The solvent used for the sol content and CLD determinations was toluene. For the determination, 5 g of the rubber was placed in 300 mL of the solvent in labeled bottles, and allowed to swell for 16 days at 21C. The sample weight was measured
every day until it reached equilibrium. The solvent was then removed. The samples were dried in air for 9 h and then in an oven at 85C for 24 h, and allowed to stand for an extra 24 h at 23C before reweighing. The CLD was calculated using the Flory–Rehner equation