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Because of the current interest in sustainability, environmental stewardship, and green chemistry, there has been a lot of interest in using agro-based raw materials for the design of polymeric materials. One of the promising biorenewable materials is sucrose, which is inexpensive and widely available. In this work we have carried out the synthesis of sucrose–toluene diisocyanate-based polyurethane through microwave-assisted reactions. Comparisons of conventional heat versus microwave reactions have been made. Microwave-assisted synthesis has been found to significantly decrease the reaction time and save energy relative to conventional heat. The sucrose polyurethane has turned out to be a suitable matrix to prepare semi-interpenetrating polymer networks (semi-IPNs) involving a second material. Two examples shown in this work are the semi-IPNs of sucrose polyurethane with polycaprolactone and soybean oil. Characterization of the polymers has been conducted with 13C NMR, FT-IR, size-exclusion chromatograph...

This paper reports the application of an amperometric biosensor for rapid and specific Salmonella Typhimurium detection in milk. This device was developed from self-assembled monolayer technique on a gold screen-printed electrode, using cysteamine thiol. Polyclonal antibodies were oriented by protein A immobilization. The biosensor structure was characterized by cyclic voltammetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. The analytical response was obtained by a chronoamperometry technique, using a direct-sandwich peroxidase-labeled system. The biosensor device showed a qualitative behavior with a very low limit of detection of 10 CFU mL−1 and a detection time of 125 min. The biosensor specificity was demonstrated in pure and mixed samples with strains of Escherichia coli and Citrobacter freundii. The performance of the biosensor was found satisfactory, and the device was tested in skimmed and whole milk samples, being able to detect S. Typhimurium quickly, without an enrichment step. This structure of immunosensor assembly can be expended in future studies for other food matrices and bacterial species, making it a useful tool to ensure food safety.

Carboxymethylated cashew gum (CMCG) film was electrodeposited on a gold surface for immobilization of polyclonal anti-Salmonella antibodies. The immunosensor response was obtained by chronoamperometry in milk contaminated with Salmonella enterica serovar Typhimurium. The CMCG film was a suitable platform for the immunosensor assembly and showed a stable structure with a 12% coefficient of variation after 30 sweeps in phosphate saline buffer (pH 7.4). The current (i) measured during the S. Typhimurium detection presented a linear calibration curve up to 105 CFU mL−1. The limit of detection was 10 CFU mL−1 with a detection time of 125 min. The immunosensor had a good performance in raw, whole and skimmed ultra-high temperature (UHT) milk without pre-enrichment step thus proving its efficacy in detecting bacteria in a complex food matrix. In addition, a high specificity was observed in the cross-reactivity tests with other bacteria. The CMGC-based immunosensor has a good potential for use as a screening test for Salmonella in the food control and prevention of foodborne diseases.

Cottonseed protein has great potential to replace formaldehyde-based adhesives due to the nature of non-toxicity, harmlessness, and non-pollution. Like soy protein-based adhesives, cottonseed protein-based adhesives also face a huge challenge in water resistance. In this work, the adhesion performance of cottonseed protein isolate (CSPI) modified by combination of H3PO4 and CaCl2 with different mole ratios was investigated and compared with those modified by 40 mM H3PO4, CaCO3, CaO, or CaHPO4. Results showed that CSPI with 40 mM CaHPO4 did not show better adhesion performance when compared with 40 mM H3PO4, CaCO3, or CaO, indicating the little/no synergy between Ca and P due to the spatial structure restriction of water insoluble CaHPO4. However, the combination of H3PO4 and CaCl2 enhanced the adhesion performance of CSPI in comparison with other modifiers, due to free Ca2+ released from water soluble CaCl2 presenting a better synergy with PO43-. At the optimal loadings of 40 mM H3PO4 and 20 mM CaCl2, 71, 86, and 56% increase in dry, wet, and soaked strengths was achieved. In addition, comparison of CSPIs with H3PO4/CaCl2 and H3PO4/Ca(NO3)2 indicates that the anions of water soluble calcium salts (CaCl2 and Ca(NO3)2) had insignificant effects on adhesion performance of CSPI. Those findings indicated that mixing of phosphoric acid and some water soluble calcium salts could synergistically enhance the adhesion performance of CSPI, thus improving the industrial acceptability of CSPI-based adhesives.

The performance of biosensors depends directly on the strategies adopted during their development. In this paper, a fast and sensitive biosensor for Salmonella Typhimurium detection was assembled by using optimization studies in separate stages. The pre-treatment assays, biomolecular immobilization (primary antibody and protein A concentrations), and analytical response (hydroquinone and hydrogen peroxide concentrations) were optimized via voltammetric methods. In the biosensor assembly, a gold surface was modified via the self-assembled monolayer technique (SAM) using cysteamine thiol and protein A for immobilization of anti-Salmonella antibody. The analytical response of the biosensor was obtained through the use of a secondary antibody labeled with a peroxidase enzyme, and the signal was evaluated by applying the chronoamperometry technique. The biosensor was characterized by infrared spectroscopy and cyclic voltammetry. Optimization of protein A and primary antibody concentrations enabled higher analytical signals of 7.5 and 75 mg mL−1, respectively, to be achieved. The hydroquinone and H2O2 concentrations selected were 3 and 300 mM, respectively. The biosensor developed attained a very low detection limit of 10 CFU mL−1 and a fast response with a final detection time of 125 min. These results indicate that this biosensor is very promising for the food safety and emergency response applications.

Soy and cottonseed proteins appear promising as sustainable and environment-friendly wood adhesives. Because of their higher cost relative to formaldehyde-based adhesives, improvement in the adhesive performance of proteins is needed. In this work, we evaluated the adhesive properties of soy and cottonseed protein formulations that included phosphorus-containing acids and esters. For cottonseed protein isolate, most of these additives improved dry adhesive strength, with methylphosphonic acid, phosphorous acid, and phosphoric acid increasing the dry strength by 47, 44, and 42%, respectively, at their optimal concentrations. For soy protein isolate, these additives did not show significant benefits. The phosphorus-containing additives also improved the hot water resistance of the cottonseed protein formulations but showed either no effect or a negative effect for the of soy protein formulations. Thus, the combination of cottonseed protein with phosphorus additives appears to be attractive as wood adhesives.

Most commercial wood adhesive use either formaldehyde-based resins or polyurethanes, both of which include potentially toxic chemicals in their formulations. As a result, proteins are being considered as greener and more sustainable wood adhesives. While most of the protein adhesive studies focus on soy proteins, there is also interest in exploring alternatives. In this work, testing of the adhesive performance of cottonseed protein isolate was undertaken in the presence of protein denaturants, i.e. guanidine hydrochloride (GuHCl), sodium dodecyl sulfonate (SDS), urea, and alkali. For comparison, soy protein isolate was also included in the study. At optimal dosage levels, the dry adhesive strength of cottonseed protein isolate could be enhanced by 38, 25, or 47% with SDS, GuHCl, or urea, respectively. The dry adhesive strength and hot water resistance of cottonseed protein isolate was generally superior to that of soy protein isolate, with or without the denaturants. Thus, the combination of cott...

Water-washed cottonseed meal (WCSM) has been shown as a promising bio-based wood adhesive. In this work, we tested the bonding strength of WCSM slurries with high solid contents and low press temperatures per industrial input for non-structural applications as European Standard Class D1 wood adhesives. Increasing the WCSM content from 11 to 20% and 30% did not substantially change the adhesive strength but increased the viscosity of WCSM slurries dramatically. The shear strength at break of the maple wood pairs bonded at 40 and 60 °C was lower than that of maple pairs bonded at 100 °C. However, the shear strength of the pairs bonded at lower temperatures (40 and 60 °C) could be improved by extending the press time from 20 to 120 min. Addition of citric acid (CA) improved the viscosity of the WCSM adhesive at 20% solid content, but lowered the adhesive strength. The addition of denaturing reagent sodium dodecyl sulfate (SDS) showed reverse impacts on the adhesive strength and viscosity, compared to...

Many copolysaccharides are compositionally heterogeneous, and the composition determined by the usual analytical or spectroscopic methods provides only an average value. For some polysaccharides, the NMR data contain copolymer sequence information, such as diad, triad, and tetrad sequence intensities. In such cases, it is possible to estimate the extent of compositional heterogeneity through NMR. Two general types of methodologies can be used: perturbed Markovian and discrete component approaches. The theoretical bases for these approaches are reviewed in this work, and three examples are shown of the application of these NMR methodologies to copolysaccharides.

The focus of this work was on the significant changes in the water dynamics of aqueous poly (N-isopropylacrylamide) (PNIPAM) solution during sol-to-gel transition. Through the use of NMR (particularly two-dimensional 2H NMR T1-T2 relaxation) and rheology, we were able to show that below 34° C fast exchange occurs among free water and water molecules adsorbed on the surface of PNIPAM molecules. At 34° C, PNIPAM becomes aggregated; most of the water molecules are trapped in the PNIPAM aggregates, where water molecules with different dynamics are found. Above 34° C, PNIPAM molecules aggregate further to form a gel network; the free bulk water then becomes dominant at this stage. On the basis of these observations, a model where water molecules interact with PNIPAM in different ways during the transition was proposed. We believe that our experimental approach provides new information and fresh perspectives on the sol-to-gel transition of PNIPAM.

This report details the design of carboxymethylated cashew gum (CG) as a platform for antibody (Ab) immobilization, which can then be used as a biosensor for bacteria detection. The CG was isolated and characterized, followed by conversion to carboxymethyl cashew gum (CMCG). The CMCG film was a viable support for antibody immobilization; it was electrodeposited on gold surface using the cyclic voltammetry technique, applying a potential sweep from −1.0 V to 1.3 V with a scan rate of 50 mV s−1 and 10 scans. The COOH groups on the surface of the film were critical in promoting Ab bonding. The immobilization of the Ab was mediated by protein A (PrA) for recognition of the antigen. Voltammetry studies were used to monitor the antibody immobilization. Finally, the analytical response of the CMCG-PrA-Ab system was evaluated with the chronoamperometry technique and was found to detect Salmonella Typhimurium bacteria rapidly and efficiently.

The physical properties of poly(lactic acid) (PLA) are influenced by its stereoregularity and stereosequence distribution, and its polymer stereochemistry can be effectively studied by NMR spectroscopy. In previously published NMR studies of PLA tacticity, the NMR data were fitted to pair-addition Bernoullian models. In this work, we prepared several PLA samples with a tin catalyst at different L,L-lactide and D,D-lactide ratios. Upon analysis of the tetrad intensities with the pair-addition Bernoullian model, we found substantial deviations between observed and calculated intensities due to the presence of transesterification and racemization during the polymerization processes. We formulated a two-state (pair-addition Bernoullian and single-addition Bernoullian) model, and it gave a better fit to the observed data. The use of the two-state model provides a quantitative measure of the extent of transesterification and racemization, and potentially yields useful information on the polymerization mechanism.

Green chemistry is a key opportunity in chemistry and chemical engineering today because it can potentially preserve the environment and human health. It entails the choice of natural biodegradable raw materials and solvents, environmentally acceptable processes, and minimal use of non-hazardous chemicals. Previously, deep eutectic solvents (DES) have found many applications in organic, analytical, and polymer chemistry. The recent discovery of natural deep eutectic solvents (NADES), where many plant-abundant primary metabolites have been found to change their state from solid to liquid at certain temperatures when mixed in a proper ratio, should accelerate their use as replacements for common organic solvents that exhibit inherent toxicity and high volatility. In this work, we have reviewed the application of NADES as green, sustainable solvents in processes that involve polymerizations and polymer reactions. It is clear that many applications have already been explored. Undoubtedly more progress will be made in the future, and NADES will become more commonly used in polymer-related processes.

Over-ripe bananas serve as a good source for non-starch polysaccharides (NSP), which can be used as a functional food ingredient and represent an opportunity for waste utilization. However, ripe banana contains a large amount of sugars, which are undesirable and need to be removed. Traditional extraction methods using alcoholic solvents have many drawbacks. This study aims to use natural deep eutectic solvents (NADES) as new and eco-friendly solvents for the extraction of soluble sugars from ripe bananas. Thirty NADES were characterized and screened, and four of them were selected as most appropriate solvents to remove soluble sugars from banana puree with the help of microwave-assisted extraction. The effects of temperature, time, and quantity of water added to NADES were evaluated. In all cases, NADES were shown to be more effective than conventional solvents (water and ethanol). Among the four NADES, malic acid:beta-alanine:water (1:1:3, molar ratio) with 30 g/100 g of water (25 °C, 30 min) was found to be the most effective in the extraction of soluble sugars from banana puree. Thus, NADES can be considered a highly efficient extraction medium for fruits (such as bananas) and can replace conventional extractions using harsher organic solvents like ethanol.

One of the desirable research goals today is to convert agro-based raw materials into low-cost functional polymers. Among the readily available natural raw materials are the fatty acids that can be obtained from the hydrolysis of plant oils or from the paper industry as byproducts. In this work, a novel iron-containing ionomer has been prepared through the reaction of fatty acids with steel dust or iron powder in the presence of carbon dioxide and water. Characterization has been achieved via 1H and 13C NMR, FT-IR, and size exclusion chromatography. The product has been shown to have an ionomeric structure, consisting of oligomers of fatty acid carboxylates (derived from Diels-Alder reaction) coupled with iron(II) and iron(III) ions (from the oxidation of iron). Because the fatty acid oligomers have low molecular weights, the ionomer easily dissolves in a solvent and can be made into different physical forms, such as liquid, solid, film, or foam.

Cardanol is a biobased raw material derived from cashew nut shell liquid. In order to extend its utility, new derivatives and additional applications are useful. In this work cardanol was first epoxidized, and a novel aniline derivative prepared from it under mild reaction conditions with the help of an ionic liquid catalyst. The reaction chemistry was studied by using nuclear magnetic resonance. The resulting aminohydrin adduct showed antioxidant property and should also be a useful synthon for further reactions. As an example, the aminohydrin was shown to undergo a condensation reaction with formaldehyde to form a prepolymer, which could be further reacted to form thermosetting resins.

Xylan is a hemicellulose, which is found abundantly in nature. In this work, a novel polyurethane was developed involving xylan and tolylene-2,4-diisocyanate (TDI). Polymer synthesis was achieved through conventional heat or microwave-assisted reaction in dimethyl sulfoxide. Because xylan has multiple OH groups on each polymer chain, the TDI/xylan molar ratio had to be adjusted to produce a soluble polymeric product. The reaction products were characterized by 13C NMR, FTIR, thermogravimetric analysis, and differential scanning calorimetry. The xylan polyurethane was shown to exhibit improved thermal stability over xylan.

The development of edible, environmentally friendly, mechanically strong and antimicrobial biopolymer films for active food packaging has gained considerable interest in recent years. The present work deals with the extraction and deacetylation of chitin nanofibers (ChNFs) from crab shells and their utilization as reinforcing and antimicrobial agents in carboxymethyl cellulose (CMC) films. ChNFs were successfully isolated from the speckled swimming crab shells for the first time through the multistep procedures involving deproteinization, demineralization, depigmentation and mechanical disintegration. Afterward, the partially deacetylated ChNFs (dChNFs) were obtained through alkali treatment. It was found that the partial deacetylation led to the exposure of more amino groups on the surface of dChNFs and thus remarkably improved their dispersion state in an aqueous solution. The ChNF/CMC and dChNF/CMC films comprising up to 10 wt % nanofibers were prepared through the solution casting method, and their pe...

As an environmentally friendlier alternative to adhesives from petroleum feedstock, soy proteins are currently being formulated as wood adhesives. Cottonseed proteins have also been found to provide good adhesive properties. In at least some cases, cottonseed proteins appear to form greater shear strength and improved hot water resistance compared with soy proteins. In the present study, blends of soy and cottonseed proteins were prepared, and their adhesive properties were found to decrease steadily with increased levels of soy protein in the formulations. In addition, cottonseed- and soy-protein based adhesives were also formulated with xylan, starch, or celluloses to determine the influence of polysaccharide fillers on protein-based adhesive properties. In some cases, adhesive shear strength was retained even when the cottonseed or soy protein was mixed with up to 75% polysaccharide. For cottonseed protein/polysaccharide formulations, hot water adhesive resistance was retained when the blend contains about 50% polysaccharides. Soy protein formulations and its polysaccharide blends generally exhibited somewhat lower hot water resistance. In view of the ability of cottonseed protein/polysaccharide blends to retain shear strength and hot water resistance properties, these blends may provide an opportunity to decrease the amount of protein used in adhesive formulations, thereby decreasing cost.

Soy protein is currently being used commercially as a “green” wood adhesive. Previous work in this laboratory has shown that cottonseed protein isolate, tested on maple wood veneer, produced higher adhesive strength and hot water resistance relative to soy protein. In the present study, cottonseed protein and soy protein isolates were tested on different wood types, and cottonseed protein again showed better performance relative to soy protein. Furthermore, the effects of several protein modifiers were evaluated, including amino acids, fatty acids, and other organic molecules with cationic or anionic charges. Aspartic acid, glutamic acid, acetic acid, butyric acid, and adipic acid gave improved performance when included with cottonseed protein isolate whereas no significant effect was observed on soy protein isolate. Both dry adhesive strength and hot water resistance were tested. The enhanced performance observed with these additives provides an additional incentive for the use of cottonseed protein in this application.

Pathogen detection is a critical point for the identification and the prevention of problems related to food safety. Failures at detecting contaminations in food may cause outbreaks with drastic consequences to public health. In spite of the real need for obtaining analytical results in the shortest time possible, conventional methods may take several days to produce a diagnosis. Salmonella spp. is the major cause of foodborne diseases worldwide and its absence is a requirement of the health authorities. Biosensors are bioelectronic devices, comprising bioreceptor molecules and transducer elements, able to detect analytes (chemical and/or biological species) rapidly and quantitatively. Electrochemical immunosensors use antibody molecules as bioreceptors and an electrochemical transducer. These devices have been widely used for pathogen detection at low cost. There are four main techniques for electrochemical immunosensors: amperometric, impedimetric, conductometric, and potentiometric. Almost all types of immunosensors are applicable to Salmonella detection. This article reviews the developments and the applications of electrochemical immunosensors for Salmonella detection, particularly the advantages of each specific technique. Immunosensors serve as exciting alternatives to conventional methods, allowing "real-time" and multiple analyses that are essential characteristics for pathogen detection and much desired in health and safety control in the food industry.

The interest in natural product-based wood adhesives has been steadily increasing due to the environmental and sustainable concerns of petroleum-based adhesives. In this work, we reported our research on the utilization of water-washed cottonseed meal (WCM) as wood adhesives. The adhesive strength and water resistance of WCM adhesive preparations on poplar, Douglas fir, walnut, and white oak wood veneers were tested with press temperatures of 80, 100, and 130 °C. Our data indicated that raising the hot press temperature from 80 to 100–130 °C greatly increased the bonding strength and water resistance of the WCM adhesives. The general trend of the adhesive strength of WCM on the four wood species was Douglas fir > poplar ≈ white oak > walnut. The rough surface of Douglas fir with tipping features could enhance the mechanical interlocking between the wood fibers and adhesive slurry, contributing to the high adhesive strength. The dimensional swelling of the bonded wood pairs due to water soaking was...

Polymer films made from cellulose esters are useful for embedding plant essential oils, either for food packaging or air freshener applications. Studies and testing were done on the physical and mechanical properties of cellulose ester-based films incorporating essential oils (EO) from lemongrass (Cybopogon citratus), rosemary pepper (Lippia sidoides) and basil (Ocimum gratissimum) at concentrations of 10 and 20% (v/w). Results obtained showed that, in all films, the addition of the essential oil caused a decrease in the water vapor permeability due to the hydrophobic nature of the oil. The use of 20% of EO caused lower transparency of the films, although the change was not observed visually. Mechanical testing was done on cellulose acetate, cellulose acetate propionate and cellulose acetate butyrate. It was found that incorporation of lemongrass, basil and rosemary pepper EO significantly affected the Young's modulus, tensile strength and elongation at break of the cellulose ester films. The results suggested that the essential oils interacted with the polymers like plasticizers. The results were confirmed with thermal and microscopic studies.

The thermal and catalytic processes of converting waste plactics into fuels are promising techniques to eliminate the refuse which otherwise is harmful to the enivironment, and decrease the dependence on fossil fuels. Thermal degradation decomposes plastic into three fractions: gas, crude oil, and solid residue. Crude oil from non-catalytic pyrolysis is usually composed of higher boiling point hydrocarbons. The optimization of conversion parameters such as the choice of catalyst, reactor design, pyrolysis temperature, and plastic-to-catalyst ratio plays a very important role in the efficient generation of gasoline and diesel grade fuel. The use of a catalyst for thermal conversion lowers the energy required for conversion, and the catalyst choice is important for efficient fuel production. The suitable selection of catalysts can increase the yield of crude oil with lower hydrocarbon content. Co-pyrolysis of plastics with coal or shale oil improves crude oil quality by decreasing its viscosity. A large number of publications have appeared on various processes, and continued improvements and/or innovations are expected in the future. Further investigations on the catalytic systems are required in order to advance the field, particularly to enhance the added value of fuels and to minimize the use of energy. This review aims to provide both the highlights of the remarkable achievements of this field and the milestones that need to be achieved in the future.

Micro and mesoporous materials are often used in catalysis, purification, composite filler, and other applications. Almond shell is an important agricultural byproduct that can be transformed to microporous and mesoporous carbon. In this work, we produced biochar from almond shell using a thermal treatment procedure in an inert atmosphere and characterized the pores with nitrogen adsorption, environmental SEM, and 129Xe NMR. The latter technique differentiates adsorbed and nonadsorbed xenon and permits the correlation of different processing conditions with xenon adsorption and diffusivity. The relevance of removing the ash produced during the charring process has been included in the study. Moreover, the xenon exchange between meso- and micro-pores has been directly observed by 129Xe NMR, demonstrating that after ash removal by water the materials have high accessibility of the pores by external fluids, thus increasing the usefulness as filtration or adsorption material.

The interest in biobased wood adhesives has steadily increased in recent years. Our previous studies have shown that water-washed cottonseed meal (WCSM) could be used as low-temperature and high-solid content biobased wood adhesives for non-structural bonding as European Standard Class D1 adhesives. In this work, we optimized WCSM-based adhesive formulations with high solid contents up to 49% for bonding of small wood items at low temperatures (40 °C). Chemical denaturing reagents guanidine hydrochloride (GdmCl) and sodium dodecyl sulfate (SDS) were added to improve the bonding capability and viscosity of WCSM. Reviewing industry preferences, four formulations with 20% and 30% of WCSM as well as 9.6% and 19.1% of SDS were used to glue “real world” pencil slat sandwiches for pencil making. All the pencils made from these sandwiches bonded at 40 °C and 1 MPa for 120 min passed the Industrial Temperature Cycle test. The results indicated that WCSM could be used as a low temperature wood adhesive, possibly for the domestic furniture and small utensils niche markets. The pencil sandwich bonding represents a specific application that could benefit from the non-toxic glue and also be an example of an interior application.

Water washing of cottonseed meal is more cost-efficient and environmentally friendly than protein isolation by means of alkaline extraction and acidic precipitation. Thus, water-washed cottonseed meal (WCSM) is more promising as biobased wood adhesives. In this work, we examined the effects of the particle size on the morphology and adhesive performance of WCSM. Pilot-scale produced and dried WCSM was treated by three grinding methods: (1) ground by a hammer mill and passed through a 0.5-mm screen, (2) further ground by a cyclone mill and passed through a 0.5-mm screen, or (3) further ground by a ball mill and passed through a 0.18-mm screen. Micro-morphological examination revealed two types of particles. The filament-like particles were mainly fibrous materials from residual linters. Chunk-like particles were more like aggregates or accumulations of small particles, with proteins as the major component. Further grinding of the 0.5-mm Hammer product with the Cyclone and Ball mill led to more fine (smaller) particles in the WCSM products. The impact of further grinding on the dry and soaked adhesive strengths was minimal. However, the decrease of the hot and wet strengths of WCSM products by the additional grinding was significant (p ≤ 0.05). Data presented in this work is useful in developing the industrial standards of WCSM products used in wood bonding.

In this work, a microwave-assisted method was developed to prepare polyurethanes from starch or maltodextrin and tolylene-2,4-diisocyanate (TDI). As compared to conventional heating, this new synthetic procedure saves energy, significantly reduces reaction time, and yet entails product yields that are comparable to those of the conventional heating procedure. The reaction products were characterized with NMR, FT-IR, thermogravimetric analysis, and scanning electron microscopy. From these analyses, the polyurethanes made with the conventional and microwave methods are shown to be similar in chemical structure and physical morphology. Furthermore, the 1H and 13C NMR spectra of the starch polyurethanes have been fully assigned for the first time.

Cottonseed meal-based products show promise in serving as environment-friendly wood adhesives. However, their practical utilization is currently limited due to low durability and water resistant properties. In this research, we tested the improvement of adhesion strength and water resistance of cottonseed meal-based adhesives by the addition of tung oil. Our data showed that the shear strength of maple wood strips glued at 100 °C by water-washed cottonseed meal (WCM) and cottonseed protein isolate (CSPI), containing tung oil, increased by 19.9% and 21.1%, respectively, compared to the tung oil-free adhesive controls. After 2 cycles of water soaking, the average of the soaked shear strength of glued maple specimens with WCM/tung oil adhesives was 3.49 MPa, representing a water resistance improvement of 46.6%, compared to the control value (2.38 MPa). For this study, the hot-press temperature (100–130 °C) was not critical for improving the water resistance of WCM or CSPI with tung oil. Optical microscopy images of the bondlines and interface showed that the improvement of adhesion strength and water resistance of cottonseed meal-based adhesives were due to the tung oil's prevention of the adhesives from diffusing away from the bond joints, while water soaking diffused the bondline, leading to weaker bond strength. The addition quantities of tung oil varied from 0.05 to 1.0% (w/v) and we observed little influence on improving the adhesive strength values, therefore, we recommend the addition of 0.1% tung oil for economics and convenience. The results of this research provide useful information on cottonseed meals as one of renewable sources of wood adhesives.

To expand the use of cottonseed protein in animal feeding, cottonseed meal was extracted with acetone- and ethanol-based solutions to remove gossypol. Phosphoric acid and water were included in the solutions to catalyze the hydrolysis of protein-bound gossypol. Both solvents were effective at reducing the total gossypol level in meal to between 5% and 10% of its initial value. Gossypol extraction occurred much faster in the ethanol-based extractions than it did in the acetone-based extractions. Treated meals tended to retain phosphorus but most of this could be removed by conducting a final water wash. Water washing also removed hydrophilic components resulting in reduced product yields but increased protein levels. Other acids, e.g., oxalic, citric, or sulfuric acid, were also effective at reducing meal gossypol. In contrast, extractions conducted without acid were not effective. The process can be used to produce low-gossypol cottonseed meals that should be useful in a broader range of feed applications.

Poly(lactic acid), (PLA), is a well known bioplastic derived from agri-based renewable materials. Because PLA's material properties depend largely on its tacticity, an improved test method for PLA tacticity would be useful. NMR analysis of PLA tacticity is revisited in this work, especially the assignments of NMR peaks from CH carbon and CH3 proton at the tetrad level in deuterated pyridine. The methyl protons are better resolved in pyridine due to solvent effects such as ring current shielding of the aromatic ring and electric field effect from the nitrogen lone pair. As an aid for the tacticity assignments, two-dimensional NMR spectra of poly(DL-lactic acid) (L/D = 50/50) and relative intensities of PLA samples have been used. The new assignments provide more detailed understanding of the 1H and 13C NMR spectra of PLA.

There is current interest in reducing the trans fatty acids (TFA) in hydrogenated vegetable oils because consumption of foods high in TFA has been linked to increased serum cholesterol content. In the interest of understanding the TFA levels, hydrogenation was carried out in this work on soybean oil and cottonseed oil at two pressures (2 and 5 bar) and 100 °C using commercially available Ni, Pd, and Pt catalysts. The TFA levels and the fatty acid profiles were analyzed by gas chromatography. The iodine value of interest is ~70 for all-purpose shortening and 95–110 for pourable oil applications. In all cases, higher hydrogen pressures produced lower levels of TFA. In the range of 70–95 iodine values for the hydrogenated products, the Pt catalyst gave the least TFA, followed closely by Ni, and then Pd, for both oils. For all three catalysts at 2- and 5-bar pressures and 70–95 iodine values, cottonseed oil contained noticeably less TFA than soybean oil; this is probably because cottonseed oil contains a lower total amount of olefin-containing fatty acids relative to soybean oil. Approximate kinetic modeling was also done on the hydrogenation data that provided additional confirmation of data consistency.

Water- and phosphate buffer (35 mM Na 2 HPO 4 /NaH 2 PO 4 , pH 7.5)-washed cottonseed meals (abbreviated as WCM and BCM, respectively) could be low-cost and environmentally friendly protein-based adhesives as their preparation does not involve corrosive alkali and acid solutions that are needed for cottonseed protein isolate (CSPI). In this work, we comparatively tested the adhesive shear strength and water resistance properties of WCM, BCM and CSPI on two hard wood veneers, maple and poplar, at press temperatures of 80, 100, 110 and 130 °C and a press pressure of 2.8 MPa. The adhesive behaviors of the three adhesives on maple and poplar veneers were similar, although not always identical. Both the adhesive shear strength and water resistance properties of the three adhesives improved with the increase of press temperature from 80 °C to over 100 °C. However, raising the press temperature improved the water resistance properties of WCM and BCM more than that of CSPI. With a press temperature of 110 °C, the adhesive shear strength and water resistance properties of WCM on both maple and poplar veneers were comparable to those of CSPI. Thus, the low-cost preparation of WCM, in comparison to the CSPI preparation, is a strong candidate for substituting synthetic wood adhesives. FT-IR spectra showed higher contents of carbohydrate in WCM and BCM than in CSPI. Cross-linking reactions between carbohydrate and protein at higher press temperatures (≥100 °C) may have contributed to the improvement of the water resistance properties of WCM and BCM.

For better understanding of the adhesive properties of different fractions of cottonseed protein, cottonseed meals from both glanded and glandless cotton varieties were separated into several fractions. Each meal was sequentially extracted with water and 1 M NaCl solution, or with phosphate buffer and NaCl solution. Adhesives were prepared from the recovered fractions and hot-pressed onto maple veneer strips and tested for their properties. The adhesive strength of the water- and buffer-washed solid fractions (i.e., the un-extractable residues of the meals) from the glanded seed ranged from 1.32 to 1.62 MPa and were unchanged or increased compared with the adhesive strength of the original meal that varied from 0.98 and 1.49 MPa. Soaking the wood specimens bonded at 80 °C revealed that the water resistance of these water- and buffer-washed adhesives was significantly improved in that they exhibited no delamination during soaking compared with the meal adhesive that showed some delamination (20–30 % of the samples). Furthermore, the water resistance of these fractions with wet shear strength around 1.5 MPa was comparable to that of cottonseed protein isolate (>90 % protein) when the joints were bonded at 100 °C. The preparations from glandless cottonseed meals showed similar adhesive performances. Additional extraction of the meals with NaCl solution reduced adhesive performance. The results suggest that water- or buffer-washed cottonseed meal fractions can be used as wood adhesives and would be less costly to prepare than cottonseed protein isolates.

Zein is a prolamine protein found in corn and has good potential in the development of industrial bioplastics. In this work, zein was modified with several isocyanates and diisocyanates in solution to evaluate its potential usage in bioplastics. The major reaction pathways were identified with the help of NMR and FTIR. For all the isocyanates employed, the surface free energy of the modified zein decreased, which phenomenon indicates decreased hydrophilicity. The moisture uptake decreased with isocyanate and diisocyanate modifications. Gel electrophoretic patterns showed that diisocyanate cross-linked a portion of zein to generate higher molecular weight species. DSC data showed single glass transition temperatures in all cases indicative that homogeneous blends were formed. The mechanical properties of modified zein were either similar to unmodified zein or reduced in some cases. Based on results from NMR and FTIR findings a reaction scheme is proposed. Our findings suggest that the reaction of zein with diisocyanates has potential usage in bioplastics formulations.

Agricultural residues are attractive raw materials for the production of industrial polymers because they are renewable and biodegradable, involve less toxic materials during manufacturing, add value to agricultural by-products, and decrease the global dependence on petroleum-based feedstock. In this work, it has been shown that agricultural residues such as wheat straw, barley straw, and rice hull can be converted to methyl cellulose, an industrial polymer used as adhesives, protective coatings, personal care, and in agriculture. Weight yields range from 30 to 70%. The degree of substitution (DS) varies from 0.8 to 2.8. In addition, the methyl cellulose can be further converted to acetylated methyl cellulose. These products have been characterized via NMR analysis.

Several modified cottonseed protein isolates were studied and compared to corresponding soy protein isolates for their adhesive properties when bonded to wood composites. Modifications included treatments with alkali, guanidine hydrochloride, sodium dodecyl sulfate (SDS), and urea. Wood composites bonded with cottonseed protein exhibited higher shear strength relative to modified or unmodified soy proteins. Cottonseed protein with SDS treatment gave comparable or better shear strength than unmodified cottonseed protein. Wood composites bonded with unmodified or SDS-modified cottonseed protein also showed superior retained strengths on a hot water test. Thus, a cottonseed protein adhesive (with or without SDS modification) seems to be a viable alternative to soy protein adhesives for wood composites.

The present work describes the isolation of cellulose nanoparticles (CNs) with different morphologies and their influence on rheological properties of CN and CN-poly (vinyl alcohol) (PVA) suspensions. Cottonseed hulls were used for the first time to extract three types of CNs, including fibrous cellulose nanofibers, rod-like cellulose nanocrystals and spherical cellulose nanoparticles through mechanical and chemical methods. Rheology results showed that the rheological behavior of the CN suspensions was strongly dependent on CN concentration and particle morphology. For PVA/CN systems, concentration of PVA/CN suspension, morphology of CNs, and weight ratio of CN to PVA were three main factors that influenced their rheology behaviors. This research reveals the importance of CN morphology and composition concentration on the rheological properties of PVA/CN, providing new insight in preparing high performance hydrogels, fibers and films base on PVA/CN suspension systems.