Polymers

spherical semicrystalline regions inside non-branched linear polymers

partial alignment of polymer molecular chains, resulting in "semi-crystalline" structures

Polyprenols are natural long-chain isoprenoid alcohols of the general formula H-(C5H8)n-OH, where n is the number of isoprene units. Any prenol with more than 4 isoprene units is a polyprenol. Polyprenols play an important function, acting as natural bioregulators and are found in small quantities in various plant tissues. Dolichols, which are found in all living creatures, including humans, are their 2,3-dihydro derivatives.

Polylysine refers to several types of lysine homopolymers, which may differ from each other in terms of stereochemistry (D/L; the L form is natural and usually assumed) and link position (α/ε). Of these types, only ε-poly-L-lysine is produced naturally.

subfield of materials science concerned with polymers such as plastics and elastomers

thumb|200px|right|Repeating unit of parylene thumb|200px|right|The para-xylylene monomer

member of a class of materials analogous to metal alloys, in which at least two polymers are blended together to create a new material with different physical properties.

polymers with with artificial molecular recognition sites generated by molecular imprinting

epoxy-based molecule

brittle failure of thermoplastic polymers

Reptation is the thermal motion of very long linear macromolecules in entangled polymer melts or concentrated polymer solutions. Derived from the word reptile, reptation suggests the movement of entangled polymer chains as being analogous to snakes slithering through one another. Pierre-Gilles de Gennes introduced (and named) the concept of reptation into polymer physics in 1971 to explain the dependence of the mobility of a macromolecule on its length. Reptation is used as a mechanism to explain viscous flow in an amorphous polymer. Sam Edwards and Masao Doi later refined reptation theory.

polymer structure with linear chains connected to a central core

Polybutene is an organic polymer made from a mixture of 1-butene, 2-butene, and isobutylene. C4 hydrocarbons, produced during ethylene steam cracking in oil processing, are also used as supplemental feed for polybutene. It is similar to polyisobutylene (PIB), which is produced from essentially pure isobutylene made in a C4 complex of a major refinery. The presence of isomers other than isobutylene can have several effects including: lower reactivity due to steric hindrance at the terminal carbon in, for example in polyisobutenylsuccinic anhydride (PIBSA) dispersant manufacture; and in the mole

narrow zone of intense shear strain during material deformation

macromolecule involving monomeric sequence-control

permeable membrane placed between the anode and cathode of an electrochemical cell

Equation in time–temperature superposition

Vitrimers are a class of plastics, which are derived from thermosetting polymers (thermosets) and are very similar to them. Vitrimers consist of molecular, covalent networks, which can change their topology by thermally activated bond-exchange reactions. At high temperatures, they can flow like viscoelastic liquids; at low temperatures, the bond-exchange reactions are immeasurably slow (frozen), and the Vitrimers behave like classical thermosets at this point. Vitrimers are strong glass formers. Their behavior opens new possibilities in the application of thermosets, such as a self-healing mat

photo-oxidation of polymers

cracks in many different elastomers due to ozone attack

thumb|Crazes in polystyrene (PS) Crazing is a yielding mechanism in polymers characterized by the formation of a fine network of microvoids and fibrils. These structures (known as crazes) typically appear as linear features and frequently precede brittle fracture. The fundamental difference between crazes and cracks is that crazes contain polymer fibrils (5-30 nm in diameter), constituting about 50% of their volume, whereas cracks do not. Unlike cracks, crazes can transmit load between their two faces through these fibrils.

technique in polymer chemistry

chemical compound