Development of amino resin for emulsion paint formulation: reactive blending of methylol urea with soybean oil

In this work, methylol urea resin (MUR) was reactively blended with various concentrations (0 - 35%) of soybean oil (SBO) in order to formulate a new two-component polymer system for application as acoating agent for emulsion paint formulation. Formaldehyde emission and some physical properties of the blended resin were evaluated. Moisture uptake and density decreased with increase in the SBOcontent in the blend. Elongation at break and viscosity also decreased initially before a gradual increase was observed as the SBO content increases. Refractive index, melting point and dry time initially increased but gradually decreased with increase in SBO content. The interactions between the two different polymers show that 25% of SBO was the optimal loading inclusion. The values of moistureuptake, formaldehyde emission, melting point and elongation at break which were 1.3%, 0.05 ppm, 120oC, and 140%, respectively, are within acceptable levels required in the coating industry. Theadvantages of this new system are low formaldehyde emission and water reduction characteristics. The polymer blend may therefore be recommended as binder for the coating industry

Study of a composite from reactive blending of methylol urea resin with natural rubber

This study was designed to study some physical properties of a composite derivable from reactive blending of methylol urea resin (MUR) with natural rubber (NR). Formaldehyde emission, decreased with increase in NR concentration in the blend. Elongation at break and viscosity recorded an initial increase but gradually decreased with increase in NR concentration. The melting point however showed an opposite behavior. The incorporation of NR significantly lowered both the refractive index and the density of this composite. The highest viscosity was recorded at 50:50% blend ratio. Formaldehyde emission level, moisture uptake and elongation at break recorded for this composite are within acceptable levels required in the coating industry. Also water resistant and flexibility compared favorably with those of conventional paint binders. The low refractive index may be favorable for low gloss coating at low pigmentation levels of coating systems

Development of amino resin for paint formulation: Copolymerization of methylol urea with polyester

In our continuous efforts to develop a paint binder from amino resin, a low formaldehyde emission methyol urea-triethanolamine (MUT) composite was synthesized through in situ esterification of formaldehyde with triethanolamine (TEA) and subsequent copolymerization of the synthesized polyester with methylol urea. The effects of addition of TEA on the polymerization process on some physical properties of the synthesized copolymer were evaluated. The copolymer was characterized by IR spectroscopy and macro phase separation techniques. At a given TEA concentration, the composite exhibited macro phase separation behavior between that of pure methylol urea and pure polyester. The IR spectra show the presence of the polyester moiety in the composite. The values of moisture uptake, formaldehyde emission, melting point and elongation at break of the copolymer were within the acceptable levels required in the coating industry. Therefore, the methylol urea/polyester copolymer resin could be a potential candidate as a binder for the coating industry

The application of tannin extract from Anogeissus leiocarpus plant as wood adhesives

This work reports the extraction and application of tannins as wood- adhesives from Anogeissus leiocarpus plant using water, acetone or a mixture of these as solvent. In terms of the quantity of extracts from polyphenolic extract of Anogeissus leiocarpus bark, water was the most effective solvent, followed sequentially by acetone and solvent mixture (90% acetone and 10% water). The use of solvent mixture in tannin extraction yielded high tannin content. The poly condensation reaction of Anogeissus leiocarpus bark extract is influenced significantly by amount of formaldehyde (9.0 ml), tannin (2.5 g), glycerol (0.6 ml), cure temperature 80OC, types and pH 7.5 of the adhesive medium. Adhesive joint of significant bond strength were obtained from Anogeissus leiocarpus tannin adhesive. Prolonged cure periods particularly at elevated temperature have adverse effect on the strength properties of these joints, especially with wood- panels as substrates. Joint prepared with adhesive derived from these extracts were tested for strength properties.Keywords: Anogeissus leiocarpus, tannin, polycondensation, Formaldehyde, cure temperature

Development of amino resins for emulsion paint formulation: effect of aldelhydic group and degree of substitution

In our continuous effort to develop a paint binder from amino resins, amino resins from different aldehydic groups were synthesized to produce urea, formaldehyde (UF), urea acetaldehyde (UA), ureaproparaldehyde (UP) and urea butaldehyde (UB) at different degree of substitution (Mono – tetra). Some physical properties of these resins were evaluated. The viscosity, gel time, density and refractive indexof the resins (except UB) were found to increase with increase in alkyl length of the aldehydic group while turbidity (except UF) increased with increase in alkyl length of the aldehydic group. On the otherhand, melting point and moisture uptake decreases with increase in alkyl length of the aldehydic group. In the case of the degree of substitution the viscosity, turbidity, melting point and moisture uptakeincreases with increase in the degree of substitution while the gel time and refractive index were found to decrease with increase in the degree of substitution. However, an initial rise followed by a gradualfall was recorded for density for the different degree of substitution for all the resins. Samples for UF and UA with the exception of monoethylol urea were too hard brittle and has low water resistance whilethose of UP and UB resins were too soft and remained as semi solid in the cured state at room temperature (30oC). This result indicates that these resins cannot be used alone as paint binder.However, monoethylol urea seems to have sieved itself out as a compromise candidate who is neither brittle nor too soft. A comparison of monoethylol urea with some physical properties of someconvectional paint binders present it as a potential binder which may be used in the coating industry

Environmental remediation from heavy metal pollution using polyacrylamide–grafted gum arabic, Moringa oleifera, and blended products of Moringa oleifera and polyacrylamide-grafted gum arabic

Graft copolymers of polyacrlamide-grafted gum arabic were synthesized, blended with Moringa oleifera and characterized by IR spectroscopy. The potentials of the products to remove heavy metals from aqueous solutions were studied at room temperature (30oC) and this was experimented on iron (III) ions (Fe3+). The extent of metal ions removal was determined from sorption capacity values of several sorbents. The results showed that all the polymeric products investigated displayed significant sorption capacities. The abilities of the grafted product polyacrylamide-grafted gum arabic (GA-g-PAAM) to clarify wastewater to a high degree and also remove heavy metals from contaminated water systems, are good indications of the importance of material transformation, especially gum arabic which is hitherto, an emulsifier, and other products of phytoorigin. The sorption capacities of the synthesized and natural products could lead to a blissful expansion of the spectrum of substances that can be used to detoxify our environment through well guided technologies.Keywords: Gum arabic, Moringa oleifera, sorption capacity, sorbent, phyto-products, detoxify, environmen

Comparative studies on the flocculation efficiencies of Moringa oleifera (MO), polyacrylamide-grafted gum arabic (GA-g-PAAM) and blended products of MO and PA-g-PAAM

Graft copolymerization of polyacrylamide onto gum arabic was carried out in aqueous medium at room temperature (30 oC) using previously optimized concentrations of initiator (ceric ion) and the monomer (acrylamide). The percentage graft yield was high (70%) due to optimization of reaction conditions. Reactive blends of Moringa oleifera (MO) and the graft copolymer (GA-g-PAAM) were also synthesized in different ratios of MO to GA-g-PAAM. The blended and unblended graft copolymers and Moringa oleifera were characterized by infrared (IR) spectroscopy. Flocculation capabilities of GA-g-PAAM, the reactive blends (RB), the physical blends (PB) and Moringa oleifera were studied on turbid river water using UV-Visible spectrophotometry at three different wavelengths (λ=400, λ=600 and λ=800 nm) in order to observe the effect of wavelength on flocculation efficiency. The results generally showed that the flocculation efficiency was a function of both flocculation time allowed and the wavelength of UV- radiation used. Hence, the flocculation efficiency was higher for longer flocculation times and longer wavelengths of UV-radiation and vice versa. The flocculation efficiencies obtained after 24 hours at λ=800 nm followed the order below: MO (99.61%) > GA-g-PAAM (94.30%) > MO & GA-g-PAAM 3:1 RB (91.16%) > 1:3 RB (89.58%) > 1:1 PB (87.07%) > 1:1 RB (82.35%). The sludge produced by the above water treatment chemicals was small in volume, biodegradable and consequently did not promote environmental degradation. Through chemical derivatization, gum arabic was transformed into a water treatment chemical with more advantages over conventional coagulants.Keywords: Sludge, Biodegradable, Environment, Turbid water, Derivatization, Coagulan

Synthesis and optimization of polyacrylamide and gum arabic graft copolymer

Graft copolymerization of polyacrylamide onto gum arabic was carried out in aqueous medium at room temperature (30oC) using various initiator (ceric ion) and monomer (acrylamide) concentrations. The extent of graft copolymer formation was determined in terms of percentage graft yield. The results obtained showed that the percentage yield of the graft copolymer is a function of both the initiator and monomer concentrations. The grafted copolymer was characterized by infrared (IR) spectroscopy. The IR spectral data for pure Gum Arabic (GA) and that of Gum Arabic-grafted Polyacrylamide (GA-g-PAAM) indicate that grafting actually occurred. The successful grafting of polyacrylamide onto gum arabic will enhance the search for materials transformation through chemical derivatization with attendant expansion of their spectra of application.Keywords: Graft copolymerization, polyacrylamide, monomer, gum arabic, Chemical derivatizatio

Chemical and nutritional properties of different fractions of Prosopis alba pods and seeds

The objective of this work was to study chemical and nutritional aspects of different fractions of Prosopis alba. Flours from whole pod, pericarp (pulp) and seeds were obtained. Polyphenols were mainly located in pulp but antioxidant activity was higher in whole pod flour and seeds. In seeds, the fraction with the highest polyphenols and antioxidant activity was the seed coat or testa. Protein content was higher in whole pod flour (5.81 %) than in pulp flour (3.52 %), presenting the seed an appreciable amount 33.6 %. These proteins were composed by monomer subunits of 85, 67, 38, 16 and 14 kDa and no prolamins and anti-tryptic activity were detected. P. alba flours presented high content of soluble sugars, mainly composed by sucrose, and also high amount of insoluble dietary fiber. The major mineral was potassium. The whole pod, due to the contribution of seeds, contained high amount of calcium, magnesium, iron and zinc, all indispensable minerals for human nutrition. Therefore, P. alba flours, mainly containing the seeds, constitute nutritional ingredients for bakery and gluten free products.Fil: Sciammaro, Leonardo Pablo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Ferrero, Cristina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Puppo, Maria Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentin