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Soybean hull is an agro‐industrial residue produced abundantly both in Brazil and worldwide. It is generated during the dehulling of the grains for oil production. This work aimed to develop materials using low‐cost, abundant, and biodegradable raw materials, as soybean hull, corn starch, polyvinyl alcohol (PVA), and glycerol. Five formulations of thermoplastic starch (TPS) were produced containing between 4% and 19% of ground soybean hull and another five formulations of the same composition but with 6% PVA added. The materials were extruded and injected to produce specimens. They were analyzed by FTIR‐ATR, mechanical tests, mass loss in water, and dimensional variations. The addition of hull to the TPS did not affect the processability of the materials, and the PVA improved the processability. Hull concentration from 8% to 15% increased the tensile strength of the materials, and the PVA reduced them. Soybean hull provided greater dimensional stability to the specimens, especially with PVA and with the highest hull contents (15% and 19%).Content of soy hulls between 8% and 15% acted as a structural reinforcer of TPS materials, forming a composite, as it increased the tensile strength, reduced the elongation, increased the stiffness, and improved the dimensional stability of the materials. [ABSTRACT FROM AUTHOR]

ABSTRACT Starch and polyvinyl alcohol (PVA) are biodegradable materials with potentiality to replace the conventional polymers in some applications. The aim of this work was to produce biodegradable films of PVA, cassava starch, and glycerol by thermoplastic extrusion using a mixture design to evaluate the effects of each component in the blend properties. Six formulations were prepared using a twin-screw extruder coupled with a calender. All the materials were visually homogeneous and presented good processability. Mechanical properties were dependent on both the relative humidity conditioning and the formulation; higher relative humidities detracted the mechanical properties, which was associated to plasticizer effect of the water. Furthermore, the mechanical properties were better when higher concentrations of PVA were used, resulting in films with lower opacity, lower water vapor permeability, and higher thermal stability, according to TGA. Biodegradable materials based on starch, PVA, and glycerol have adequate mechanical and processing properties for commercial production. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42697. [ABSTRACT FROM AUTHOR]

Mixtures of starch and other polymers have been used to produce biodegradable materials with low-cost and enhanced properties. In this study, films containing starch mixed with alginate (ALG) and/or polyvinyl alcohol (PVOH) were characterized. Films produced using binary starch-alginate mixtures (F3, F5, and F9) had the highest tensile strength (19-28 MPa) and elongation capacity (22-17%). However, films produced using ternary starch-alginate-PVOH mixtures (F8 and F9) exhibited the best water-barrier efficacy, with lower water-vapor permeability (WVP) values (5 × 10 and 5.56 × 10−13 g/s/Pa/m1, respectively) than that of the starch films (23.60 × 10−13 g/s/Pa) and diffusion coefficient ( Dw) values approximately seven times lower than that of films produced solely with starch. The results of the infrared analyses showed a decrease in the band representing OH stretching in films created using ternary starch-alginate-PVOH mixtures, suggesting interaction between the polymers. The films containing starch mixed with ALG and PVOH showed low monolayer. The results indicated that ternary blends created better physical barriers to the passage of water vapor and diminished the availability of active sites for water binding. The optimal proportions were found to be 80% starch, 11.4% ALG and 8.6% PVOH. [ABSTRACT FROM AUTHOR]

Blends of starch with polyesters have commonly been used in the production of biodegradable films. However, the components in the blend are not always miscible; therefore, the use of compatibilisers is recommended. The objective of the present work was to study the compatibilisation effect of adipic acid (0.5%; 1.0%; 1.5% (w/w)) on films consisting of starch/glycerol/poly (butylene adipate-co-terephthalate) ( PBAT) produced by reactive extrusion. Films compatibilised with adipic acid exhibited statistically significant increase in tensile strength (from 7.28 to 8.45-9.13 MPa), elongation (in this case only with 0.5% of adipic acid) (516.51-679.10%), Young's modulus (21.72-28.75 MPa) and reduction in water vapour permeability (9.76-8.32 × 10−11 g per s.m.Pa) compared with the control film, which lacked the compatibiliser. Films produced using the compatibiliser also presented a microstructure with fewer cracks. There were no differences in the thermal degradation and crystallinity profile of the films. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to produce thermoplastic starch (TPS) films and to enhance their properties by reinforcing them with hydrophilic and hydrophobic nanoclays. TPS films were prepared by extrusion and thermopressing, and their crystallinity, water vapor permeability (WVP), and mechanical properties were studied. The hydrophilic nanoclay lowered the material WVP due to the formation of an intercalated composite. The hydrophobic nanoclays increased the rigidity of the films but did not alter the tensile strength. The blending of nanoclays with thermoplastic starch modifies the mechanical properties and WVP, and these changes are strongly associated with the dispersion of nanoclay in the polymer matrix. The dispersion, in turn, depends on the compatibility of the matrix and the nanoclay in terms of the hygroscopicity and the concentration in which the nanoclay is used. The addition of nanoclays to starch-based films is a promising way to enhance them for industrial manufacture. [Copyright &y& Elsevier]

Soybean hull is an agro-industrial residue of extensive generation in the soybean oil-producing industry, where approximately 5% of the processed volume of soy beans is converted into hulls. The main use for soy hulls is animal feed, being of great importance to find more ways of consumption for the hulls. This research proposed a noble application for soy hulls: using the hulls as a source for extracting cellulose fibers. Cellulose fibers were extracted from the hulls by alkaline treatment, ground (< 600 µm) and added to thermoplastic starch (TPS). Polyvinyl alcohol (PVA) was also added to the materials produced in order to promote better compatibility between the components. Ten formulations were produced, containing between 4 and 19 wt% of cellulose, and 2 controls. Half of the formulations contained 6 wt% PVA. Cellulose fibers and soybean hulls were characterized by FTIR-ATR and SEM, and the analyzes showed partial purification of the cellulose fibers, with a purity of 92 wt%. The composites were produced by extrusion followed by injection, and characterized by stress-strain, FTIR-ATR and dimensional stability after injection (shrinkage and warpage) tests. Cellulose fibers did not increase the tensile strength (TS) of the composites, but reduced the deformation capacity by 62% (to 19% of fibers) compared to the control. Cellulose fibers together with PVA increased the TS by up to 22% (to 19% fibers and 6% PVA in the composition), making the material more mechanically resistant. For this same formulation, the deformation capacity was reduced by a maximum of 75%, and the modulus of elasticity was increased by a maximum of 230% (the composite became more resistant and rigid). Cellulose fibers reduced the shrinkage value of the specimens, reducing the shrinkage value to less than 1% for the formulations containing 19% cellulose fibers. The cellulose fibers associated with 6% PVA had a synergistic action in the shrinkage of the specimens, further reducing the shrinkage in length (0.4% length shrinkage for 15% cellulose fibers; 0.1% length shrinkage for 19% cellulose fibers). The addition of cellulose fibers and 6% PVA to TPS made the composites more rigid and mechanically reinforced, and also with greater dimensional stability after injection. • Soybean hulls are an agro-industrial residue that requires new destinations. • PVA contributes to improving the properties of TPS materials containing cellulose. • Cellulose fibers and PVA practically zeroed the shrinkage of the specimens. [ABSTRACT FROM AUTHOR]

A mixture design was used to analyse the effects of polyvinyl alcohol (PVA) on glycerol-plasticised cassava starch sheets obtained by flat extrusion from a twin-screw extruder. PVA was the main component that improved the properties of the sheets, and glycerol presented the opposite effect. The properties ranging: tensile strength (0.22-1.5 MPa), Young's modulus (0.45-7.29 MPa), elongation at break (59-111%), puncture resistance (10-107 N/mm), puncture elongation (5.64-10.13 mm), crystallinity index (17-21%) and water vapour permeability (3.39-7.40 × 10−5 g m−1 day−1 kPa−1) for the sheets. Scanning electron microscopy showed good compatibility between the components of the blend because the resultant materials were continuous and cohesive and did not exhibit phase separation. The sheets were not significantly different from others, based on XRD and FTIR analyses, consistent with the literature. PVA was able to improve the mechanical and barrier properties of starch-based sheets. [ABSTRACT FROM AUTHOR]

Abstract: Biodegradable films were produced using the blown extrusion method from blends that contained cassava thermoplastic starch (TPS), poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) with two different extrusion processes. The choice of extrusion process did not have a significant effect on the mechanical properties, water vapor permeability (WVP) or viscoelasticity of the films, but the addition of PLA decreased the elongation, blow-up ratio (BUR) and opacity and increased the elastic modulus, tensile strength and viscoelastic parameters of the films. The films with 20% PLA exhibited a lower WVP due to the hydrophobic nature of this polymer. Morphological analyses revealed the incompatibility between the polymers used. [Copyright &y& Elsevier]

The valorisation of agro-industrial by-products can be used as an alternative source for producing healthy food ingredients and materials. The volatile profile measured by headspace solid-phase microextraction-gas chromatography-mass spectrometry, mechanical, antioxidant and antibacterial properties of biodegradable cassava starch film extruded with the addition of different percentages of apple pomace (AP) by-product were evaluated. Characteristic volatile compounds were identified in the samples, such as α-farnesene, sulcatone and ethylphenyl propanoate. The film containing 8% AP had higher total phenolic content (3.32 mg GAE/g, Gallic acid equivalent) and antioxidant activity (2.78 mmol Trolox/g) than the control film (0.71 mg GAE/g and 1.03 mmol Trolox/g). The minimum inhibitory concentration against Staphylococcus aureus , Salmonella thyphimurium , and Escherichia coli for the films containing AP was higher than 12.5 mg/mL for all species. The results suggest that the antioxidant and antibacterial activities and mechanical properties, are dependent on the quantity of the AP added to films. Due to its antioxidant activity and mechanical properties, the AP could have real potential use as a functional ingredient in biodegradable packaging with the advantage of having good antibacterial properties. [Display omitted] • A new functional biodegradable film was obtained with apple pomace. • A large number of phenolics from apple pomace remained in the extruded films. • Film's antioxidant activity was dependent on apple pomace concentration. • Apple pomace could improve the biological properties of extruded films. • Suitable mechanical proprieties were observed in films with apple pomace. [ABSTRACT FROM AUTHOR]