The use of NMR to measure crosslink densities in elastomer blends to enhance properties

Swollen-state NMR, a technique developed over the past 10 years, has shown considerable utility for measuring crosslink densities in both filled and u nfilled blend vulcanizates. Factors affecting crosslink density distributio ns have been identified for three different blends systems, NR/NBR, NR/EPDM and NR/BR, Where a gross maldlistribution in crosslink distribution exists in a blend, improvements there lead to better physical properties, Even in a blend system where crosslinks distributions are already seemingly reason ably well balanced, changes can be made to the crosslink distribution which benefit physical properties.