Re: I need the structure of rubber after vulcanization.

Susan,

It is important to recognize that all representations of polymers are AVERAGE 
data, not exact schematics of a molecule that my bretheren in inorganic 
chemistry have the benefit of. Also, I don't have the ability [or skill] to do 
justice to the various cis/trans conformations encountered and for simplicity 
I'll omit the hydrogens.

   C       C
   |       |
   C=C     C=C
  /    \   /  \
~C      C-C    C-C~
 |        |
 |        -----Sx
 | C       C   |
 Sx|       |   |
 | C=C     C=C |
 |/   \   /   \|
~C     C-C     C-C~




The ~ represents the rest of the chain and x varies from 1 to 8.

For rubber articles such as surgical gloves the sulphur/rubber ratio is about 
3:100. For a hard rubber object [combs, bowling balls, Ebonite] the ratio is 25 
to 35:100.

It isn't as orderly as shown: not all sulphur forms bonds with two different 
rubber molecules. Sometimes it links back on to the same one it began on. 
Remember, too, that this all happens in three dimensions so that the actual 
crosslink density must include entanglements that are formed when one rubber 
molecule is "tied up" by another one even in the absence of virtual links.

Some latex protein is also immobilized by this reaction, but the requirement of 
high flexibility for a glove also requires a relatively low degree of "cure" 
and much of the latex proteins remain labile and extractable and, ultimately, 
allergenic to sensitized individuals.

This is very serious public policy problem for the government [and especially 
the CDC and FDA] and one which has not recieved enough attention.

I don't know the focus of your paper, but don't ignore other latex products 
such a catheters, ventilators, toy ballons and condoms.

I've spent 10 years in and out of this exact field and would be glad to provide 
whatever additional help I can.

Your MAD Scientist,

Ken Johnsen