Question

toothbrushes are available with soft, medium and hard bristles, generally made ofpolyamides. a) propose at least two distinctly different ways by which the bristles could becontrolled to provide soft, medium or hard performance. b) if you had bristles from differenttoothbrushes, what tests or experiments would you perform to determine the ways that wereactually used to control the hardness? c) why are polyamide polymers used?

Answer 1

Toothbrush bristle hardness can be adjusted by manipulating the bristle diameter and the degree of polymerization. Tests such as hardness measurements, diameter checks, and polymer chain length analysis can identify the control mechanisms. Polyamides like nylon are used for their strength, abrasion resistance, and flexibility suitable for oral hygiene.

Step-by-step explanation:

The hardness of toothbrush bristles, which are generally made of polyamides like nylon, can be controlled through different methods. Bristle diameter and the degree of polymerization are two possible ways to adjust the hardness. A thin diameter generally leads to softer bristles, while a thicker diameter results in harder bristles. The degree of polymerization, or the length of the polyamide chains, also affects flexibility; shorter chains can make the bristles softer, whereas longer chains can make them harder.

To determine how the hardness of toothbrush bristles is controlled, one could perform tests including hardness testing, measuring the diameter of the bristles, and conducting polymer chain length analysis using spectroscopic methods. Such experiments can help identify the specific attributes that contribute to the bristle stiffness.

Polyamides, such as nylon, are used for bristles because they have good mechanical strength, are resistant to abrasion, can be easily formed into filaments, and they possess a certain degree of flexibility which is necessary for the varied applications within oral hygiene practices.