Research On Curing Law And Property Of Preservative Prepared By Neem Oil Microcapsule In Poplar

The botanical wood preservatives were more environmentally friendly than chemical wood preservatives.But the stability of botanical wood preservatives was not good.In order to protect the efficacy and improve the s tability of botanical wood preservatives,microencapsulation techniques were used combine with botanical wood preservatives.Poplar was the research object of this paper.Neem seeds are used as raw materials in this article.And the core material of the microcapsule is Neem oil extracted from n-hexane.The wall material of the microcapsule is melamine formaldehyde resin.To get more preservatives into the wood,the samples were impregnated in preformulations of Microcapsule wood preservative from Neem oil.Then temperature-programmed route was used to polymerize the preformulations into microcapsule s tructure.Then the distribution and morphology of microcapsules under different temperature co ntrol were com pared by s canning electron microscopy(SEM).The morphology of the internal microcapsules in treated woods under different temperatures was observed by scanning electron m icroscopy(SEM).At the same time,the decay resistance experiment was carried out on the samples treated at different temperatures,and the samples were analyzed by infrared spectroscopy and thermogravimetric analysis.Leaching experiment and ultraviolet aging experiments were used to further determine the properties of the wood preservative.The main research contents and conclusions of this paper are as follows:(1)The distribution and morphology of microcapsules,prepared from Neem ethanol extract and from Neem oil,in wood samples were observed by scanning electron microscopy.Two kinds of microcapsules in wood were compared and n eem oil was selected as the core material.(2)Under a tmospheric pressure impregnation,the s amples were impr egnated in preformulations of Microcapsule wood preservative made from Neem oil.T he i mpregnated wood s amples were treated with the procedure t emperature rise method.The t emperature control points were 40?,50?,60?,70?,80?,90?,100?,110?,120?.Following conclusions can be found by comparing the SEM of each sample.With increasing temperature,the num ber of microcapsules has increased and the distribution of the microcapsules becomes uniform.But at a certain temperature,the microcapsules begin to break down.With increasing temperature,the damage to the m icrocapsules i ncreased,and the number of destroyed microcapsules increased.When the temperature reached 120?,almost all the microcapsules inside the wood were destroyed.(3)Decay resistance experiments were carried out on samplest reated under different temperatures.Samples before and after decay were analyzed by Fourier infrared spectroscopy and Thermogravimetric analysis.The following conclusions were obtained by mass loss rate analysis,Fourier infrared spectroscopy analysis and thermogravimetric analysis.The decay resistance of neem oil microcapsules was better than that of neem oil.Wall material has no resistance effect to decay.And there was no chemical reaction between the wall material and the core material.This suggested that the Neem oil microcapsule preservative experienced a persistent release of its antibacterial properties because the protection of wall material.By comparing samples treated at different temperatures,it is found that the decay resistance of samples was related to the formation of microcapsules.(4)The wood samples treated by neem oil microcapsule preservative were used for leaching experiment and ultraviolet aging experiments.Through experiments,the following conclusions were obtained.The leach-resistant property of neem oil microcapsule was better than that of neem oil.The leach-resistant property of neem oil microcapsule was related to the distribution of microcapsules in wood.The anti-aging property of neem oil microcapsule was better than that of neem oil.This indicated that the wall material of Neem oil microcapsule could protected the core material,reducing the environmental effect on core material.Therefore,the stability of neem oil preservative will improved and the release time of the antibacterial effect will become longer.