| The wood has been widely used in furniture, flooring, construction and decoration industries because it has many advantages such as beautiful texture, strong weight ratio, workability, national degradation. As natural biological materials, wood is vulnerable to the invasion of various bacteria of insects in the natural environment, seriously affecting the service life.Wood must be treated with preservatives in many use cases. Many wood preservatives are harmful to people. Thus, the development of efficient non-toxic, non-polluting and environment-friendly preservatives have been the inevitable trend. In recent years, the use of inorganic nano-oxide sterilization has become an active research direction.As the most commonly used antibacterial materials, nano-TiO2has many advantages such as chemically stable, insoluble, non-toxic,antibacterial and strong bactericidal, low cost, which provides a model for the development of new efficient wood preservatives. In this paper, the dispersion of nano-TiO2powder was improved by selecting different dispersants (surfactants, coupling agents), in aqueous solution, the effect of the types and amount of dispersant on nano-preservative suspension stability,the effect of dispersion modified on crystal type and dispersion mechanism was aslo explored; The optimum impregnation process was determined by single-factor experiments and orthogonal experimental method using dispersant type, temperature and time as factor. The effect of the dispersant type and preservative concentration on resistance leachability were investigated. Microscopic distribution of nano-TiO2in the timber was characterized and fixation mechanism was investigated by using XRD and FTIR. The conclusion were as follows:(1)The dispersity of nano-TiO2suspension firstly increased, then decreased as the amount of the two kinds of dispersed agent increased, when addition amount of titanate NDZ-105, six partial sodium were5%,3%-5%, stable nano-Ti02wood preservative were obtained; nano-particle after dispersion maintained the original crystal diffraction characteristics; six partial sodium, NDZ-105association on the surface modification of nano-particlesby chemical adsorption, hydroxyl, respectively. The compound use both has cooperative dispersion effect.(2)The best impregnation process after orthogonal experiment:the best combination of factors:the temperature30℃, impregnation timel6h, six partial sodium and NDZ-105composite dispersant. temperature on the influence of weight gain rate the most obvious, time is the second smallest, and dispersant kinds of effects the minimum.(3)Preservatives prepared same species of dispersant, as the concentration increased, the fixed rate increased at first and then reduced; preservatives after dispersion coupling agent and surfactant the highest rate of surfactant treatment, the lowest.(4)SEM showed that the nano-TiO2mainly distributed in the catheter, wood fiber, and near the wood ray parenchyma cell walls inside, sharped with granule or ball.(5)XRD analysis showed that, the wood after preservative treatment material retained the original diffraction characteristics, with17℃,22.5℃iffraction intensity decreased, and sharp titanium ore appeared, which showed that TiO2has been successfully into the timber internal; FTIR results showed that, the preservative dispersed by six partial sodium has not made chemical combination with polar wood; the hydrogen bond was formed between wood cellulose hydroxyl and preservative dispersed by NDZ-105, or cross linked with wood by use of molecular of coupling agent; As for the preservative dispersed by combined dispersant, not only chemical combination that formed by NDZ-105,but coordinate bond were formed between carboxyl and phenolic hydroxyl. |
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