Surface Drying Time Research Articles

A simplified but improved numerical approach to determine moisture balance for plastic shrinkage cracking in concrete

This paper introduces an improved numerical approach for evaluating moisture balance on concrete surface which can initiate plastic shrinkage cracking on the surface of fresh concrete in concrete slab. Because plastic shrinkage cracks occur when the tensile stress induced from the surface drying of concrete exceeds the tensile strength in the freshly placed concrete, moisture balance calculated by the introduced approach can be used as the primary indicator for plastic shrinkage cracking. The numerical approach introduced in this paper therefore emphasized an exact evaluation of bleeding and evaporation on the concrete surface. In determining bleeding, the approach introduced in the previous study was improved through the consideration of additional influencing factors of the accelerator and steel fiber and the supplementation of additional experimental data. For reliable prediction of evaporation, an empirical relation was newly introduced. The reduction of evaporation rate with time was taken into consideration, and the use of the weighed characteristic velocity rather than the direct application of the wind velocity was recommended. Determination of an exact distribution for the weighed characteristic wind velocity on the surface of a concrete slab was based on computational fluid dynamic (CFD) analyses. In particular, the effect of installing a windscreen along the sides of the concrete slab was intensively examined. Upon verification of the introduced numerical approach through correlation studies between experimental data and numerical results, additional parametric studies were also performed to numerically examine the relative contribution of each influencing factor in plastic shrinkage cracking. Moreover, the introduced approach can effectively be used for the on-site prediction of surface drying time of a concrete slab and for the preparation of a proper curing strategy to mitigate plastic shrinkage cracking.

Preparation and Properties of Waterborne Acrylic-Modified Epoxy Phosphate Resin and Its Coating

An acrylic acid-modified epoxy phosphate resin coating was synthesized by a four-step method marked “A-B-C-D”, and it was used as an efficient protective layer for steel structures. The coating exhibited good properties, mainly including water resistance (≥240 h), salt spray resistance (≥300 h), surface drying time (≤1 h), and adhesion (≥6.5 MPa).

Curing characteristics and performance of a bio-based polyurethane engineered sealant with high bonding strength: Effect of R value and chain extender content

Polyurethane (PU) engineering sealants can be used to fill construction joints and pavement cracks with excellent practical results. However, traditional engineering sealants have the disadvantages of poor strength and raw materials that are not environmentally friendly. In this paper, a novel composition system of bio-based polyurethane engineering sealant was developed. The effects of the isocyanate/macroglycol molar ratio (nNCO/nOH, R value) for component A and the contents of amine chain extender (AME) on the curing characteristics and properties of the PU sealant were investigated using a series of experiments. Firstly, the curing process of the sealant was studied by Fourier transform infrared spectroscopy (FTIR) test, surface drying time test and gel time experiments. Secondly, the basic physical properties of the sealant were studied by tensile and hardness tests. And the water resistance of the sealant was judged. Then, the characteristics of molecular movement of polyurethane sealant were analyzed by dynamic mechanical analysis (DMA). The tensile cross-sections of the specimens were observed by scanning electron microscopy (SEM). Finally, the thermal stability of sealants was studied by thermogravimetric (TG) analysis. The results indicated that the material developed in this research can be used as a high-performance engineering sealant in actual projects. The increase in the R value and the decrease in AME content resulted in a longer curing process of the sealant. The rise of R value and AME content was able to raise the tensile strength, bonding strength and hardness of the sealant. The water resistance of the sealant was better. Also, the glass transition temperature (Tg) and storage modulus could also be increased and the thermal stability of the previous stage could be reduced by increasing the R value and AME content. Considering both the performance and construction requirements, the optimum R value and AME contents are recommended to be 2.1 and 1.4%, respectively.

Effects of Photoinitiators on Curing Performance of Wood Wax Oil Coating on Wood

With the increasing shortage of petroleum resources and the growing seriousness of environmental pollution, the exploitation and application of bio-based coatings derived from renewable resources have become increasingly important for the woodworking industry. Wood wax oil (WWO) is a new type of bio-based natural coating material that offers an eco-friendly solution for wood protection. This paper focused on the utilization of tung oil and beeswax as the primary raw materials for the preparation of wood wax oil. The WWO was based on the oxidation polymerization of tung oil, which served as the foundation for the preparation process. The effects of the photoinitiator TPO-L on the curing performance of the WWO were investigated, and the curing mechanism of the WWO system induced by photoinitiators was analyzed and characterized by infrared spectroscopy. Through ultraviolet irradiation experiments and coating quality tests, the effects of incremental photoinitiators on the properties of the surface drying time, gloss, color, hydrophobicity, and solution resistance of the treated ash wood were studied. The results indicated that the addition of photoinitiators was beneficial for the rapid polymerization of wood wax oil. A UV light intensity of 30 w was found to be sufficient to initiate the curing process. Specifically, when using TPO-L as the initiator at a concentration of 3 wt%, the surface could be surface-dried within 10 min under UV exposure. Under these curing conditions, wood wax oil coatings based on tung oil with comprehensive curing properties can be obtained. Additionally, adding 6% beeswax to the tung oil can effectively enhance the hydrophobicity of pure tung-oil-based wood protective coatings.

PAINTS FORMULATION USING DIISOCYANATES AND 1,4 –DIAMINO ANTHRAQUINONE (1,4 DAQ) AS PIGMENTS AND POLYVINYL ALCOHOL AS BINDER, CHARACTERIZATION AND THEIR APPLICATION ON WOOD SUBSTRATE

The Paint and coatings industry produces a huge variety of products that protect, preserve, and also beautify the objects to which they are applied, however, the components are expensive, therefore there is the need to look for alternative constituents which are cheaper and more durable. Emulsion Paints were formulated using colourants produced from diisocyanates and 1,4 diamino anthraquinone and polyvinyl alcohol as binder. The constituents of the paint was stirred mechanically in a ceramic mortar and pestle for 1 hour, and it was applied on the substrate (ceiling board). The coated samples were subjected to physical characterization, viscosity, surface drying time, weathering and lightfastness and compared with a commercial paint (Emulsion paint). The results indicates a very good light fastness property of 6-7, for paints produced from hexamethylene diisocyanate and where resistant to weathering, while paints produced from 1,4 phenylene diisocyanate showed a poor light fastness of 1-2, however it also indicated resistant to weathering. Hexamethylene diisocyanate, is less expensive and is more durable and economical in emulsion paint production compared to 1,4 phenylene diisocyanate which fades easily and is also expensive.

Effect of Hot-Air Drying Conditions on the Drying Efficiency and Performance of a Waterborne Coating on Pine Wood

In this study, we investigated the drying behavior of a waterborne wood coating (WWC) on pine wood using hot air drying. An analysis of variance of the experimental data revealed that both temperature and humidity exerted significant effects on the surface drying time. An analysis of the structure and wettability indicated a faster moisture migration rate through the cross section than through the tangential section of porous wood. We also determined that temperature, humidity and their interactions significantly affected the glossiness, while temperature had a greater effect on the wear resistance of the WWC films than humidity. The drying conditions had a minimal effect on the adhesion strength. By considering both the drying efficiency and the coating performance, the optimal drying conditions for the WWC on pine wood were determined to be 60 °C and 55% relative humidity. Our findings suggest that establishing a correlation between drying performance and substrate can ensure the quality of WWCs for practical applications in the wood coating industry.

Preparation of Polyurethane-Modified Silicone Rubber Insulating Coating and Its Application in 10 kV Overhead Bare Wire Wrapping

Room-temperature vulcanized rubber is an excellent polymer material with excellent electrical insulation and mechanical properties, which can be used for field insulation of high-voltage bare wire. In this paper, a room-temperature cured coating material was prepared from α,ω-dihydroxy polydimethylsiloxane (PDMS), polyurethane-modified silicone material (PU-Si), and Methyltris(methylethylketoxime) silane (MOS). The study showed that the coating made by adding PDMS (70 g), PU-Si (30 g), CaCO3 (90 g), MOS (7 g), KH792 (5 g), and Mg(OH)2 (30 g) had a surface drying time of 19.1 min, tensile strength of 3.2 Mpa, volume resistivity greater than 4 × 1014 Ω·cm, breakdown voltage greater than 20 kV/mm, and flame retardant performance of the FV-1 level. The comprehensive performance of the insulation material meets the national standard of “Aerial insulated cables for rated voltage of 10 kV” (GB/T14049-2008), while the insulation material has been successfully applied to the overhead line renovation project of the State Grid Hubei Electric Power Company (Wuhan, China).

Preparation and Performance of Repair Materials for Surface Defects in Pavement Concrete.

Concrete surface defects are very complex and diverse, which is a great test for repair materials. The efficiency and durability of the repair system depend on the bonding effect between the concrete and the repair material. However, the rapid increase in system viscosity during the reaction of repair materials is an important factor affecting the infiltration effect. In the present work, the infiltration consolidation repair material was prepared, and its basic properties (viscosity, surface drying time and actual drying time, infiltration property) and mechanical properties were evaluated. Finally, the infiltration depth, film-forming thickness, and anti-spalling ability of concrete under a single-side freeze-thaw cycle are revealed. The results showed that using ethyl acetate could rapidly reduce the viscosity of the repair material, and the repair material could penetrate 20-30 mm into the concrete within 10 min. It was found by laser confocal microscopy that the thickness of the film formation after 3 days was only 29 µm. In the mortar fracture repair test to evaluate the bond strength, the bond strength of the repaired material reached 9.18 MPa in 28 days, and the new fracture surface was in the mortar itself. In addition, the freeze-thaw cycle test was carried out on the composite specimens under salt solution to verify the compatibility of the designed repair material with the concrete substrate. The data showed that the average amount of spalling was only 1704.4 g/m2 when 10% ethyl acetate was added. The penetrating repair material in this study has good infiltration performance, which can penetrate a certain depth in the surface pores and form a high-performance consolidation body, forming a "rooted type" filling.

Drying Process of Waterborne Paint Film on Bamboo Laminated Lumber for Furniture

In this study, bamboo laminated lumber for furniture was coated with waterborne acrylic paints. The effects of different environmental conditions (including temperature, humidity and wind speed) on the drying rate and performance of the waterborne paint film were investigated. Then, the drying process was optimized using the response surface methodology, and the curve model of drying rate was established, which can provide a theoretical basis for the drying process of the waterborne paint film for furniture. The results showed that the drying rate of the paint film changed with the drying condition. With an increase in temperature, the drying rate increased, and the surface and solid drying time of the film decreased. Meanwhile, with an increase in humidity, the drying rate decreased and the surface and solid drying time increased. Moreover, the wind speed can influence the drying rate, but the wind speed does not significantly affect the surface and solid drying time. The adhesion and hardness of the paint film were unaffected by the environmental conditions, but the wear resistance of the paint film was affected by the environmental conditions. Based on the response surface optimisation, the fastest drying rate was realised at a temperature of 55 °C, humidity of 25% and wind speed of 1 m/s, and the optimal wear resistance was realised at a temperature of 47 °C, humidity of 38% and wind speed of 1 m/s. The paint film drying rate reached the maximum value in 2 min and tended to remain constant after the film was completely dried.

Formulation design of a new type of epoxy resin-based insulating adhesive and research on its high temperature resistance

A series of new epoxy resin adhesives were prepared by low viscosity bisphenol A epoxy resin E-44 and E-51as the matrix, low molecular polyamide 650# and phenolic modified JT-3008 as the curing agent, silicon micro powder and calcium carbonate as the fillers. The gelation time, surface drying time and shear strength of the samples were deeply tested. The thermal decomposition temperature and high temperature resistance of the samples were determined by TG analysis. Meanwhile, the surface fracture morphology was observed by SEM. The results showed that a new kind of heat epoxy resin insulation adhesive with long gelation time and convenient construction and meeting the requirements of production adjustment was successfully obtained through the optimization design of the formula,. The new epoxy resin insulation adhesive showed excellent mechanical properties with 18.00 MPa shear strength, which can be used at 380 ℃ for a short period of time and 130 ℃ for a long time. The new adhesive developed in this paper can be widely used in high voltage switchgear and other insulation materials, which has good application prospects.

Formulation design of a new type of epoxy resin-based insulating adhesive and research on its high temperature resistance

A series of new epoxy resin adhesives were prepared by low viscosity bisphenol A epoxy resin E-44 and E-51as the matrix, low molecular polyamide 650# and phenolic modified JT-3008 as the curing agent, silicon micro powder and calcium carbonate as the fillers. The gelation time, surface drying time and shear strength of the samples were deeply tested. The thermal decomposition temperature and high temperature resistance of the samples were determined by TG analysis. Meanwhile, the surface fracture morphology was observed by SEM. The results showed that a new kind of heat epoxy resin insulation adhesive with long gelation time and convenient construction and meeting the requirements of production adjustment was successfully obtained through the optimization design of the formula,. The new epoxy resin insulation adhesive showed excellent mechanical properties with 18.00 MPa shear strength, which can be used at 380 ℃ for a short period of time and 130 ℃ for a long time. The new adhesive developed in this paper can be widely used in high voltage switchgear and other insulation materials, which has good application prospects.

Effect of carbon fiber on the properties of polymer cement based building sealant

AbstractThe working property, bond property, and mechanical property of five kinds of polymer cement based building sealant (PCBS) with different carbon fiber content were tested. The effect of carbon fiber on the properties of PCBS was discussed by analyzing the variation of the leveling performance, consistency, low temperature flexibility, surface dry time, elastic recovery rate, tensile mechanical property, and shear mechanical property of PCBS with carbon fiber content. And the modification mechanism of carbon fiber on PCBS was interpreted using scanning electron microscopy and mercury intrusion porosimetry techniques. The results shows that PCBS still has good working property and bonding property with carbon fiber addition. As the carbon fiber content increases, the leveling performance and low temperature flexibility of PCBS are unaltered., the consistency increases, while the surface drying time and elastic recovery rate decrease. The tensile and shear mechanical properties of PCBS can be improved by adding carbon fiber. With the increase of carbon fiber content, the strength performance indexes of PCBS increase, while the energy consumption performance indexes first increased followed by a decrease. When the carbon fiber content is 0.1%, the properties of PCBS is the best. The pore structure of PCBS gradually deteriorates, and the total porosity and the percentage of macropores increase with carbon fiber addition. Carbon fiber primarily exerts cracking resistance and internal deterioration effects in PCBS.

A novel humidity self-regulating interior wall coating composite based on red mud derived from alumina production

Aimed to resolve the problem of excessively high indoor humidity in subtropical areas and develop a new resource disposal technique for red mud, a novel humidity self-regulating interior wall coating composite based on red mud (HRCRM) was successfully prepared using red mud as a matrix material and vermiculite as a humidity regulator. The effects of component proportion, ambient humidity, exposure time on hygroscopicity of this composite were systematically investigated. This composite exhibited good humidity regulating ability with the largest water absorption rate of 16.38% under experimental conditions. Moreover, various properties were tested including surface drying time, hardness, adhesion, coating appearance, water resistance and reusability, meeting the national standard requirements well. The mechanism was comprehensively analyzed by XRD, TG-DTG, FESEM, and FTIR, indicating that the humidity self-adjusting function of HRCRM was realized by regulating the interlayer water storage of vermiculite. This study can provide theoretical and technical guidance for residential environment improvement in subtropical areas and comprehensive utilization of red mud.

Influence of Dentin Surface Roughness, Drying Time, and Primer Application on Self-adhesive Composite-Cement Bond Strength.

To investigate the effect of roughness and drying time of dentin as well as the number of coats of a self-adhesive composite-cement primer on the bond strength of self-adhesive composite cement. Sixty human teeth were prepared and assigned to 12 groups (n = 5), according to three experimental factors: 1) dentin surface roughness, rough or fine, as achieved by 250- and 600-grit silicon carbide papers, respectively; 2) dentin wetness based on air-drying time (5 or 10 s); and 3) the self-adhesive composite-cement primer applications (no-coat, 1-coat, and 2-coat). Composite resin blocks were made with hybrid composite resin (M1 GraceFil) and cemented with G-CEM ONE (both GC). Cement-dentin sticks (12) were prepared, and the microtensile bond strength (μTBS) test was performed. Failure modes were observed with a stereomicroscope (40X), and bonding interfaces were evaluated with confocal laser scanning microscopy (CLSM). Statistical analysis was performed using three-way ANOVA and Tukey's post-hoc comparisons test (α = 0.05). Dentin roughness (250-grit > 600-grit, p = 0.000), drying time (5-s drying > 10-s drying, p = 0.000), and primer application (no-coat < 1-coat = 2-coat, p = 0.000) had significant effects on bond strength. These factors also showed significant interactions with each other (p = 0.003). The highest μTBS (31.8 ± 3.1 MPa) was observed in the 1-coat/fine roughness/10-s drying group and the lowest μTBS (13.4 ± 2.7 MPa) in the no-coat/coarse roughness/5-s drying group. CLSM showed higher penetration of cement in the primer-coated groups compared to that in the no-coat groups. Bond strength between the self-adhesive composite cement and dentin was higher in the fine-roughness dentin group than in the coarse-roughness dentin group, and in the 5-s drying group compared to the 10-s drying group. Applying a primer to dentin improved bond strength of the self-adhesive composite cement.

Synthesis of DC–3074 and Z–1 Silicones Modified Epoxy Resin and Comparison of Salt Spray Resistance

In order to improve the chemical resistance of epoxy resin and its toughness and corrosion resistance, in this paper, silicone modified epoxy resin was prepared with epoxy resin and two kinds of silicones, Dow Corning DC–3074 and Chenguang Z–1, as raw materials and dibutyltin dilaurate (DBTDL) as catalyst. The structure of the modified epoxy resin was characterized by Fourier transform infrared (FTIR) spectrometer and its performance was tested. The results showed that the epoxy resin modified by DC–3074 had better salt spray resistance compared with the Z–1. Therefore, the DC–3074 was selected as the epoxy resin E–51 modifier. The silicone modified resin was further synthesized with E–51 as the matrix resin, 12.5% DC–3074 silicone as the modifier, and 0.5% DBTDL as the catalyst. The obtained cured coatings showed good performance with the following results: product fineness of 20–25 μm, solid content of more than 95%, surface drying time of 25 min, smooth appearance, hardness of 2 H, adhesion level of 0, and salt spray resistance time of 432 h. The prepared modified epoxy resin coating has good salt spray resistance and good application prospect.

Failure Mechanism Analysis and prevention of Silver Electrode Corrosion

In this paper, the failure mechanism of sulfide corrosion of a batch of silver electrodes was studied by means of environmental simulation test, scanning electron microscopy (SEM), energy spectrum analysis (EDS), micro-CT, infrared spectroscopy analyzer(FTIR), pyrolysis gas chromatography mass spectrometry (Py-GC-MS) and specific surface area (BET) analysis. The results showed that the H2S in the air entered the silver electrode surface through the rubber by the adsorption and permeation effects, and corroded the silver electrode. What’s more, The change of pore size in silicone rubber will affect the H2S corrosion reaction. The smaller the pore, the higher the specific surface area and the more polar H2S molecules adsorbed by rubber. So the special pore distribution of the size of the intercalation was beneficial to reduce the diffusion resistance of H2S molecules in rubber. The above analysis results also provided ideas and direction for the improvement of silicone rubber. The pore distribution of silicone rubber could be controlled by controlling the viscosity and the surface drying time of the glue solution, so as to ensure the filling effect of the silicone rubber and prevent the corrosion failure of the silver electrode.

Design and Testing of a Protocol to Study Varnishes Intended to Protect Graphic Works

ABSTRACT This paper presents a method and protocol for the study of varnishes and be protective layers applied throughout history to graphic works. The study is based on the characteristics and behaviour of varnishes when facing different types of deterioration. The methodology is founded on a series of physical–chemical tests that identify the characteristics of a varnish when applied to paper (surface and total drying time, degree of adherence, and penetration into the substrate) and in treatments, determining its resistance to adverse conditions of humidity, temperature, and light (resistance to humidity, immersion in water, and ageing by dry heat or in a climatic chamber). The effects of these tests are evaluated by taking into account a series of physical–chemical parameters characteristic of varnishes on graphic works: weight, dimensions, thickness, texture, optical features, and pH. Variations among these parameters serve to measure the resistance of varnishes to adverse conditions and natural ageing, whether they are applied as a conservation treatment or historically. All the information necessary to facilitate the transfer of this method to researchers and professionals is compiled in a protocol. This document comprises general information, descriptions of procedures and materials, and a series of annexes that serve simultaneously to collect and to study the data. The protocol is therefore designed to serve both as a tool when applying the method and as the germ of a database for the study of varnishes on graphic works. Shellac varnish was selected to test the method and the protocol. This resin has been used in the past to provide a waterproof varnish for paper-based maps as well as for images. Errors identified during the development of the protocol were ultimately corrected by incorporating new tests, items, and annexes. The protocol has proven to be a practical tool for the study of varnishes regarding their behaviour in the case of graphic works.

Preparation and properties of ultraviolet/thermal dual-curable polyurethane acrylate

Ultraviolet (UV)/thermal dual-curable polyurethane acrylate (PUA) mixtures were prepared using a PUA oligomer, tripropylene glycol diacrylate (TPGDA), benzoyl peroxide (BPO), 2,4,6-trimethylbenzoyldiphenyl phosphine oxide (TPO), and cobalt isooctanoate. For purposes of comparison, a UV-curable PUA mixture was prepared by mixing the PUA oligomer, TPGDA, and TPO. When placed under a UV lamp (400 W, 50 mW/cm2), the surface drying time of each curable mixture was approximately 2 s. The content of volatiles during UV curing (the intensity of the lamp was 100 mW/cm2) was less than 0.3 wt%, and the content of potential volatiles (the test condition was heating at 110 °C for 1 h after UV curing) was below 1.0 wt%. Compared with the UV-cured sample, the UV/thermal dual-cured sample containing cobalt isooctanoate had more favorable properties, that is: (1) better acid and alkali resistance; and (2) better thermal stability and higher gel content. The temperature at 5 wt% weight loss (T5wt.%) and the gel fraction of the UV-cured sample (the curing condition was 1 min of UV irradiation) were 269.4 °C and 94.6%, respectively. The T5wt.% and the gel fraction of the UV/thermal dual-cured sample (cured at 100 °C for 10 min after 1 min of UV irradiation) were 318.2 °C and 99.8%, respectively. BPO and cobalt isooctanoate had little effect on the surface drying rate of the curable mixtures, and the performance of the cured samples was improved by thermal treatment following irradiation with UV. Considering the dyeing effect of BPO, this system provides a more practical approach to the complete curing of colored UV-curable resins.

Assessment of Influence and Threshold Ratios of Titanium Dioxide and Calcium Carbonate as Pigments on the Physico-Mechanical Properties of Emulsion Paint

Titanium dioxide (TiO2) also known as Titanium White, is an inorganic, synthetic pigment used in paint to protect the substrate from harmful effects of ultraviolet light when lead pigments are regarded as toxic. However, its use is being limited since it causes flu-like symptoms, respiratory problem and skin irritation. Calcium carbonate (CaCO3) is a chemical commonly used as an extender pigment in cement to provide bulkiness at relatively low cost. Because of the problem associated with TiO2, it is of importance to regulate and optimize the use of TiO2 relative to CaCO3 and their influence on the physico-mechanical properties of emulsion paints. Nine paint specimens were formulated using 0 – 80 grams per litre of TiO2 and 120 – 200 grams of CaCO3, respectively at 10 gram interval. The following tests were performed on them: specific gravity, viscosity, pH, surface drying time, hard drying time, wash-ability/adhesion and opacity tests, in accordance to Nigerian Industrial Standard (NIS) 278: 1990. The result shows that all samples met specifications of 10 poise maximum, 5%, 7.5-9.0, 20 minutes, 2 hours, and 201 minimum, for viscosity, specific gravity, pH, surface drying time, hard drying time and wash-ability/adhesion properties, respectively. However, six sample specimens only met the requirement of NIS 278:1990 of 2coats for good opacity. In conclusion, TiO2 has no negative effect on the other physio-mechanical properties except the opacity of the paint and so specimens 7, 8 and 9, and ratio 30:170 is considered the threshold values for the paint production.

Nanocellulose-Reinforced Polyurethane for Waterborne Wood Coating.

With the enhancement of people’s environmental awareness, waterborne polyurethane (PU) paint—with its advantages of low release of volatile organic compounds (VOCs), low temperature flexibility, acid and alkali resistance, excellent solvent resistance and superior weather resistance—has made its application for wood furniture favored by the industry. However, due to its lower solid content and weak intermolecular force, the mechanical properties of waterborne PU paint are normally less than those of the traditional solvent-based polyurethane paint, which has become the key bottleneck restricting its wide applications. To this end, this study explores nanocellulose derived from biomass resources by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method to reinforce and thus improve the mechanical properties of waterborne PU paint. Two methods of adding nanocellulose to waterborne PU—chemical addition and physical blending—are explored. Results show that, compared to the physical blending method, the chemical grafting method at 0.1 wt% nanocellulose addition results in the maximum improvement of the comprehensive properties of the PU coating. With this method, the tensile strength, elongation at break, hardness and abrasion resistance of the waterborne PU paint increase by up to 58.7%, ~55%, 6.9% and 3.45%, respectively, compared to the control PU; while the glossiness and surface drying time were hardly affected. Such exploration provides an effective way for wide applications of water PU in the wood industry and nanocellulose in waterborne wood coating.