Study On Preparation Methods And Properties Of Modified Phenol-Formaldehyde Resins Based On Bio-Oil

Phenol formaldehyde(PF)resin is the general name of resin polymer which is made by condensation of aldehydes and phenols in the presence of acidic or alkaline catalyst.According to the resin structure,phenolic resin is divided into resol phenolic resin(resol PF)and novolac phenolic resin(novolac PF).Resol phenolic resin is one of the main adhesives used in wood-based panel industry.It has excellent heat resistance,chemical resistance,durability,flame retardancy,high tensile strength,high adhesion and other advantages.It is often used as outdoor wood-based panel adhesive.Novolac phenolic resin is a kind of linear resin,which is a solid at room temperature.It is commonly used in the manufacture of switches,sockets,plugs and other daily necessities and other industrial products.Phenol,the main raw material of phenolic resin,is a kind of petroleum derived chemicals,which is nonrenewable.Its price and supply depend on fossil raw materials to a large extent.Bio-oil is a kind of liquid biological product produced by pyrolysis of lignocellulosic biomass.It contains monomeric phenols and oligomeric polyphenols with different number of phenolic rings.It has the potential to replace phenol in phenolic resin and make phenolic resin industry have better sustainable development.In this study,a series of modified phenolic resins and blend resins were prepared by using bio-oil instead of phenol or blending with phenolic resin.The properties of modified resins and blend resins were compared,and the application process of isocyanate in phenolic resin was discussed.The main research contents are as follows:(1)study on basic properties and chemical composition of bio-oil and refined bio-oil;(2)Comparative Study on properties of bio-oil modified resol phenolic resin and its blends with phenolic resin;(3)study on properties of bio-oil modified novolac phenolic resin and its blends with isocyanate.The relationship between the structure and properties of the resin is discussed:(1)Compared with bio-oil,refined bio-oil has higher content of phenols,higher viscosity,pH value and lower water content.(2)Compared with the bio-oil modified resol phenolic resin,the refined bio-oil modified resol phenolic resin has higher thermal stability and better bonding performance.When the refined bio-oil replaces 50% phenol,the boiling water bonding strength reaches the maximum value(1.88 MPa).(3)Compared with the blend resol phenolic resin prepared by bio-oil,the blended resol phenolic resin prepared by refined bio-oil has higher thermal stability and better bonding performance.When the amount of refined bio-oil is 13% of the phenolic resin,the boiling water's bonding strength reaches the maximum(1.59 MPa).(4)When the ratio of isocyanate and refined bio-oil modified novolac phenolic resin is75:25,the boiling water resistance adhesive strength of the prepared blended resin reaches the maximum value(2.24 MPa).(5)The infrared test results show that the structure of resol phenolic resin is changed by adding bio-oil and refined bio-oil;with the increase of the proportion of bio-oil in the blend resin,the infrared structure of the resin was closer to that of bio-oil;chemical reaction occurred after the blending of isocyanate and novolac phenolic resin,and the isocyanate group was consumed.(6)Thermogravimetric analysis shows that the addition of bio-oil improved the thermal stability of modified / blended resol phenolic resin,and the thermal stability of bio-oil modified novolac phenolic resin was improved after blending with isocyanate.