1. Fifteen kilogram of polychloroprene is vulcanized with 5.2 kg sulfur. What fraction of the possible crosslink sites is bonded to sulfur crosslinks, assuming that, on the average, 5.5 sulfur atoms participate in each crosslink?
2. Compute the weight percent sulfur that must be added to completely crosslink an alter- nating acrylonitrile-butadiene copolymer, assuming that four sulfur atoms participate in each crosslink.
3. The vulcanization of polyisoprene is accom- plished with sulfur atoms according to Equa- tion 15.4. If 45.3 wt% sulfur is combined with polyisoprene, how many crosslinks will be associated with each isoprene repeat unit if it is assumed that, on the average, five sulfur atoms participate in each crosslink?
4. For the vulcanization of polyisoprene, com- pute the weight percent of sulfur that must be added to ensure that 10% of possible sites will be crosslinked; assume that, on the av- erage, 3.5 sulfur atoms are associated with each crosslink.
5. Demonstrate, in a manner similar to Equa- tion 15.4, how vulcanization may occur in a chloroprene rubber.