Author/Authors :
Liu، نويسنده , , Gengxin and Ma، نويسنده , , Hongwei and Lee، نويسنده , , Hyojoon and Xu، نويسنده , , Hongde and Cheng، نويسنده , , Shiwang and Sun، نويسنده , , Hao and Chang، نويسنده , , Taihyun and Quirk، نويسنده , , Roderic P. and Wang، نويسنده , , Shi-Qing، نويسنده ,
Abstract :
We explored a new synthetic strategy for ultra-high molecular weight long-chain branched (LCB) polymers with equal spacing between adjacent branch points. This method can synthesize LCB polystyrene (LCB-PS) with total molecular weight of 4.9 million g/mole, 16 branches of 140 kg/mole and polydispersity index of 1.5. The introduction of multiple branch points with long side chains allows the LCB-PS to resist the elastic-driven decohesion. Even after a large step extension of stretching ratio λ = 7.4, the specimen would not undergo elastic breakup that occurs in linear PS even at λ = 2.7. These LCB-PSs are also extraordinarily more stretchable during startup uniaxial extension, with the maximum engineering stress emerging at stretching ratio λ max ≈ 4 M bb / M e , where Mbb is the molecular weight of backbone and Me is the molecular weight between entanglements.
