Q&A: polym|what criteria are there for selecting a crosslinking agent for polymerizable groups in polym. reactions?
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Q&A–: what criteria are there for selecting a crosslinking agent for polymerizable groups in polym. reactions?
for example , is there the special cross linking agents for allyl compounds?
The following is the answer: (Hint: The reader is not the correct identification.)
Answer by neillup
Among the factors that I have used and seen used:
1) Toxicity
2) Cost
3) Compatability with the other components of the polymer
4) Reactivity
5) Stability when incorporated into the molecule
6) Number of reacting sites (difunctional, trifunctional, tetrafunctional, etc.)
7) When the crosslinking takes place (during the polymerization, subsequent to the polymerization) 
“Tightness” of crosslink desired – Very loose crosslinking as in a high swelling gel or very frequent crosslinks as in a structural thermoset
There are special crosslinking agents for allyl compounds. Divinyl benzene and pentaerythritol tetracrylate are such compounds.
An example of a crosslinking agent used for subsequent crosslinking is divinylsulfone (DVS) This is commonly used in responsive gels. However, it is exceedingly expensive (probably $ 1000/lb or more) and rather toxic, so it is only used in laboratory work for demonstrations of concept.
Answer by Mr Hex Vision
Theres no special agents for allyl compounds that make crosslinking, but it depends on how many functional groups there are.
Most polymers are formed with compound with 2 functional groups (both the same) that react with another compound with 2 others, or in the case of allyl groups one is used and it is polymerised by radical means. In these cases a 2 D linear polymer is formed and there is no crosslinking.
For cross linking to occur you have to be able to form a 3 D polymer.
In the case first case as I said above instead of one of the monomers having 2 functional groups that react it can have 3 functional groups. While 2 of the functional groups react with other functional groups the third one can further react to form a new polymer chain and hence crosslinking happens.
In the case of ally compound a di ally compound such as divinylbenzene is to link growing chains up. The degree of crosslinking will depend on the amoult of the di ally compound you would add.
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polym
Welcome to my blog,In the blog: natural polymer .
polym–: Which evolutionary force is acting in the self-incompatibility system? The S-alleles are one of the most polym
orphic and rapidly evolving gene systems in plants. What would be a good hypotheis to explain this fact.
The answer in the following: (Hint: The reader is not the correct identification.)
Answer by Some Dude
Avoidance of inbreeding.
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