Adhesive qualities of soybean protein-based foamed plywood glues

The potential of soy protein-based plywood glues for foam extrusion was evaluated. Standard glue mixes containing the soy flours Honeysoy 90, ISU-CCUR, Nutrisoy 7B, and defatted Soyafluff, and the soy concentrates Arcon F and Procon 2000 showed excellent foaming and adhesive qualities but did not have the ability to refoam. To improve refoaming capability, the formulations were modified by increasing the quantities of soy flour or concentrate so that they provided 3.48 g protein/100 g of glue mix. This was the amount of protein contributed by animal blood when it was used as the extender in the standard formulation for foamed glue. All the modified glues containing soy flour or concentrate had good refoaming properties and adhesive strengths that were at least equal to that of the control glue. Simple cost analysis also indicated that when soy flour was used, the modified formulations were cheaper to produce than the current blood-based glue.     

Comparative functionality of soy proteins used in commercial meat food products

The use of soy isolates, concentrates, and texturized flours in meat food products is discussed. Functional characteristics of soy products in relation to their market application are reviewed. Soy isolates find more limited usage in meat food systems (2%) than the concentrates and textured soy flours (8–12%). In weak meat systems containing large amounts of fat (30–45%), the concentrate emulsifier and isolate are more important than the texturized soy flour. In chopped meat systems with 18–25% fat, the textural properties of soy flour (extruded) are more important than the use of an isolate. However, combinations of concentrate emulsifier and texturized flour are used. The method of cooking, i.e. fresh, deep fat-fried, or char-broiled, will affect the usage of soy combinations. In comminuted cooked cured meat food mixes, soy concentrates, and textured flours currently are being used. Nutritional properties are improved by inclusion of available ingredients high in lysine and methionine. Functional measurements of textural properties have been completed using the Instron with a Lee Kramer cell. Both model emulsion systems and finished product results substantiate the accuracy of textural properties in soy-meat mixes using the Instron.     

Comparison of different foaming agents in making plywood glue

Foaming of a phenol formaldehyde resin was studied. Twenty‐one foaming agents were tried out in the experiments. Foaming was evaluated by viscosity, density, and surface tension measurements. The study shows that spray dried blood and β‐lactoglobulin‐enriched whey were the best foaming agents to foam phenol formaldehyde resin. There are also some other materials, which might work as foaming agents for phenol formaldehyde resin after some formula optimization. They include sodium lauryl sulfate, sodium‐n‐alkyl (C₁₀‐C₁₃) benzene sulfonate, and a fatty acid amine derivate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1060–1064, 2004     

Pea and lentil protein extraction and functionality

These studies have demonstrated that peas and lentils can be used as protein sources for flours, concentrates and isolates. Less research attention has been devoted to lentil protein extraction, probably because of the greater cost of lentils as compared to peas. Pin-milling and air classification is well adapted to extracting pea flours to produce pea protein concentrates. Apparently, air-classification can be applied successfully to starch rich legumes, but will not give satisfactory results with lipid rich legumes. Wet processes, including alkaline and salt and acid solubilization, together with isoelectric precipitation or ultrafiltration, have been developed. The pea and lentil protein extracts of these processes exhibit comparable and complementary functionality to homologous soybean products. Air-classified pea protein concentrates are different from soy protein concentrates because of residual starch which can be useful for particular functional applications. Pea isolates appear to exhibit better foaming properties and more solubility than soy isolates, but pea isolates have to be more concentrated than soy isolates to produce viscous dispersions. The economic feasibility of pea and lentil protein extracts is related directly to protein content of the flour, unique functionality of the extracts, marketability of the by-products of extraction and the cost of peas or lentils. Presented at the 78th American Oil Chemists' Society Annual Meeting, May 17–21, 1987, New Orleans, LA.     

Mechanical control of foaming in stirred‐tank reactors

The foam‐breaking characteristics of rotating‐disk mechanical foam‐breakers (MFRDs) fitted to stirred‐tank reactors (STRs) containing various foaming liquids were evaluated. The critical disk rotational speed, N_c, required for foam‐breaking and the liquid hold‐up, ?_L, in ascending foam reflected, respectively, the foam‐breaking behaviour of MFRDs and the foaming behaviour of STRs. Empirical equations for the prediction of N_c and ?_L, which can be applied independently of the type, concentration and temperature of foaming liquid, were obtained. The foam‐breaking power, P_kc, of MFRDs was also clarified in relation to the level of ?_L which is related to the difficulty or ease of mechanical foam‐breaking. © 2001 Society of Chemical Industry     

Properties of calcium carbonate filled and unfilled polystyrene foams prepared using supercritical carbon dioxide

Foaming behaviors of four polystyrenes (PSs) filled and unfilled with various amounts of CaCO₃ using supercritical carbon dioxide were investigated. The PSs include three general purpose grades with different molecular weights (different melt index) and one high impact grade. By adjusting foaming conditions, foam density was determined for each investigated sample. In general, the sample with a lower molecular weight (i.e. higher melt index) yielded a lower foam density for the three general purpose PSs. With the addition of CaCO₃ filler, foam density would increase. The inclusion of rubber in high impact PS was found to complicate its foaming behavior. A qualitative correlation between various types of filled/unfilled PSs and foam density was found in a certain range. An optimum foaming temperature range was required to obtain low foam density for each sample. The corresponding change in matrix modulus by employing various PSs and various filler contents apparently affected the resulting foam density. Although several factors were involved in foaming conditions, the addition of CaCO₃ filler played a significant role in reducing cell size and increasing cell density of the PSs foams investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2276–2284, 2006     

Effects of foaming and antifoaming agents on the performance of a wet flue gas desulfurization pilot plant

Foaming is a common phenomenon in industrial processes, including wet flue gas desulfurization (FGD) plants. A systemic investigation of the influence of two foaming agents, sodium dodecyl sulphate (SDS) and egg white albumin (protein), and two commercial antifoams on a wet FGD pilot plant operation has been carried out. Foaming caused by 0.03 g SDS/(L slurry) reduced the desulfurization degree from 84 to 74% and the solids and limestone concentrations of the slurry from 58 to 48 g/(L slurry) and from 1.4 to 1.0 g/(L slurry), respectively. These effects were attributed to the foaming transferring small particles to the foam layer present on top of the slurry in the holding tank. The addition of 0.03 g antifoams/(L slurry) to SDS foam eliminated the foam, but the desulfurization degree remained low. Potential mechanisms for the observed behavior are analyzed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2382–2388, 2014     

可断键均三嗪脂肪磺酸盐表面活性剂的泡沫性能研究

采用改进的Ross-Miles法研究了4种不同烷基链长的可断键均三嗪脂肪磺酸盐表面活性剂(OSEAT、DSEAT、TSEAT、HSEAT)的泡沫性能,考察了质量浓度、温度、Ca2+浓度对它们泡沫性能的影响。结果表明,OSEAT的抗钙能力最强,其起泡性和稳泡性几乎不受Ca2+浓度的影响;DSEAT的起泡性最好,在0.46 g/L时达到最大发泡力185 mm,且抗温能力强,当Ca2+浓度小于200 mg/L时,其抗钙能力比较强;TSEAT的起泡性较好,且具有一定的抗温、抗钙能力;HSEAT在水溶液中稳泡性最优,其发泡力随温度的升高而增大,55℃时达到最大值144 mm。与普通表面活性剂C12-LAS的泡沫性能比较,DSEAT发泡能力比C12-LAS强,泡沫稳定与C12-LAS接近。     

Protein solubility characteristics of commercial soy protein products

Solubility characteristics of commerical soy protein products (flours, concentrates, and isolates) were determined under various conditions. From the solubility profiles at various pH values and NaCl concentrations, soy protein isolates can be divided into three groups. One group had high solubility near the pl. Another group had low solubility near the pl, but high solubility at pH 11. The third group had low solubility even at pH 11. Except for the hydrolyzed products, the protein solubilities of the soy protein products at various salt concentrations were very low. Temperature did not significantly affect the protein solubility, although a few products showed more than a 20% increase at temperatures >50°C. Soy protein concentrates and soy protein isolates showed similar solubility profiles. The proteins in all commercial products (except flours) tested were denatured, as evident from the solubility profiles in the presence of salt and the enthalpy values from DSC.     

Bond quality of soy-based phenolic adhesives in southern pine plywood

Increased demand for wood adhesives, environmental concerns, and the uncertainty of continuing availability of petrochemicals have led to recent attention on protein-based adhesives. This study was conducted to investigate the glue bond qualities of soy-based phenolic adhesive resins for southern pine plywood. Two types of soy-based resins were formulated and tested. The first was made by cross-linking soy flour with phenol-formaldehyde (pf) resins at neutral pH. The second type was obtained by cross-linking soy flour hydrolyzates with pf resin under alkaline conditions. Plywood bonded with the neutral phenolic soy resins containing 70% soy flour and 30% 1.6 g/cm² pf without the use of extenders and fillers compared favorably with the traditional southern pine pf glue mixes. Plywood bonded with alkaline phenolic soy resins, containing 40 or 50% 0.5 g/cm² PF with the addition of extender (19% corn-cob powder), provided better adhesive glue bond properties than traditional southern pine pf glue mixes. These results suggest that soy-based phenolic adhesive resins have potential for the production of exterior southern pine plywood.     

Mechanical control of foaming in tower reactors

Rotating-disk mechanical foam-breakers (MFRDs) were applied to the control of foaming in bubble column (BC) reactors containing complex solutions and biological media. The foaming behaviour of BCs and the foam-breaking behaviour of MFRDs fitted to BCs were evaluated respectively from the changes in the liquid hold-up in ascending foam, ?_b, and the required critical disk rotational speed, N_c, for foam-breaking. The differences in ?_b and N_c, reflecting the difficulty or ease of foam-breaking among the liquids, correlated well with differences in the foaming characteristic term, F_CT, of respective liquids, which could be determined on the basis of the results measured in the experimental small foaming apparatus which were different from those measured in the gas-bubbling apparatus employed in practice. The usefulness of the empirical correlations for the prediction of ?_b and N_c, which can be applied independently of the type and concentration of foaming liquid or their physical properties, was also demonstrated.     

Extrusion Foaming of Poly (lactic acid)/Soy Protein Concentrate Blends

Poly(lactic acid) (PLA) and soy protein concentrate (SPC) were compounded using poly(2‐ethyl‐2‐oxazoline) as compatibilizer by twin‐screw extrusion, and the resulting blends were foamed by a chemical blowing agent (CBA) using the same extruder. Effects of foaming temperature and CBA content on cell density and foam density were investigated. Polymeric methylene diphenyl diisocyanate (pMDI) as a co‐compatibilizer was added prior to foaming extrusion and its effects on foam morphology and properties were also studied. The results showed that cell density and foam density were greatly influenced by foaming temperature and CBA content. Using the strong interfacial modifier pMDI in PLA/SPC blends resulted in high‐cell density and low‐foam density when CBA concentration was low.

     

Modeling flow and cell formation in foam sheet extrusion of polystyrene with CO2 and co-blowing agents. Part II: Process model

In foam extrusion, process parameters, material properties, and the blowing agent have an influence on the resulting foam properties. For safety and environmental reasons, carbon dioxide (CO₂) has gained importance as physical blowing agent for the production of low-density polystyrene foam sheets. The sole use of CO₂ often leads to corrugation, open cell structures, or surface defects on the foam sheet. As an alternative, blowing agent mixtures based on CO₂ and organic solvents such as ethanol, acetone, or ethyl acetate can be used, changing solubility and flow behavior of the gas-loaded melt. A model approach for describing foam extrusion of polystyrene with various blowing agent mixtures in an annular gap die is developed. Part I of the paper describes the modeling of material properties. In Part II, the process model including nucleation and cell formation in the flow field is developed and applied to a foam sheet extrusion process. Based on the material model, melt flow and formation of cells are modeled by a step-wise calculation along the die, showing good agreement with experimental data. Dimensionless numbers are used to describe the foaming process and a parameter study based on these dimensionless numbers is presented.     

Gemini Surfactants Foam Formation Ability and Foam Stability Depends on Spacer Length

A series of cationic gemini surfactants containing different spacer length were synthesized and analyzed structurally. It was shown that the surface tension (σ) and critical micelle concentration (CMC), which had a maximum for the n-C₄H₈ spacer depended on the spacer length. The foaming ability and foam stability are high for the gemini surfactants with short spacers (C₂H₄ to n-C₄H₈), while longer spacers lead to a distinct decrease of these foam parameters. Foaming properties are discussed in terms of configuration and conformation of a surfactant molecule and in relation to micellization state kinetic.     

New ultra high molecular weight acrylic processing aids for rigid PVC foaming

Foaming of rigid polyvinyl chloride (PVC) is studied as a function of high molecular weight acrylic processing aids. The industrial process to evaluate quality of foam is discussed in detail. The role of acrylic processing aids to improve melt strength and hence foaming of PVC is explained. It is demonstrated that increase in molecular weight of acrylic processing aids increases its effectiveness. It is found that ultra-high molecular weight processing aids is 25%–30% more efficient than relatively lower, but still high, molecular weight acrylic processing aids. The higher molecular weight processing aids provided comparable foaming performance at lower loading levels. Foaming reduced the density of PVC compounds to 0.32–0.34 g/cm³. More than 1000% expansion is achieved in the melt extrusion process using a chemical blowing agent. Fusion characteristics are also studied. Fusion times for initial fusion peaks are in the range of 42–44 s while the fusion times of the second fusion peaks are in the range of 74–94 s. The higher molecular weight processing aids maintained fusion characteristics of PVC compounds, warranting no significant changes in commercial process.     

Modeling flow and cell formation in foam sheet extrusion of polystyrene with CO2 and co-blowing agents. Part I: Material model

In foam extrusion, process parameters, material properties, and the blowing agent have an influence on the resulting foam properties. For safety and environmental reasons, carbon dioxide (CO₂) has gained importance as a physical blowing agent for the production of low-density polystyrene foam sheets. The sole use of CO₂ often leads to corrugation, open cell structures, or surface defects on the foam sheet. As an alternative, blowing agent mixtures based on CO₂ and organic solvents such as ethanol, acetone, or ethyl acetate can be used, changing solubility and flow behavior of the gas-loaded melt. Modeling of the foaming process in the extrusion die could help to reduce experimental effort and accelerate the development of novel blowing agent mixtures. A model approach to describe the melt behavior of polystyrene loaded with various blowing agent mixtures in the extrusion die is developed. Part I of the article describes the modeling of material properties, that is, rheological behavior by a Carreau-WLF approach with shift factors for temperature, pressure, and blowing agent effects on the glass transition temperature. Solubility behavior is modeled by a combined Henry solubility coefficient approach, showing good agreement with experimental data. Based on the material model, a process model is developed in Part II of this work.     

Thermally expandable microcapsules for polymer foaming—Relationship between expandability and viscoelasticity

A new thermally expandable microcapsule was developed for use with foaming polypropylene (PP) by injection molding and extrusion processes at operating temperatures above 200°C. The microcapsule consists of a blowing agent as the core and a shell polymer. The rheological properties of the shell polymer were controlled by a crosslinking agent to design the expandability and shrinkage. The effects of rheological properties on the expandability and the surface appearance of foam products were thoroughly investigated. It was found that storage modulus G′ and tan δ significantly affected the expandability and shrinkage and were controllable through crosslinking polymerization. Visual observation of batch foaming, rheological measurement, and experiments of foam injection molding and extrusion elucidated the existence of the optimal degree of crosslinking that could realize more than 30% density reduction while maintaining a smoothsurface at PP foam injection molding and extrusion. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Investigation on Foam Self‐Generation Using In Situ Carbon Dioxide (CO2) for Enhancing Oil Recovery

In situ carbon dioxide (CO₂) foam flooding has proved to be economically feasible in the oil field, but its self‐generation behavior in the bulk scale/porous media is far from understood. In this study, the optimum in situ CO₂‐foaming agent was first screened, and then in situ foam was investigated in the bulk. In situ foam flooding was conducted to evaluate the displacement characteristics and enhanced oil recovery of this system. The results showed that the foaming agent comprising 0.5% sodium dodecyl sulfonate (SDS) + 0.5% lauramido propyl hydroxyl sultaine (LHSB) gave the best foam properties and that the in situ CO₂ foam with a slow releasing rate is effective both in bulk scale and in porous media, allowing a considerable enhancement of oil recovery in sand packs with different permeabilities.     

A novel strategy for realising environmentally friendly pigment foam dyeing using polyoxyethylene ether surfactant C14EO5 as a foam controller

Development of an environmentally friendly pigment dyeing process with excellent colour depth and levelness is an effective strategy for solving pollution problems in traditional dyeing. A functional polyoxyethylene ether nonionic surfactant, tetradecyl alcohol polyoxyethylene ether with an EO chain length of 5 (C₁₄EO₅), was used as a foam controller, namely a foaming agent and foam stabiliser, in the pigment foam dyeing process. The foamability and the foam stability of C₁₄EO₅ were tunable by adjusting its concentration. The foaming ratio and the foam half-life of C₁₄EO₅ were 5.22 and 32.21 min, respectively, at a concentration of 8 wt%. The addition of pigment dispersion (ranging from 1 to 6 wt%) slightly affected the foaming ratio and the foam half-life owing to the interplay of increased viscosity and pigment particle destabilisation. After the influences of binder on foam properties of C₁₄EO₅ were investigated, the concentration of binder and the stirring time for foaming were determined as 15 wt% and 7 min respectively. Owing to the stable foaming ratio and foam half-life of the pigment foam dyeing dispersion, the colour depth of dyed cotton fabric was tailored solely by changing the dosage of pigment dispersion. Furthermore, the dyed cotton fabric showed not only a high K/S value but also perfect colour levelness and fastness. These results demonstrate that the pigment foam dyeing process with a foam controller, C₁₄EO₅, reduces chemical and water consumptions, as well as improving the colour depth and levelness. This represents a significant step forward as regards environmentally friendly pigment dyeing.     

Carbon dioxide foaming of glassy polymers

The mechanism of foaming a glassy polymer using sorbed carbon dioxide is studied in detail. A glassy polymer supersaturated with nitrogen forms a microcellular foam, if the polymer is quickly heated above its glass transition temperature. A glassy polymer supersaturated with CO₂ forms this foam-like structure at much lower temperatures which indicates the T_g-depressing effect of CO₂. Having this interpretation in mind, the overall sample morphology, i.e., a porous foam enclosed by dense outer skins, can be completely explained. The dense skins, however, are not homogeneous but show a nodular structure when analyzed by SEM and AFM. Foaming experiments with samples having a different thermal history suggest that the nucleation mechanism underlying the foaming process is heterogeneous in nature. © 1994 John Wiley & Sons, Inc.