Polyhydrocarbons with Aromatic Rings in the Main Chain

1 POLYHYDROCARBONS WITH AROMATIC RINGS IN THE MAIN CHAIN General aspects 

Polymers with more complicated structures, containing triple bonds in addition to the aromatic cycles in the backbone or having substituents on the aromatic ring, also are known and have specific applications. 

Thermosetting phenolic resins form a separate class of polymers containing aromatic rings and aliphatic carbon groups in the polymeric network. These resins are formed from the reaction of phenol (or substituted phenols) with formaldehyde. The fully crosslinked macromolecule is insoluble and infusible. Other thermosetting resins are known in practice, some derived from the reaction of melamine or of urea with formaldehyde. Because these have a different chemical structure, containing nitrogen, they are included in a different class (see Section 15.3). 

6% of products are volatile at 25 C and consist of 2.83% xylene, 0.29% toluene, 0.28% methylethylbenzene, 0.14% methylstyrene, 0.06% benzene, products nonvolatile at 25° C consist of dimeric to octa meric fragments 

toluene, p-xylylene, p-ethy toluene, p-methyldibenzyl, 1,2-di-p-to y ethane, 4,4 -dimethyistilben0 79% residue, 10% chain fragments, 11% volatiles comprising Hi, CHj, HjO, HCI (from the catalyst) oligomers, no benzene or biphenyl 

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