ACTUATION FORCE testing allows measurement of the force required to, for example, release hair fixatives or air freshening sprays from aerosols; liquid soap, shampoo or cream from dispensers.
Manually-actuated spray pump dispensers or finger pumps rely on the consumer to generate a hydraulic pressure in the pumping engine in order to dispense the fluid. Dispenser designs may change or vary or the ever-increasing market for child friendly products may require adaptations.
When operating a pump-type liquid soap dispenser, for example, a child may have difficulty applying sufficient force in the appropriate direction to operate the pump, which may cause the dispenser to move, tip, or otherwise fail to discharge the product toward the intended target. An actuation force test typically uses a hemispherical probe to apply the force and provides an imitative test to assess such issues.
COHESIVENESS is the tendency of a product to cohere or stick together. The intermolecular attraction by which the elements of a body or mass of material are held together determine its cohesiveness.
The property is related to the internal stickiness of a product and is usually determined by measurement of the amount of force to remove an item from the product mass.
High cohesiveness may be favourable for products such as paint where easy removal of a brush from the main mass of paint needs to be a clean separation and without the tendency to extend from the surface of the mass to the brush for a considerable distance. However, low cohesiveness may be a favourable property of a product such as honey or syrup where considerable extension of the product from its main body of material is accepted.
COMBABILITY is the ease with which hair can be combed. Keeping healthy and manageable hair is very important as hair and hairstyle contributes to a large extent to the overall facial image of a person.
The loss in manageability can directly be attributed to an alteration of the hair surface. The state of the cuticle governs the frictional properties of hair fibres and determines how the hair feels to the touch and how it combs.
These physical changes lead to a rough hair surface and can directly be correlated to the fact that higher forces will be required to comb, for example UV-damaged hair.
Combability measurement is a method of choice to assess any alteration of the hair cuticle due to external aggressions and has already been proven to be a sensitive tool to detect UV-induced hair damage.
Halina Stanley investigates the history of chewing gum, how the chemistry of the gum affects its properties, and how scientists are using this knowledge to make chewing gum less of a pollutant.
Here's a taster...
"Love it or hate it, chewing gum is a ubiquitous and usually benign activity. Benign, that is, until some idiot decides to put some in your hair. Wouldn’t it be nice if gum didn’t stick to carpets, shoes and the underside of school desks? Terry Cosgrove, professor of chemistry at Bristol University, UK, has decided to take action; his easily removable chewing gum may save millions in cleaning bills.
