Nâng cao chất lượng trang sức bề mặt sản phẩm gỗ bằng sơn polyurethane (PU) phân tán nano tio2 tt tieng anh

MINISTRY OF AGRICULTURE AND MINISTRY OF EDUCATION AND RURAL DEVELOPMENT TRAINING VIETNAM NATIONAL UNIVERSITY OF FORESTRY PHAM THI ANH HONG IMPROVING THE FINISHING QUALITY OF WOOD PRODUCTS USING POLYURETHANE (PU) COATING DISPERSED BY TIO2 NANO MAJORITY: FORESTRY PROCESSING TECHNOLOGY CODE: 9549001 SUMMARY OF ENGINEERING DOCTORAL THESIS HA NOI, 2020 Research work is completed at: Vietnam National University of Forestry Scientific instructors: Scientific instructor 1: Associate Professor, Dr Cao Quoc An Scientific instructor 2: Professor, Dr Tran Van Chu r Reviewer 1:…………………………………………… Reviewer 2:…………………………………………… Reviewer 3:…………………………………………… The defense will be taken in front of the Institutional Board of Thesis Evaluation at: Vietnam National University of Forestry At: … time, Date ….Month… Year 2020 The thesis can be found in the libraries: National Library; Vietnam National University of Forestry Library ABSTRACT Official thesis title: ”Improving the finishing quality of wood products using Polyurethane (PU) coating dispersed by TiO2 nano” I INTRODUCTION Wood is anisotropic material easy to change color, size under the influence of the environment so the wood products in our country today are finished by some kind of coatings to increase the aesthetics and protect the surface of the products against moisture, light, and microorganisms that destroy wood, etc The finishing stage can be done before or after assembling the product This is an important stage in the production of wood furniture Polyurethane (PU) coating is the most commonly used to finish wood products because they have many advantages: coating film dries fast, smooth flat, adhesion is good, hardness and gloss are high and the price is reasonable However, this coating has big disadvantages is that its resistance to natural light is poor, so the coating film will be discolored To overcone the above drawback, some scientists have studied to improve the quality of PU coating film by nanomaterials such as SiO 2, ZnO, TiO2, etc Most of the results showed that PU coating after combining with nanomaterials are both antibacterial and self-cleaning, resistant to ultraviolet (UV), scratch, abrasion, hardness is increased, moisture resistance is also improved Titanium dioxide (TiO2) is a semiconductor material, wide prohibit region, wide prohibit region, white This is a non-toxic material, environmental friendliness, has high chemical stability, antibacterial, kills mold and self-cleaning surface and resists to UV rays, moisture resistant, improves adhesion strength, impact the durability, cleans the air, cleans the water and low cost Stemming from the above reasons, I conduct to study the thesis: “Improving the finishing quality of wood products using Polyurethane (PU) coating dispersed by TiO2 nano” II OBJECTIVES, RESEARCH CONTENTS, AND METHODOLOGY 2.1 Research objectives 2.1.1 Overall objectives Building a scientific basis and the practice of some technological factors to improve the quality of wood products finishing by PU coating combined with TiO nanomaterials, from there, contributing to improving the use-value and expanding the consumption market for wood products 2.1.2 Specific objectives - Determining the effects of concentration and time disperses TiO nanomaterials to some quality targets of coating film; - Determining the effects of pressure and speed moves of the spray gun to some quality targets of coating film; - Proposing reasonable technology parameters to improve the quality of wood products surface finished by PU coating 2.2 Research content - Synthesize information about PU coating, TiO nanomaterials, method disperses nano into coating and wood products finishing technology - Studying the effect of concentration and time disperse TiO nanoparticles to some quality targets of coating film; - Studying the effect of pressure and speed moves of the spray gun to some quality criteria of coating film; - Analyzing, evaluating the results, and proposing suitable technology parameters to improve the quality of wood products finishing by PU coating combined with TiO nano 2.3 Main research method The multi-factor experimental method: Number of experiments: N = 2n + 2n + = 22 + x + = (1) Table 1.1 Experimental domain affects the concentration and time disperse TiO2 nanoparticles to some quality targets of the coating film Variable level Variable Impact factor -1 +1 + range Concentration of TiO2 nano (C, %) 0.05 0.1 0.15 0.2 0.25 0.05 Time disperse (τ, hours) Table 1.2 Experimental matrix on the effect of concentration and time disperse TiO2 nanoparticles to some quality targets of the coating film Code form Real form Output parameters No X1 X2 C (%) (hrs) Y1 Y2 Y3 Y4 -1 -1 0.1 2 +1 -1 0.2 -1 +1 0.1 4 +1 +1 0.2 0.05 0.25 + 0.15 + 0.15 0 0.15 After finding the optimal parameters about concentration and dispersion time of TiO2 nanoparticles in PU paint, the thesis conducted experiments with multi factors about the influence of pressure and speed moves of the spray gun to some quality targets of the coating film The number of experiments is also calculated by the formula (1): N = Table 1.3 Modes spray PU paint after mixing with TiO nano Variable level Variable Impact factor -1 +1 + range Spraying pressure (P, MPa) 0.1 0.14 0.18 0.22 0.26 0.04 Speed moves of spray gun (V, 60 65 70 75 80 m/min) Table 1.4 Experimental matrix on the influence of the pressure and speed moves of the spray gun to some quality targets of the coating film Code form Real form Output parameters No X1 X2 P (MPa) V (m/min) Y1 Y2 Y3 Y4 -1 -1 0.14 65 +1 -1 0.22 65 -1 +1 0.14 75 +1 +1 0.22 75 0.1 70 + 0.26 70 0.18 60 + 0.18 80 0 0.18 70 III RESULTS AND DISCUSSION 3.1 Effect of concentration and time disperse TiO2 nanoparticles to the quality of the coating film 3.1.1 Check the stability of nano TiO in the solvents Check the stability of nano TiO in the solvents TiO2 nano is dispersed in the solvent contain Las TiO2 nano is dispersed in the solvent without Las Figure 3.1 The turbidity of TiO2 nanomaterials with concentration at 0.15% is dispersed in the Butyl acetate solvent The turbidity of TiO nanoparticles disperse in Butyl acetate solvent without Las surfactants reduced quickly over time compared with TiO nanoparticles disperse in Butyl acetate solvent containing Las surfactants 3.1.2 Determine the existence of TiO2 nanoparticles in PU coating film on wood surface Na no TiO2 Figure 3.2 SEM image of PU control coating (x 4000) Figure 3.3 SEM image of PU-TiO2 coating film with concentration 1.05% disperse in hours (x 500) The SEM images showed that the surface status of the PU control film and the PU-TiO2 film on the wood surface did not show cracking or flaking 3.1.3 Effect to the hardness of the coating film The correlation equation between the concentration and time disperse TiO nanoparticles with the hardness of the coating film: Equation in code form: Y = 2.575 + 5.011X1 – 0.083X12 + 0.075X2 – 0.250X2X1+ 0.003X22 (3.1a) Equations in real form: Y = -23.417 + 167.899C – 33.320C2 + 0.733 - 1.000C + 0.0001 (3.1b) Results analyze the variance (Anova) of hardness of coating films at the concentration and time disperse TiO nanoparticles: Error sources Factor Error Total Squared Sum (SS) 260.851 292.593 553 445 Degree of Square freedom (df) medium (MS) value (F) Fk-1; n-k;1-α (Fcrit) 140 149 28.983 2.089 13.868 1.947 Statistical The results showed that F> Fcrit, this proves that the hardness of the coating film between the concentration and time disperse TiO nanoparticles was different Through the research results, the hardness of PU-TiO2 coating film is higher than that of the control PU coating 3.1.4 Affects the abrasion resistance of the coating film The correlation equation between the concentration and time disperse TiO2 nanoparticles with the ratio of loss due to abrasion: Equation in code form: Y = 0.217 – 1.003X1 + 1.972X12 – 0.012X2 + 0.117X2X1 – 0.001X2 (3.2a) Equations in real form: Y = 26.196 - 288.915C +788.879C - 0.391 + 2.334C 0.001 (3.2b) Results analyze the variance (Anova) the ratio of loss due to abrasion of coating films at the concentration and time disperse TiO2 nanoparticles: Error sources Squared Sum (SS) Degree of freedom (df) Square medium (MS) Statistical value (F) Fk-1; n-k;1-α (Fcrit) Factor 838.802 93.200 46.599 1.947 Error 280.002 140 2.000 Total 1118.804 149 The results showed that F> Fcrit, this proves that the ratio of loss due to abrasion of the coating film between the concentration and time disperse TiO2 nanoparticles was different The ratio of loss of mass due to the abrasion of PU-TiO2 film is lower than that of the control PU coating When the concentration and dispersion time of TiO nanoparticle changed, the ratio of abrasion loss of PU-TiO2 coating film also decreases from 0.1305% to 0.157% 3.1.5 Affect the resistance of chemical and water of the coating film The relationship between the concentration and dispersion time of TiO nanoparticles with the resistance of chemical and water of the coating film is shown in figure 3.4 Acid acetic Alcohol etylic cafe Tea Water Figure 3.4 Relationship between concentration and dispersion time of TiO nanoparticles with the resistance of chemical and water of the coating film PU-TiO2 coating film has better resistance of chemical and water than the control PU coating When the concentration and dispersion time of TiO nanoparticles change, the durability of water and chemical of the PU-TiO2 coating was also changed significantly 3.1.6 Affects the UV resistance of the coating film a) Results of measuring the discoloration of the coating film The correlation equation between the concentration and time disperse TiO nanoparticles with the resistance to discoloration of the coating: Equation in code form: Y = 17.161 – 44.428X1 + 65.833X12- 0.226X2 + 0.100X2X1 + 0.017X22 (3.3a) Equations in real form: Y = 34.342 – 184.288C + 263.332C2 - 0.186 + 0.400C 0.00072 (3.3b) Results analyze the variance (Anova) the color deviation ∆E of coating films at the concentration and time disperse TiO nanoparticles: Degree of Square Statistical Squared Sum F k-1; n-k;1-α Error sources freedom medium value (SS) (Fcrit) (df) (MS) (F) Factor 472.853 52.539 21.488 1.947 Error 342.306 140 2.445 Total 815.159 149 The results showed that F> Fcrit, this proves that the color difference of the coating film between between the concentration and time disperse TiO nanoparticles was different PU-TiO2 coating film has lower color deviation compared with the control PU coating When the concentration and dispersion time of TiO nanoparticles change, the color deviation of the PU-TiO2 coating also decreases from 14.85 to 9.62 b) The result of measuring the gloss of the coating film The correlation equation between the concentration and time disperse TiO nanoparticles with the gloss of the coating film after illuminating UV ray: Equation in code form: Y = 45,750 + 151,439X1 - 25,694X12- 1,326X2 + 0.022X2 13,283X2X1 - 0,022X22 (3.4a) Equations in real form: Y = 20,486 + 272,108C - 102,776C2 - 40,743 + 263,660C - 0,0222 (3.4b) The gloss of PU-TiO2 film after illuminating UV ray is higher than that of control coating film When changing the concentration and dispersion time of TiO2 nano, the gloss of PU-TiO2 film oscillates from 50.34 GU to 72.81 GU 3.1.7 Determine the suitable value of the concentration and time disperse TiO nano We have the optimal problem model as following: We have the optimal problem model as following: Y1 = -23,417 + 161,899C – 33,320C2 + 0,733 - 1,000C + 0,00012  Max Y2 = 26,196 - 288,915C +788,879C2 - 0,391 + 2,334C - 0,0012  Min Y3 = 34,342 – 184,288C +263,332C2 - 0,186 + 0,400C - 0,00072  Min Y4 = 20,486 + 272,108C - 102,776C2 - 40,743 + 263,660C - 0,0222  Max 0,05  C  0,25;    After solving the system of equations, we obtained the results: C = 0.159;  = 3,682 3.1.8 Testing with the optimum values of concentration and time disperse TiO nano The thesis will proceed to disperse TiO2 nano into PU warnish and paint on the wood surface according to the parameters as following: concentration of TiO nano: C = 0.16%; Time disperses: = 3.68 hours; Pressure spray: P = 0.18 Mpa; Speed spray: T = 70 m/min Table 3.1 The results of testing some quality targets of coating film on the wood surface with appropriate parameters C and The ratio of The color The gloss after Quality Hardness mass loss due deviation after illuminating targets (H) to abrasion, illuminating UV ray Sample (%) UV ray (GU) Control PU coating 2.80 0.1401 19.27 43.14 PU coating film combined 3.59 0.1152 11.24 65.19 with TiO2 nano Level of improvement 22.01% 17.77% 41.67% 33.82% Table 3.2 Comparing between calculated values and experimental values of some quality targets of the coating film The ratio of The color The gloss after Quality Hardness (H) mass loss due deviation after illuminating targets to abrasion illuminating UV ray (%) UV ray (GU) Value Theory 3.59 0.1152 11.24 65.19 Experiment 3.53 0.1158 11.54 64.66 Through the results in table 3.2, it shows that when experimenting with the appropriate parameters has been found, the quality targets of PU coating combined with TiO2 have changed significantly compared with the control PU coating When comparing the calculated value and the experimental value of the quality targets: hardness, the ratio of mass loss due to abrasion, color deviation, and gloss after illuminating UV rays, there is no significant deviation (table 3.2) Thus, the computed optimal value can be accepted 3.1.10 The chemical structure analysis of the coating film based on infrared spectrum Table 3.3 FTIR spectral properties of PU coating film and PU coating film combined with TiO2 nano Number of waves (cm -1) Functional groups Control coating 3342.52 2926.60 1735.81 1537.64 1120.75 741.13 The coating has nano 3325.61 2926.51 1733.22 1537.61 1121.08 741.22 corresponding OH CH2 C=O C=NH C-OC6 H5 Figure 3.5 Infrared spectra of control PU coating Figure 3.6 Infrared spectra of PUTiO2 coating (C = 0.16%; τ = 3.68 hrs) Through analysis results of infrared spectrum in table 3.3 and figure 3.5, 3.6 shows, intensity absorb infrared rays characteristic for functional groups chemical structure in PU coating combined with TiO nano has not changed significantly compared with the control PU coating Thus, when adding TiO nanomaterials to PU coating at the research concentration, it did not affect the components of the PU coating 3.2 The effect of pressure and speed move of the spray gun to the quality of coating film 3.2.1 Affect to the thickness of coating film The correlation equation between the pressure and speed move of spray gun with the thickness of coating film in formulas 3.5a and 3.5b Equation in code form: Y= 45,539+121,756X –211,444X12+0,721X2 0,680X2X1– 0,010X22 (3.5a) Equations in real form: Y=12,642+68,143P+22,153P2-0,815V+2,720PV- 0,0004V2 (3.5b) Results analyze the variance (Anova) the thickness of coating film at the pressure and speed move of spray gun: Degree of Square Statistical Squared Sum Fk-1; n-k;1-α Error sources freedom medium value (SS) (df) (MS) (F) (Fcrit) Factor 38577.416 4286.380 1504.081 1.947 Error 398.977 140 2.850 Total 38976.393 149 The results showed that F> Fcrit proves that the thickness of the coating film between the pressure and speed move of spray gun was different When the pressure and speed move of spray gun changes, the thickness of the coating film was significantly affected, changing from 46.52 m to 70.11 m 3.2.2 Effect to the time dries completely of coating film The correlation equation between the pressure and speed move of spray gun with the time dries completely of coating film: Equation in code form: Y = 27,223 – 4,439 X1+ 6,556 X12 + 0,666 X2 + 0,343 X2X1 0,004 X22 (3.6a) Equations in real form: Y = 107,082 – 48,242P + 26,223 P2 – 1,276V + 1,373PV 0,0001V2 (3.6b) Results analyze the variance (Anova) the time dries completely of coating film at the pressure and speed move of spray gun: Error sources Squared Sum (SS) Degree of Square freedom (df) medium (MS) Statistical value (F) Fk-1; n-k;1-α (Fcrit) 1.947 Factor 4930.574 547.842 265.176 Error 289.234 140 2.066 Total 5219.808 149 The results showed that F> Fcrit, this proves that the time dries completely of coating film between the pressure and speed move of spray gun was different The time dries completely of coating film at the spray levels are significantly different, changing from 24.04 hours to 29.01 hours 3.2.3 Affect to the gloss of coating film The correlation equation between the pressure and speed move of spray gun with the gloss of coating film: Equation in code form:Y = 35.064 + 399.600X1 – 661.111X12 + 10.730X2 – 1.207X2X1 – 0.078X22 (3.7a) Equations in real form: Y = -122.507 + 83.134P + 281.944P2 + 3.727V - 4.827PV 0.003V2 (3.7b) Results analyze the variance (Anova) the gloss of coating film at the pressure and speed move of spray gun: Error sources Squared Sum (SS) Degree of freedom (df) Square medium (MS) Statistical value (F) Fk-1; n-k;1-α (Fcrit) 1.947 Factor 77775.488 8641.721 3653.021 Error 331.189 140 2.366 Total 78106.677 149 The results showed that F> Fcrit, this proves that the gloss of coating film between the pressure and speed move of spray gun was different The pressure and speed movement of the spray gun affect the gloss of coating film at different levels, changing from 65.5 GU to 92.1 GU 3.2.4 Affect to the UV resistance of coating film The correlation equation between the pressure and speed move of spray gun with the UV resistance of coating film: Equation in code form: Y = 2.809 + 31.242X1 + 71.417X12 – 0.646X2 – 1.120X2X1 + 0.007X22 (3.8a) Equations in real form: Y = -14.912 – 228.928P + 285.667 P2 + 1.698V - 4.480PV 0.0003V2 (3.8b) Results analyze the variance (Anova) the UV resistance of coating film at the pressure and speed move of spray gun: Degree of Square Statistical Squared Sum Fk-1; n-k;1-α Error sources freedom medium value (SS) (df) (MS) (F) (Fcrit) Factor 552.506 61.390 28.932 1.947 Error 297.058 140 2.122 Total 849.564 149 The results showed that F> Fcrit, this proves that the UV resistance of coating film between the pressure and speed move of spray gun was different Color deviation ΔE of coating film at the spray levels is different, changing from 8.57 to 14.25 10 3.2.5 Determine the pressure and speed moves of the spray gun accordingly to finish wood surfaces by PU-TiO2 coating We have optimal problem model as following: Y4 = 12,642 + 68,143P + 22,153P - 0,815V + 2,720PV - 0,0004V2  Max Y5 = 107,082 – 48,242P + 26,223 P2 – 1,276V + 1,373PV - 0,0001V2  Min Y6 = -121,507 + 83,134P + 281,944P2 + 3,727V - 4,827PV - 0,003V2  Max Y7 = -14,912 – 228,928P + 285,667 P + 1,698V - 4,480PV - 0,0003V2  Min 0,1  P  0,26; 60  V  80 After solving the above system of equations, we obtained the results: P=0.188; V=70.75 3.2.6 Testing with optimum value of pressure and speed moves of spray gun The thesis will proceed to disperse TiO nano into PU warnish and paint on the wood surface according to the parameters as following: concentration of TiO2 nano: C=0.16%; Time disperse: =3.68 hours; Pressure spray: P=0.19 MPa; Speed spray: T=71 m/min Table 3.4 The results of testing some quality targets of coating film on the wood surface with parameters P and V are appropriate Quality Thickness, The time dries The color deviation targets completely, Gloss, GU after illuminating m Sample hours UV ray Control PU coating 58.94 26.08 86.84 19.14 PU- TiO2 coating 60.29 26.41 87.39 11.32 Level of improvement 2.24% 1.25% 0.63% 40.85% Table 3.5 Comparing between calculated values and experimental values of some quality targets of the coating film Quality Thickness, The time dries The color deviation Gloss, GU after illuminating targets completely, m Sample hours UV ray Theory 60.71 26.43 88.06 11.19 Experiment 60.29 26.41 87.39 11.32 Through the results in Table 3.4 show that when experimenting with the appropriate parameters has been found, the quality targets of PU coating combined with TiO2 nano have changed significantly compared with the control PU coating On the other hand, when comparing the calculated value and the experimental value of the quality targets: Thickness, time dries completely, gloss, and color deviation of the coating film after illuminating UV rays, there is no significant deviation (table 3.5) Therefore, the computed optimal value can be acceptable General remark: The thesis has proposed appropriate technological parameters to improve the quality of wood surface finishing by PU coating combined with TiO2 nano: Dispersing TiO2 nano into PU coating at concentration 0.16% through Butyl acetate solvent containing Las surfactant in 3.68 hours and spraying PU-TiO2 coating at pressure 0.19 MPa with the speed moves of the spray gun 71 m/min is suitable LIST OF ARTICLES, SCIENCE WORKS PUBLISHED Pham Thi Anh Hong, Cao Quoc An, Nguyen Thi Vinh Khanh, Effects of Page concentration nano titandioxid (TiO2) to quality of polyurethane (PU) paint film 117-125 on surface wood products Journal of Agriculture and Rural Development, Number 2-2018; Pham Thi Anh Hong, Cao Quoc An, Effect of some technological factors dispersion titandioxid (TiO2) nano to the quality of the coating film on wood 102-112 products Journal of Science and Forestry Technology, Number 1-2019; Pham Thi Anh Hong, Tran Van Chu, Cao Quoc An, Phan Duy Hung, effects of air pressure and spraying speed to quality of the coating film on wood surface Journal of Agriculture and Rural Development, Number 5-2018 111-118 ... SCIENCE WORKS PUBLISHED Pham Thi Anh Hong, Cao Quoc An, Nguyen Thi Vinh Khanh, Effects of Page concentration nano titandioxid (TiO2) to quality of polyurethane (PU) paint film 117-125 on surface... time disperse TiO2 nanoparticles to the quality of the coating film 3.1.1 Check the stability of nano TiO in the solvents Check the stability of nano TiO in the solvents TiO2 nano is dispersed... coating combined with TiO2 nano: Dispersing TiO2 nano into PU coating at concentration 0.16% through Butyl acetate solvent containing Las surfactant in 3.68 hours and spraying PU -TiO2 coating at pressure