Definition of plasticity and examples in chemistry

Definition of plasticity and examples in chemistry
Plastic definition and composition

Plastic is any synthetic or semi-synthetic organic polymer. In other words, plastics always contain carbon and hydrogen, although other elements may be present. While plastic can be made from almost any organic polymer, most industrial plastics are made from petrochemicals. Thermoplastics and thermoset polymers are two types of plastics. The name "plastic" refers to plasticity, ability to deform without breaking.

Polymers used to make plastics are almost always blended with additives, including colorants, plasticizers, stabilizers, fillers, and reinforcing agents. These additives affect chemical composition, chemical-mechanical properties and cost of plastic.

Definition of plasticity and examples in chemistry
Thermosets and thermoplastics

Thermoset polymers, also known as thermoset plastics, take a permanent shape when cured. They are amorphous and are believed to have an infinite molecular weight. On other hand, thermoplastics can be heated and reshaped over and over again. Some thermoplastics are amorphous and some have a partially crystalline structure. Thermoplastics typically have a molecular weight between 20,000 and 500,000 amu. (atomic mass units).

Plastic example

Plastic is often referred to as an abbreviation for its chemical formula:

  • Polyethylene terephthalate: PET or PET
  • High density polyethylene: HDPE
  • Polyvinyl chloride: PVC
  • Polypropylene: polypropylene
  • Polystyrene: PS
  • Low density polyethylene: LDPE
  • Properties of plastics

    The properties of plastic depend on chemical composition of constituent parts, their location and processing.

    All plastics are polymers, but not all polymers are plastics. Plastic polymers are made up of chains of linked subunits called monomers. When identical monomers are joined together, they form homopolymers. Various monomers combine to form copolymers. Homopolymers and copolymers may be linear or branched.

    Other plastic properties include:

  • Plastic is usually hard. These can be amorphous solids, crystalline solids, or semi-crystalline solids (crystallites).
  • Plastic is generally a poor conductor of heat and electricity. Most of them are insulators with high dielectric strength.
  • Vitreous polymers tend to be rigid (eg polystyrene). However, flakes of these polymers can be used as films (eg polyethylene).
  • Almost all plastics exhibit elongation under load and do not recover when load is removed. It's called "crawling".
  • Plastic is generally durable and degrades slowly.
  • Fun facts about plastic

    More plastic facts:

  • The first fully synthetic plastic was Bakelite, created in 1907 by Leo Baekeland. He also coined word "plastic".
  • The word "plastic" comes from Greek word plastikos which means that it can be shaped or shaped.
  • About a third of all plastic produced is used to make packaging. Another third goes to siding and plumbing.
  • Pure plastics are generally water-insoluble and non-toxic. However, many additives in plastics are toxic and can end up in environment. Examples of toxic additives include phthalates. Non-toxic polymers can also decompose into chemicals when heated.