The morphology,rheological, and mechanical properties of wood flour/starch/poly(lactic acid) blends

An entirely biosourced blend composed of poly(lactic acid) (PLA), starch, and wood flour (WF) was prepared by a co‐extruder with glycerol as a plasticizer. The morphology, rheological properties, and mechanical properties of the WF/starch/PLA blends were comprehensively analyzed. The results showed that with the decrease of the starch/WF ratio, the morphology experienced a large transformation, and the compatibility of the blends was found to be superior to other blends, with a starch/wood flour ratio of 7/3. The dynamic mechanical thermal analysis (DMA) results demonstrated the incompatibility of the components in WF/starch/PLA blends. Following the decrease of the starch/WF ratio, the storage modulus (G″) and the complex viscosity (η*) of the blends increased. The mechanical strength first increased, and then decreased with the increase of the WF concentration. The water absorption results showed that the water resistance of the blends was reduced with the lower starch/WF ratio. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44743.     

Mechanical and thermal properties,morphology and relaxation characteristics of poly(lactic acid) and soy flour/wood flour blends

Poly(lactic acid) (PLA) is a biodegradable polymer derived from sugar‐based materials, and its applications are varied. PLA blends are commonly employed to overcome certain disadvantages such as poor impact strength, low heat distortion temperature, poor processability and relatively high cost. In this study, blending PLA with soy flour (SF), wood flour (WF) and sodium bisulfite‐modified SF was used to improve the adhesion to PLA. In all cases, 0.5 wt% methylenediphenyl diisocyanate (MDI) was used as a coupling agent. Mechanical and thermal properties, morphology and relaxation characteristics of the blends were investigated. The results showed that MDI was an effective coupling agent for the WF/PLA system in improving tensile strength and elongation. Differential scanning calorimetry results indicated that SF and modified SF act as nucleation agents and facilitate the crystallization behavior of PLA by increasing the percentage crystallinity. From mechanical relaxation of the temperature‐variant system, we determined how the mechanical relaxation time evolves during the course of heating and obtained the Kohlrausch–Williams–Watts parameter and activation energy (ΔE). PLA and its blends exhibited highly homogeneous relaxational dynamics in their transition from glass to liquid, and ΔE of PLA and its blends is mainly affected by their densities and compositions. Copyright © 2010 Society of Chemical Industry     

Preparation of resistant starch/poly(vinyl alcohol) blend films with added plasticizer and crosslinking agents

We report on the physical properties of films synthesized with native corn starch (NCS) and resistant starch (RS4) prepared with NCS. NCS and RS4/poly(vinyl alcohol) (PVA) blend films were synthesized with a mixing process and casting method. Glycerol (GL) and citric acid (CA) were used as additives. Glutaraldehyde (GLU) was used as a crosslinking agent of the films. RS4 was synthesized with sodium trimetaphosphate and sodium tripolyphosphate as a crosslinker. Then, the RS4 thus synthesized was confirmed by the pancreatin–gravimetry method, swelling power, differential scanning calorimetry, and X‐ray diffraction. The tensile strength, elongation, swelling behavior, and solubility of the films were measured. The results of the measurements indicated that the RS4‐added film was better than the NCS‐added film. In particular, the RS4/PVA blend film with CA as an additive showed physical properties superior to those of the other films. Also, the physical properties with GLU added as a crosslinking agent to the films were investigated. With increasing GLU contents, the tensile strength increased but the elongation, swelling behavior, and solubility values of the GL‐added and CA‐added films decreased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Surface characterization of glass and poly(methyl methacrylate) soiled with a mixture of fat,oil, and starch

Micro-organisms on food contact surfaces provide a 'biotransfer potential', i.e. the ability to contaminate foods during processing or preparation. Surfaces coated with organic materials can act as sites for microbial attachment. This investigation into the surface properties of glass and poly(methyl methacrylate) substrates soiled with a milk powder, oil, and starch composite has found that fatty acid esters dominate the surface chemistry. A lower concentration of proteinaceous material was also detected, with the concentration dependent on both the underlying substrate and the thickness of the soiling material. The physical surface structure of the fouled surfaces showed a complicated surface topography with features of the order of tens of micrometres wide and up to 2 μm high, which increased in size with increasing thickness of the soiling layer. The features reflect bulk incompatibilities between the components of the soiling material and demonstrate the heterogeneity of the surface as presented to micro-organisms.     

Optimization of transesterification of castor oil with ethanol using a central composite rotatable design (CCRD)

In the present study, the synthesis of fatty acid esters from castor oil using an alkaline catalyst was optimized. The variables reaction time, catalyst amount and oil:ethanol molar ratio were studied using a central composite rotatable design. The effects and significance of the models on the response variable and on ethyl biodiesel yield derived from pure castor oil were evaluated using a response surface curve and analysis of variance. All the variables significantly affected the reaction yield, the amount of catalyst being the most effective. The highest yield was obtained using an oil:ethanol molar ratio of 1:11, 1.75% KOH and a reaction time of 90 min.     

Obtention and evaluation of a precooked flour of auyama (Cucurbita maxima) and rice, enriched with oleaginous proteins and/or skim milk

The purpose of the present study was the production of a precooked blend made of pumpkin squash and rice flour (PRB), processed with drum dyer. The blend was supplemented with different protein sources: soy, sesame and deffated milk. The following formulations were obtained: I) PRB + 10.5% deffated soy flour; II) PRB + 15% deffated milk; III) PRB + 5% deffated sesame flour + 10% deffated milk; IV) PRB + 5% deffated soy flour + 10% deffated sesame flour, and V) PRB + 9.5% deffated soy flour + 9.5% deffated milk. All formulations were submitted to physico-chemical, nutritional and sensorial evaluation. The protein content of the formulations varied from 14.6% to 17.9%. Rat assays gave satisfactory net protein ratio values. Soups prepared with the formulations were qualified as having good organoleptic characteristics. The production of some of the formulations described above, would contribute to a larger utilization of pumpkin, as it would allow the easy preparation of salted and sweet dishes (soups, cakes, etc).     

Self‐supporting‐film from starch,poly(vinyl alcohol), and glutaraldehyde: Optimization of composition using response surface methodology

Use of starch based biodegradable packaging film can partially reduce the landfilling problem from non‐biodegradable petroleum based alternatives. The aim of this work was to optimize raw material blend composition containing corn‐starch (CS), and low amount of poly(vinylalcohol) (PVA) and glutaraldehyde (GA) to produce self‐supporting‐film (SSF), using response surface methodology. Rotatable central composite design was used to evaluate the effect of CS (6.25–7.50), PVA (0.00–1.25), and GA (0.00–1.25), in g/100 mL of the blend, on tensile strength (TS), percent elongation (%El), and water vapor permeability (WVP) of the film. The most significant (p < 0.01/0.05) factors were: CS and GA for TS, CS and PVA for El, and PVA for WVP. The SSFs were thin, flexible and transparent; the optimum composition (g/100 mL) to maximize TS and El, and minimize WVP was 7.50 (CS), 0.875 (PVA), and 0.125 (GA), which produced SSF showing TS: 11.66 MPa, %El: 8.56, and WVP: 0.13 g mm/m² /kPa/h. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44436.     

Poly(vinyl chloride)–Acacia bark flour composite: Effect of particle size and filler content on mechanical,thermal, and morphological characteristics

This article describes the effect of filler [obtained from bark of Acacia (Babool)] content and its particle size (ranging from 100 to 150 μm and <50 μm) on the properties of poly(vinyl chloride) (PVC) composites. Bark of the fast‐growing species Acacia was used as powder for making PVC composites, which may find applications as a substitute to high‐cost wood and to avoid deforestation. A two‐roll mill was used for mixing varying amounts of bark flour with PVC formulation. Samples for testing were prepared by compression molding. Tensile strength and percentage of elongation at break decreased, whereas modulus increased with an increasing amount of bark flour. A significant increase in storage modulus (E′) was observed upon incorporation of filler. Improvement in properties was significant in the presence of filler, having a particle size <50 μm as compared to filler, having a particle size ranging from 100 to 150 μm. Morphological characterization was conducted by using scanning electron microscopy. A uniform dispersion of filler was observed in PVC matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of the extrusion process on the functional characteristics and protein quality of quinua (Chenopodium quinoa, Willd)

In order to have available a human food of high nutritive value, and conscious of the protein quality of the quinua, as well as its carbohydrate, vitamin and mineral content, its behavior during the extrusion process was tested in the present study. To eliminate saponins, a simple method was developed which consisted of washing the seeds through an aluminum container, using a wooden stirrer. Seven treatments were studied: washed quinua, washed and cooked quinua, washed and expanded quinua No. 1 and No. 2, and washed and texturized quinua No. 1 and No. 2; casein was used as control. Biological evaluation trials were carried out in Holtzman rats, following the PER method. To detect the possible effects of the processed quinua on the experimental animals, hematological as well as histopathological studies of the vital organs were performed. A maximum PER of 2.43 was obtained for the texturized quinua, 2.16 for the expanded quinua, 2.6 for the cooked quinua, while the casein control yielded a PER of 3.00. The physico-chemical characteristics of the quinua flour were determined, as well as those of the expanded and texturized products. The product obtained was subjected to an organoleptic trial and it can be stated that the results obtained were satisfactory. The product can be consumed directly without major modifications and has an acceptable flavor. The nutritive value of quinua was not impaired; it compared favorably with the best diets recommended for the population, especially of those with a lower income. The results obtained in the present study suggest the possibility of increasing the nutritional value of the product, as well as its acceptability.     

Mechanical properties and biomass carbon ratios of poly(butylene succinate) composites filled with starch and cellulose filler using furfural as plasticizer

Polymer composites consisting of poly(butylene succinate) (PBS) as matrix and corn starch (CS) or cellulose filler (CF) with a small amount of furfural (FR) from biomass were prepared by a hot‐pressing method at 120°C from a powder mixture. Mechanical properties of the composites' films were investigated using tensile test methods. The strain of these films was found to be developed by adding CS or CF and further improved by adding FR. The strain at break PBS with 15 wt % FR was improved by more than 16 times of that of PBS without FR. The biomass carbon ratios of polymer composites with oil‐based PBS (major component) and with biobased CS, CF, and FR were evaluated by ¹⁴C concentration ratio measured by accelerator mass spectrometry (AMS) based on ASTM D6866. PBS with 40 wt % CS or CF had a biomass carbon ratio of 31 and 36%, respectively. PBS with 15 wt % FR had a biomass carbon ratio of 3.4%. This deviation was confirmed by FR content calculated from the peak area of the ¹H‐NMR spectrum of PBS with FR which was 3.4%, almost the same as the biomass carbon ratio measured by AMS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Immobilization of a cyclodextrin glucanotransferase (CGTase) onto polyethylene film with a carboxylic acid group and production of cyclodextrins from corn starch using CGTase‐immobilized PE film

Carboxylic acid groups were introduced onto polyethylene (PE) film by radiation‐induced graft copolymerization. Subsequently, the clodextrin glucanotransferase (CGTase) was immobilized on the PE film with a carboxylic acid group. The activity of the immobilized CGTase on PE film was in the range of 0.40–1.04 U/cm² per min. The production of cyclodextrins (CDs) from corn starch was examined using the CGTase‐immobilized PE film. The production ratios of CDs using CGTase‐immobilized PE film was in the following order: α–CD > β–CD > γ–CD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2451–2457, 2002     

Preparation and properties of thermoplastic starch/montmorillonite nanocomposites using N,N‐bis(2‐hydroxyethyl)formamide as a new additive

N,N‐Bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new additive to prepare thermoplastic starch/montmorillonite (TPS/MMT) nanocomposites. Here, BHF acted as both plasticizer for TPS and swelling agent for MMT. The hydrogen bond interaction among BHF, starch, and MMT was proven by Fourier transform infrared (FTIR) spectroscopy. By scanning electron microscope (SEM), starch granules were completely disrupted. Atomic force microscopy demonstrated that partially exfoliated TPS/MMT nanocomposites were formed. The crystallinity of corn starch, MMT, BHF‐plasticized TPS (BTPS), and TPS/MMT nanocomposites was characterized by X‐ray diffraction (XRD), XRD demonstrated that partially intercalated TPS/MMT nanocomposites were formed. The water resistance of TPS/MMT nanocomposites increased compared with that of pure BTPS. Mechanical properties of BTPS and TPS/MMT nanocomposites were examined. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Development of poly(lactic acid) films with propolis as a source of active compounds: Biodegradability,physical, and functional properties

Active films (AFs) using poly(lactic acid) (PLA) as a polymeric matrix containing various propolis concentrations (5, 8.5, and 13%) as the active agent (AA) were developed using a casting method. The purpose was to determine the effects of the incorporation of AA on the physical properties of the films and to evaluate the antioxidant and antimicrobial activities. Tensile strength and elastic modulus of the AFs decreased relative to the control (PLA without AA). Introducing the active substances from propolis into the PLA also affected its thermal properties (glass transition). Adding AAs to the polymer generated more opacity with a green-yellowish color compared to the control. In addition, AFs exhibited reduced water vapor permeability as the AA concentration increased. Biodegradation assay showed that the AFs degraded faster than the control. AFs exhibited antioxidant activity, which was measured as the ability to scavenge free radicals (2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)), due to the presence of bioactive compounds (phenolics). Antimicrobial activity was evaluated against Escherichia coli and showed a reduction over 4-log cycles. Therefore, incorporation of propolis is a useful strategy for the development of active packaging with antioxidant and antimicrobial effects, which increase the shelf life of food products. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47090.     

Preparation and properties of thermoplastic pea starch using N,N‐bis(2‐hydroxyethyl)formamide as the plasticizer

N,N‐bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for pea starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and pea starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscope (SEM), pea starch granules were completely disrupted, and the homogeneous materials were obtained. The crystallinity of pea starch and BHF‐plasticized thermoplastic pea starch (BTPS) was characterized by X‐ray diffraction (XRD). Rheological properties of TPS were analyzed. The water resistance of BTPS was better than that of glycerol‐plasticized thermoplastic pea starch (GTPS). At RH 33%, the tensile strength of BTPS was higher than that of GTPS for TPS containing 30% plasticizer. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Optimization,equilibrium, and kinetic studies of adsorptive removal of cobalt(II) from aqueous solutions using Cocos nucifera L.

Water discharged by several industries contains toxins, and it needs to be treated before disposal or reuse. In the present study, feasibility of adsorptive removal of Cobalt(II) ion in waste water, using Cocos nucifera leaf powder, is exhaustively studied and reported. Effects of contributing parameters like Cobalt(II) ion concentration, initial solution pH, adsorbent dosage, and temperature are studied and the levels of parameters optimized, following a two level?four full-factorial experimental design with 6 center points and 24 non-center points. 15?g/L of Cocos nucifera leaf powder could reduce the Cobalt(II) ion concentration by 84.82% in 70?min at a pH of 5.0 and a temperature of 303?K. Freundlich model is marginally superior to Langmuir, Halsey, and Temkin models in representing the equilibrium, at the optimized conditions. Pseudo-second-order kinetics model describes the adsorption process with a rate constant of 0.1238?g/mg-min. From thermodynamic analysis, it is noted that the adsorption is endothermic and facilitated.     

Incorporation of a nano/micro CuO formulation into phenol formaldehyde (PF) resin: Curing kinetics,morphological analysis,and application

The effects of incorporation of nano-CuO into phenol formaldehyde (PF) resin during sythesis on curing kinetics, nano-CuO structure and bond quality were investigated on orientated strand board (OSB). Apparent activation energy of the PF resins modified with CuO was decreased during the reaction indicating an acceleration of both addition and condensation reactions. X-ray diffraction data indicated that the Cu was in a bivalent state. Morphological analysis confirmed that CuO was uniformly dispersed at both nano and micro scales. Addition of nano-CuO to PF resin was associated with significantly higher internal bond strength on OSB panels. The results suggest that nano-CuO enhances the properties of conventional PF resin to imporve panel properties.