Water-soluble Phenol Formaldehyde Resin Research Articles

Study of Plugging Compositions Based on Synthetic Resins for Repair and Insulation Work in Wells.

This research is aimed at analyzing existing plugging compositions and developing a new plugging composition based on phenol-formaldehyde resin. This paper presents the results of studies of a hardening composition based on phenol-formaldehyde resin for repair and insulation work in wells. The plugging composition consists of two parts: Component "A" (resin and additives) and Component "B" (hardener). A resol-type water-soluble phenol-formaldehyde resin was selected for testing. The resin was additionally modified with special additives to improve performance properties. A mixture of acids was chosen as a hardener. Concentrations of resin and hardener were selected to ensure optimal loss of fluidity of the composition for different temperatures. The main physicochemical properties of the plugging composition were determined. The elastic-strength characteristics of the developed composition after curing at various temperatures (Poisson's ratio, Young's modulus, and compressive strength) were assessed. It has been experimentally proven that samples based on phenol-formaldehyde resin do not collapse completely under load but undergo longitudinal and transverse deformations. As the amount of hardener in the system increases, the compressive strength decreases. The presence of the elastic-strength properties of cementing compositions based on synthetic resins distinguishes them favorably from hardening compositions based on cement and microcement.

High-Temperature-Resistant Profile Control System Formed by Hydrolyzed Polyacrylamide and Water-Soluble Phenol-Formaldehyde Resin.

To realize the effective profile control of a heavy oil reservoir, hydrolyzed polyacrylamide (HPAM) and water-soluble phenol-formaldehyde resin (PR) were chosen to prepare the profile control system, which gelled at medium or low temperatures and existed stably at high temperatures in the meantime. The effects of phenolic ratios, PR concentration, and HPAM concentration on the formation and strength of the gels were systematically studied by the gel-strength code method and rheological measurements. And the microstructure of the gels was investigated by scanning electron microscope measurements. The results showed that the gelling time of the HPAM-PR system was 13 h at 70 °C. The formed gel could stay stable for 90 days at 140 °C. In addition, the gels showed viscoelastic properties, and the viscosity reached 18,000 mPa·s under a 1.5 s-1 shearing rate due to their three-dimensional cellular network structure. The formation of the gels was attributable to the hydroxyl groups of the PR crosslinking agent, which could undergo the dehydration condensation reaction with amide groups under non-acidic conditions and form intermolecular crosslinking with HPAM molecules. And the organic crosslinker gel system could maintain stability at higher temperatures because covalent bonds formed between molecules.

Effects of bamboo species, steam-heating treatment, and adhesives on mechanical properties and dimensional stability of oriented bamboo scrimber boards

Effects of bamboo species, adhesives, and steam-heating treatment (SHT) were examined relative to mechanical properties and dimensional stability of oriented bamboo scrimber board (OBSB) made from makino bamboo (Phyllostachys makinoi Hayata) and moso bamboo (P. pubescens (Mazel)) strips. Results indicated that OBSB produced using makino bamboo culms bonded with water-soluble phenol formaldehyde resin (PF) had significantly higher ultrasonic wave velocity (Vu (//)), tap tone sound velocity (Vt (//)), dynamic modulus of elasticity (DMOEu (//)), and DMOEt (//) than that produced using moso bamboo bonded with water-soluble urea formaldehyde resin (UF) (p < 0.05). The two types of OBSB showed the same trend of DMOEu > DMOEt > modulus of elasticity (MOE). In addition, OBSB made using steam-heated makino bamboo and PF had the largest modulus of rupture (MOR) (210.5 MPa), exceeding that of OBSB made using laminated bamboo timber and wood-plastic composite (WPC). However, OBSB made using steam-heated moso bamboo and UF exhibited the highest screw holding strength (SHS). Improvement in dimensional stability was observed in OBSB manufactured using steam-heated culms. Finally, OBSB glued with UF had lower water absorption, thickness swelling, and volumetric swelling than that glued with PF.

A Modified Glue for Producing Particle Boards and Boards Based on Waste of Annual Plants

This paper proposes a water-soluble phenol-formaldehyde resin modified by an alkyd oligomer for reducing the surface tension of an adhesive composition and improving its distribution over wood particles or particles of annual plants during the production of compressed board materials for construction purposes. It was found that the physical and mechanical characteristics of boards increase when produced with the use of the modified glue obtained with a small change in its production technology.

Improved mechanical properties and thermal stability of phenol formaldehyde resin by incorporating poly(vinyl alcohol)-grafted reduced graphene oxide nanohybrid

Poly(vinyl alcohol) grafted reduced graphene oxide (PVA-rGO) nanohybrid has been synthesized by a facile hydrothermal method. Transmission electron microscopy, ultraviolet-visible spectroscopy, fourier transform infrared spectroscopy and 1H NMR spectroscopy confirmed that the PVA chains were successfully grafted onto the surface of graphene oxide sheets by esterification reaction, and meanwhile graphene oxide was reduced to rGO during hydrothermal process. Thermogravimetric analysis indicated that the PVA content in PVA-rGO was evaluated to be around 26.9 wt%. Subsequently, PVA-rGO nanohybrid was incorporated into a water-soluble phenol formaldehyde resin (PF) matrix to fabricate PVA-rGO/PF composites via a solution blending and casting approach. The mechanical properties and thermal stability of PVA-rGO/PF composites were investigated by universal mechanical tester, impact tester and thermogravimetric analysis. And the results showed that their mechanical properties and thermal stability were improved significantly by the addition of 3 wt% of PVA-rGO, which was mainly attributed to a good dispersion of PVA-rGO in PF matrix as well as a strong interfacial interaction between the PVA-rGO nanohybrid and PF matrix, as revealed by the results of scanning electron microscopy. Our study provides a new insight into the study of water-dispersible graphene functionalized with polymer molecules and its applications in water-soluble polymers.

Comparative Researcehs of the Properties of Laboratory Plywood and Some Industrial Manufactured Wood-Based Panels

The aim of the researches in the master thesis is studying the impact of the changes in plywood structure on their physical and mechanical properties. These changes are related to the change of the layer’s position in the panels’ structure along the axis of symmetry without changing the number and the thickness of the veneers. Four models of laboratory nine layered plywood were made for studying this impact. The evaluation of the models quality was made on the base of the obtained values from the tests of their physical and mechanical properties, as well as on the base of the comparative analyze of these values and the values obtained from the tested properties of comparative model of industrial manufactured plywood.
 The laboratory plywood models are made in controlled laboratory conditions by the method of hot dry pressing. Beech peeled veneers with thickness of 1,2; 1,5; 2,2 and 3,2 mm are used for plywood manufacturing. As gluing component for plywood manufacturing, pure water-soluble phenol formaldehyde resin with concentration of 47,10 % is used. The models are preserved with phenol formaldehyde foil, which is impregnated in the surface layers during pressing. Four panels from each model are made, as well as two additional panels without surface phenol formaldehyde foil from the second model in order to perceive the differences in physical properties between preserved and non-preserved laboratory models.

Comparative Researcehs of the Properties of Laboratory Plywood and Some Industrial Manufactured Wood-Based Panels

The aim of the researches in the master thesis is studying the impact of the changes in plywood structure on their physical and mechanical properties. These changes are related to the change of the layer's position in the panels' structure along the axis of symmetry without changing the number and the thickness of the veneers. Four models of laboratory nine layered plywood were made for studying this impact. The evaluation of the models quality was made on the base of the obtained values from the tests of their physical and mechanical properties, as well as on the base of the comparative analyze of these values and the values obtained from the tested properties of comparative model of industrial manufactured plywood.
 The laboratory plywood models are made in controlled laboratory conditions by the method of hot dry pressing. Beech peeled veneers with thickness of 1,2; 1,5; 2,2 and 3,2 mm are used for plywood manufacturing. As gluing component for plywood manufacturing, pure water-soluble phenol formaldehyde resin with concentration of 47,10 % is used. The models are preserved with phenol formaldehyde foil, which is impregnated in the surface layers during pressing. Four panels from each model are made, as well as two additional panels without surface phenol formaldehyde foil from the second model in order to perceive the differences in physical properties between preserved and non-preserved laboratory models.

Facile preparation of water soluble phenol formaldehyde resin-derived activated carbon by Na2CO3 activation for high performance supercapacitors

We developed a one-pot strategy to fabricate activated carbons by using water soluble phenol-formaldehyde resin as precursor and Na2CO3 as activating agent. The prepared carbon materials have a typical hierarchical pore texture and a large specific surface area (SSA) of 1357m2g−1. When used as electrode materials for supercapacitors, the material shows a high specific capacitance of 226Fg−1 at 0.05Ag−1, good rate capability of 62.4% in the range of 0.05–20Ag−1 and outstanding cycling stability (only 2.5% loss in specific capacitance after 5000 cycles). These results suggest a low-cost and environmentally friendly design of electrode materials for high-performance supercapacitors.

Synthesis and application of water-soluble phenol-formaldehyde resin crosslinking agent

Polyacrylamide and water-soluble phenol-formaldehyde resin can produce crosslinking reaction to generate the movable gel, which can be used in deep profile control to enhance oil recovery. In this paper, the preparation process of water-soluble phenol-formaldehyde resin crosslinking agent (polyhydroxymethyl phenolic) was presented, including the raw material mixture ratio and synthesis process. The water-soluble phenol-formaldehyde resin was synthesized by the technology of two-step base catalysis with NaOH and Ba(OH)2•8H2O composite catalyst. The movable gel prepared with this crosslinking agent and polyacrylamide has good stability and long shelf life through the performance evaluation experiment. The above movable gel was applied to deep profile control and obtained better flooding efficiency.

Study on the Effect of Tween 60 on Dispersion Property of Water-Soluble Phenol-Formaldehyde Resin

To study the effect of Tween 60 on dispersion property of water-soluble phenol-formaldehyde resin (PFR), the size and zeta potential of PFR/Tween 60 molecule aggregates and the surface tension, turbidity and blocking property of PFR/Tween 60 dispersion were measured. The results of the study show that when Tween 60 concentration in the PFR/Tween 60 solutions is lower than CMC, the dispersion property of PFR solution is not affected by Tween 60 significantly. When Tween 60 concentration in the PFR/Tween 60 solutions is higher than CMC, the Tween 60 molecules, and PFR molecules form complex molecule aggregates in water which affected the dispersion property of PFR solution significantly. The interaction between Tween 60 molecule and PFR molecule in the complex molecule aggregates is stronger than the interaction between PFR molecules in the PFR molecule aggregates.

Effect of carbon content and calcination temperature on the electrochemical performance of lithium iron phosphate/carbon composites as cathode materials for lithium-ion batteries

Lithium iron phosphate/carbon (LiFePO4/C) composites were prepared by a convenient method with water-soluble phenol-formaldehyde resin as the carbon precursor. The morphology, crystalline structure, thermal stability, and composition of as-prepared LiFePO4/C composites were investigated by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and Raman spectrometry. Their electrochemical performance was examined based on cyclic voltammogram with a LAND battery testing system while the effect of carbon content and calcination temperature was highlighted. Results show that carbon content and calcination temperature dramatically influence the discharge capacities and rate performance of LiFePO4/C composites. The optimal calcination temperature is 700°C, and the optimal carbon content (mass fraction) is 8.7%. The LiFePO4/C composite prepared under the optimal conditions exhibits an initial room temperature discharge capacity of 150.2mAhg−1 at a 0.2C rate and a constant discharge capacity of about 105.7mAhg−1 at a 20.0C rate after 50 cycles, showing promising potential as a novel cathode material for lithium ion batteries.

Dispersion Properties of a Water-Soluble Phenol-Formaldehyde Resin

Dispersion properties of the water soluble phenol-formaldehyde resin are studied by measuring of hydrodynamic diameter, Zeta potential of the resin molecule aggregate and the critical coagulating concentration of the resin solution. The results shows that a 50 mg/L resin solution prepared with distilled water is transparent, in which the hydrodynamic diameter and the Zeta potential of the resin molecule aggregate is about 9 nm and −38.08 mV, respectively. With addition of electrolytes, the Zeta potential of the resin molecule aggregate is decreased, and the solution turns turbid. The ratio of critical coagulating concentration (CCC) of NaCl to MgCl2, AlCl3, Na2SO4 for the resin solution is 1 : 0.026 : 0.00033 : 0.49. pH can also influence the resin dispersion significantly. When the pH > 7, the resin aggregate is negatively charged with a high Zeta potential, and the solution is stable. The isoelectric point of the aggregate is pH around 3.2. When the pH < 3.2, the resin aggregate is positively charged with Zeta potential of 3 ∼ 5 mV, the system becomes a turbid suspension.

Structure and characterization of Chinese fir (Cunninghamia lanceolata) wood/MMT intercalation nanocomposite (WMNC)

With water-soluble phenol-formaldehyde resin as an intermediate, Chinese fir (Cunninghamia lanceolata) wood/montmorillonite nanocomposite (WMNC) was prepared through vacuum impregnation and characterized with XRD, SEM, FTIR and TG-DTA analyses. The XRD analysis indicated that the wood crystallinity of WMNC decreased, the MMT exfoliated and some nano silicate layers entered into the non-crystallized microfibrillar region of the wood cell wall. Wood structure is anisotropic and its impregnation is anisotropic. Due to the nonuniformity of the MMT organic modification, PF intercalation and wood impregnation, the MMT configuration and distribution in wood were diverse. The SEM graphs of WMNC showed that some silicate grains were blocked in the wood cell lumen, some silicate layers adhered to the inner surface of the wood cell wall, and some exfoliated MMT layers even penetrated the wood cell wall. The obtained hydroxyl of WMNC increased and its ether linking decreased. It was considered that MMT and wood interacted not only with hydroxyl bonds, but also involved some chemical linking. Compared with untreated wood and the PF-impreg, the pyrolysis process of WMNC changed; its starting decomposing temperature decreased and its pyrolysis weight loss at high temperatures greatly decreased. The WMNC indicated certain nanoeffects of the composition of the inorganic MMT nanolamellae.

Preparation of Chinese fir wood/MMT nanocomposites and the factors affecting it

The nano intercalation compounding of wood and MMT has important implications for the modification of wood and for the development of new materials. With water-soluble phenol formaldehyde resin as an intermediary, the nanocomposites of Chinese fir (Cunninghamia lanceolata) wood and montmorillonite (MMT) were prepared via three impregnation methods, i.e. normal pressure, once and twice vacuum methods. Based on the weight percent gain (WPG) of impregnated wood, the effects of compounding wood and MMT in terms of concentration, impregnating temperature and time, wood moisture content and wood extraction treatments, on sapwood and heartwood are discussed. Results show that: 1) the optimum MMT concentration in the impregnation solution is 3% for sapwood and 5% for heartwood; 2) room temperature is suitable in practice; 3) treatment pressure should be set at a high enough value in order to ensure sufficient permeation; 4) the effects of different impregnation methods on sapwood and heartwood are different, the heartwood extractives affect WPG significantly; cell wall permeability of sapwood is better than that of heartwood; 5) the cold water, hot water and benzene-ethanol solution extractions can all greatly improve the permeability of heartwood, hot water can dissolve some hemicellulose of low aggregation and hot water extraction improves wood cell wall permeability; 6) with an increase in wood moisture content, the permeable space in wood is reduced, but with a certain amount of water, instantaneous spaces are created and the permeation dynamic increases. This effect is especially apparent for difficult impregnating situations in heartwood and impregnation under normal pressure.

Preparation and characterization of wood/montmorillonite nanocomposites

With montmorillonite (MMT) organically modified as organophilic MMT (OMMT) and water-soluble phenol formaldehyde resin (PF) as intermediate, Chinese fir (Cunninghamia lanceolata) wood/MMT nanocomposites (WMNC) were prepared via nano intercalation compounding and characterized by XRD, SEM and FTIR. Results show that: 1) the preparation of OMMT is very successful; 2) the self-made PF can effectively intercalate into MMT to increase markably its gallery distance and even exfoliate its nano silicate laminae; 3) the XRD analysis indicates that some exfoliated MMT enters the non-crystallized region of microfibrils in wood cell walls and the crystallinity degree of wood in WMNC decreases; 4) the SEM graphs show that multiform MMT exists in WMNC. Some grains block in wood cell lumen, some layers adhere to the wood surface of the inner cell wall and some exfoliated nanolaminae even insert into wood cell walls; and 5) the FTIR analysis suggests that MMT and wood in WMNC perhaps interact via certain chemical bonding.

Microwave Drying of Resin Impregnated Paper*

A pilot scale apparatus was constructed for impregnating paper with water soluble phenol formaldehyde resin and subsequently microwave drying it.Comparison of the properties of the papers dried at various microwave power application levels with the properties of similar papers dried in a hot air, natural convection oven showed that the microwave dried papers had a more uniform resin concentration distribution across the sheet thickness, were superior in internal bond strength and in surface abrasion resistance. The surface abrasion resistance and internal bond results support the contention that the resin distribution is more uniform in the microwave dried papers. No signficant differences were observed in the tensile breaking strength, stretch, or Young’s modulus between papers which were microwave dried or oven dried. Results obtained in a bending test suggest, but do not unequivocally prove, the microwave dried papers are more flexible.