ESR Studies on Fracture Mechanism of Solid Polymers Induced by Mechanical Fracture

我们speculated that a mehcano anion and a mechano cation were produced by a heterolytic carbon-carbonbond scission due to the mechanical fracture of solid polymer.The production of the mechano anionswas assigned by a detection of tetracyano ethylene anion radical （TCNE^<·^^->）fractured with TCNE in vacuo in the dark at 77k using ESR method. the mechano anions被诊断from polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP)，and polyvinylidenefluouride .The yields of The mechano anions （ratios of The heterolytic）carbon-carbon bond scission) were obtained as PTFE (16%), PE (27%)， PP(37%)，PVDF (85%)The production of PVDF mechano cation was assigned by The detection ofpolyisobutylvinylether (IBVE) produced by a cationic polymerization on isobutylvinylether （IBVE）initiated by PVDF mechano cation. The molecular weights of PIBVE were obtained as Mw=6.2 X 10^4，Mn=2.3 X 10^4.We concluded that the mechano anions and the mechano cations were produced by thehomolytic carbon-carbon bond scission of polymer main chain due to mechanical fracture of solidpolymers,and the ionic yield was affected by a polarity of the carbon carbon bond due to an electron affinitysubstitution groups attached to the polymer chain。

We speculated that a mehcano anion and a mechano cation were produced by a heterolytic carbon-carbon bond scission due to the mechanical fracture of solid polymer.The production of the mechano anions was assigned by a detection of tetracyano ethylene anion radical (TCNE^<・^^->) from polymers fractured with TCNE in vacuo in the dark at 77 K using ESR method. The mechano anions were obtained from polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), and polyvinylidenefluouride (PVDF).The yields of the mechano anions (ratios of the heterolytic carbon-carbon bond scission) were obtained as PTFE (16 %), PE (27 %), PP(37 %), and PVDF (85 %)The production of PVDF mechano cation was assigned by the detection of polyisobutylvinylether (PIBVE) produced by a cationic polymerization on isobutylvinylether (IBVE) initiated by PVDF mechano cation. The molecular weights of PIBVE were obtained as Mw=6.2 X 10^4, Mn=2.3 X 10^4.We concluded that the mechano anions and the mechano cations were produced by the homolytic carbon-carbon bond scission of polymer main chain due to mechanical fracture of solid polymers, and the ionic yield was affected by a polarity of the carbon-carbon bond due to an electron affinity of substitution groups attached to the polymer chain.