Development Of Paraffin Wax Based Pickering Emulsion Stabilized By Nontmorillonite And Its Application In Wood

Wood is a kind of porous material composed of cellulose,hemicellulose and lignin.It contains a large number of hydrophilic hydroxyl groups that are easy to absorb and adsorb water,which may cause deformation and cracking.So it is necessary to improve its dimensional stability through wood modification treatment.In order to solve the problems,this study prepared paraffin wax based Pickering emulsion stabilized by montmorillonite,which was suitable for wood modification.In this study,paraffin wax based Pickering emulsion stabilized by montmorillonite was respectively prepared by sodium montmorillonite,montmorillonite modified with silane coupling agent and using dicumyl peroxide(DCP)as a free radical initiator.Moreover,paraffin wax based Pickering emulsion stabilized by organic montmorillonite and surfactant was also prepared.The average particle size of the emulsion was analysed by laser particle size analyzer and the morphology of the emulsion was characterized by confocal laser scanning microscope.Several methods,such as X-ray diffractometer,Fourier transform infrared spectroscopy and scanning electron microscope were used to characterize the treated wood.The effect of emulsion concentration on physical and mechanical properties of wood was also investigated.The main results of this study are summarized as below.(1)All the emulsions stabilized by sodium montmorillonite were oil in water emulsion,and the emulsion stability increased with the increase of particle concentration.(2)The surface modification of sodium montmorillonite was carried out by the addition of silane coupling agent.The particle size and stability of emulsion were affected by oil/water ratio and particle concentration.With the increasing oil/water ratio,the particle size of emulsion increased gradually and the stability decreased.When the oil/water ratio is 1:4,the particle size is the smallest and the stability is the best.The particle size of emulsion decreased with the increasing particle concentration.When the particle concentration increased to 2.0wt%,the emulsion droplets were uniform and stable.(3)The average particle size of the emulsion prepared by adding the free radical initiator dicumyl peroxide(DCP)with different mass fractions was up to micron grade(<2?m).When the mass fraction of DCP was 0.05wt%,the average particle size of the emulsion was the smallest,with some of particles even less than 100nm.The surface hardness and surface hydrophobicity of the treated wood were improved.(4)The average particle size of paraffin wax based Pickering emulsion stabilized by organic montmorillonite and surfactant was about 1?m.The surface hydrophobicity and dimensional stability of the treated wood were improved significantly after treatment with different concentrations of emulsion.4%treatment group can improve the hydrophobicity of wood to the greatest extent.The mechanical properties(modulus of rupture,modulus of elasticity,compression strength and impact strength)of treated wood have been effectively improved and the 2%treatment group was the best.