SI22669A - ZnO NANOPARTICLES AND NANOWIRES WITH ORGANOPHILIC SURFACE AND THEIR NANOCOMPOSITES WITH POLYMETHYL METACRYLATE - Google Patents

Abstract

The subject of the invention are nanoparticles and nanowires of zinc oxide (ZnO) with organophylic surface, synthesised in various diols in the presence of para-toluene sulphonic acid (p-TsOH), and their nanocomposites with polymethyl metacrylate (PMMA), prepared without additional modification of ZnO particle surface. The procedure of preparation of nano-ZnO is carried out by hydrolysis of a zinc compound in various diols in the presence of para-toluene sulphonic acid as catalyst and comprises the following steps: mixing and sonification of the solution for 5 to 60 minutes; heating of the solution for 30 to 90 minutes at temperatures between 100 and 300 degrees Celsius; settling of the zinc oxide compound for up to 24 hours; separation of the suspension from the precipitate; washing of the suspension; drying of the suspension. The preparation of nanocomposites composed of a metacrylic or acrylic polymer and unmodified nano-ZnO consists of the following steps: preparation of the mixture of a metacrylic or acrylic monomer, initiator and zinc(II) oxide; mixing and sonification for 5 to 60 minutes; optionally partial polymerisation of MMA; optionally repeated addition of 0.1 to 40% of the initiator; transfer into a mould; polymerisation at a temperature between 35 and 80 degrees Celsius; cooling down of the polymer and its separation from the mould.

Description

The subject of the invention

The object of the invention are zinc oxide - ZnO nanoparticles and ZnO nanoparticles synthesized in various diols in the presence of para-toluene sulfonic acid (p-TsOH) and their nanocomposites with polymethyl methacrylate (PMMA) prepared without further modification of the ZnO particle surface. ZnO nanoparticles and nanowires are useful as a semiconductor filler in PMMA for various electronic applications; as light and UV converters in nanocomposites with PMMA matrix for solar engineering; as UV absorbers and light stabilizers for exterior plexiglass, in opaque PMMA exterior nanocomposites and in coating systems having PMMA or copolymers dominated by methacrylic or acrylic polymer.

The prior art

Recently, research has focused on the environmentally friendly synthesis of nanoparticles and other nanostructures, and on the preparation of nanocomposites from nanoparticles and various matrices following procedures suitable for industrial application. One of the environmentally acceptable pathways for the synthesis of ZnO nanoparticles is hydrolysis in various diols. Thus, patent application KR20050043442 describes the synthesis of ZnO powder in glycol. The scientific literature cited under order numbers 1 to 6 describes the synthesis of ZnO in various alcohols. It mainly involves the preparation of ZnOs in various mono and diols without or with the addition of acid or base as a catalyst. The disadvantage of nano ZnO synthesized in monoalcohols is the poorer organophilicity of the surface, which necessitates additional surface modification for the preparation of nanocomposites. Additional modification of the surface makes such a nanopolymer more expensive and may also impair certain properties of the nanocomposite. A disadvantage of ZnO synthesis processes in monoalcohols and diols without the addition of p-TsOH, in order to synthesize ZnO with a particle size below 100 nm, is the low concentration of the starting compound. Due to the low concentration of the starting compound, the consumption of solvents in the synthesis of such nanoparticles is very high, which again significantly increases the cost of such nanoparticle.

-2 The process of ZnO synthesis in diols using p-TsOH as a catalyst has not been reported in the literature. The literature listed from Nos. 7 to 13 describes the preparation of polymeric ZnO nanocomposites prepared in various monoalcohols. All authors use additional surface modification of ZnO particles to achieve a homogeneous ZnO distribution in the PMMA matrix. Additional modification usually impairs temperature stability - as exemplified in the literature under no. 13 - and also the mechanical properties of the nanocomposite, since most modifiers have a softening effect. No description of the use of ZnO synthesized in diols for the preparation of PMMA nanocomposites has been found in the professional literature.

Literature:

1. L.R.Collins, S.E. Taylor, J. Mat. Chem., 2, 1992, 1277

2. D. Jezequel, J. Guenot, N. Jouini, F. Fievet, J. Mat. Res., 10 (1), 1995, 77-83

3. C. Feldman, Scripta Mater., 44, 2001,2193-2196

4. C. Feldman, J. Merikhi, J. Coli. Interf. Sci., 223, 2000, 229-234

5. М.М. Demir, R.M. Munoz-Espi, I. Lieberwirth, G. Wegner,. J. Mat. Chem., 16, 2006, 2940-2947

6. T. Ahmad, S. Vadiya, N. Sarkar, S. Ghosh, and A. Ganguli, Nanotechnology, 17, 2006, 12361240

7. М.М. Demir, M. Memesa, P. Castignolles, G. Wegner, Macromol. Rapid Comm., 27, 2006, 763-770

8. S.C. Liufu, H.N. Xiao, Υ.Ρ. Li, Polym. Deg, Stabil., 87, 2005, 103-110

9. М.М. Demir, K. Koynov, U. Akbey, C. Burbeck, I. Park, I. Liebenvirth, G. Wegner, Macromolecules, 40, 2007,1089-1100

10. V. Khrenov, M. Klapper, M. Koch, K. Mullen, Macromol. Chem. Phys., 206, 2005, 95-101

11. E. Tang, G. Cheng, X. Pang, X. Ma, F. Xing, Colloid Polym. Sci., 284, 2006, 422-428

12. N. Lu, X. Lu, X. Jin, C. Lu, Polym. Int., 56, 2007, 138-143

13. P. Liu, Z. Su, and J. Macromol. Sci. PartB, Physics, 45, 2006, 131-138

The object of the invention

It is an object of the invention to synthesize ZnO nanoparticles based on particle size below 100 nm with a narrow size distribution and with a defined shape, e.g. beads, wires, etc. that have organophilic

-3 Surface by a process that allows the synthesis of nano ZnO with a particle size below 100 nm at concentrations of the starting compound of at least 0.1 mol / L. The invention also provides homogeneous nanocomposites of methacrylates or acrylates and said ZnO-based filler, with improved UV, light and temperature stability with more or less unchanged mechanical properties, and a simple process for preparing such nanocomposites by polymerizing methacrylic or acrylic monomer in bulk or by casting from a solution or by casting methacrylic or acrylic polymer, which may also be transparent if necessary.

Description of the invention

The invention will be described by way of embodiments and illustrations showing:

Figure 1: TEM micrographs of ZnO nanoparticles synthesized by a polyol process without the addition of ptoluene sulfonic acid in: a) diethylene glycol (DEG), b) tetraethylene glycol (TEG)

Figure 2: X-ray diffractogram of a ZnO sample synthesized by a polyol process without p-TsOH Figure 3: FTIR spectrum of a ZnO powder sample synthesized by a polyol process without p-TsOH Figure 4: TEM micrographs of nano ZnO particles synthesized by the addition of p-TsOH in different diols : a) BD, b) TEG, c) DEG, d) EG, e) PD

Figure 5: X-ray diffractogram of nano ZnO powder synthesized with the addition of p-TsOH

Figure 6: FTIR spectrum of nano ZnO powders synthesized by the addition of p-TsOH

Figure 7: TEM micrographs of PMMA / ZnO - ZnO nanocomposites synthesized in DEG:

Figure 8: UV-vis spectra of PMMA / ZnO nanocomposites with different ZnO content: A) 1%, B) 0.1%, C) 0.01%, D) 0.01%, E) 0%

Figure 9: DTG curves of PMMA / ZnO nanocomposites with different ZnO proportions

Figure 10: TEM micrographs of PMMA / ZnO nanocomposites - ZnO synthesized in TEG

Figure 11: TEM micrographs of PMMA / ZnO - ZnO nanocomposites synthesized in different diols: a)

BD, b) TEG, c) DEG, d) EG

Figure 12: UV-vis spectra of PMMA / ZnO nanocomposites (ZnO synthesized in different diols in the presence of ρ-TsOH): A) 0.01%; B) 0.1% C) l%, D) 0%

Figure 13: DTG curves of PMMA / ZnO nanocomposites (ZnO synthesized in the presence of p-TsOH) with different ZnO concentrations

-4Figure 14: TEM micrograph of PMMA / ZnO nanocomposite (ZnO synthesized in PD in the presence of pTsOH) prepared by prepolymer process (Procedure B)

Figure 15: UV-vis spectrum of PMMA / ZnO nanocomposite (ZnO conc = 0.1%) depending on the preparation process: A) preparation directly from the monomer (Process A), B) preparation via the prepolymer (Process B), C) sample without ZnO

Figure 16: UV-vis spectra of PMMA / ZnO nanocomposite (ZnO synthesized in EG) as a function of ZnO concentration: A) commercial plexiglass, B) PMMA / ZnO nanocomposite (0.05% ZnO synthesized in EG) prepared by process C, C) sample without ZnO

Figure 17: TEM micrograph of PMMA / ZnO nanocomposite prepared by casting from solution

Figure 18: UV-spectrum of PMMA / ZnO nanocomposite prepared by casting from solution: A) PMMA / ZnO nanocomposite (0.1% ZnO), B) sample without ZnO

The invention is a ZnO nanoparticle of size 20 to 300 nm with an organophilic surface synthesized in different diols and their transparent or opaque nanocomposites with methacrylic or acrylic polymers prepared by polymerization of methacrylic and acrylic monomers in bulk or by casting from polymer solutions.

The essence of the process for the preparation of zinc (II) oxide - ZnO nanoparticles and nanoparticles is the hydrolysis of a zinc compound from the group: Zn (CH3COO) 2x2H2O, Zn (C5H ₇ O2) xH2O, ZnC ₂ O ₄ xH ₂ O, ZnSO ₄ x7H2O, Zn (NO3 ) ₂ x6H ₂ O, Zn (PO ₄ ) 2, ZnCl ₂ , ZnBr2 in the presence of a catalyst, a pair of toluene sulfonic acid (p-TsOH), in different diols of the group: ethylene glycol - EG, 1,2-propane diol - PD , 1,4-butane diol BD, di (ethylene glycol) - DEG or tetra (ethylene glycol) - TEG at temperatures between 100 and 300 ° C. To the diol is added a weighed amount of zinc compound at a concentration of 0.005 - 5 mol / L, a calculated amount of deionized water (0.5 to 4 mol H2O per mol Zn) and p-TsOH at a concentration of 0.001 to 2 mol / L. The mixture is sonicated for 5-60 minutes and heated for 30-90 minutes at constant temperature between 100 and 300 ° C while stirring continuously. After one hour, the ZnO suspension was poured into a beaker and allowed to settle for 24 hours. If the suspension is stable, it is centrifuged. The resulting product was sonicated twice in ethanol (washing) and centrifuged. The washed product is air-dried.

-5The essence of the process for the preparation of PMMA nanocomposites or other methacrylic or acrylic polymer and ZnO is that unmodified ZnO prepared by hydrolysis in diols is used to prepare nanocomposites according to the procedures described in embodiments (Methods A, B and C). After all the processes, nanocomposites are formed with a largely homogeneous particle distribution in the PMMA matrix. Mix a weighed amount of MMA and / or other monomer from the methacrylate or acrylate group in the beaker: methyl, ethyl, isopropyl, n-propyl, n-butyl, t-butyl, n-pentyl, n-hexyl, phenyl, naphthyl, ethylhexyl, oleyl, palmityl, stearyl methacrylate or acrylate; initiator (0.01 to 1% concentration and nano ZnO at a concentration of 0.0001 to 10%. The mixture is sonicated for 5-60 min and then either transferred directly into a glass mold and polymerized until completion of the reaction at 35 to 90 °. C or transferred to the reactor for 1 to 24 hours and partially polymerized the MMA at 35-80 ° C for one to two hours without sonication or continuous sonication, then 20% of the initiation was added and the mixture was transferred to a glass mold. The mixture in the mold is sonicated again for 5-60 minutes and then the mold is transferred to a water bath where the monomer is polymerized to completion of polymerization at a temperature of 35-90 ° C for 1 to 24 hours After completion of polymerization, the mold is cooled and the resulting composite is separated from the mold.

For the preparation of a nanocomposite from a solution of methacrylic or acrylic polymer (Method D embodiments), a solution of PMMA and / or other methacrylic or acrylic polymer from the group is mixed in the beaker: poly (methyl, ethyl, isopropyl, n-propyl, n-butyl, t- butyl, n-pentyl, n-hexyl, phenyl, naphthyl, ethylhexyl, oleyl, palmityl and stearyl methacrylate or acrylate) in an organic solvent and nano ZnO according to claim 2 at a concentration of 0.0001 to 10%, after which the mixture is dispersed with a dispersant stirrer at 200 to 20000 rpm for 20 - 360 sec and then the mixture is sonicated for 5-60 min. and then poured it into a mold or sprayed it on a suitable base and dried.

The synthesized nanocomposite materials have a high absorption capacity in the UV spectrum of 280 to 380 nm, and, when properly prepared, are transparent to visible light. PMMA nanocomposites with 0.1 and 1% ZnO absorb 95 to 99.5% of the incident UV light, and those with 0.01% ZnO 80-95% UV light. The synthesized nanocomposites also have improved thermal stability, since the initial decay temperature rises by 30-40 ° C if the material contains 1% nano ZnO. With the addition of ZnO at a concentration of 0.1% or more, the impact is also improved

-6 toughness of nanocomposites by 5 to 10%. Very low concentrations greatly improve the resistance to sunlight as ΔΕ decreases from 10-11 for pure PMMA to values from 1 to 6 for PMMA / ZnO nanocomposites.

Nanocomposites prepared by polymerization into methacrylic or acrylic monomer masses can be used as UV and light-stabilized opaque or transparent materials, including plexiglass in solar technology, for glazing, for facade cladding, for highway enclosures and in high-rise areas UV and light and heat loads. Nanocomposites prepared by casting a solution of methacrylic or acrylic polymer are used as UV and light stabilized opaque or transparent coatings in areas where high UV and light and heat loads occur.

The invention provides the preparation of nano ZnO undefined and defined ID and 3D forms, i.e. nanoparticles and nanowires and different degrees of crystallinity with an organophilic layer on the particle surface by a polyol process in different diols with the addition of p-TsOH as a catalyst. The advantage of using p-TsOH is the high reproducibility of syntheses in terms of size and shape of ZnO nanoparticles. By the addition of p-TsOH, ZnO particles with a defined size between 20 and 50 nm can be reproducibly synthesized, which have an increased crystallinity compared to ZnO synthesized without p-TsOH. With the addition of p-TsOH, the synthesis of 20-50 nm nanoparticles can be carried out at a precursor concentration of up to 5 mol / L, resulting in large savings in solvent volume and energy. The advantages of using diols over monoalcohols are the higher viscosity of the medium, which reduces the agglomeration of the particles, and the higher boiling point, which enables the preparation of nanoparticles with a higher degree of crystallinity. Due to the organophilic layer, ZnO particles are uniformly dispersed in a polymethacrylic or polyacrylic matrix, which allows the preparation of their homogeneous nanocomposites without additional surface modification. Surface modification greatly raises the price of nanoparticles, which is inherently high, which greatly reduces their potential application in practice. Nano ZnO synthesized by the polyol process is homogeneously dispersed in the PMMA matrix to a concentration of 10% without further modification.

Another novelty is the ZnO nano in the form of nanoparticles of 30 - 500 nm in length and 5-30 nm in diameter, synthesized by a polyol process with the addition of p-TsOH and at high precursor concentrations (0.1 -5

-Ίmol / L). ZnO nanowires also have an organophilic layer on the particle surface that allows the preparation of nanocomposites without additional surface modification.

Novelty is transparent nanocomposites of polymethacrylates or polyacrylates with ZnO with improved UV and light resistance, that is, light and UV resistant plexiglass and also opaque nanocomposites on a methacrylic or acrylic basis, prepared by polymerization in mass or from a solution of polymethacrylates or polyacrylates. cases. Organophilic layer on the particle surface effectively dispersed Synthesized nanoZnO is a very effective UV absorber, since the addition of 0.05% quantitatively absorbs UV light in the UV range from 290 to 370 nm, which is significantly better than the literature data where 60-70% absorption is achieved UV light with the addition of 10 to 30% ZnO. The addition of 0.05 to 0.1% nano ZnO synthesized by the polyol process greatly improves the resistance to sunlight as the color change ΔΕ from 10 - 11 for pure plexiglass is reduced to values from 1 to 5. In addition from 0.1 to 1% nano ZnO raises the initial decay temperature by 20 to 40 ° C, which means that the temperature range of use of these materials also rises. In addition, the addition of unmodified ZnO nano does not delay but improves the toughness of the composite by 5 to 10%.

Implementation examples

The embodiments of the patent do not limit, but merely explain.

1) Synthesis of nano ZnO with the addition of deionized water

In di (ethylene glycol) DEG or in tetra (ethylene glycol) TEG, add the measured amount (conc = 0.005 - 5 mol / L) of Zn (CH3COO) 2x2H2O, and the calculated amount of deionized water (0.05 - 4 mol H ₂ About 1 mol Zn). The mixture is sonicated for 5-60 minutes and heated for 30-90 minutes at constant temperature between 100 and 300 ° C while stirring continuously. After one hour, the ZnO suspension was poured into a beaker and allowed to settle for 24 hours. If the suspension is stable, it is centrifuged at 3000 to 12000 rpm for 1 to 24 hours. The resulting product was sonicated twice in ethanol (washing) and centrifuged at 3000 to 12000 rpm for 1 to 24 hours. The washed product is air-dried.

2) Synthesis of nano ZnO with the addition of deionized water and p-TsOH

-8V diol (ethylene glycol - EG, 1,2-propane diol - PD, 1,4-butane diol - BD, DEG or TEG) add the required amount (conc. = 0.005 - 5 mol / L) of Zn (CH ₃ COO) 2 Χ2Η2Ο, calculated amount of deionized water (0.5 to 4 mol H2O per mol Zn) and p-TsOH at a concentration of 0.001 to 2 mol / L. The mixture is sonicated for 5-60 minutes and heated for 30-90 minutes at constant temperature between 100 and 300 ° C while stirring continuously. After one hour, the ZnO suspension was poured into a beaker and allowed to settle for 24 hours. If the suspension is stable, it is centrifuged at 3000 to 12000 rpm for 1 to 24 hours. The resulting product was sonicated twice in ethanol (washing) and centrifuged at 3000 to 12000 rpm for 1 to 24 hours. The washed product is air-dried.

3) Preparation of the nanocomposite of methacrylic or acrylic polymer and ZnO by polymerization in mass between glass panes (Procedure A)

The MMA, initiator (concentration from 0.001 to 1%) of AIBN and nano ZnO at a concentration of 0.0001 to 10% are mixed in the beaker. The mixture is sonicated for 5-60 min and then transferred to a mold between the glass panes. The mixture in the mold is sonicated again for 25-60 min and then transferred to the water bath where the monomer is polymerized until the reaction is complete at 35-90 ° C for 20 hours. After polymerization is complete, the mold is cooled and the resulting nanocomposite is separated from the mold.

4) Preparation of nanocomposite methacrylic or acrylic polymer and ZnO with synthesis of prepolymer and subsequent polymerization in mass between glass panes (Procedure B)

In the beaker, mix the weighed amount of MMA, the initiator (concentration from 0.001 to 1%) of AICN and the nano ZnO at a concentration of 0.0001 to 10%. The mixture was sonicated for 5-60 min and then transferred to the reactor and partial polymerization of MMA was carried out at 35-80 ° C for one to two hours. An additional 20% of the initiator is then added and the mixture is transferred into a mold between the glass panes. The mixture in the mold is sonicated again for 5 60 min and then the mold is transferred to a water bath where the monomer is polymerized to completion of the reaction at 35-90 ° C for 1 to 24 hours. After polymerization is complete, the mold is cooled and the resulting nanocomposite is separated from the mold.

5) Preparation of the nanocomposite of methacrylic or acrylic polymer and ZnO with prepolymer synthesis accompanied by sonication throughout the prepolymer synthesis process and subsequent polymerization in mass between the glass panes (Procedure C)

-9 In the beaker, mix the weighed amount of MMA, the initiator (concentration from 0.01 to 1%) of AIBN and the nano ZnO at a concentration of 0.0001 to 10%. The mixture is sonicated for 5 - 60 mi and then transferred to the reactor and partial polymerization of MMA is carried out at 35-80 ° C for one to two hours with continuous sonication so that the reactor is heated in an ultrasonic bath. An additional 20% of the initiator is then added and the mixture is transferred into a mold between the glass panes. The mixture in the mold is sonicated again for 5-60 minutes and then transferred to the water bath where the monomer is polymerized to completion of the reaction at 35-90 ° C for 1 to 24 hours. After polymerization is complete, the mold is cooled and the resulting nanocomposite is separated from the mold.

6) Preparation of the nanocomposite of methacrylic or acrylic ZnO polymer with rhodopine casting (Procedure D)

In the beaker, the PMMA solution in the organic solvent and nano ZnO according to claim 2 is mixed at a concentration of 0.0001 to 10%, after which the mixture is dispersed with a dispersive agitator at 200 to 20000 rpm for 20 - 360 sec and then the mixture is sonicated for 5- After 60 minutes, it is then poured into a petri dish or sprayed onto a suitable base and dried.

Test results

Synthesis of nano ZnO

SEM micrographs (Figure 1) show 100 nm ZnO nanoparticles synthesized by polyol procedure in DEG with the addition of 0.05 to 4 mol of deionized water / 1 mol of Zn. The particles have an irregular spherical shape, a narrow size distribution and are partially agglomerated. SEM micrographs (Figure 2) show 300 - 400 nm ZnO nanoparticles synthesized in TEG. The XRD diffraction pattern of the particles shows typical ZnO peak maxima at angles of 31.8; 34.5; 36.2; 47.6; 56.6; 62.9; 66.4; 67.9; 69.1; 72.6; 76,9. The relatively wide signals indicate that the crystallite size is very small. The IR spectrum of both samples shows a pronounced ZnO absorption band in the range of 420 to 480 cm ^-1 (Figure 3). The fairly strong absorption bands around 1000 cm ^-1 and in the range 1300 - 1650 cm ¹ show that the sample also contains a relatively large proportion of the organic component - solvent residues and / or their degradation products.

-10 ZnO nanoparticles synthesized in BD, TEG, DEG, EG and PD with the addition of deionized water and pTsOH acting as a catalyst are in Figure 4. The particles are mostly crystallites of size 20-60 nm and are more agglomerated than those synthesized without p-TsOH (Figure 1). On TEM micrographs in Figure 4c, ZnO nanowires of 40 - 150 nm in length and 10-30 nm in width were synthesized in DEG. The degree of agglomeration is even more pronounced in the nanowires than in the other samples, most likely due to the greater contact surface between the particles. In the XRD diffraction pattern of particles sitetyzed in the presence of p-TsOH, very narrow diffraction bands are present (Fig. 5), which means that the synthesized samples are highly crystalline ZnO. The IR spectrum of these particles shows a pronounced ZnO band in the range of 420 to 480 cm ^-1 , while the absorption bands of the adsorbed organic compounds are much less intense than in samples synthesized without p-TsOH.

Preparation of nanocomposites by mass polymerization (Procedure A)

The TEM micrographs in Figure 7 show the distribution of ZnO particles synthesized in DEG without the presence of p-TsOH in the PMMA matrix of the PMMA / ZnO nanocomposite. Figure 7a shows that ZnO is homogeneously distributed over the polymer matrix but partially agglomerated (Figure 7b). Figure 8 shows the UV-VIS spectra of PMMA / ZnO nanocomposites with different concentrations of nano ZnO. The addition of 0.1 and 1% nano ZnO in PMMA absorbs more than 98% of the incident UV light, while at concentrations of 0.01 and 0.001% nano ZnO the absorption is still greater than 80% of the incident UV light. The absorption in the visible region is also high, so the samples are only partially transparent - translucent. The DTG curves of PMMA / ZnO nanocomposites with different concentrations of nano ZnO indicate that 0.1% nano ZnO raises the initial decay temperature by 20 ° C, while 1% ZnO raises it by 35 ° C (Figure 9). Such materials are potentially wearable as UV stabilized plexiglass with improved durability.

TEM micrographs in Figures 10 a and b show the distribution of ZnO nanoparticles synthesized in TEG in the PMMA / ZnO nanocomposite matrix. The nano ZnO particles are homogeneously distributed in the PMMA matrix and also the agglomeration is minimal (Figure 10 b). Obviously adsorbed TEG molecules on the ZnO surface

The -11 particles allow them to be homogeneously dispersed in PMMA despite relatively large particle sizes (300 nm).

PMMA / ZnO nanocomposites - ZnO synthesized with p-TsOH (Procedure A)

TEM micrographs in Figure 11 show the distribution of ZnO nanoparticles synthesized in different diols in the presence of p-TsOH. ZnO particles synthesized in the presence of p-TsOH (Figure 11 a) are slightly more agglomerated than those without it (Figure 7 and 10) but still homogeneously distributed over the PMMA matrix.

UV absorption is very high in the UV range from 280 to 380 nm, since 0.1 and 1% ZnO absorb more than 98% of the incident UV light, and even at a concentration of 0.01%, the absorption is still 70 to 90% of the incident UV light (Figure 12). With ZnO synthesized in EG, we can also prepare a nanocomposite that absorbs close to 90% of UV light in the 280 - 360 nm range, and in the visible range (400 - 700 nm) the transmittance for visible light is practically 100% (Figure 12). Such a nanocomposite has potential use as a UV stabilized plexiglass with improved temperature resistance.

Nano ZnO synthesized in the presence of p-TsOH stabilizes the PMMA matrix in temperature. The stabilizing effect is most pronounced at concentrations of 0.1 and 1% as the PMMA decay shifts by a few tens of degrees Fahrenheit toward higher temperatures (Figure 13). PMMA with the addition of 0.1% ZnO or more has potential use as a PMMA material with improved thermal stability.

Preparation of PMMA / ZnO Nanocomposites with Pre-Polymer Synthesis (Procedure B)

Preparation of PMMA / ZnO nanocomposites by first partially polymerizing MMA, or by preparing a prepolymer, enables the preparation of PMMA / ZnO nanocomposites, which are optically clearer or more transparent to visible light (Figure 14). Figure 15 shows the UV - visible spectrum of the PMMA / ZnO nanocomposite prepared by direct polymerization of MMA (A) and by polymerization via prepolymer according to method A (B). It can be seen that the nanocomposite prepared via prepolymer (B) is much more permeable to visible light, whereas the absorption into UV (range

-12from 280 to 360 nm) in both cases more than 98% of the incident UV light (Figure 15). The addition of nano ZnO also improves the impact toughness of these materials by 3 - 5% with the addition of 0, 05% ZnO and 8 - 10% with the addition of 0.1% nanoZnO.

Samples of nanocomposites prepared by Process B with ZnO nanofillers synthesized in PD, EG, and DEG were determined to be resistant to succulent light (Sun test). The results are summarized in Table 1 and show a strong improvement in the resistance to sunlight irrespective of the ZnO pattern and concentration. This indicates the high potential use of PMMA / nanoZnO composites in areas with high light load such as e.g. facade panels or cladding, highway noise barriers, thermal solar systems and acrylic coatings for metals and wood, etc.

Table 1: Results of the determination of the resistance to sunlight (Sun test) of PMMA / ZnO - ZnO nanocomposites synthesized in different diols and different concentrations of nano ZnO

Diol ZnO concentration (%) AE ^a Blind rehearsal 0 10,6-10,8 PD 0.05 1.0 - 1.3 PD 0.1 3,1-4,6 EG 0.05 4.1 - 4.3 EG 0.1 1,7-2,1 DEG 0.05 1,8-2,4 DEG 0.1 4,6-6,1

^a ΔΕ is the change in color value measured by the colorimeter with respect to the non-exposed sample

Preparation of PMMA / ZnO Nanocomposites with Pre-Polymer Synthesis (Procedure C)

By introducing sonication during the entire synthesis of the prepolymer (process C), the optical properties of the nanocomposite in the visible part of the spectrum approximate the optical properties of commercial UV stabilized plexiglass (Figure 16).

-13Preparation of PMMA / ZnO nanocomposites with solution casting (Procedure D)

Homogeneous nanocomposites can also be prepared from PMMA solution in ethyl methyl ketone (Figure 17). The nanocomposites thus prepared have a UV absorption of 50 to 80% in the UV range of 290 to 360 nm (Figure 18). Due to the weight, they are potentially useful for coatings in areas with high UV and light load.

Claims (17)

PATENT APPLICATIONS 1. The process for the preparation of zinc (II) oxide nanoparticles and nanoparticles - ZnO nano - with an organophilic surface by hydrolysis of the zinc compound in the presence of a catalyst, toluene sulfonic acid vapor, in different diols and preparative nano ZnO is hereinafter used unmodified. The method according to claim 1, characterized in that it comprises the following steps: mixing and sonicating the solution for 5 to 60 minutes. heating the solution for 30 to 90 minutes at temperatures of 100 to 300 ° C; deposition of zinc oxide compound up to 24 h; separating the suspension from the precipitate; washing the suspension; drying the compound. A process according to claim 1 or 2, characterized in that the zinc compounds are selected from Zn (CH ₃ COO) 2x2H2O, Zn (C ₅ H ₇ O ₂ ) xH2O, ZnC ₂ O ₄ xH2O, ZnSO ₄ x7H ₂ O, Zn (NO ₃ ) 2x6H ₂ O, Zn (PO ₄ ) ₂ , ZnCl ₂ , ZnBr ₂ and diols selected from ethylene glycol - EG, 1,2-propane diol - PD, 1,4-butane diol - BD, di ( ethylene glycol) - DEG or tetra (ethylene glycol) - TEG. A process according to any one of claims 1 to 3, characterized in that a zinc compound is added to the diol at a concentration of 0.005-5 mol / L, preferably 0.1 to 1 mol / L, and the calculated amount of water is 0, 5 to 4 mol H ₂ O per mol Zn. 5. A process according to any one of claims 1 to 4, characterized in that the catalyst, steam of toluene sulfonic acid, is in a concentration of from 0.001 to 2 mol / L, preferably from 0.01 to 0.5 mol / L. 6. Zinc (II) oxide nanoparticles and ZnO nanosheets - with an organophilic surface prepared by the hydrolysis process of a zinc compound in the presence of a catalyst, toluene sulfonic acid vapor, in diols prepared according to any one of claims 1 to 5, which are hereinafter used unmodified. A process for the preparation of nanocomposites composed of methacrylic or acrylic polymer and unmodified nano ZnO prepared according to any one of claims I to 6. A process according to claim 7, characterized in that it comprises the following steps: preparation of a mixture of methacrylic or acrylic monomer, initiator and zinc (II) oxide according to any one of claims 1 to 6; mixing and sonication for 5 to 60 min; optional partial polymerization of MMA; optional initiator re-addition of 0.1 to 40%; molding polymerization at 35 to 80 ° C; polymer cooling and mold separation. -159. The process of claim 7 or 8, characterized in that the mixing of nano ZnO prepared according to claims 1 to 6 is carried out in MMA or in the methacrylic and acrylic monomer of the group methyl, ethyl, isopropyl, n-propyl, n-butyl, t-butyl, n-pentyl, n-hexyl, phenyl, naphthyl, ethylhexyl, oleyl, palmityl and stearyl methacrylate or acrylate; at concentrations of 0.0001 to 10%, preferably 0.01 to 1%. A process according to any one of claims 7 to 9, characterized in that the initiator is added at a concentration of 0.0001 to 1%, preferably 0.002 to 0.01%. Process according to any one of claims 7 to 10, characterized in that the weighed amount of MMA and / or other methacrylic or acrylic monomer is mixed, the initiator at a concentration of 0.01 to 1 and the nano ZnO according to claim 6, prepared according to any one of of claims 1 to 5 at a concentration of 0.0001 to 10%, after which the mixture is sonicated for 5-60 min. and then transferring it to the mold or optionally transferring it to the reactor and partially polymerizing the MMA or other monomer at 35-80 ° C for one to two hours; thereafter, from 1 to 40% of the initiator is added and the mixture is transferred into a mold between the glass panes and sonicated again for 5-60 min; the mold is then heated at 35-90 ° C for 1 to 24 hours to polymerize the monomer until the reaction is complete; after polymerization is complete, the mold is cooled and the resulting nanocomposite is separated from the mold. 12. Nanocomposite materials with improved UV, light, temperature and mechanical properties prepared according to the method of claims 7 to 11. Nanocomposite materials prepared according to claims 7 to 11, characterized in that they are used as UV and light-stabilized opaque or transparent materials, including plexiglass in solar technology, for glazing, for facade cladding, for highway and rail fences areas where high UV and light and heat loads occur. 14. Process for the preparation of nanocomposites from a solution composed of a methacrylic or acrylic polymer of the group: poly (methyl, ethyl, isopropyl, n-propyl, n-butyl, t-butyl, n-pentyl, n-hexyl, phenyl, naphthyl, ethylhexyl , oleyl, palmityl and stearyl methacrylate or acrylate) and nano ZnO prepared according to any one of claims I to 6. A process according to claim 14, characterized in that it comprises the following steps: preparation of a mixture of methacrylic or acrylic polymer and zinc (II) oxide according to any one of claims 1 to 6 in an organic solvent; dispersing with a dispersing agitator; mixing and sonication for 5 to 120 min; molding or injection molding on any substrate; drying the film. -1616. The process according to any of claims 14 to 15, characterized in that the mixing of nano ZnO prepared according to claims 1 to 6 in PMMA solution or other suitable methacrylic or acrylic polymer is carried out at concentrations of 0.0001 to 1%, preferably from 0.01 to 0 , 1%. 17. A process for preparing nanocomposites consisting of methacrylic or acrylic polymer and nano ZnO, characterized in that a solution of PMMA and / or any other methacrylic or acrylic polymer in an organic solvent and nano ZnO according to claim 2 is mixed in a beaker at a concentration of 0 , 0001 to 10%, after which the mixture is dispersed with a dispersive agitator from 200 to 20000 rpm for 20 to 360 seconds and then the mixture is sonicated for 5 to 60 min. and then poured into a mold or sprayed onto a suitable base and dried. 18. Nanocomposite materials in the form of thin films with improved UV, light, temperature and mechanical properties, characterized in that they are prepared by the process of claims 14 to 17. 19. Nanocomposite materials prepared according to claims 14 to 17, characterized in that they are used as UV and light-stabilized opaque or transparent coatings in areas where high UV and light and heat loads occur.