Currently, matches are a very ordinary household item, which at first glance is not of particular interest. Nevertheless, these thin wooden sticks have a whole range of properties that ensure the effectiveness and safety of their use. The composition of matches is very complex and includes many components, each of which performs its own function.
What matches are made of
Any match consists of two parts:
- wood stick, otherwise called straw;
- incendiary head.
The latter functions only when in contact with a special layer called a spread or grater. It is applied to the side surfaces of the box and serves for the primary ignition of the match. The chemical composition of the grating mass is very complex.
Straws are most often made from pine or aspen, but poplar, linden and other rocks that are suitable for their properties can also be used. In this case, a thin tape (veneer) removed from the tree bark serves as a raw material.
The head is the mosta complex and multicomponent part of a match. It is an incendiary mass attached to the end of a straw.
What properties should a match have
In addition to the well-known ability to ignite as a result of friction against the boxes, matches have the following properties:
- the ember of the burnt part of the straw does not smolder, which is necessary for fire safety;
- the flame that arose on the head does not go out immediately, but goes to the straw;
- slag from a burnt head does not crumble;
- The spread does not ignite completely (only at the point of contact with the head).
All these conditions are fulfilled due to the special composition of matches. Moreover, even the simplest part - the straw - is impregnated with special chemicals.
Composition of match head
Currently, there are many formulations of incendiary masses. However, in any match, the composition of the head always includes the following groups of substances:
- oxidizing agents - give oxygen, fueling the combustion process (potassium bichromite or chlorate, berthol s alt, pyrolusite, etc.);
- combustible components - a variety of substances (sulfur, organic adhesives of plant and animal origin, phosphorus compounds) can be used as them;
- dyes - give the head a certain color;
- fillers - prevent violent combustion (iron oxide, crushed glass);
- acidity stabilizers - prevent the occurrence of side chemical reactions (calcium carbonate, zinc oxide andetc.);
- gluing substances - hold all components together and at the same time have combustible properties.
Some components closely interact with each other, performing several functions at once. Thus, pyrolusite not only serves as a source of oxygen, but also catalyzes the decomposition of Berthol s alt, and iron oxide prevents explosive ignition and at the same time gives the head a characteristic color (rust).
Thus, it is fundamentally wrong to say that the key component of the composition of a match is sulfur or phosphorus. The presence of a combustible substance that can be ignited by friction will not in itself provide the desired effect. The ignition of the head and the spread of fire to the base of the straw is a whole chain of physical and chemical processes.
The composition of matches also depends on their variety. So, some are able to ignite on any surface that provides sufficient friction, while others - only when interacting with the appropriate coating applied to the box. In the latter case, we are talking about the so-called safety matches, the heads of which do not contain the primary igniting substance, which is phosphorus sulfide. This component is present only in the grating mass.
Straws
Straw wood must meet several requirements:
- high porosity - provides good chemical absorption capacity;
- rigidity - prevents the matchstick from bending when it hits the surface to ignite;
- easy to handle.
The last property is necessary for ease of manipulation with raw materials in the manufacture of thin bars of the desired size.
Straws cut from wood veneer are impregnated with special anti-smoldering agents (phosphoric acid, dimonium phosphate), which form a film on its surface during the burning of a match. The wood near the head contains paraffin, which contributes to the effective spread of the flame. Without this component, the match would go out almost immediately after ignition.
Grate mass
The composition of the grating mass also depends on the type of matches and the recipe of a particular manufacturer. The most template version corresponds to the following scheme:
- flammable substance - made from red phosphorus;
- pyrolusite - performs the same functions as in the head;
- calcium carbonate;
- poorly burning substances (red lead, kaolin, calcium carbonate, gypsum) - prevent ignition of the entire spread;
- antimony chloride;
- fastening component (adhesive).
Red phosphorus plays the main role in ignition. And the necessary friction is created by the glass powder, which is present in the spread and head, giving their surfaces a roughness. This component also limits the spread of flash across the plaster.
How does a fire happen
The ignition of a match does not start at all on the head, but on a special surface of the box. As noted above, red phosphorus is responsible for the spark. When rubbing the head againstWhen put on, it turns into white phosphorus, a substance that ignites easily on contact with oxygen. As a result, a spark is formed, which ignites the sulfur and Berthol s alt contained in the head. Other combustible components then ignite.
At the same time, the flame on the match head is supported by oxidizing agents, and on the spread it immediately goes out due to substances that block its spread.
