Water Soak Test Research Articles

Four-Ingredient Blends of Poly(lactic acid) with Cottonseed Oil and Meal for Biocomposite Utilization

The development and characterization of agricultural byproduct-based biocomposites are an important part of green chemistry. In this work, four-ingredient blends were formulated with the melt blending method. The set of composites (named as CSO series) was made with poly(lactic acid) (PLA) as the major matrix, washed cottonseed meal (WCSM) as a filler, cottonseed oil (CSO) as a compatibilizer, and glycerol (GLY) as a plasticizer. The morphological analysis showed the homogenous dispersion of the cottonseed byproducts into the PLA matrix to some extent. The thermogravimetric analysis revealed that thermal stability was impacted by the ingredient’s addition. The functional group analysis of the sample and simulation by Fourier transform infrared spectra confirmed the chemical interactions of PLA with WCSM in the blend products. CSO was most likely subjected to physical blending into the products. The mechanical strengths of those composites were affected by the ratios of PLA-CSO. Generally, the tensile strengths were in the range of 0.74–2.1 MPa, which indicate its suitability for low-strength biodegradable plant container development. The blend products had a lower water absorption during the water soaking test. This work shows the feasibility of incorporating cottonseed WCSM and CSO into a PLA composite for sustainable agricultural applications.

Static compression behavior and strength weakening mechanism of dynamically damaged granite after water soaking

In backfill mining, the surrounding rock is dynamically damaged by intermittent mining and blasting. After backfilling, bleed water from the backfill seeps into the surrounding rock, leaving the surrounding rock in a water-rock coupling environment. To study the mechanical properties of surrounding rock in such a scenario, two types of granite specimens were prepared, namely, impact-damaged (ID), impact-damaged and water-soaked (IDWS) specimens. A modified split Hopkinson pressure bar (SHPB) system was first applied to execute the dynamic tests with different impact numbers and confining stresses to prepare the ID specimens. Subsequently, the IDWS specimens were prepared by water soaking tests on half numbers of the ID specimens. Finally, static uniaxial compression tests were performed on ID and IDWS specimens. The test results indicate that the peak strength of ID and IDWS specimens increases with the increase of confining stress, and first increases and then decreases with the increase of number of impacts. The total strength weakening factor of the IDWS specimens is composed of the impact strength weakening factor and the water-induced strength weakening factor, as well as the coupling effect of the two factors. Impact loading increases the number of microcracks and pores inside the IDWS specimens, resulting in a larger contact area between water and microcracks and pores. Compared with ID specimens, water induces more tensile cracks in the IDWS specimens according to the results of electron microscope scanning. This is manifested as the transfer from macro shear failure mode to macro tensile failure, and further reduces the peak strength of the IDWS specimens.

Factors Affecting the Strength Formation Mechanism and Water Stability of Geopolymer Stabilized Phosphogypsum in Road Construction

By adjusting the content of geopolymer in geopolymer stabilized phosphogypsum (GSP) as roadbed filler, along with the mixing ratio, this paper mainly explores tendencies in the mechanical properties and water stability of GSP. This research is based on macro-mechanical properties such as unconfined compressive strength, resilience modulus, California bearing ratio and shear strength. It is also based on water stability tests, such as the water soaking test, dry and wet cycle test and expansion test, to explore changes in water stability. As for the durability of GSP, this paper is mainly based on the realization of a long time observation of mechanical properties and water stability. In the existing research, most of the stabilized phosphogypsum (PG) base material or roadbed filler consists of cement, lime, etc. In this paper, a new exploration is carried out on the composition of stabilized PG material, realized without the participation of cement. The 28 d compressive strength of GSP reaches 2.5 MPa, and over time this strength grows, which prevents the phenomenon of strength inversion that may occur in conventional cement-stabilized PG. In addition, a long-term soaking experiment was designed in this study based on the material after the strength was stabilized for up to 90 d. After the strength was steady, the GSP with the best water stability still had a softening coefficient of 80% after experiencing water immersion for 7 d. After determining the feasibility of the mechanical properties and water stability of GSP as roadbed filler, we further explored the strength formation mechanism of GSP by microscopic tests (XRD and SEM). This shows that geopolymer can stabilize PG in two main ways: one is the hydration reaction with PG to generate C-S-H gel and ettringite, and the other is to connect PG not involved in the chemical reaction to form a dense whole through generated hydration products. Geopolymer, stabilizing a high amount of PG, not only provides a new method for the consumption of PG, but also has more stable performance than cement, and has certain advantages in economy. In addition, the advantage of this study is that good performance can be achieved by simply sieving PG and adjusting the geopolymer ratio in practical engineering projects.

Performance Evaluation for Cohesionless Soil Stabilized with Lignin and Polymerized Lignin

Abstract Lignin is a natural copolymer found in plants that is a major waste from bioenergy and paper industries. In this study, comprehensive laboratory testing programs were carried out to evaluate the strength improvements and water resistance of soil after being stabilized by lignin and polymerized lignin. The chemical polymerization of pre-treated lignin involves a process of linking short lignin molecules to form longer ones and consuming hydrophilic functional groups to improve its stability under wet conditions. Various testing combinations were considered, including four lignin or polymerized lignin contents (0, 6, 8, and 10 %) and four lime contents (0, 2, 4, and 6 %). The results show that lignin-stabilized soil will take at least 14 days to reach maximum strength, whereas the minimum curing period is 21 days for soil stabilized with polymerized lignin. The optimum dosage is 8 % when lignin or polymerized lignin is used for soil stabilization. Polymerized lignin can provide approximately 10 to 20 % more strength improvement than lignin; however, lime seems work better with lignin than polymerized lignin when added as a strength booster. The water soaking tests showed that polymerized lignin has better moisture resistance than lignin, and additional lime can further improve the performance of stabilized soil with respect to water susceptibility. However, the strength of specimens cannot fully recover, decreasing slightly after each dry–wet cycle for both specimens treated by lignin and polymerized lignin. The total decrease is about 5∼10 % after two cycles. The temperature and pH value control and oxygen supply approach used in this study will be an important reference for future studies.

Phosphorous-nitrogen-silicon modified graphene oxide based fire retardant coating for cotton fabric

A facile and effective method to prepare novel phosphorylated amino graphene oxide (PA-GO) fire retardant material was discussed in this report. PA-GO was prepared using graphene oxide nanoparticle, (3-aminopropyl)trimethoxysilane (APTMS), formaldehyde, and hypophosphorous acid. PA-GO imparted excellent fire retardancy to the fabric when applied on cotton fabric by a dip coating method. The PA-GO coated cotton fabric (CTPA-GO) was tested using various characterization techniques to understand its morphology, composition, thermal stability, and combustion nature. When cotton fabric (control) and CTPA-GO (coated fabric) were exposed to a flame, control fabric burned rapidly producing ash, whereas coated fabric released little smoke at start but did not ignite and maintained its original shape and size even after exposing to flame for >160 s. The PA-GO coating cross-linked with cotton fabric at higher temperature formed thermally stable structure and opposed the exposure of fire to the underlined fibre. The limiting oxygen index (LOI) value for the coated fabric was 32.3 % as compared to the control sample 17.9 %. The tensile strength of the fabric was retained effectively after PA-GO treatment. Pigment acrymine binder paste was used to improve the durability of the coating on fabric inside water, which helped in maintaining the fire retardant properties after water soak test.

Enhanced Electrical and Mechanical Performance of InSnZnO TFTs With Multifunctional Laminated Organic Passivation Layer

To realize high-performance and stable electrical characteristics for ZnO-based thin-film transistors (TFTs) under various environments, we propose InSnZnO (ITZO) TFTs with multifunctional laminated organic (MLO) passivation layers (PVLs). The MLO PVLs were constructed from self-assembled monolayers (SAMs) and an ultraviolet (UV) light absorber-modified polydimethylsiloxane (PDMS) layer. The SAMs can passivate the ITZO surface and suppress the chemical reaction during the spin-coating process, and the modified PDMS layer can block UV light. The MLO-treated ITZO TFTs exhibited a high-performance and robust stability with high mobility (~21.18 cm2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> V−1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula> s−1), a considerable ON– OFF current ratio (~ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.65\times10$ </tex-math></inline-formula> 9), and a steep subthreshold slope (~100 mV/dec). The shift of the threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\textit V}_{{\mathrm {th}}}$ </tex-math></inline-formula> ) under gate bias stress and UV light illumination stress was investigated for the devices with different PVLs. The ITZO TFTs with MLO PVLs showed improved stability under positive gate bias stress (PBS), positive gate bias illumination stress (PBIS), and negative gate bias illumination stress (NBIS) compared to untreated and SAM-treated ITZO TFTs. Furthermore, the MLO-treated ITZO TFTs achieved a weak response to 365-nm UV light and showed superb stability with the negligible change of electrical performance, even after a 1-h water soaking test and a 100-day storing test. In addition, the MLO PVL exhibited high flexibility without signs of cracking even after 10 000 bending cycles and was proven suitable for fabricating flexible oxide TFTs.

Dimensional stability and mechanical properties of extruded-compression biopolymer composites made from selected Nigerian grown wood species at varying proportions

250 µm particle size of wood and polyethylene (PE) materials were compounded at mixing proportions of 60/40, 70/30, and 80/20 (with an increase in polymer to decrease in wood content) and extruded using a single screw extruder at a temperature range of 110–135 °C. The particles of Gmelina Arborea, Tectona grandis, Cordiamilleni, and Nauclea diderichii with recycled Polyethylene were compounded and compressed at 175 N/mm to produce biopolymer composites. The biopolymer composites were subjected to dimensional stability test at 24 h of the water soak method and the ability to withstand load-bearing capacity was investigated. The outcome of the results shows that extruded-compressive biopolymer composites had values ranging from 0.06–1.43 g/cm3, 0.38–3.41%, and 0.82–6.85% for observed density, water absorption, and thickness swelling at 24 h of a water soak test. The mechanical properties values ranged from 0.28 Nmm−2–21.35 Nmm−2 and 0.44–550.06 Nmm−2 for flexural modulus and strength; and 191.43 Nmm−2–1857.24 Nmm−2 and 0.35 Nmm−2–243.75 Nmm−2 for tensile modulus and strength respectively. It was observed that moisture uptake and strength displayed by the composites vary accordingly in values obtained for wood species at different mixing proportions. As observed that the more polyethylene content is compounded to wood, the better its dimensional stability, and flexural and tensile properties. The wood particles of Cordiamilleni compounded at a proportion of 60 to 40 (polyethylene/wood) performed best in dimensional stability and load-bearing capacity. This study confirmed the effect of methods on wood species and recycled PE for manufacturing wood polymer-based composite for both indoor and outdoor applications.

Effects of Maleic Anhydride Grafted Polypropylene on the Physical, Mechanical and Flammability Properties of Wood-flour/Polypropylene/Ammonium Polyphosphate Composites

In this study, maleic anhydride grafted polypropylene (MAPP) was incorporated as coupling agent in the wood-flour/polypropylene/ammonium polyphosphate composites (flame-retardant WPCs). The effects of MAPP content (5 wt.%, 10 wt.% and 15 wt.%) on the physical, mechanical and flammability properties of flame-retardant WPCs were investigated. The water soaking tests showed that the incorporation of MAPP could reduce the hygroscopicity of flame-retardant WPCs. The mechanical properties of WPCs were evaluated by three-point bending tests, unnotched Izod impact strength tests, and dynamic mechanical analysis. The results showed that the flame-retardant WPC containing 10 wt.% MAPP (WPC/APP/MAPP-10 %) performed the best flexural properties, the highest impact strength, E′ value, and tan δ at room temperature. The limiting oxygen index (LOI) tests and cone calorimetry tests showed that the incorporation of 10 wt.% MAPP endowed the flame-retardant WPC with the highest LOI value, the lowest peak-heat release rate, total heat release, CO/CO2 weight ratio and total smoke release. Moreover, the characterization of the WPCs combustion residues performed that WPC/APP/MAPP-10 % had the most complete carbonaceous structure with the highest graphitization degree after combustion. In general, the addition of 10 wt.% MAPP could impart the flame-retardant WPC with the optimum physical-mechanical properties and flame-retardant performance.

Wood Permeability Assessment of Young Teak (Tectona grandis L.f.)

Wood properties of young teak (Tectona grandis L.f.) is inferior, and then preservative treatment is one possible solution to enhance its service life. The uptake and movement of preservatives through wood cell structure is directly connected to the wood permeability. There are two simple methods to identify wood permeability: water soaking and bubble test methods. This paper assesses the young teak permeability by water soaking and bubble test methods. The assessment was conducted into five cm thick young-teak discs by soaking in the red-dye water and blowing air into the discs which had been coated with soap. Results show that the heartwood is less permeable than sapwood. Red-dye penetrates almost 100% of the sapwood area, and the red-dye did not penetrate in the heartwood. Red-dye only penetrates in the cracked heartwood through the void volume in the cracking heartwood. There is a transition zone between sapwood and heartwood, and it is refractory. Bubble test with air pressure from compressor could open the air-pathway in the heartwood and sapwood of young-teak discs taken from Bogor. The bubble test result of young-teak discs from Madiun showed air-pathway only in the sapwood, but heartwood. The air pressure is not capable of moving the vapour through the wood cell. It indicates that the heartwood of young-teak from Madiun is less permeable and less possibility for pressure treatment.

The making of Class C fly ash as high-strength precast construction material through geopolymerization

A study has been carried out to apply fly ash as a high strength, water-resistant precast construction material through geopolymerization. Experiment results show that the working conditions such as water content, the concentration of NaOH, curing temperature, and curing time significantly affect the mechanical property of geopolymer matrix. Through optimization, an above-100 MPa compressive strength has been achieved with the geopolymerization products. The optimum working conditions involves 10 M NaOH concentration, 14–15% water content, and curing at 90 °C in an oven for 1 day or at ambient condition for 3 weeks. Adding Ca(OH)2 does not help to increase the compressive strength of the specimen. Water soaking tests show that the geopolymerization product has a very high water resistance without losing noticeable compressive strength, even after a 1-month soaking time. To elucidate the geopolymerization mechanism, microscopic techniques such as SEM/EDS (scanning electron microscopy and energy-dispersive X-ray spectroscopy), XRD (X-ray diffraction) and ATR-FTIR (attenuated total reflectance Fourier transform infrared) are also applied to investigate the microstructure, the elemental and phase composition of geopolymerization products. The findings of the present work provide a novel method for applying fly ash as a high-strength water-resistant precast construction material.

Selected Properties of Overlaid Magnesium Based Composite Panels for Flooring

The objective of this work was to evaluate some of the mechanical and physical properties of the flooring materials manufactured from panels having magnesia substrate overlaid with oak veneer (Querqus alba) and linoleum sheets. Commercially manufactured panels were used in this work. Bending characteristics, internal bond strength, thickness swelling, and surface quality of the samples were evaluated. The highest modulus of elasticity (MOE) value of 4406 MPa for the sample type-A2 was loaded in the direction of the substrate followed by 3478 MPa for linoleum covered samples which were loaded in the same direction. Internal bond strength values of the panels did not show any significant differences from each other. Dimensional stability of the specimens in the form of thickness swelling for both 2-h and 24-h water soaking tests resulted in values ranging from 0.11 to 0.19%. The surface quality of the samples was not substantially influenced as a function of water exposure. Based on the results in this work magnesium substrate overlaid with oak veneer and linoleum panels could have potential to be used as flooring material with accepted properties.

Water Absorption and Hygrothermal Aging Behavior of Wood-Polypropylene Composites.

Environmentally sound composites reinforced with natural fibers or particles interest many researchers and engineers due to their great potential to substitute the traditional composites reinforced with glass fibers. However, the sensitivity of natural fiber-reinforced composites to water has limited their applications. In this paper, wood powder-reinforced polypropylene composites (WPCs) with various wood content were prepared and subjected to water absorption tests to study the water absorption procedure and the effect of water absorbed in the specimens on the mechanical properties. Water soaking tests were carried out by immersion of composite specimens in a container of distilled water maintained at three different temperatures, 23, 60 and 80 °C. The results showed that the moisture absorption content was related to wood powder percentage and they had a positive relationship. The transfer process of water molecules in the sample was found to follow the Fickian model and the diffusion constant increased with elevated water temperature. In addition, tensile and bending tests of both dry and wet composite samples were conducted and the results indicated that water absorbed in composite specimens degraded their mechanical properties. The tensile strength and modulus of the composites reinforced with 15, 30, 45 wt % wood powder decreased by 5.79%, 17.2%, 32.06% and 25.31%, 33.6%, 47.3% respectively, compared with their corresponding dry specimens. The flexural strength and modulus of the composite samples exhibited a similar result. Furthermore, dynamic mechanical analysis (DMA) also confirmed that the detrimental effect of water molecules on the composite specimens.

Optically Transparent Protective Coating for ITO-Coated PET-Based Microwave Metamaterial Absorbers

In spite of indium tin oxide (ITO)-coated polyethylene terephthalate (PET) sheets being a thriving candidate for flexible and transparent microwave metamaterial absorbers (MMAs), these materials are not robust under severe environmental and handling conditions. The ITO coatings are brittle and have poor scratch resistance when coated over flexible PET sheets; hence, their electrical performance degrades in time. Here, thin films of polyvinyl butyral (PVB) and also its composite with 3-aminopropyltriehoxysilane (APTES) processed at room temperature have been investigated as protective coatings over ITO-coated PET sheets, particularly for MMA application. Prior to coating, the effectiveness of various surface treatments to increase the ITO's wettability by exposure to UV light, chemicals, and air plasma was demonstrated by contact angle measurements. Furthermore, the consequences of surface treatments on the adhesion of the protective coatings to the ITO surface were studied using microindentation, pencil scratch test, ultrasonication test, water soak test, and shower test. Measurements of microwave absorption of the coated and uncoated substrates (PET and ITO-PET) over the X-band (8.2-12.4 GHz) showed a similar electromagnetic (EM) response approximately. Finally, free-space measurements of the MMA before and after PVB coating at its top and bottom were compared from 4 to 16 GHz, and the maximum EM absorption was found to have increased from 95.94% to 98.56%. Optical transparency of coated ITO-PET was quantified by measuring the optical transmittance at 632.8-nm wavelength using red laser and found to be equal to 68.9 ± 6.9. The mechanical strength of the developed coatings is analyzed by nanoindentation technique by obtaining values of hardness and elastic modulus.

Organo-Inorganic Hybrid Intumescent Fire Retardant Coatings for Thermoplastics Based on Poly(Vinylphosphonic Acid).

Thin coatings of crosslinked poly(vinylphosphonic acid), PVPA, display good adhesion and excellent intumescent, fire-retardant barrier properties when applied to the surfaces of a typical thermoplastic, such as poly(methyl methacrylate), but perform relatively poorly in water-soak tests. To strengthen and further improve the barrier properties of the intumescent char and to make the coating more hydrophobic, PVPA has been complexed with various inorganic and organic species. The chars formed from coatings of some of these hybrid materials are less friable than chars from coatings synthesized from crosslinked PVPA alone, and show higher levels of water tolerance with no significant reduction in dry adhesion to the substrate.

Effect of Vapor-Phase Surface Acetylation of Japanese Cedar Wood on Fungal Degradation and Dimensional Stability

Vapor-phase acetylation of heartwood in Japanese cedar wood (Cryptomeria japonica D. Don) was carried out as a surface acetylation method to elucidate the relationship between the depth of acetylated area and fungal decay resistance. The acetylated wood (VPAW), prepared with acetic anhydride vapor by heating at 80°C for 72 h, indicated a significant fungal decay resistance and dimensional stability in water-soaking test, similar to liquid-phase acetylated wood (LPAW). The VPAW provided more than 15% of the weight percent gain (WPG) up to a depth of 7 mm from the wood surface, while LPAW gave ∼20% WPG uniformly throughout the wood. However, 24-h vapor-phase acetylation, giving 15% WPG at a depth of 0–2 mm, showed insufficient fungal decay resistance. These results showed that at least 7 mm thickness of the acetylated region with 15% WPG was required to suppress the fungal decay of acetylated wood under laboratory conditions.

Modelling virgin compression line of compacted unsaturated soils

In this paper, the volumetric collapse of an unsaturated soil, upon soaking to saturation under a certain stress level, is referred to as soaking collapse. The soaking collapse for a soil under virgin condition is assumed equal to the difference between the soil’s virgin compression line (VCL) and its normal consolidation line (NCL) at saturated condition based on results of oedometric constant water content compression and soaking tests performed on a compacted Nanyang expansive clay. A one-parameter model is proposed to describe the variation of the soaking collapse with the pre-soaking degree of saturation under virgin condition once (1) a soil’s yielding point can be clearly defined and (2) the degree of saturation during virgin compression is known. This model can be used to predict the VCL from the NCL. Data of the Nanyang expansive clay, along with published data of nine soils that were derived from constant water content or constant suction compression tests (including oedometric and triaxial compression), were used to calibrate and validate the model. It is shown that the model, when combined with a degree of saturation-volume model and the information of yielding and NCL, can predict reasonable VCLs for all examined soils and suitably capture several characteristics of the VCL including the nonlinearity and pressurised saturation. A constant model parameter of 1.5 is found suitable for all examined soils. The model is also used to predict the VCLs of two compacted soils from the constant degree of saturation compression, which is a recently developed testing technique to evaluate the compression behaviour of unsaturated soils, with reasonable agreement achieved.

Effects of typical soybean meal type on the properties of soybean-based adhesive

In order to effectively apply soybean meal for the preparation of water-resistant soybean-based adhesives for plywood, the effects of three typical soybean meal products, namely, low-temperature soybean meal (LM), high-temperature soybean meal (HM), and physical soybean meal (PM), on the properties of soybean-based adhesive were investigated. The results indicated that the number of reactive groups in the three soybean meals followed the order LM > HM > PM, which in turn led to various crosslinking densities when these soybean meals were crosslinked by epichlorohydrin-modified polyamide (EMPA) during the curing process. The LM soybean adhesive had 6.6% higher soaking bond strength and 16.5% higher boiling-dry-boiling bond strength than the HM soybean adhesive, and 19% higher soaking bond strength and 33% higher boiling-dry-boiling bond strength than the PM soybean adhesive, respectively. These three soybean meals could be used to prepare soybean adhesives for interior-use plywood because all plywood panels bonded with their adhesives passed a water-soaking test at 63 °C for 3 h, but only the LM soybean adhesive achieved the desired water resistance for floor-base plywood. Among the three evaluated soybean meals, LM was the most promising raw material for the preparation of soybean-based adhesive because of a greater number of reactive groups, higher crosslinking density, and superior bond strength. Plywood panel bonded with HM soybean adhesive had a water resistance lower than, but very close to, the standard required value (>0.8 MPa) for floor-base plywood.

Flexible Waterproof Rechargeable Hybrid Zinc Batteries Initiated by Multifunctional Oxygen Vacancies-Rich Cobalt Oxide

Although both are based on Zn, Zn-air batteries and Zn-ion batteries are good at energy density and power density, respectively. Here, we adopted Ar-plasma to engrave a cobalt oxide with abundant oxygen vacancies (denoted as Co3O4- x). The introduction of oxygen vacancies to cobalt oxide not only promotes its reversible Co-O ↔ Co-O-OH redox reaction but also leads to good oxygen reduction reaction and oxygen evolution (ORR/OER) performance (a half-wave potential of 0.84 V, four-electron transfer process for ORR, and 330 mV overpotential, 58 mV·dec-1 Tafel slope for OER). We then constructed a battery system based on both Zn-Co3O4- x and Zn-air electrochemical reactions. The hybrid battery reveals both a high-power density of 3200 W·kg-1 and high-energy density of 1060 Wh·kg-1. Furthermore, the developed flexible solid-state hybrid batterydemonstrates good waterproof and washable ability (99.2% capacity retention of after 20 h water soaking test and 93.2% capacity retention after 1 h washing test). Interestingly, the fabricated flexible battery can work under water, and after the power is exhausted, the battery can automatically recover electricity output as long as it is exposed to air. The developed device is suitable for wearable applications considering its electrochemical performances, great environmental adaptation, and "air recoverability". In addition, this study underscores the approach to develop hybrid energy-storage technologies through modification of electrode materials.

Combined effect of water uptake and temperature on wood polymer composites

ABSTRACTWood polymer composites are materials frequently used for outdoor applications, since they can operate under a large range of temperature and moisture conditions. The present work investigates the combined effect of water soaking and temperature (ranging from 10 up to 40 °C) on wood flour filled high density polyethylene. Water soaking tests have revealed that the percentage of absorbed water at the saturation plateau increases with temperature due to the induced stiffness reduction of the polymeric matrix. This hypothesis has been confirmed by scanning electron microscopy analyses, which has allowed to observe the filler–matrix interface and to measure the wood flour particle size. In addition, instrumented Charpy impact tests have shown a strong toughness reduction as a consequence of fiber–matrix debonding induced by particle swelling, which worsens with temperature. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46674.

Investigation of poly (glycidyl methacrylate-co-styrene) as a curing agent for soy-based wood adhesives

In this study, poly (glycidyl methacrylate-co-styrene) (PGS) emulsions were synthesized through a free radical initiated emulsion polymerization of glycidyl methacrylate (GMA) and styrene. The PGS was characterized with FTIR, and investigated as a curing agent for soybean flour (SF)-based wood adhesives. Seven-ply plywood panels were prepared with the SF-PGS adhesives and were evaluated for their water resistance through a three-cycle water-soaking test. Effects of the PGS/SF weight ratios, hot press temperature, hot press time, and usage of NaOH on the water resistance of the resulting plywood panels were investigated. Decrease in the relative amount of GMA in the PGS reduced the effectiveness of the PGS as a curing agent in the SF-PGS adhesives. Plywood panels made with the SF-PGS adhesives met the industrial requirement for interior plywood.