Search results
Results from the WOW.Com Content Network
In chemistry and biology, a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural polymers (such as proteins ).
Gelation occurs when a polymer forms large interconnected polymer molecules through cross-linking. [1] In other words, polymer chains are cross-linked with other polymer chains to form an infinitely large molecule, interspersed with smaller complex molecules, shifting the polymer from a liquid to a network solid or gel phase.
Finally, the formation of cross-linked polymers involves tetrafunctional structural units. For example, in the synthesis of cross-linked polystyrene, a small fraction of monomeric styrene (or vinylbenzene) is replaced by 1,4-divinylbenzene (or para-divinylbenzene). Each of the two vinyl groups is inserted into a polymeric chain, so that the ...
Polyfullerene is a basic polymer of the C 60 monomer group, in which fullerene segments are connected via covalent bonds into a polymeric chain without side or bridging groups. They are called intrinsic polymeric fullerenes, or more often all C 60 polymers. Fullerene can be part of a polymer chain in many different ways.
The use of non-covalent interactions such as hydrogen bonding, pi-stacking or crystallization that lead to physical cross-links between polymer chains is one way of introducing dynamic cross-linking. The thermoreversible nature of the physical cross-links results in polymer materials with improved mechanical properties without losing ...
In polymer chemistry, an organogel is a class of gel composed of an organic liquid phase within a three-dimensional, cross-linked network. Organogel networks can form in two ways. The first is classic gel network formation via polymerization.
The sugar component consists of alternating residues of β-(1,4) linked N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Attached to the N-acetylmuramic acid is an oligopeptide chain made of three to five amino acids. The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer.
Cross-linked polymers: Wide-meshed cross-linked polymers are elastomers and cannot be molten (unlike thermoplastics); heating cross-linked polymers only leads to decomposition. Thermoplastic elastomers , on the other hand, are reversibly "physically crosslinked" and can be molten.