Pore structure of the phenolic porous material and its mechanical property

To enlarge the knowledge about the control methods of pore size of phenolic porous material and to know the effect of pore size on its mechanical property, experiments were carried out. On the basis of the theory of bubble nucleation, large stirring speed can overcome the surface energy of bubble formation and the nucleating agent can provide a large number of nucleation sites for foaming system. We adopted the methods of accelerating the stirring rate and adding nucleating agent to improve bubble nucleation. Pore size, size distribution and the effects of stirring speed and nucleating agent concentration on them were investigated by scanning electron microscope and computerized image analysis program. Results showed that with the increase of stirring speed, the mean pore size decreases from 246 to 138 µm and the structural homogeneity of phenolic porous material was improved obviously. The nucleating agent has a great effect on the pore structure and optimal amount (5%) at which the pore size is small in level of micrometer and has a good distribution. In addition, the compression testing was carried out by Universal Testing Machine and the test results suggested that the change of micrometer pore structure improves the compression strength of porous material effectively.