Definition - What does Polymer mean?
A polymer is a substance whose molecules have high molar masses and are composed of a large number of repeating units. Polymers can be both natural and synthetic.
Polymers have a range of applications that far exceed that of any other class of material available. Its applications include a wide range of applications, such as:
- Packaging materials
- Textile and industrial fibers
- Electronic devices
- Biomedical devices
- Optical devices
- Precursors for many newly developed high-tech ceramics
Polymers have unique physical properties, including toughness, visco-elasticity, and a tendency to form glass and semi-crystalline structures rather than crystals. Polymers are brittle at low temperatures and have low impact strengths, and have a brittle-to-ductile transition over a narrow temperature range.
Corrosionpedia explains Polymer
A polymer is a large molecule composed of many repeated subunits, known as monomers. Due to their broad range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function.
Natural polymers include:
Synthetic polymers include:
Polymers are formed by chemical reactions in which a large number of monomers are joined sequentially, forming a chain. In many polymers, only one monomer is used. In others, two or three different monomers may be combined. Polymers are classified by the characteristics of the reactions by which they are formed:
- Addition polymer - when all atoms in the monomers are incorporated into the polymer
- Condensation polymer - when some of the atoms of the monomers are released into small molecules, such as water
Most addition polymers are made from monomers containing a double bond between carbon atoms. Such monomers are called olefins, and most commercial addition polymers are polyolefins.
Condensation polymers are made from monomers that have two different groups of atoms which can join together to form, for example, ester or amide links. Polyesters are an important class of commercial polymers, as are polyamides (nylon).
Properties of polymers are changed through polymer degradation. Polymer products can be affected by environmental factors, such as:
- Galvanic action
Degradation often occurs due to the scission of polymer chain bonds via hydrolysis, leading to a decrease in the molecular mass of the polymer. Polymer degradation causes failure of polymer products.
Polymer degradations are frequently undesirable, but in some cases, such as biodegradation and recycling, they may be intended to prevent environmental pollution. Degradation can also be useful in biomedical settings. The most common form of degradation is a decrease in polymer chain length.