What is crosslinking density?
The cross-link density is defined by the density of chains or segments that connect two infinite parts of the polymer network, rather than the density of cross-link junctures. From: Bio-Based Polymers and Composites, 2005.
What is cross linking in physics?
Crosslinking is the general term for the process of forming covalent bonds or relatively short sequences of chemical bonds to join two polymer chains together. The resulting modification of mechanical properties depends strongly on the cross-link density.
How is crosslink density measured?
Traditionally, the crosslink density of rubber can be measured by some methods, such as, “Gel Fraction”, “Swelling Solvent”, or “Compression Modulus”. However, these methods are usually not ideally to be used in industrial production, because they take too long time before the density can be determined.
What does cross linking do?
The goal is to keep the cornea from bulging more. It’s called “cross-linking” because it adds bonds between the collagen fibers in your eye. They work like support beams to help the cornea stay stable. Corneal cross-linking is the only treatment that can stop progressive keratoconus from getting worse.
Does crosslinking increase density?
The bulk density increases with the increase of crosslink density for crosslinked polymers. The higher the temperature is, the more discrete the bulk density distribution is. The distribution of the bulk density with various temperatures for different crosslink densities.
How does cross linking affect the properties of rubber?
In the rubber industry elastomers are usually cross-linked to improve and engineer the physical and chemical properties of the rubber end-products , , . The cross-links prevent flow and provide the rubber products with a high degree of elasticity and toughness even far above their glass-transition temperature.
What is a crosslinking agent?
Crosslinking reagents (or crosslinkers) are molecules that contain two or more reactive ends capable or chemically attaching to specific functional groups (primary amines, sulfhydryls, etc.) on proteins or other molecules. This article describes the chemistry and variety of crosslinkers that exist.
What is cross linking proteins?
Protein cross-linking is the process of binding two or more protein molecules together to facilitate scientific probes on protein-protein interactions. To achieve this effect, specific crosslinking reagents (crosslinkers) are used to chemically join the protein molecules.
How successful is cross linking?
How effective is corneal cross-linking? It is very effective – the success rate is more than 95% for an ‘epi-off’ treatment. In the remaining 5% of patients where there is further progression or change, a second treatment may be required.
Can Cross Linking be repeated?
Corneal Cross-Linking can often be repeated when treatment is not effective.
How does cross linking affect strength?
The results show that increasing the cross-link density leads to larger failure stress and toughness. For larger cross-links density, the second elastic regime of the tropocollagen molecules is activated. Fibrils with high trivalent cross-link density exhibit a more “brittle-like” behavior.
How is the density of a crosslink determined?
It is defined as the number of moles of effective crosslinks per mass or volume of polymer and is the inverse of the average molecular weight or mass between crosslink points, [M.sub.c] Swelling analysis is a useful technique for measuring crosslink density.
How is the cross link density of vinyl polymers affected?
The cross-link density is affected by the functionality of the cross-linker molecule. Vinyl polymers are typically represented as having two functional groups, f, per vinyl group, n:
How is the degree of crosslinking in rubber determined?
The degree of crosslinking is affected by temperature, pressure, and the time of heating time. These conditions will determine the flexibility behaviors of the final rubber. “”Crosslink Density” is used to measure the degree of crosslinking between rubber and sulfur.
Which is better heat resistance or cross linking density?
For the cross-linking polymer used as plastics such as epoxy resin, the greater the cross-linking density, the better the heat resistance and the tensile strength. However, the high degree of cross-linking will lead to a decline in impact strength.