High Water Resistance Research Articles

Functional Surface Coating on Cellulosic Flexible Substrates with Improved Water-Resistant and Antimicrobial Properties by Use of ZnO Nanoparticles

It is of significant interest to create functional flexible surfaces that simultaneously exhibit high water-resistance and antimicrobial performances for medical or packaging applications. This study reported a synthesis of functional surface coating on flexible cellulose materials (filter papers) with ZnO nanoparticles and binds of renewable soybean oil-based polymers. Self-aggregation of ZnO nanoparticles could form ZnO particles with two regular morphological patterns. Rather than a rod-like morphology, a flower-like ZnO benefited a promotion of surface hydrophobicity. Moreover, surface with the flower-like ZnO showed a 51.6% promotion on antimicrobial activities against Gram-negative bacteria (E. coli) than the rod-like ZnO. A low binder/ZnO ratio of 0.2 led to a remarkable improvement on water repelling performances without negative effects on a coating adhesion of ZnO. Under this condition, a hydrophobic surface was achieved with a large static contact angle of 138° when applying ZnO nanoparticles at a dosage of 3 g m−2.

Analysis of Resin Mortar Shrinkage and Adhesion

Resin mortars and concretes have high water resistance and very good resistance to aggressive environment. For this reason, they are often used as repair or waterproof layers e.g. in tanks for liquids. Materials used in this regard should be characterized by relatively low shrinkage and high adhesion to a substrate.The research program was carried out on selected resin mortars composed of quartz sand and a two-component epoxy resin of high viscosity and adhesion to substrate. The shrinkage development of tested resin mortars was analyzed in the paper. The tests were conducted in automatic measurement system, so-called gutters. In this device the whole volume changes (both expansion and shrinkage) can be measured starting from the moment when material is placed into gutter. The resin mortar adhesion to a concrete substrate was also tested and discussed in the paper.

The Development of Strength and Microstructure of the Resin Mortar

Intensive development of building chemistry enabled the effective development of building materials based on resins. Polymer concrete is an example of such material. Its advantages are high mechanical strength, particularly flexural and tensile ones, and good resistance to vibrations in comparison with ordinary concrete. Furthermore, the high water resistance and resistance to aggressive media cause that resin-based mortars or concretes, despite their high price, are building materials widely used. The article presents a study on the strength development of selected resin mortars, prepared from a two-component epoxy resin and different proportions of quartz sand. The development of mortar compressive and flexural strength at 1, 3, 7 and 28 days of hardening was analyzed. The mortar microstructure of tested material was also investigated by the means of the Zeiss Nova scanning microscope.

Cooperation of Three Chromophores Generates the Water-Resistant Nitrate Nonlinear Optical Material Bi3 TeO6 OH(NO3 )2.

Nitrates have long been ignored for practical uses as nonlinear optical (NLO) materials because they are usually very easy to dissolve in water; despite this, the π-conjugated [NO3 ]- is among the most desirable NLO-active structural units. The cooperation of three structural chromophores, namely, Bi3 O6 OH short chains with 6s2 lone pair electrons, distorted TeO6 octahedra with d10 electrons, and π-conjugated [NO3 ]- triangles, generates a new nitrate NLO material, Bi3 TeO6 OH(NO3 )2 , which exhibits an enhanced phase-matchable NLO response of three times that of KH2 PO4 (3×KH2 PO4 ), exceeding those of most nitrate NLO materials. Remarkably, the new material did not show obvious weight loss and degeneration of NLO response after being dipped in de-ionized water for 24 h, indicating that it is highly resistant to water. Theoretical calculations reveal that foreign water molecules cannot stably stay in the crystal lattice of Bi3 TeO6 OH(NO3 )2 . These findings highlight the introduction of diverse chromophores into the nitrate systems as an effective approach for developing practical nitrate NLO materials that are of high water-resistance and good optical performance.

Usability of Malatya Pyrophyllite in the Traditional Ceramic Industry

In the present study, the usability of the pyrophyllite in the traditional ceramic industry was investigated. The raw pyrophyllite was obtained in Malatya, Turkey. The characterization of the raw pyrophyllite and the prepared ceramics which were heated at the different temperatures in oven (800, 900, 1000 and 1100 °C) were done by XRF, XRD, FTIR, SEM and the main physical properties, like total shrinkage, water absorption capacity and compression strength were determined. As a result of experimental studies; the raw pyrophyllite had to be mixed with the feldspar and another clay (Unye clay) with having high plasticity in order to shape easily and a high water resistance. The optimum receipt was found as 70 wt % pyrophyllite, 20 wt % Unye clay and 10 wt % feldspar. The main properties of the obtained ceramics were specific white baking colour and high temperature resistance properties.

GPR POTENTIAL WHEN INVESTIGATING QUATERNARY DEPOSITS IN LAKES OF KARELIA

The results of the GPR observations carried out in three lakes of Karelia: Lake Verkhneye (the White Sea Biological Research Station of the Moscow State University), Nizhneye Nilmozero and Vendyurskoye, were summarized. A screened 300MHz antenna was used for the survey. The GPR potential, including parameters such as propagation distance in water and in soil, was analyzed. Water resistivity measurements were carried out for each lake. Characteristics of the Quaternary profile (being the main factor that influence the propagation depth of electromagnetic waves) were studied. It was demonstrated that high water resistivity and, possibly, the lack of clay in the profile suggest GPR can perform well for the depth range of 10-15 m below the bottom and at water depths up to 12-15 m. The GPR method, which is far more cost efficient compared to seismoacoustics, can be applied to deals with many production as well as scientific problems.

The Synthesis of Styrene-Oligoester Copolymer and Investigation of Their Physico-mechanical Properties

<p>The copolymerization reaction of commercial propylene oxide with glycidylmethacrilate in the presence of BF<sub>3</sub>·O(C<sub>2</sub>H<sub>5</sub>)<sub>2</sub> catalyst have been investigated. The composition and structure of copolymerization products and anchored functional groups have been determined using IR and gel chromatographic methods. The physico-mechanical properties and utility of polyfunctional unsaturated oligoester were investigated. The obtained thermoset product via the reaction of the oligoester with both styrene and oligostyrene obtained from the bottom of column as a waste material during the rectification operation of styrene in the presence of radicalic initiator has a good adhesion capability, hardness and high heat and water resistance. Thus the waste material was converted to the high valuable polymeric material.</p>

전분 접착제의 접착 효율 및 골판지의 내수성 향상을 위한 첨가제의 적용

In order to improve the bonding efficiency of starch adhesives and water resistance of corrugated board, mixing ratio of additives dosage was changed and its effects were analyzed. When the additives dosage was increased, bonding strength, vertical compression strength, bursting strength and water resistance were increased, because of hydroxyl groups or acetyl groups in starch adhesives and cellulose fibers of corrugated board were cross-linked by additives. When 1.0% glyoxal dosage was added, flat crush strength and vertical compression strength were increased. With 1.5% glyoxal, bonding strength and bursting strength were increased. However, 2.0% glyoxal dosage was added, most of strength except bursting strength were decreased. Thus, when the appropriate amount of additives are added during corrugated board production process, increased bonding efficiency of starch adhesives and higher water resistance of corrugated board can be achieved.

Preparation and investigation of hydrophilic, photocatalytic, and antibacterial polyacrylic latex coating containing nanostructured TiO2/Ag+-exchanged-montmorillonite composite material

In order to prepare a self cleaning and antibacterial coating, nanostructured TiO2/Ag+-exchanged-montmorillonite composite material was prepared and used as additive in a commercial grade polyacrylic latex coating. FT-IR and UV–visible spectroscopy, X-ray diffraction patterns and FESEM were used to characterize the composition and structure of the nanocomposites and coatings. The polyacrylic coatings, prepared by the using of TiO2/Ag+-exchanged-montmorillonite additive, showed better UV and visible light absorption, hydrophilic property, photodegradation of organic pollutants, stability in water and antibacterial properties than pristine commercial grade polyacrylic latex coating. According to the results, the modified polyacrylic coating containing 3%w of nanostructured TiO2/Ag+-exchanged-montmorillonite composite material as additive, with TiO2 to Ag+-exchanged-montmorillonite ratio of 2:1, was the best coating considering most of the useful properties such as low water contact angle, high photodegradation efficiency, and high water resistivity. The water contact angle for unmodified polyacrylic latex coating was 68° while it was decreased to about 10° or less for modified coating after 24h LED lamp illumination.

Silica Encapsulation of SrAl<sub>2</sub>O<sub>4</sub>:Eu<sup>2+</sup>, Dy<sup>3+</sup> Phosphors by Sol-Gel Method

SrAl2O4:Eu2+,Dy3+ phosphors were synthesized under different temperature by high temperature solid phase method. Encapsulation modification of SrAl2O4:Eu2+,Dy3+ by using SiO2glycol were made over chemically unstable against water. Photoluminescence measurement result shows that when the sintering temperature is 1300 °C, the initial afterglow brightness of SrAl2O4:Eu2+,Dy3+ is up to the highest, 12101 mcd/m2. FTIR results showed that new IR peaks at 1085 cm−1 due to the vibration of Si-O-Si and at 931cm−1 due to the vibration of Si-O-Al appeared after silica encapsulation. This verified that the silica encapsulation is not only a physical absorption process but also involving chemical bonding process. Both phosphors before and after encapsulation have same emission peak at 510 nm. A dense layer of silica formed on phosphor surface has the highest water-resistance after being encapsulated for 2h under the condition of pH 4 and encapsulation amount 10:1. The pH value of aqueous solution contained phosphor was steadily 8, and the initial afterglow brightness decreased only by 9%, that is, from 12101 to 11011 mcd/m2.

Hardening Performance of Phosphogypsum-Slag-Based Material

Hardening, hydration performance and mechanism of the phosphogypsum-slag-based binding material were studied in this paper. The phosphogypsum-slag-based binding material was prepared by mixing 45% phosphogypsum, 48% slag, 7% cement clinker and chemical activator at 1% relative to the binder. The compressive and flexural strength of the phosphogypsum-slag-based binding material reached the standard for compound silicate cement grade 32.5. Moreover, the softening coefficient of mortars with phosphogypsum-slag-based binding material was the same as mortars with P•C32.5. In particular, the pH value of pastes or mortars with this binding material was far lower than those with P•C32.5 and it had small impact on environment. Microscopic analysis with XRD and SEM revealed that: bar-like ettringite crystals, portlandite and the rest dihydrate gypsum crystals contacted each other as structural framework. These crystals were bonded firmly together by foil-like C-S-H gels and formed compacted body with a dense structure of high strength and water resistance.

Study of the Influence of Complex Additives on Properties of the Gypsum-Cement-Puzzolan Binder and Concretes on its Basis

Gypsum materials and products are related to progressive building materials because of their simplicity, efficiency, and low energy intensity of production of gypsum binders. Sufficient supply of natural gypsum provides the advantageous production of gypsum binding materials. Products based on gypsum binders have relatively low heat and sound conductivity and low weight, as well as environmental friendliness. Gypsum materials are fire-resistant, have good performance concerning steam and air permeability, the ability to absorb excess moisture from the air and release it at lower humidity which in its turn contributes to a favorable microclimate in the premises. However, gypsum binders and materials are characterized by such negative traits as high water demand and low water resistance. Furthermore, plaster concretes inherent limited strength, low frost resistance, and the necessity of a long period for drying during their manufacture. To improve the operational performance, properties of the gypsum-cement-pozzolan binder were studied where portland cement and silica fume were used as an active mineral additive. It is shown that with the use of active mineral additives in combination with the silica fume it is possible to obtain a binder with a low coefficient of softening and high resistance to frost.

Combined treatment for conversion of fast-growing poplar wood to magnetic wood with high dimensional stability

Magnetic wood with high performance was prepared from fast-growing poplar wood via a novel two-step combined treatment. The poplar wood was first magnetized via coprecipitation of ferric and ferrous ions and then polymerized in situ by impregnation with a furfuryl alcohol solution. The resulting products were characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, and vibrating sample magnetometry. The properties and morphology were also evaluated. The results showed that: (1) Fe3O4 nanoparticles were successfully synthesized in poplar wood, and the average size was 16 nm; (2) the magnetic properties of the composites were remarkable, and the magnetic stability and acid resistance of the modified wood were improved by the furfurylation; (3) after furfurylation, the magnetic wood recovered from the severe collapse induced by the magnetic treatment and exhibited high dimensional stability and water resistance.

STARCH-BASED EDIBLE FILM AND COATING FROM LOCAL PACHYRHIZUS EROSUS

Edible films and coatings usage are constantly increasing in the food industry. It can be consumed, coated on food or placed as barrier between the food and the surrounding environment. It can also help extend food shelf-life and quality of the food. Pachyrhizus known by the locals as sengkuang was use in search of their novelty to be used as starch-based edible films and coatings products. Through this project research, significant findings were found in the starch-based edible films and coatings made. A compatible amount of plasticisers were used to help the product in flexibility. Apart from a nice clarity appearance, the physical testing results showed low values of 34.53% for solubility, 19% for swelling, 0.014 mm for thickness and 0.112 g cm/day m² for water vapor permeation. These indicated that the product has a high water resistance. The mechanical test also gave impressive results with 0.313 for coefficient of friction (COF) and 7.9 MPa for tensile strength value. Since their application is still underutilised, this research is carried out in search of cost efficient resources for the production of edible-films and coatings as well as to utilise this food crop in Malaysia.

Water-resistant and high oxygen-barrier nanocellulose films with interfibrillar cross-linkages formed through multivalent metal ions

Once-dried 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibril (TOCN) films with sodium carboxylate groups (TOCN–COONa) were soaked in aqueous MgCl2, CaCl2, AlCl3 and FeCl3 solutions to change the counterion to TOCNs–COOM films (M: metal ion). Dry TOCN–COOM films had high Young's moduli (11–20GPa) and tensile strength (170–280MPa). In particular, the wet TOCN films with aluminum and iron (III) carboxylates had high Young's moduli and tensile strengths of ~3GPa and 30–40MPa, respectively, even at water contents of ~470%. Moreover, the dry TOCN films with calcium and aluminum carboxylates had extremely low oxygen permeabilities of 0.08 and 0.15mLµmm−2day−1kPa−1, respectively, even at 80% relative humidity, which are outstanding values compared to those of other films reported previously. These results are explained in terms of the high water resistance of the films, which is caused by the formation of interfibrillar cross-linkages through multivalent metal ions.

Unique adhesive properties of pressure sensitive adhesives from plant oils

We report novel insights into the adhesive performance of bio-based pressure sensitive adhesives (PSAs). Three different homopolymers based on renewable fatty acid methyl esters were characterized in terms of their mechanical and adhesive properties. The polymers display the typical dependence of adhesive properties on molecular weight and degree of crosslinking, as quantified by shear modulus, tack and peel measurements. The absolute values of characteristic adhesion parameters are in the range of commercially available petrochemical PSAs. Curing of applied PSA films at elevated temperature results in a pronounced maximum in tack and peel strength at a critical curing time, which corresponds to a change from cohesive to adhesive failure. Thus, demand-oriented tailoring of adhesive properties can be achieved via an appropriate choice of curing time. Moreover, these bio-based adhesives offer improved adhesion on hydrophobic substrates and high water-resistance without any whitening, thus rendering them an attractive alternative to conventional petroleum-based products. These peculiar features are attributed to the high hydrophobicity of the used monomers.

WOOD PROCESSING BY-PRODUCTS TREATED WITH THE LIGNIN-BASED CONDITIONER AS MULCH FOR SOIL PROTECTION

Wood processing by-products such as bark of different wood species and hydrolysis lignin were applied as soil mulch. The lignin-based soil conditioner (LSC) representing a lignin-based polyelectrolyte complex with the different composition (a lignin/polymer mass ratio) was obtained under laboratory conditions and was intended to protect sandy soil from erosion by simultaneous application of a soil conditioner as an adhesive, mulch and plant seeds by hydroseeding. The study revealed the pronounced dependence of the properties of the treated wood-originated mulch on the wood species as well as on the composition, the applied concentration and the application rate of LSC. A comparison of the obtained results showed that the treated hydrolysis lignin was characterised by higher compressive strength, higher water resistance and lower moisture losses from sandy soil for a given LSC composition and application rate than the bark-based mulch. The conditioner concentrations don't have negative impact on the germination of seeds plants of the coastal dune zone.

Effect of the Addition of CeO2 to Iron Phosphate Glass for Catalytic Applications.

We investigated the effect of CeO2 content on the catalytic behavior and chemical properties of the (100 - x)(80P2O5-20Fe2O3)-xCeO2 (x = 0, 4, 8, 12, 16, 20 and 24 wt%) glass system. Using thermogravimetric analysis, we confirmed that the catalytic activity increased until a CeO2 content of 16 wt%, beyond which, it decreased. The reasons for the change in the catalytic properties of the glass samples were determined using Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and density analyses. It was confirmed using the FT-IR and XPS-01s spectra that CeO2 acts as a network modifier in iron phosphate glass. When the CeO2 content is above 16 wt%, the number of non-bridging oxygen atoms decreases with increasing CeO2 content. For these reasons, the catalytic properties decrease when the CeO2 content is more than 16 wt%. From the dissolution rate measurements, it can be observed that cerium-iron phosphate has a high water resistance. Also, as we expected, it can be confirmed that the chemical durability is improved with increasing CeO2 content.

MECHANICAL CHARACTERISTICS OF RECYCLED ASPHALT BY SUPERPAVE TECHNIQUE, NAJRAN AREA, KSA.

The physical and mechanical properties of RAP depend on the properties of aggregate, asphalt binder, pavement type, amount of time of the original pavement in service, method of recover in Existing flexible pavements represent available supplies of aggregates that can be recycled. This can significantly contribute to environmental preservation by reducing the amount of new materials required for highway construction and avoiding the problems associated with disposal of the old pavement materials. Recycling also reduces the amount of energy needed to produce the new construction materials and transport those materials to the roadway construction site. Recycling has been defined as “the reuse, usually after some processing, of a material that has already served its first-intended purpose”. The recycling procedures in pavement construction have many economical advantages over the traditional procedures. This paper evaluated the performance Superpave mix designs containing recycled asphalt pavement (RAP). The RAP used in each mix design contained aggregate from the same source as the virgin aggregate. The 3-Tier concept was used to incorporate RAP into the mixtures in the first (less than 15%),15: 25 % and third (greater than 25%) tiers. Each mix was also made by modifying the respective binder with rubber. In general, the mixtures containing RAP improved the rutting resistance and either increased, or had no significant effect on the indirect tensile strength (ITS). The tensile strength ratio (ITS) was not affected by the addition of RAP.The recycled asphalt mixture samples were tested in the laboratory. The results indicated that asphalt in the old mixtures used for recycling have low penetration and high softening point. It has also been indicated that asphalts in the recycled mixtures made by the Rejuvenating method have not been rejuvenated completely. The results also showed that Fatigue life of the recycled mixtures is longer than that of the conventional mixture. Other characteristics have been identified such as water-resistance, which showed that the recycled asphalt has high water-resistance.

On immobilization of high-level waste in an Y–Al garnet-based cermet matrix in SHS conditions

A method of high-level waste (HLW) radionuclide immobilization in a long-life matrix based on Y–Al garnet, a material highly chemically resistant to natural environments, has been developed for the ultimate HLW isolation from the environment. Model systems containing Ce, Nd, Sm, Zr, Mo, 238U, and 241Am were used in the study as simulators of HLW radionuclides. An energy-saving technology of self-propagating high-temperature synthesis (SHS) was employed to synthesize the matrix material with fixation of HLW radionuclide simulator elements in the Y–Al garnet structure. The results of an X-ray phase analysis for the synthesized materials have shown that the simulator elements, as well as uranium and americium are incorporated strongly in the structure of Y–Al garnet predominantly forming the matrix's major neoformation fit for environmentally safe disposal. The produced synthetic mineral-like matrices feature high water resistance, the property confirmed by a very low rate (10−9–10−10g/cm2⋅day) of americium leaching into water. Besides high strength of the americium fixation in the structure of Y–Al garnet, the latter's carryover is small at high temperatures due to a short duration of the process.The technically, economically and environmentally attractive novel HLW immobilization technique proposed herein may form the basis for the closing process of the spent nuclear fuel reprocessing.