Application of poly (vinylbutyral) nanocomposites in environment design.
In the past 10 years, synthetic nano-composite has developed very fast and received general concern in material science and industry, raising an upsurge of studies on nanometer materials. Polymer / lamellose metasilicate nano-composite combines perfectly both the rigidity, dimensional stability, heat stability of inorganic materials and the toughness, machinability, dielectric property of macromolecule materials.It will have extensive applications in the future. With the deepening of studies on nanoparticle properties, people have found that a lot of inorganic nanometer oxides, such as SiO2, TiO2 and ZnO, etc., demonstrate the optical properties completely different from those of bulk phase materials [1-3]. Therefore, by introducing some inorganic nanoparticle into PVB materials with good transparency in the visible light region, it may bring a significant change to the properties of PVB in the ultraviolet region, which is of great importance to expand the application of this material. Especially when applied to materials of environmental design, it can solve effectively the problem of light pollution caused by ultraviolet ray.
Nanometer materials mean in the materials, the microstructure size including microgranule size, grain size, distribution of phase 2 enzyme, should be less than 100nm.Meanwhile, the materials prepared should have characteristics different from those in regular materials. None of the two can be dispensed with. Because of the small particle size, unsaturated bonds and hydroxy groups of different link states on the surface, the surface of nanometer SiO2 is of high energy and high polarity. As a result, nanometer SiO2 is very apt to demonstrate the coalescent property, which makes it difficult to disperse in macromolecule materials with the surface of low energy and low polarity.
In order to overcome this problem, we can make use of momentary and partial high temperature and high pressure produced by supersonic cavatition, KH-570 added as dispersing agent, to disperse SiO2 coacervate.Put several ml. of pure KH-570 into a beaker, mix with nanometer SiO2 and ethanol (the amount of coupling agent accounts 1% of nanometer SiO2), stir for 2 hours at a high speed, and keep the rotational speed at 2000 r/min. After the soliquoid is formed, put it into a 50-ml beaker and use a supersonic shaker to oscillate the beaker 5 hours without stop. Then modified SiO2 ethanol soliquoid is formed. Finally, increase the temperature to 80 . to volatilize the solvent and the remainder are modified nanoparticles[4-7]. This study focuses on the preparation of poly-vinyl-butyral nano-composite and its application in environment design.
2. EXPERIMENT PART
2.1 Preparation of PVB resin
Put 10g PVA into a flask of 250ml and with a blender, reflux condensing tube and a thermostat. Then add water in it(with 10% solution), and the amount of water needed should be calculated in advance. Heat the flask as long as the PVA in it starts to melt, and keep the temperature not exceed 80[degrees]C. in the whole process.
After PVA melts thoroughly, add hydrogen peroxide in the flask to make the degradation of PVA , to ensure that the weight ratio between PVA and the latter is roughly 10.200. Several minutes later lower the system temperature to 39[degrees]C, then add hydrochloric acid and butyl baldheaded in and keep the thermostat at 3h. Leave the precipitation separated out from the process for some minutes, and then blend with sodium hydroxide solution to counteract.
Filter the mixed solution and then wash the leached residue with water. Dehydrate the leached residue and put it in an oven to dry it, and make sure the temperature below 57[degrees]C. The white and flowing powder is PVB powder.
2.2 Modification of PVB resin and applied in laminated glass
Put dried PVB powder in absolute ethyl alcohol, and turn it into slimy and transparent solution. Measure modified SiO2 at different amount from absolute PVB, and blend it under the influence of ultrasonic. The SiO2 got from the mixture of two solutions compare with absolute PVB is 0.2.4.6.8.10 PVB/SiO2 weight percentage blender. Pour the solution with SiO2 into single glass, which is sealed with latex. Use a glass rod to scrape the liquid surface. Take some of the mixed solution, and pour it in a clean mould, and keep it under indoor temperature for a while, and take it out when it is dry enough. This way, a transparent coating of 0.2 mm.0.3 mm thick is ready for use.
3. ANALYSIS AND DISCUSSION OF THE RESULTS
3.1 spectrogram analysis of compound material infrared assimilating
Picture one is infrared assimilating spectrogram of PVB/SiO2 compound material
[GRAPHIC 1 OMITTED]
Comparing 3435.136[cm.sup.-1]([delta] [gamma] [approximately or equal to] 40[cm.sup.-1]) Hydroxyl absorption peak in pure Si[O.sub.2] infrared assimilating (picture c) with 3468[cm.sup.-1] Hydroxyl absorption peak in pure PVB infrared assimilating(picture b), it is still maintained after forming PVB/Si[O.sub.2] compound material. But the peak position moves to the Low wave number 3319[cm.sup.-1] , maybe because of the Hydrogen bond effect between the hydroxide radical which is forming compound material SiO2 and the hydroxide radical of PVB. The hydroxide radical of the compound material Absorption peak becomes wider and infrared shift. What's more, in compound material(picture c) 1643[cm.sup.-1] absorption peak which is belong to C=O expansion and contraction vibration absorption of PVB, high and wide
1138[cm.sup.-1] absorption peak results from Antisymmetry expansion and contraction vibration of Si-O-Si. It is very clear to see from the picture that 812 [cm.sup.-1] Si-O-Si Symmetrical expansion and contraction vibration peak and 459[cm.sup.-1]Si-O-Si bending vibrations absorption peak. Compared to Si[O.sub.2] and PVB spectrogram, peak position is not changed obviously. It is said that the speciality of Si[O.sub.2] and PVB is existing in PVB/ SiO2 compound material. So the chemical bond occurs unlikely. At 1100[cm.sup.-1].1180 [cm.sup.-1] circular Si-O-Si bond absorption peak is higher than pure SiO2. It could mean SiO2 which is in compound material may form reticulation structure in PVB. With SiO2 increased content, it accelerates the network structure formation which is centered by SiO2. And the PVB/SiO2 composite materials show good performance in
UV shielding and toughness these two areas.
[GRAPHIC 2 OMITTED]
Picture 2 is the PVB/SiO2 X-ray diffraction collection of illustrative plates of the compound material, because both pure PVB and pure SiO2 belong to amorphous aggregation state structure, it's X-ray diffraction picture respectively show a diffusion broad diffraction peak at 2 theta angle 19[degrees]' and 23[degrees]' After PVB/SiO2 compound material formed, a more spacious diffusion diffraction peak appear at 2 theta angle 18[degrees].27[degrees], After 2 theta angles 45[degrees], even curve appears, which indicates compound material is not only crystalline state, and there is also long-range structure to some extent.
[GRAPHIC 3 OMITTED]
3.2 Compound materials ultraviolet absorption spectrometry analyses
Picture 3 demonstrates the PVB/SiO2 compound material and visible spectrum with different SiO2 contents., From the picture, pure PVB material can hardly screen ultraviolet 290 nm ~ 400 nm (curve a), , and within 240 nm vicinity range there are still certain degree permeates (T [approximately or equal to]24 %), This means this material can not only screen ultraviolet from 290 nm to 400 nm, but is also poor at screening ultraviolet with high energy. Therefore, the pure PVB film can not screen material covered by it from the destruction of ultraviolet effectively. After the formation of PVB/SiO2 compound material, the rate of permeation is really low around240nm (<9%), what's more, the effect of screening is better between 290nm to 400nm. when SiO2 is 4 w t %, about 40 % ~ 50 % ultraviolet can be screened away.. With the rising of material with SiO2, the effect of screening off ultraviolet becomes better and better. It can be seen from it that after SiO2 disperses homogeneously to PVB material, it characteristics of absorbing ultraviolet is brought into full play. Besides, in 400 nm ~ 800 nm visible light, material has demonstrated higher transparency. Therefore, institute preparation PVB/SiO2 nanometer compound material has the fine ultraviolet glossy shield characteristic. Therefore, prepared PVB/Si[O.sub.2] nanometer compound material has the fine ultraviolet glossy shield characteristic; moreover, its transparency is fairly good in visible light area.
3.3 The mechanical properties of composite materials testing analysis
It is can be known from picture 4, if we put Si[O.sub.2] particle into PVB, the tensile strength increases with the silica content increasing. It will reach the max when the Si[O.sub.2] content is 4% and after that it will fall. The elongation at breakof pure PVB material is only about 18.45%.performing a certain degree of brittleness. The yield phenomenon is not obvious when it ruptures. After the nanometer Si[O.sub.2] is put it the PVB, we observes necking contraction and Stress Blushing in tensile process obviously. The test specimen stretch cross section appears extremely their regular fold phenomenon. These tough characteristic is even more obvious along with theSi[O.sub.2] content increase. In Si[O.sub.2] content when 5%, the break elongation ratio reaches the maximum value, also for pure PVB 7--8 times. Later gradually will reduce along with the Si[O.sub.2] quantity increase, and flatten out, but pure PVB was still higher than 3--4 times. At the same time, in the break elongation ratio maximum value place, the longitudinal strength also reaches the maximum value. This is because nanometer Si[O.sub.2] has the high active surface, intensely was adsorbing the PVB molecular chain, between the PVB member chain and the Si[O.sub.2] granule has formed the effective physical effect network. This net plays the even distributed load role in the pulling test process, reduced has had the break possibility, thus caused the compound material the break elongation ratio large scale enhancement, enable the longitudinal strength also to have the certain degree improvement.
[GRAPHIC 4A OMITTED]
[GRAPHIC 4B OMITTED]
4. NEW NANOMETER COMPOUND MATERIALS IN ENVIRONMENT DESIGN APPLICATIONS
4.1 The Application of Transparent Materials on Environment Design With its rich nature, refine, transmission, reflection and refraction, light becomes a quite important factor on construction environment design. When blended with transparent materials, it creates perfect decoration effect, therefore gets peoples' favor.
Dated from New Babylon Dynasty, glass appears in the form of glaze tile, taking the role of shell and bitumen to be the main surface decoration materials in that time. On modern construction, decoration with glass becomes a fashion. Being used to decorate the door and window, glass plays the function of partition, meanwhile it is provided with advantage of wind-against, rain-proof, skylight and perspective. On form, part or whole glass is adapted. As showed in Picture 5, Japan Nation's New Gallery which was designed by famous Japanese architect has the glass curtain wall. It is elegant and with tension in external feature, capacious and unobstructed in internal space. The transparent feature of glass is interpreted completely. With its fine previous to light, glass is applied to the light fixtures and light screen.
Glass itself is transparent with no color. But treated by the new techniques such as melting, casting, lining, gluing and gripping will displays the different sense of reality. The environment created for the room inside and outside has been insightful, brightly, the multi-colored decoration effect. But, the people while enjoy the glass the rich visual feeling which brings to the people, also light contamination concern and silently withstanding ultraviolet ray, the pain and the worry which brings to the people.
4.2 Light pollution to human body injury
The light pollution is refers to the modern society to produce excessive or not the suitable ray radiation, creates to the human life and the production environment not good affects. According to the light wave length it may divide into the ultraviolet ray pollution, the infrared light pollution and the laser pollution and so on. The main injury of the ultraviolet ray to the human body is the eye cornea and the skin. The wave length which is in 250 ~ 305nm may create the eye cornea damaged, may cause the eye to create one kind to call the fear light ophthalmia the side pain keratol eukoma injury. Besides severe pain, but also often causes to burst into tears, the eyelid convulsion, the eye cornea hyperemia and the eyelash shape twitches and so on. The wave length which is in 280 ~ 320nm and 250 ~ 260nm partial may create the skin the damage, mainly is causes the red spot and the urine blister. It is serious when can cause the epidermis necrosis and shed skin. The infrared to the human body injury is also the eye and the skin. The wave length which is 7,500 ~ 13,000 Egypt's part,may create the eye ground retina injury. The person eye if exposes for a long time to the infrared possibly causes the cataract. A stronger infrared may cause the skin damage. The situation is similar with scalds. At first it is burningly painful, then creates the burn.
The people not only can receive the harmful light in the naturalenvironment the radiation, similarly also has the light contamination concern in very many artificial environment, such as in ballroom, bar and so on. The black light lamp which produces the ultraviolet ray intensity is higher than in the sunlight by far the ultraviolet ray intensity, also the duration to the human body harmful influence to be longer. The people if accept this kind of illumination for a long time, may induce to flow the nosebleed, to escape the tooth, the cataract, even causes the leukemia and other canceration.
Therefore, in the environment design light contamination should be concern by the environment designer doublely.
4.3 Nanometer compound materials may effectively solve in the glass construction environment ultraviolet ray contamination concern
The PVB/SiO2 nano-composite has not merely good shielding effectiveness of ultraviolet light and infrared light, but good perspectivity within the range of visible light region. Therefore, when PVB resin is applied to the laminated glass, the outer wall in the architectural design as well as various lamps and lanterns, it has good shielding effectiveness of ultraviolet and infrared rays. In this way, the problem of light pollution can be solved.
1ST. Infrared spectroscopic analysis indicates that the inorganic nanometer Si[O.sub.2] particle has already been grafted to the polymer PVB. X-ray diffraction analysis indicates that PVB/Si[O.sub.2] nano-composite is amorphous, and the long chain structure macromolecule still exists. Ultraviolet transmissibility analysis shows that the introduction of nanometer Si[O.sub.2] particle could strengthen the ultraviolet shielding property of the PVB / nanometer SiO2 composite.
2ND. Stretch analysis indicates that when SiO2 particle is added into the PVB, the mechanics property of the material could be changed. This could improve the toughness of the material, and the breaking elongation of the material is greatly improved at the same time. Maximum breaking elongation appears when the TiO2 content accounts for 4%, and the tensile strength also reaches a maximum value, which is 6-8 times that of pure PVB. The tensile strength would gradually reduce until it becomes stable, but still 3-4 times higher than pure PVB. The poly vinyl butyral (PVB) itself has filming nature. It can form film without adding plasticizer.
3RD. Prepared PVB/SiO2 nano-composite has good ultraviolet shielding property and good transparency clarity in visible spectra area. When applied to laminated glass, outer wall glass as well as various lamps and lanterns, PVB resin could have good shielding effectiveness of the ultraviolet ray and reduce the light pollution caused by ultraviolet ray.
* Received 19 March 2008; accepted 8 November 2008
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LI Qingshan1 GAO Wenjie (1,2) MA Pengsheng (1,3)
(1) Key Lab of Metastable Materials Science and Technology Yanshan University Qinhuangdao, 066004, China. (2) College of art design, Dalian Industrial University, Dalian,116034, China. (3) Jilin University,Changchun,130000, China.
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|Author:||Li, Qingshan; Gao, Wenjie; Ma, Pengsheng|
|Publication:||Advances in Natural Science|
|Date:||Dec 1, 2008|
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