Preparation And Performance Of A Wood Preservative Microcapsule Based On Bioactivities Of Neem Seed

Melia azederach seeds (neem seeds) have bacteriostatic and insect-resistant active substance. Compared to the traditional chemical wood presrvative, the preservative made of Melia azederach seeds extract has a better environment friendly property. In order to determine the best extraction method and extraction conditions, ultrasonic oscillations, microwave extraction and water bath mixing, these three methods were used to extract the active substance from neem seeds powder. Neem extract microcapsule is made of neem extract and MUF by using water bath mixing method, and3D microscope was used to determine whether to form under the preparing conditions. The anticorrosive antibacterial property of neem extract and its microcapsule were analyzed in vitro and in vivo(Poupuius ussurensis specimens) tests. Environment stability of neem active ingredient was analyzed through ultraviolet accelerated weatherometer simulating the effect of environmental factors on the extract and its microcapsule. These results and conclusions can be provided for scientific basis and theoretical basis for development and application of wood preservative production from plant sources such as neem extract in future. In this paper, the main research results and conclusions are as follows:(1) Three different extraction methods were used to extract anticorrosive antibacterial active ingredients from neem seeds powder. By comparing the extraction rate, and the results show that at the temperature of50℃, under the condition of the ratio (powder to ethanol)1:12, the microwave extraction technology is the best method, and its extraction rate is as high as12.84%. The microcapsule can be formed of neem extracts and melamine modified urea-formaldehyde resin (MUF) with feasible test method-water bath mixing method.(2)Perform in vitro experiment on neem extract and its microcapsule with Oxford cup method drilling on the medium. The results show that neem extract and its microcapsule can inhibit the white-rot fungus (Coriolus versicolor) from growing to a certain extent. The antibacterial performance of neem extract is weaker than ACQ-B’s, but its microcapsule’s antibacterial performance is slightly worse than ACQ-B, MUF has no antiseptic antibacterial properties.(3)The antibacterial performances of neem extract and microcapsule are reduced after UV treatment. On the basis of bacteriostatic ring diameter, the performance of microcapsule is reduced less than neem extract’s. The results show that neem extract stable performance is poorer than its microcapsule through in vitro experiment, and MUF coated to extract plays a protective role that it can delay the extract drug releasing.(4)Specimen agents’maintenance doses are at about84kg/m3through Full cell method processing. After the weather resistance test treatment and indoor corrosion test, the weightlessness rate of specimens that processed by neem extract changes significantly, the rate weightlessness of specimens that processed by neem extract microcapsule and ACQ-B changes slightly, these results indicate that the microcapsule dressing material-MUF in specimens protects antiseptic activity of the neem extracts from influence of environmental factors, and it can extend the antiseptic bacteriostasis effect.(5) Microcapsule can be formed of neem extract and MUF in specimens, and the structure of microcapsule is confirmed by SEM. Based on the hypha growth and the change of the microcapsule form in specimens, the performance of MUF that protect anti-corrosion extract and extend its effect is confirmed. Then, the microcapsule structure makes the bacteriostatic performance of neem extract microcapsule and ACQ-B balance.(6) Due to the presence of Cu2+, specimens appeared obvious color change treated by ACQ-B. However, specimens treated by neem extract and its microcapsule have not a significant color change. After drying processing under the same conditions, obvious deformation is appeared on specimens treated by ACQ-B, but not on specimens treated by neem extract microcapsule. These also highlight the wood preservative microcapsule that made from plant sources. The neem extract microcapsule can not only extend the antiseptic efficacy and the time of corrosion, but also remain the size and color of wood.