Storage Modulus Values Research Articles

Synthesis and Characterization of a Low-Molecular-Weight Novolac Epoxy Derived from Lignin-Inspired Phenolics.

The need for renewable polymers capable of replacing their petrochemical counterparts continues to grow as sustainability concerns rise. Bisguaiacol (BG), a bioinspired alternative to bisphenol-A (BPA), has been synthesized using vanillyl alcohol and guaiacol via an electrophilic aromatic condensation. Purification provides both BG and an oligomeric coproduct with a consistent number average molecular weight and dispersity of ∼650 Da and ∼1.00, respectively. This coproduct has been well characterized as a low-molecular-weight novolac averaging five hydroxyls per molecule and was transformed into an epoxy resin suitable for use in thermosetting resins. The bioinspired thermoset produced in this work, consisting of the epoxidized coproduct and an amine curing agent (Epikure W), exhibited a glass transition temperature over 100 °C and glassy storage modulus value of ∼3 GPa at 25 °C. When compared to a commercial cresol novolac epoxy, the cured epoxidized coproduct resin shows comparable thermal and thermomechanical properties. When compared to a commercial BPA-based resin, the cured epoxidized coproduct resin shows improved mode 1 fracture values of 1.34 J m1/2 (K1C) and 448.16 J/m2 (G1C). By utilizing the coproduct strategically, the overall production of BG has the potential to become more economically feasible.

Rheological investigation of the influence of dextran on the self-assembly of lysine derivatives in water/dimethylsulfoxide mixtures

Hybrid molecular/macromolecular gels were formulated by mixing amino-acid based gelators with dextran, a nonionic bacterial polysaccharide, in mixtures of water and dimethylsulfoxide. Gelators were hydrophobic derivatives of L-lysine in which the Nα was acylated with dodecanoic acid and the Nε was acylated by benzoyloxycarbonyl or o-chloro-benzoyloxycarbonyl group. Increasing dextran concentration led to a decrease of the stationary values of storage and loss modulus of the gels. In addition, gel formation was slowed down upon increasing dextran concentration. Nevertheless, the characteristics of aggregates as well as their kinetics of growth, as deduced from rheological data, remained identical to those observed with gelator alone (mainly linear fractal aggregates and unidirectional growing mechanism) whatever dextran concentration. Raman microscopy confirmed conclusions drawn from rheological data. It was concluded that dextran macromolecules were mainly at the origin of steric hindrance with supramolecular aggregates.

Fabrication and characterization of Pickering emulsions stabilized by desalted duck egg white nanogels and sodium alginate.

The waste of salted egg white resources has always been a serious problem in the food industry. In this current study, we report on a kind of Pickering emulsion system, which was stabilized by duck egg white nanogels (DEWNs) and sodium alginate (SA), followed by which this system was crosslinked by calcium carbonate (CaCO3 ) via controlling the gluconolactone (GDL) concentrations, aiming to open up a promising route for making full use of these protein resources. The droplet size of the emulsion exhibited a reduction with an increase in SA concentrations, indicating that higher negative charges and steric hindrance was useful for a stable emulsion system. Meanwhile, the result of rheology measurement showed that storage modulus (G') values were higher than loss modulus (G″) values of the samples at higher GDL concentration, revealing the formation of elastic gel-like networks in the system, which was fabricated by SA and Ca2+ released by the CaCO3 particles. The gel-like network structure in the continuous phase improved both the freeze-thaw and thermal stability of the obtained Pickering emulsion system. Encouragingly, the Pickering high internal phase emulsions (HIPEs, φ=0.75) stabilized by DEWN/SA3 -GDL3 were prepared, which could be stored at 4°C for at least 30 days without oiling-off and creaming. These findings not only develop a green ultra-stable Pickering emulsion system but also extend the potential commercial applications of duck egg white proteins in the food, cosmetics, and pharmaceutical industries. © 2021 Society of Chemical Industry.

Ultrasound-triggered nicotine release from nicotine-loaded cellulose hydrogel

Ultrasound (US)-triggered nicotine release system in a cellulose hydrogel drug carrier was developed with three different cellulose concentrations of 0.45 wt%, 0.9 wt%, and 1.8 wt%. The nicotine-loaded cellulose hydrogels were fabricated by the phase inversion method when the nicotine and cellulose mixture in the 6 wt% LiCl/N, N-dimethylacetamide solvent was exposed to water vapor at room temperature. Nicotine was used as the medicine due to its revealed therapeutic potential for neurodegenerative diseases like Alzheimer's and Parkinson's diseases. The behavior of US-triggered nicotine release from nicotine-cellulose hydrogel was studied at 43 kHz US frequency at the changing US output powers of 0 W, 5 W, 10 W, 20 W, 30 W, and 40 W. The significant US-triggered nicotine release enhancement was noted for the hydrogels made with 0.9 wt% and 1.8 wt% cellulose loading. The matrix made with 0.9 wt% cellulose was exhibited the highest nicotine release at the 40 W US power, and differences in nicotine release at different US powers were noticeable than at 0.45 wt% and 1.8 wt% cellulose loadings. For the three cellulose hydrogel systems, the storage modulus (G′) values at the 0.01 wt% strain rate were dropped from their initial values due to the US irradiation. This reduction was proportionately decreased when the US power was increased. The deconvolution of FTIR spectra of nicotine-loaded cellulose films before and after US exposure was suggested breakage of cellulose-nicotine and cellulose-water in the matrix; thus, the stimulated nicotine release from the cellulose matrix was promoted by the US irradiation.

Physicochemical and in vitro digestibility properties on complexes of fermented wheat starches with konjac gum

In this study, the wheat starch with natural fermentation for 72 h was combined with konjac gum (KGM) at different concentrations (0, 0.1, 0.3, 0.5%, w/w), and the changes in physicochemical and digestible characteristics of the complexes were investigated. The results showed that KGM clumped fermented starch (FS) granules together and caused the FS gels to form a close network structure. The addition of KGM significantly decreased the amylose content and swelling power, and reduced peak viscosity, final viscosity, and setback value (SB), which indicated that FS-KGM complexes possessed soft gel structure and could resist the short-term retrogradation. KGM impeded the increase of relative crystallinity, retrogradation enthalpy and gel firmness of FS during storage, suggesting the long-term retrogradation of FS was retarded by KGM. All starch pastes had a weak gel-like structure, and higher storage modulus (G′) and loss tangent (tan δ) values obtained after the addition of KGM. In vitro digestion results showed that KGM could slow the hydrolysis of FS, resulting in the increase of slowly digested starch (SDS) and resistant starch (RS). In particularly, the FS-0.3KGM showed the ideal structure, the best anti-retrogradation effected, and slowest the hydrolysis.

Effects of arginine-glucose Maillard reaction products on the physicochemical and gel properties of chicken myofibrillar protein

Maillard reaction can influence the functionalities of myofibrillar protein (MP). Protein-saccharide Maillard-type conjugates improve the solubility of MP but impair its thermal gelling ability. Besides, the influences of Maillard reaction occurred between reducing sugar and free amino acids on MP were not inspected yet. In this study, arginine-glucose Maillard reaction products (MRPs) were adopted to investigate their effects on the physicochemical and gel properties of chicken MP. The results showed that Arg-Glc MRPs significantly decreased surface hydrophobicity and the content of reactive sulfhydryl group, subsequently influenced the gelling behavior and gel properties, e.g., water holding capacity and gel strength. The dynamic rheological results revealed that MRPs reduced the storage modulus value effectively. Scanning electron microscopy showed that the three-dimensional network structure of MP gel became coarser and irregular by the treatment of Arg-Glc MRPs. These results suggested that Arg-Glc MRPs have influences on both the physicochemical properties and the gel properties of MP, which may provide new information to the effects of MRPs on the water holding capacity and texture of meat products.

Investigation of frequency dependent mechanical properties of porous materials using dynamic mechanical analyzer and frequency-temperature superposition theory

In acoustic design of engineering applications - such as in the acoustic analysis of passenger vehicles - poroelastic materials are of great importance. One of the most influencing properties in determining their noise-reduction potential is the storage modulus. The purpose of this study is to examine the frequency dependence of storage modulus of selected porous acoustic materials at least up to 1000 Hz. This is executed by using the combined use of dynamic mechanical analyzer and frequency-temperature superposition theory. All other methods for measuring the storage modulus fall short in determining frequency-dependence above 100 Hz: quasi-static mechanical analyzer is mostly used for determining an averaged constant value deduced from low-frequency measurements, while the usage of an electromagnetic shaker capable for high-frequency excitation may include effects of fluid motion inside the pores, thus significantly modifying the results. Frequency-temperature superposition enables to determine the storage modulus values in a wide frequency range, based on low-frequency measurements, where fluid-structure interaction is negligible. It was found that the modulus varied significantly up to and beyond 1000 Hz, and thus, acoustical characterization of these materials can be significantly improved using the proposed method. The work concludes with recommendations to improve the accuracy of the results.

Exploring the studies of charge transportation of an aromatic acid based Co(II)-Metallogel scaffold fabricated Schottky device

An efficient supramolecular metallogel of Cobalt(II) has been synthesized through the ultra-sonication technique. Cobalt(II)-salt (Cobalt acetate tetrahydrate), organic acid like terephthalic acid along with N,N-dimethyl formamide solvent are the key ingredients of the Co(II)-metallogel. The rheology-based experimental values of storage and loss modulus of the Co(II)-metallogel prove the mechanical efficiency of the metallogel-material. The chemical compositions are found through elemental investigations. The infrared spectral results help to realize the metallogel formation strategy. The electrical characteristics of the synthesized metallogel have been properly investigated. The semiconducting feature of the metallogel-material has been experimentally verified. The measured current-voltage characteristics of Cobalt(II)-metallogel (Co-TA) based thin film type metal-semiconductor (MS) junction-device shows a non-linear rectifying behaviour, representing a Schottky diode (SD) performance with promising electronic charge transport property.

Effect of substituting whey cream for sweet cream on the textural and rheological properties of cream cheese

In the manufacture of cream cheese, sweet cream and milk are blended to prepare the cream cheese mix, although other ingredients such as condensed skim milk and skim milk powder may also be included. Whey cream (WC) is an underutilized fat source, which has smaller fat droplets and slightly different chemical composition than sweet cream. This study investigated the rheological and textural properties of cream cheeses manufactured by substituting sweet cream with various levels of WC. Three different cream cheese mixes were prepared: control mix (CC; 0% WC), cream cheese mixes containing 25% WC (25WC; i.e., 75% sweet cream), and cream cheese mixes with 75% WC (75WC; i.e., 25% sweet cream). The CC, 25WC, and 75WC mixes were then used to manufacture cream cheeses. We also studied the effect of WC on the initial step in cream cheese manufacture (i.e., the acid gelation process monitored using dynamic small amplitude rheology). Acid gels were also prepared with added denatured whey proteins or membrane proteins/phospholipids (PL) to evaluate how these components affected gel properties. The rheological, textural, and sensory properties of cream cheeses were also measured. The WC samples had significantly higher levels of PL and insoluble protein compared with sweet cream. An increase in the level of WC reduced the rate of acid gel development, similar to the effect of whey phospholipid concentrate added to mixes. In cream cheese, an increase in the level of added WC resulted in significantly lower storage modulus values at temperatures <20°C. Texture results, obtained from instrumental and sensory analyses, showed that high level of WC resulted in significantly lower firmness or hardness values and higher stickiness compared with cream cheeses made with 25WC or CC cream cheeses. The softer, less elastic gels or cheeses resulting from the use of high levels of WC are likely due to the presence of components such as PL and proteins from the native milk fat globule membrane. The use of low levels of WC in cream cheese did not alter the texture, whereas high levels of WC could be used if manufacturers want to produce more spreadable products.

Upgrading Hepatic Differentiation and Functions on 3D Printed Silk-Decellularized Liver Hybrid Scaffolds.

We developed hybrid liver-specific three-dimensional (3D) printed scaffolds using a solubilized native decellularized liver (DCL) matrix and silk fibroin (SF) and investigated their ability to support functional cultures of hepatic cells. Rat livers were decellularized by perfusing detergents via the portal vein, solubilized using pepsin to form DCL, and characterized. SF blended with gelatin (8% w/v) was optimized with varying percentages of DCL to obtain silk gelatin-DCL bioink (SG-DCL). Different compositions of SG-DCL were studied by rheology for optimum versatility and print fidelity. 3D printed six-layered scaffolds were fabricated using a sophisticated direct-write 3D bioprinter. Huh7 cells were cultured on the 3D printed scaffolds for 3 weeks. 3D printed SG scaffolds without DCL along with 2D films (SG and SG-DCL) and 2D culture on tissue culture Petri dish control were used for comparative studies. The DCL matrix showed the absence of cells in histology and SEM. The combined SG-DCL ink at all of the studied DCL percentages (1-10%) revealed shear-thinning behavior in the printable range. The storage modulus value for the SG-DCL ink at all DCL percentages was higher than the loss modulus. In comparison to 2D controls, hepatic cells cultured on 3D SG-DCL revealed increased proliferation until 2 weeks and an upregulated expression of hepatocyte markers, including asialoglycoprotein receptor 1 (ASGR1). The Wnt pathway gene β-catenin was upregulated by more than 4-fold in 3D SG-DCL on day 3, while it showed a decline on day 7 as compared to 3D SG and also 2D controls. The expression of the epithelial cell adhesion molecule (EpCAM) was however lower in both 2D SG-DCL (2-fold) and 3D SG-DCL (2.5-fold) as compared to that in 2D controls. Immunofluorescence studies validated the protein expression of ASGR1 in 3D SG-DCL. Albumin (ALB) was not identified on SG scaffolds but prominently expressed in 3D SG-DCL constructs. In comparison to 2D SG, both ALB (1.8-fold) and urea (5-fold) were enhanced in cells cultured on 3D SG-DCL on day 7 of culture. Hence, the SG-DCL 3D printed scaffolds provide a conducive microenvironment for elevating differentiation and functions of hepatic cells possibly through an involvement of the Wnt/β-catenin signaling pathway.

Physicochemical and rheological properties of cooked extruded reformed rice with added protein or fiber

The effect of soy protein isolate (SPI) and dietary fibers [maize bran (MB), resistant maltodextrin (RMD)] on cooked extruded rice quality-related parameters and relating rheology to the human gastric emptying measurement of Lag phase were investigated. DSC onset temperature (To) and peak temperature (Tp) of extruded rice substituted with 20 % SPI (20SPI-ER) were higher than of extruded rice substituted with 20 % MB (20MB-ER) and substituted with 20 % RMD (20RMD-ER). Peak viscosity of 20SPI-ER was lower than that of 20MB-ER and 20RMD-ER, indicating that SPI delayed starch gelatinization. Hardness and stickiness values of cooked 20SPI-ER were significantly higher than those of the control, 20MB-ER, and 20RMD-ER. Storage modulus (G′) value of cooked 20SPI-ER was also higher than the control. It is possible that the swelling of starch granules was decreased when 20%SPI was supplemented. For human gastric emptying, cooked 20SPI-ER resulted in the highest lag phase, indicating that the time of grinding and mixing in the stomach took longer for this reformed rice. Overall the soy-containing cooked extruded rices were somewhat harder than the fiber-containing rices, which may not be as appealing to consumers, though they had a slightly longer Lag phase in the stomach which could relate feeling of fullness.

Mechanical and thermal properties of cellulose nanocrystals from jute fibers reinforced epoxy composites

This study investigated the effects of loadings of cellulose nanocrystals (CNC) extracted from jute fibers on the chemical, mechanical and thermal properties of the Epoxy matrix. The CNC/Epoxy composites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrometry, tensile tests, dynamic mechanical analysis, and thermogravimetric analysis. Experimental results showed that the tensile strength, modulus, and work of fracture showed a statistically significant increase from 1 to 5 wt.% CNC loading. In addition, TG measurements revealed that the onset temperature (Tonset) and temperature at maximum decomposition rate (Tmax) for composites decreased compared to neat epoxy with increasing CNC concentration. Dynamic mechanical analysis studies showed that the storage modulus values at 35 °C and 120 °C decreased for lower 1 wt% CNC content sample compared to neat epoxy, then increased for samples loaded with 3 and 5 wt% of CNC.

Effect of natural deep eutectic solvents on thermal stability, syneresis, and viscoelastic properties of high amylose starch

This work aimed to use natural deep eutectic solvents to modify the thermal, textural, freeze-thaw, and rheological properties of high amylose rice starch. Three different natural deep eutectic solvents (NADES) composed of sugar and organic acids were applied to modify the properties of starch dispersion. In presence of NADES, the onset temperature of starch was decreased, in comparison with starch in aqueous and glycerol medium. During thermal decomposition, starch with the aqueous and glycerol systems showed two-step weight losses whereas with NADES starch showed single-stage weight losses or decomposition. Moreover, negligible syneresis was observed for starch-NADES dispersion after 3rd cycle of the freeze-thaw process. The flow behavior of starch-NADES dispersion follows Herschel–Bulkley models as R2 (0.996 ≤ R2 ≤ 0.999) are higher than the Mizrahi-Berk model. The flow behavior index (n) of starch-NADES dispersion was closer to 1, indicated a nearly Newtonian fluid. The loss modulus (G″) value of starch-NADES dispersions was markedly higher than the corresponding storage modulus (G′) value and thus materials behaved like viscoelastic liquid. The present study manifested a green way to modify the properties of the high amylose starch to improve the processing stability.

Cellulose Nanocrystals vs. Cellulose Nanofibers: A Comparative Study of Reinforcing Effects in UV-Cured Vegetable Oil Nanocomposites.

There is an opportunity to use nanocellulose as an efficient renewable reinforcing filler for polymer composites. There have been many investigations to prove the reinforcement concept of different nanocellulose sources for thermoplastic and thermoset polymers. The present comparative study highlighted the beneficial effects of selecting cellulose nanofibers (CNFs) and nanocrystals (CNCs) on the exploitation properties of vegetable oil-based thermoset composite materials—thermal, thermomechanical, and structural characteristics. The proposed UV-light-curable resin consists of an acrylated epoxidized soybean oil polymer matrix and two different nanocellulose reinforcements. High loadings of up to 30 wt% of CNFs and CNCs in irradiation-cured vegetable oil-based thermoset composites were reported. Infrared spectroscopy analysis indicated developed hydrogen-bonding interactions between the nanocellulose and polymer matrix. CNCs yielded a homogeneous nanocrystal dispersion, while CNFs revealed a nanofiber agglomeration in the polymer matrix, as shown by scanning electron microscopy. Thermal degradation showed that nanocellulose reduced the maximum degradation temperature by 5 °C for the 30 wt% CNC and CNF nanocomposites. Above the glass transition temperature at 80 °C, the storage modulus values increased 6-fold and 2-fold for the 30 wt% CNC and CNF nanocomposites, respectively. In addition, the achieved reinforcement efficiency factor r value for CNCs was 8.7, which was significantly higher than that of CNFs of 2.2. The obtained nanocomposites with enhanced properties show great potential for applications such as UV-light-processed coatings, adhesives, and additive manufacturing inks.

Thermal, dynamic-mechanical and electrical properties of UV-LED curable coatings containing porcupine-like carbon structures

In this work, multi-functional coatings based on a UV-LED curable epoxy-acrylate resin and different loadings (namely, 1, 2.5, 5 and 10 wt%) of carbonaceous structures having a peculiar porcupine (PuP)-like morphology were formulated and thoroughly characterized through thermal, dynamic-mechanical and electrical analyses. More specifically, biochar-based particles derived from cellulose nanocrystals were modified through the growth of carbon nanofibers onto their outer surface, aiming at combining the effects of globular and high aspect ratio structures in a single filler. The preliminary characterization of the carbonaceous structures documented the achievement of a highly carbonized material involving spherical biochar particles having an average diameter ranging from 15 to 20 µm, covered by fibers displaying length up to 100 µm. As assessed by dynamic-mechanical characterization, the UV-LED cured composite films showed a progressive increase of the storage modulus values as a function of the amount of embedded PuP structures, indicating a strong level of interfacial interactions between the polymer network and the particles. Furthermore, the introduction of increasing amounts of PuPs induced a progressive increase of the material thermal conductivity (from 0.109 W/mK for unfilled cured resin, up to 0.161 W/mK, for the composite film containing 10 wt% of filler) and a remarkable enhancement of the electrical conductivity (up to (3.1 ± 0.2)*10−2 S/m, for the composite film containing 10 wt% of filler), thus pointing out the effectiveness of the proposed approach of surface modifying biochar particles in obtaining composite coating films with superior properties.

Multi-Scale Analysis of Changes in Crack-Free Flattened Moso Bamboo After Saturated Steam Treatment and Flattening Process

ABSTRACTIn this study, Moso bamboo was firstly softened by saturated steam and then pressed flat by a machine. The modification effect (high-temperature saturated steam) was characterized by FTIR, XRD, SEM, and wet chemistry. The dynamic mechanical analysis (DMA) was used to investigate the effects of three variables (temperature, time, and moisture content) on the thermal-mechanical properties of Moso bamboo. The results indicated that high-temperature saturated steam can effectively soften bamboo cells under high pressure at high temperature. As expected, in comparison with reference samples, the content of hemicellulose and cellulose decreased, while that of relative lignin increased. The results of the changes in main chemical composition were further confirmed by FTIR, which showed that the intensity of the main peak belongs to hemicellulose decreased, so the polysaccharide such as hemicellulose went through the process of hydrolysis and pyrolysis. An increase in the moisture content of bamboo led to a decrement in storage modulus value, which can be attributed to the plasticizing effect. Both temperature and time had a positive effect on the reduction in glass transition temperature. This conclusion not only helps to understand the relationship between bamboo and water, but also provides guide for the utilization and production process of crack-free flattened bamboo board and its products in the construction and building fields.

The rheological characteristics of soy protein isolate-glucose conjugate gel during simulated gastrointestinal digestion

• Gels were prepared using soy protein isolate-glucose conjugates cross-linked by transglutaminase. • The mechanical properties of gels were increased by glycation with limited reaction time. • The rheological properties of SPI-glc conjugate and mixture gels after in vitro gastrointestinal digestion have been studied. • Conjugate gels had slower gastric digestion kinetics than gel prepared by SPI-glc mixture. • There were no differences in simulated intestinal digestion among SPI-glc conjugate and mixture gels. In this study, soybean protein isolate (SPI) and glucose (glc) were conjugated by wet Maillard reaction at 95 °C for 0–6 h with a mass ratio of 1:2. The degree of grafting and SDS-PAGE of SPI-conjugates were studied and a highest degree of grafting (23.14 %) was achieved at reaction time of 4 h. Gels were then prepared by crosslinking SPI-glc mixture or conjugates using transglutaminase, and their mechanical properties were charactered by hardness and gumminess. To further study the impact of conjugation on the gastrointestinal digestion of gel, rheological properties of gels after in vitro gastric and intestinal digestions were evaluated through amplitude and frequency sweep tests. Compared with SPI and SPI-glc mixture, gels formed by conjugates with 1 h and 4 h reaction time showed significantly higher viscosity, storage modulus (G') and complex modulus (G*) values after gastric digestion, indicating that these conjugate gels had slower gastric digestion kinetics. There were no significant differences among these samples in simulated intestinal digestion. Therefore, the SPI-glc conjugate gels may have great potential to be used for gastric delivery.

Improvements in thermal and mechanical properties of composites based on thermoplastic starch and Kraft Lignin

Thermoplastic starch (TPS) is a widely studied biopolymer as an alternative to the use of conventional polymers. In this sense, the incorporation of fillers or reinforcements coming preferably from other substances of natural origin, can be an alternative to try to improve some mechanical and thermal properties of starch polymers. Thus, Kraft Lignin (KL), can be an excellent filler to be incorporated, since it presents mechanical and thermal properties and reduces the cost and weight of the final compounds. TPS films were prepared by casting using dimethyl sulfoxide (DMSO) as solvent and additives with 2, 4 and 8% KL. Characterization of TPS films and compositions with KL were carried out by Fourier-Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), Dynamic Thermomechanical Analysis (DMTA), tensile testing and contact angle. Samples were also analyzed for biodegradation and for the ability to remove contaminants in water, Metil Orange (MO), by Ultraviolet-Visible Spectroscopy (UV–Vis). The FT-IR spectra of the films showed bands typical of functional groups derived from starch and lignin, with the intensity of these bands varying among the samples studied. Micrographs revealed slightly different morphologies among the films, but all showed irregular shapes with structures that appeared as plots. Increasing the percentage of KL led to an increase in contact angle values, showing a more hydrophobic behavior. In the TGA analysis, it was possible to observe a change in the main degradation event of the films for lower temperatures, especially of TPS – 4 and 8% KL compared to the TPS film. Films with KL had the peak of maximum degradation shifted to temperatures below the starch film, where the decrease in intensity of the main peak in the TPS - 4% KL and TPS - 8% KL samples demonstrates that there was less mass loss in the event. There was also in the percentage of residue as the addition of KL was increased The DMTA analyses allowed for the conclusion that presence of KL in TPS film allowed for an increase in its energy storage property, and that the loss modulus followed a decreasing order of storage modulus values to TPS - 8% KL from TPS. For the tensile strength property only TPS - 4% KL has significant improvement, and the elongation at break showed an increase for TPS – 4 and 8% KL compared to TPS. Samples showed a continuous and progressive biodegradation process, being completely biodegraded within 10 days. The monitoring of the ability to remove contaminants from water by UV–Vis, also showed promising results of compounds for this application. The best results were obtained, in most tests, for the TPS- 4% KL films.

Preparation of chemically functionalized and self compatibilized short coir fiber ‐ high density polyethylene composites

AbstractThe interphase adhesion plays key role in the performance of composites. The commonly employed strategies include blending with an external compatibilizer or utilizing chemical grafting followed by purification and copolymerization. Here, we showcase a reformed and simple approach in the fabrication of chemically functionalized, self compatibilized composites [PE‐TCF5%‐MA2%] by insitu grafting of maleic anhydride in the polymer melt, followed by the reactive compatibilization of treated short coir fiber. Micro‐structural analysis of the composites revealed enhanced fiber/matrix adhesion. The improved mechanical, viscoelastic, and thermal properties of composites can be attributed to new interfacial bond formed, which was confirmed by Fourier transform infrared [FTIR] studies. PE‐TCF5%‐MA2% exhibited approximately 74% and 25% improvement in tensile strength compared to untreated (PE‐UCF) and treated (PE‐TCF) fiber composites respectively. Dynamic mechanical analysis of composites displayed similar trend with highest value of storage modulus recorded for PE‐TCF5%‐MA2%. Final decomposition temperature of all composites was shifted to higher side. Peak degradation temperature was increased with a marginal increase of residual char. Together with the goodness of agro‐based fiber and feasiblity of this low cost method suggests the potential of PE‐TCF‐MA toward bulk industrial prodution of composite panels.

Effect of emulsifier blend on quality attributes and storage of high protein buffalo milk ice cream

High protein (10%) ice cream was developed at our lab using whey protein isolate. In comparison to conventional ice cream, it lacked severely in sensory attributes viz. flavour, meltdown and body and texture. Attempts were made to improve the quality attributes of high protein ice cream by increasing polysorbate 80 (PS80) level in the emulsifier blend (0.15%) from 0 to 100%. Increasing PS80 level resulted in significant (p < 0.05) decrease in consistency coefficient (0.85 ± 0.09 Pa sn at 0% PS80 to 0.52 ± 0.09 Pa sn at 100% PS80) and increase in loss modulus and storage modulus values. Particle size distribution revealed an increase in the mean size of fat globule clumps with increasing PS80 level (d90 4.03 μm at 0% PS80 to d90 6.72 μm at 100% PS80). Overrun and melting rate were decreased with increasing PS80. Instrumental hardness decreased when PS80 increased from 20 to 40%, however >40% PS80 led to higher hardness values. Sensory evaluation revealed that sample containing 40% PS80 in the emulsifier blend (0.06% w/w in ice cream mix) was most preferred by panelists. During storage period, high protein ice cream had lesser extent of changes in quality attributes and higher sensory acceptability than control.