Plastics - materials consisting of synthetic polymers (man-made and non-naturally occurring) or modified natural polymers and modifying additives such as, for example, powder or fibrous fillers, thermal stabilizers, UV stabilizers, flame retardants, anti-static agents, foaming agents, dyes, etc. The term "plastics" functions in addition to commonly used colloquial terms, e.g. plastic. The strictest term covering all materials containing as the main component of the polymer, without distinction whether it is of artificial or natural origin, is the term "polymeric materials".

Polymeric materials are a separate group of materials in addition to ceramics, metals and their alloys and wood, which, due to the structure of cellulose molecules, also belong to natural polymeric materials.

The advantages of plastics are the ease of processing (low costs of making large series of finished products compared to other groups of materials). This last feature mainly decided about the great development of the plastics industry in the 20th century.

The disadvantages of polymer materials are: low resistance to high temperatures and lower mechanical properties (eg hardness, susceptibility to creep) in comparison to, for example, metals or ceramics. Although the mechanical properties of most polymer materials are smaller in relation to metals, fibers made of some polymer materials (eg aromatic polyamides - Kevlar) can show higher tensile strength (above 3500 MPa) even in relation to high quality steels. Polymer composites are characterized by very high strength.

The disadvantages of polymer materials include a very long time of decomposition if a man litter them with the natural environment or when they are stored in landfills. From the beginning of their mass production, 9% was recycled, 12% were burned, and 79% were thrown away to landfills [1]. At the same time, polymeric materials are excellent secondary materials for reprocessing in recycling technologies, where at the end they should end "their lives" as fuel, due to the high calorific value, often comparable to coal. Despite advanced technologies in waste incineration plants, which eliminate the emission of harmful compounds into the environment [footnote needed], there is still a high social resistance during the selection of the waste incineration plant location. The combustion of polymeric materials in households is prohibited, including due to the low combustion temperature, it can cause the emission of strongly poisonous compounds into the atmosphere.