| 摘要 |
A polyisoolefin-based polymer composition having a multimodal molecular weight distribution and a level of unsaturation of greater than about 4 mol% is described, which can be prepared by co-polymerizing 70-96 vol% isoolefin monomer and 30-4 vol% β- pinene or multi-olefin monomer, based on volume of isoolefin monomer and β-pinene or multi-olefin monomer, in a solution comprising 0-30 vol% aliphatic hydrocarbon diluent, based on volume of the solution, and an alkylaluminum halide initiator system. The polyisoolefin-based polymer composition has a multimodal molecular weight distribution having a first molecular weight fraction having a peak molecular weight (Mp) of less than about 300 kg/mol, and a second molecular weight fraction having a peak molecular weight (Mp) of greater than about 1000 kg/mol or at least 3 times greater than the Mp of the first molecular weight fraction. The composition is processable while maintaining physical characteristics and dimensional stability necessary for handling prior to vulcanization. |
