic name for any chemical product which is used industrially and domestically to clean, and to remove stains. It often refers, specifically, to a dilute solution of sodium hypochlorite, also called "liquid bleach".

    Many bleaches have broad spectrum bactericidal properties, making them useful for disinfecting and sterilizing and are used in swimming pool sanitation to control bacteria, viruses, and algae and in many places where sterile conditions are required. They are also used in many industrial processes, notably in the bleaching of wood pulp. Bleaches also have other minor uses like removing mildew, killing weeds, and increasing the longevity of cut flowers.[1]

    Bleaches work by reacting with many colored organic compounds, such as natural pigments, and turning them into colorless ones. While most bleaches are oxidizing agents (chemicals that can remove electrons from other molecules), some are reducing agents (that donate electrons).

    Chlorine, a powerful oxidizer, is the active agent in many household bleaches. Since pure chlorine is a toxic corrosive gas, these products usually contain hypochlorite which releases chlorine when needed. "Bleaching powder" usually means a formulation containing calcium hypochlorite.

    Oxidizing bleaching agents that do not contain chlorine are usually based on peroxides such as hydrogen peroxide, sodium percarbonate, and sodium perborate. These bleaches are called 'non-chlorine bleach,' 'oxygen bleach' or 'color-safe bleach.'[2]

    Reducing bleaches have niche uses, such as sulfur dioxide used to bleach wool, either as gas or from solutions of sodium dithionite;[3] and sodium borohydride.

    Bleaches generally react with many other organic substances besides the intended colored pigments, so they can weaken or damage natural materials like fibers, cloth, and leather, and intentionally applied dyes such as the indigo of denim. For the same reason, ingestion of the products, breathing of the fumes, or contact with skin or eyes can cause health damage.

    Summary

    • A fabric softener is an after-treatment laundry aid that imparts a softer and fluffier texture.
    • Bleach is the generic name for any chemical product that is used industrially and domestically for cleaning and stain removal.

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