Crosslinked waterborne polyurethane with high waterproof performance

2016 ◽  
Vol 7 (23) ◽  
pp. 3913-3922 ◽  
Author(s):  
Fangfang Yu ◽  
Liwei Cao ◽  
Zhaohui Meng ◽  
Naibo Lin ◽  
Xiang Yang Liu
Keyword(s):  
Thermal Properties ◽  
Water Absorption ◽  
Waterborne Polyurethane ◽  
High Water ◽  
Contact Angles ◽  
Water Contact ◽  
Fluorinated Acrylate ◽  
Waterborne Polyurethanes

Fluorinated acrylate and siloxane waterborne polyurethanes with crosslinked structure exhibit low water absorption, high water contact angles, and high mechanical/thermal properties.

Superhydrophobic paper coating containing nonconventional clay

TAPPI Journal ◽  
2010 ◽  
Vol 9 (11) ◽  
pp. 33-40 ◽  
Author(s):  
BEHUDIN (BEKO) MESIC ◽  
CHRISTIAN KUGGE ◽  
LARS JÄRNSTRÖM
Keyword(s):  
Water Absorption ◽  
Cross Sections ◽  
Transmission Rate ◽  
High Water ◽  
Contact Angles ◽  
Water Contact ◽  
Barrier Performance ◽  
Superhydrophobic Paper ◽  
Hydrophobic Clay ◽  
Scanning Electron

Hydrophobic clay fillers have not been widely used in dispersion coatings for linerboard because of the difficulty of dispersing them in water. This work investigated whether hydrophobic clay can be used as filler in barrier dispersion coatings. Hydrophobic clay was compared with conventional clay in terms of coating consolidation, structure, wetting, and barrier performance. All coatings were applied to linerboard sheets made using a laboratory dynamic sheet former. The coated linerboards were examined using scanning electron microscopy and Raman spectroscopy, and were characterized with respect to water absorption, vapor transmission rate, and contact angles. The results show that a coating containing hydrophobic clay provides a superhydrophobic character to paper; i.e., a high water contact angle (150°) and relatively low water absorption. Raman mapping of cross-sections revealed that the latex distribution is uniform in the presence of either conventional clay or hydrophobic clay, and that the distribution of hydrophobic clay tends to be more uniform than conventional clay, which might reflect good mixing and consolidation of hydrophobic clay.

scholarly journals Preparation of Polydimethylsiloxane-Modified Waterborne Polyurethane Coatings for Marine Applications

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4283
Author(s):  
Min-Gu Kim ◽  
Kyoung-Il Jo ◽  
Eunji Kim ◽  
Jae-Hyung Park ◽  
Jae-Wang Ko ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Structural Characteristics ◽  
Testing Machine ◽  
Waterborne Polyurethane ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Water Contact ◽  
X Ray ◽  
Waterborne Polyurethanes ◽  
Marine Applications

A series of waterborne polyurethane dispersions (WPUs) modified with hydroxyl-terminated polydimethylsiloxane (PDMS) were prepared by incorporating PDMS into the soft segments of polyurethane chains. The structural characteristics of the prepared samples were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and particle size analysis (PSA). The effect of PDMS content on the thermal and mechanical properties of PDMS-modified waterborne polyurethanes (PS-WPU) was investigated. In addition, the water resistance and dimensional stability of the PS-WPU were investigated by measuring its water absorption ratio and water contact angle along with universal testing machine measurements.

Supramolecular functionalized polybenzoxazines from azobenzene carboxylic acid/azobenzene pyridine complexes: synthesis, surface properties, and specific interactions

RSC Advances ◽  
2015 ◽  
Vol 5 (17) ◽  
pp. 12763-12772 ◽  
Author(s):  
Mohamed Gamal Mohamed ◽  
Chi-Hui Hsiao ◽  
Kuo-Chih Hsu ◽  
Fang-Hsien Lu ◽  
His-Kang Shih ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Surface Properties ◽  
High Water ◽  
Contact Angles ◽  
Supramolecular Complex ◽  
Specific Interactions ◽  
Water Contact ◽  
Pyridine Complexes

Supramolecular complex of azobenzene carboxylic acid/pyridine functionalized benzoxazine system featured significantly lower curing temperatures and maintain high water contact angles.

scholarly journals 698 PB 306 WETTABILITY AND SURFACE TENSION OF FRUIT SURFACES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 533a-533 ◽  
Author(s):  
L. Cisneros-Zevallos ◽  
M. E. Saltveit ◽  
J. M Krochta
Keyword(s):  
Surface Tension ◽  
Water Repellency ◽  
High Water ◽  
Contact Angles ◽  
Stone Fruits ◽  
Water Contact ◽  
Wetting Behavior ◽  
Apple Cultivars ◽  
Chemical Groups ◽  
Apple Fruits

Nettability is an important factor to be considered in postharvest treatments such as washing, aqueous dippings, coatings, etc. Pome fruits (ten apple and four pear cultivars) and stone fruits (nectarine and plums) were evaluated for wetting behavior and surface tension at room temperature. Nettability was assessed by measuring contact angles of water. Surface tension was calculated by measuring contact angles of methylene iodide and water or by a series of pure surfactants using Zisman's method. Wetting behavior on apple fruits depended on cultivar, with water contact angles ranging from 75° to 131°. For pear fruits, wetting also depended on cultivar. Calculated surface tensions of pear fruits were in general higher than most apple cultivars tested. In stone fruits, plums presented a high water-repellency with a contact angle of 137°. The wetting of fruit surfaces seems to be governed by the nature of the chemical groups exposed on the surface of the cuticle and also by the surface roughness, as evidenced by tire high values of some contact angles.

Topography and Wettability of Waterborne Polyurethane Coatings with Varying Amounts of Hard Segments

2013 ◽  
Vol 634-638 ◽  
pp. 3033-3037
Author(s):  
Yu Hong Qi ◽  
Zhan Ping Zhang ◽  
Yan Zhang ◽  
Mei Miao
Keyword(s):  
Laser Scanning ◽  
Hard Segment ◽  
Soft Segment ◽  
Hydrophobic Surface ◽  
Waterborne Polyurethane ◽  
Contact Angles ◽  
Water Contact ◽  
Hard Segment Content ◽  
Fouling Release ◽  
Hard Segments

Topography and wettability plays an important role to fouling release performance of a coating. Surface morphology and water contact angles (WCA) depending on time of three waterborne polyurethane (WPU) coatings were studied by laser scanning microscope and optical contact angle meter. The results show that WPU coatings with low hard segment content are consisted of hard segment domains, soft segment domains and crack-like non-cohesive regions. With increasing hard segment content, nanostructured micro-phase separated topography is easier to forming, and crack-like non-cohesive regions is reduced. A stable hydrophobic surface in the WPU system can be obtained by drying coating at 60C as well as adding hard segment content to improve fouling release performance of the coatings.

scholarly journals Anti-adherent Molds Yield Hydraulic Concrete Samples Suitable for Assessments of Surface and Water Absorption

2021 ◽  
Vol 10 (4) ◽  
pp. 245-252
Author(s):  
Ernesto Mora ◽  
Erick Castellón
Keyword(s):  
Water Absorption ◽  
Quality Parameters ◽  
Contact Angles ◽  
Water Diffusion ◽  
Concrete Sample ◽  
Hardened Concrete ◽  
Water Contact ◽  
Hydraulic Concrete

To assess several quality parameters of hydraulic concrete, cubic samples of this material are commonly assembled in engineering laboratories using molds. It is ubiquitous the use of cubic metallic molds of volume 125 cm3; these molds require the application of demolding substances (such as oils) on their surfaces to avoid the adhesion of the final hardened concrete sample to the molds. Despite this common practice suitable for evaluating mechanical traits of the materials, the use of a demolding agent spoils the concrete samples for the assessment of surface and water absorption parameters. To overcome this difficulty, we propose a new anti-adherent cubic mold that requires no demolding agent. The construction of the new mold based on anti-adherent polytetrafluoroethene (PTFE, Teflon®) is described with its use. To assess the claimed advantages of the new anti-adherent molds in testing surface and water diffusion traits of concrete samples, experiments on water contact angles, rates of water absorption and drying were performed on concrete specimens obtained with the classic and the new PTFE molds. It was proved the advantage of the anti-adherent mold over common metallic molds. The use of an oil as demolding agent in the concrete samples assembled in metallic molds produced conspicuous differences of water contact angles and absorption in comparison to clean concrete samples produced with PTFE molds.

scholarly journals Preparation, characterization and application of fluorinated acrylate copolymer emulsion for the conservation of stone building heritages in Putuo Zongcheng Temple, China

2020 ◽  
Author(s):  
Jiangfang Chang ◽  
Qinghe Niu ◽  
Wei Wang
Keyword(s):  
Water Absorption ◽  
Mass Loss Rate ◽  
Contact Angles ◽  
Spontaneous Imbibition ◽  
Wettability Alteration ◽  
Polymerization Process ◽  
Salt Crystallization ◽  
Sem Images ◽  
Fluorinated Acrylate ◽  
Acrylate Copolymer

Abstract Recently, the stone building heritages in Putuo Zongcheng Temple are experiencing a certain degree of weathering damage, which mainly manifests in the blistering, fissuring, flaking and detachment of the carved balustrades of stone bridge, the footings of wall, the front paws and pedestals of stone lions. To prevent the deterioration of the stone building heritages, the fluorinated acrylate copolymer emulsion was successfully prepared with ethyl metrhacrylate, n-butyl acrylate and 2,2,3,4,4,4-hexafluorobutyl methacrylate as monomers. The structure and surface morphology characteristics of this copolymer were described the Fourier Transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM), respectively. The FTIR spectra confirms that the adopted monomers have been involved in during the copolymer polymerization process. The SEM images reveal that the surface of the prepared copolymer is obviously more dense, compact and smooth than the porous structure of stone building heritages. The ageing resistance of the copolymer was quantitatively studied by the ultraviolet aging test, the contact angle and imbibition spontaneous tests were adopted to estimate the wettability alteration of the copolymer emulsion for the stone samples. Results show that the mass loss rate of the prepared copolymer increases rapidly and then tends to be stable when irradiated by ultraviolet light. And the fluorinated copolymer with 16.65% HFMA content possesses the optimal ageing resistance and the superb hydrophobicity. The contact angles of the coated stone samples range from 91.90o to 119.80o, which are all larger than 18.80o-69.05o of the un-coated samples. Similarly, the spontaneous imbibition test also ensures that, both the maximum water absorption capacity and the imbibition equilibrium time of the samples treated by this copolymer emulsion are lesser. Considering the influence of water on rock weathering, the fluorinated copolymer emulsion coating is an potential method to avoid the degrading of stone building heritages, because it depresses the infiltration of water and then avoids or weakens the dissolution effect, salt crystallization, water absorption swelling and freeze-thaw weathering.

scholarly journals In Situ Incorporation of Diamino Silane Group into Waterborne Polyurethane for Enhancing Surface Hydrophobicity of Coating

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1667 ◽  
Author(s):  
Jinghui Lyu ◽  
Kaiyue Xu ◽  
Ning Zhang ◽  
Chunshan Lu ◽  
Qunfeng Zhang ◽  
...  
Keyword(s):  
Water Resistance ◽  
In Situ Polymerization ◽  
Condensation Reaction ◽  
Waterborne Polyurethane ◽  
Surface Hydrophobicity ◽  
Water Contact ◽  
Coating Surface ◽  
Waterborne Polyurethanes ◽  
Ft Ir

A series of waterborne polyurethanes (WPU) with crosslinked siloxane were obtained through introducing 3-(2-aminoethylamino)propyldimethoxymethylsilane (APTS) into WPU by in situ polymerization. The properties of WPU modified by APTS were studied through a variety of experimental methods. The water contact angle of the WPU coating surface increased from 64° to 86°, and the water resistance reduced to 3.90% when 3 wt% APTS was added, which improved the coating surface hydrophobicity. Firstly, Fourier transform infrared (FT-IR) and 1H-NMR spectra demonstrated the successful incorporation of APTS to polyurethanes and completed the hydrolytic condensation reaction-generated Si–O–Si crosslinking structure. Furthermore, the surface energy of the membrane was reduced when the crosslinking structure migrated and enriched on the surface of film. Besides, the crosslinking structure was abundant, and the distribution of siloxane in WPU was more uniform.

Functionalization of technical textile tapes

2018 ◽  
Vol 2 (89) ◽  
pp. 72-84
Author(s):  
W. Urbaniak-Domagała ◽  
E. Kobierska
Keyword(s):  
Hydrophobic Effect ◽  
Hierarchical Structures ◽  
High Water ◽  
Contact Angles ◽  
Slow Increase ◽  
Water Contact ◽  
Reduced Pressure ◽  
Dry Process ◽  
Hydrophobic Barrier ◽  
Fabric Surface

Purpose: The aim of the study was to deposit a hydrophobic barrier coating on technical tapes in order to protect them from water and to test and assess the obtained products. Design/methodology/approach: The coatings were deposited on elastic, textile substrates using PACVD of hexamethyldisiloxane vapours with an RF commercial plasma system under reduced pressure. Findings: The coatings increased the hydrophobicity of the technical tapes, which was confirmed by high water contact angles and reduced water sorption by the tape. The polymerization of the monomer vapour plasma was achieved without carrier gas. With a relatively slow increase in the deposition, rough coatings were obtained on a submicroscopic level, as opposed to the commonly produced smooth ppHMDSO coatings. This rough character enhanced the hydrophobicity of the surface according to the Wetzel or Cassie models. The modification processes did not significantly affect the basic mechanical properties of the tapes, such as Young’s modulus and tensile strength. The ppHMDSO coatings are resistant to aging and mechanical wear and retain their hydrophobic barrier properties. Research limitations/implications: The quantitative assessment of the wettability of a substrate with a rough surface is difficult and often ambiguous. This element of physicochemical metrology is wide open for innovation. Practical implications: The use of this plasma technique to make textile barrier products shows several merits, such as an economically justifiable, pro-ecological and dry process. The hydrophobicity of the textile substrates can also be obtained using other monomers. Originality/value: The formation of local hierarchical structures on the top layer of the fabric surface enhance the hydrophobic effect.

Scalable Methods to Obtain Superhydrophobicity onto Metallic Surface

2016 ◽  
Vol 879 ◽  
pp. 2501-2506 ◽  
Author(s):  
Núria Llorca-Isern ◽  
Ana Maria Escobar ◽  
Oriol Rius
Keyword(s):  
High Water ◽  
Contact Angles ◽  
Single Step ◽  
Leaf Structure ◽  
Metallic Surface ◽  
Dodecanoic Acid ◽  
Water Contact ◽  
Lotus Leaf ◽  
Scalable Methods ◽  
Common Application

Superhydrophobic surfaces, with extremely high water contact angles (CAs) of more than 150° are of special interest due to their various anti-adhesive and self-cleaning properties. Recent studies demonstrate that the superhydrophobicity principally results from the presence of binary structures at both the micrometre and nanometre scales together with the low-energy wax-like materials on the surfaces. Materials with similar properties, to those of the lotus leaf structure are very useful in several areas, such as the aeronautical industry and civil engineering; so many methods have been developed to mimic the lotus leaf structure. Metals are very important and irreplaceable engineered materials in many industrial fields. An alternative method for enhancing superhydrophobicity on different metals is proposed. The method proceeds by coating the metallic surface with a superhydrophobic reactive such as dodecanoic acid being a common application its use in paints with eco-friendly properties. The goal of this study is to induce direct superhydrophobicity by a single step and coating process on prepared surfaces of pure commercial aluminium 99.9 wt %, pure commercial 99.9 wt % copper and stainless steel grade 316L (UNS S31603). The chemical reaction proceeds by etching the activated surface with lauric acid in ethanol solutions.

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