Pore Structure Of The Phenolic Porous Plastic And Its Mechanical Property

Phenolic porous plastic is an important porous material, which grows at a rapid pace in current material science. The fine chemical structure gives phenolic porous plastic excellent properties, including low flammability, no dripping during combustion and low generation of toxic gas during combustion, high dimensional stability and solvent resistance. Just because of its unique comprehensive performance phenolic porous plastic plays an important role in the civil construction, heat preservation of vehicles and military aircrafts, pharmaceutical and electronic applications.Nevertheless, the largest weakness of phenolic porous plastic is its inherent brittleness and low strength, which severely limit its wide applications. Due to these drawbacks of phenolic porous plastic, researchers have put numerous efforts to improve its toughness and strength properties, mainly focus on chemical modification and filler reinforcement. In fact, the pore size and pore size distribution of porous materials has a crucial effect on the strength. 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. In the lab condition of finely foaming, the focus of the experiment is to control the pore structure aperture. Based on the bubble nucleation mechanism and foam stability theory, through the improvement of air nucleating state and the inhibition of eliminating foam to control the pore size and get the technology of controlling pore size and pore distribution of phenolic porous plastic. We also discussed the effect of pore structure of phenolic porous plastic on its mechanical properties.According to the physical process of phenolic porous plastic formation, we know that:pore size of porous plastic is mainly controlled by the stage of bubble nucleation and the stage of bubble growth. To achieve control of the pore size of porous plastic, we need to improve the bubble nucleating state and the inhibition of eliminating bubble. In this work, we using the ways above to achieve control of the pore diameter of porous plastic.In the aspect of improving air nucleating state, we adopted the method of accelerating the stirring rate and adding nucleating agent to control the pore structure of porous plastic. The researches show that:high stirring speed could decrease pore size and improve pore size distribution. Meanwhile the change of the pore size improves the compression strength of porous materials effectively. Loading of heterogeneous nucleating agent can also influence the pore size of phenolic porous materials obviously. With the increase of nucleating agent content, the pore size decreased firstly and then increased. However, mechanical properties just have opposite change law. The pore size can be made up to a minimum of97μm and the the compression strength reached the maximum, when the addition of HGB was5%. And the heterogeneous nucleation agents with different particle sizes effect the pore size of porous plastic differently.In the aspect of inhibition of eliminating bubble, we using a series of different cosurfactants to control the pore size. The experimental results show that:with the increase of molecular mass of polyether glycol type cosurfactants, the pore size decreased firstly and then increased. The polypropylene glycol type cosurfactant has the most excellent adjustment ability of phenolic porous plastic pore size. And the cosurfactants also play an important role on the compression strength of phenolic porous material. In addition, we adopt the method of adjusting the temperature of forming porous plastic to achieve the balance of blowing reaction and curing reaction. As a result phenolic porous plastic fine pore structure can be got under the appropriate temperature.Finally we got the phenolic porous plastic with good pore size distribution and its pore size can be controlled optional between246μm to73μm. At the same time the compression of the phenolic porous plastic was improved.