Efficient disentanglement of polycarbonate melts under complex shear field

Investigating the Influence of Incorporation of Boron Nitride on the Kinetics of Isotactic Polypropylene Entanglement Recovery

“…Compared to those before the shear experiment, the lower value of zeroshear viscosity can be observed in all samples after the shear experiment, which is consistent with previous researche studies. 5,18,39 This observation indicates that the molar mass between entanglement (M e ) of samples, which is inversely proportional to the entanglement density, is much larger after the shear experiment. What needs to be illustrated is that this reduction in zero-shear viscosity is not because of the orientation structure of BN shown in Figure 1 or thermal degradation, which will be discussed in the FTIR results.…”

“…Hence, it is theoretically feasible to reduce the melt viscosity of polymer materials by reducing their entanglement density. Moreover, this restriction of the movement of molecular chains has an important effect on kinetic processes related to the movement of molecular chains or segments, such as glass transition, crystallization, melt flow rate (MFR), etc. − …”

“…When an external field is applied to the polymer melt, the entanglements between molecular chains are partially disentangled and the ability of the molecular chain movement is enhanced . This method, known as the treatment of the external processing field, , compared with other current methods, such as the dilute solution method and controlled synthesis of polymer, , is the most efficient way for preparing partially disentangled polymers and has the potential capability of preparing partially disentangled polymers on a large scale . Ibar ,, proposed that disentangling polymers at their molten state is more applicable for large-scale production of the “in-pellet” disentangled materials for certain polymers.…”

“…17 This method, known as the treatment of the external processing field, 19,20 compared with other current methods, such as the dilute solution method 21 and controlled synthesis of polymer, 22,23 is the most efficient way for preparing partially disentangled polymers and has the potential capability of preparing partially disentangled polymers on a large scale. 18 Ibar 19,20,24 proposed that disentangling polymers at their molten state is more applicable for large-scale production of the "in-pellet" disentangled materials for certain polymers. However, this disentangled state of disentangled polymers cannot be effectively maintained.…”

Investigating the disentanglement of long chain branched polypropylene under different shear fields

“…[2][3][4] Entanglements between macromolecules, regardless of twists, knots and link or loops, have a significantly effective influence on the viscoelastic behavior. Subsequently, the processability, 5,6 crystallization behavior, [7][8][9] and mechanical properties in the solid state 10,11 would be altered dramatically. The ways to disentanglement involving polymerization, 12,13 dilute solution method, [14][15][16] slow crystallization from solution 17 and shear modification [18][19][20][21] were widely applied to understand the role of entanglement on the comprehensive properties of polymer materials.…”