The Gelling Behavoir of Phenol Resin Gel Under the Shearing of Oscillator

In order to study the gelling behavior of the phenolic resin gel under dynamic conditions,the IKA oscillator was employed to determine the relationship between shearing time and the viscosity of phenolic resin gel,the difference between the gelation time under static condition and that under shearing condition,and the critical gelling velocity and the restorability of the viscosity after shearing.The results show that the gelation time of phenolic resin gel is delayed and the strength of the gel is reduced along with the increase of shearing velocity.Compared with the gelation time under static condition,the initial gelation time is advanced under low shearing velocity(10.47~15.71 s-1),and the initial gelation time is delayed under high shearing velocity(18.32~23.55 s-1).The gelation time is delayed and the gel strength is reduced with the increase of polymer concentration and cross linker concentration.The initial gelation time under oscillatory shearing is 2~4 hours shorter,and the initial viscosity is 0.04~1.00 lower than that under static conditions,the final gelation time is 2~6 hours longer and the final viscosity is 0.65~0.95 times lower than that under static conditions.There exists critical gelling velocity,when the shearing velocity is higher than the critical value,the phenolic resin gel is not able to form,and vice versa.The viscosity is able to restore after the shearing action is removed,and the restorability is declined with the extenion of shearing time,and the reduction of polymer concentration and crosslinker concentration.