Juliana Olivato - Academia.edu (original) (raw)

Papers by Juliana Olivato

Research paper thumbnail of Production and Characterization of Starch/PVA Blends with Bioactive Compounds from Malt Bagasse

Macromolecular Symposia

Starch is an abundant and renewable material for producing biodegradable films and, to improve th... more Starch is an abundant and renewable material for producing biodegradable films and, to improve their mechanical performance is usually blended with polymers of better performance, as poly(vinyl alcohol) (PVA). Malt bagasse or brewer spent grain is a by‐product of brewing, mostly used as animal feed, and has bioactive compounds with proven antioxidant properties. On this basis, this work aims to produce starch‐PVA blends incorporated with malt bagasse extracts of two different types of beer, Pilsen, and Weiss. The inclusion of the Weiss (WMB) and Pilsen (PMB) malt bagasse extracts has no significant influence on the water solubility of the films. FEG‐SEM images present no tendency to phase separation at the sample surfaces, with a higher roughness of samples containing PMB extracts and improved homogeneity with the presence of WMB extracts. The inclusion of the bioactive extracts, regardless of concentration, has preserved the resistance and flexibility of the blends. Thermogravimetr...

Research paper thumbnail of Application and characterisation of industrial brewing by‐products in biodegradable starch‐based expanded composites

International Journal of Food Science & Technology

SummaryConcern headed under waste management promotes the development and application of biodegra... more SummaryConcern headed under waste management promotes the development and application of biodegradable materials. Naturally occurring lignocellulosic fibres, such as malt bagasse (MB), are often low‐cost industrial by‐products with attractive properties. This work focused on extruding starch‐based expanded composites, containing two different brewing residues, Pilsen malt bagasse (PMB) and Weiss malt bagasse (WMB). Their mechanical, thermal and structural properties were evaluated. The expansion index was higher in the WMB10 extruded composite (25.73 ± 4.75), also evident in the SEM‐FEG images which show more quantity and uniformity of pores. WMB5 and WMB10 resulted in a 50% decrease in composite water solubility relative to the Control. The hardness (N) of the samples was reduced by using MB fibres of both types, producing a less stiff and brittle material, which contributes to a potential application as alternative biodegradable packaging for non‐biodegradable materials based on e...

Research paper thumbnail of Halloysite/cellulose derivatives‐based bionanocomposites for controlled naproxen delivery

Journal of Applied Polymer Science, 2021

Bionanocomposites are biocompatible, biodegradable, low‐toxicity materials inorganic/biopolymer‐b... more Bionanocomposites are biocompatible, biodegradable, low‐toxicity materials inorganic/biopolymer‐based, carrying drugs for controlled delivery. The development of novel materials aiming to improve drug efficacy and reduce its toxicity is a continuous focus of the pharmaceutical industry. In this work, we report the development of an innovative controlled naproxen delivery system. The bionanocomposites are composed of naproxen‐loaded halloysite and ethylcellulose/hydroxypropylmethylcellulose blends produced by the spray drying technique. Chemical modification in the halloysite nanotubes was performed, aiming to improve the ionic interactions with the naproxen. The bionanocomposites drug‐load efficiency and interactions were characterized by physicochemical analysis. We also evaluated the naproxen release and its transport mechanism. Results show an efficient drug loading into halloysite, varying from 70% to 90%. Moreover, the naproxen release was delayed up to four times (compared wit...

Research paper thumbnail of Starch-based biodegradable active packaging with Euphorbia umbellata (PAX) Bruyns bioactive extract

Journal of Packaging Technology and Research, 2021

Research paper thumbnail of Antimicrobial dressing of silver sulfadiazine-loaded halloysite/cassava starch-based (bio)nanocomposites

Journal of Biomaterials Applications, 2021

(Bio)nanocomposites have been studied for biomedical applications, including the treatment of wou... more (Bio)nanocomposites have been studied for biomedical applications, including the treatment of wounds. However, wound infection is one of the main problems of wound care management, and the use of wound dressings with antibacterial agents is essential. This work focused on developing and characterizing silver sulfadiazine-loaded halloysite/cassava starch-based (bio)nanocomposites potentially suitable as antimicrobial dressing. Silver sulfadiazine was complexed inside the halloysite nanotubes lumen, and the drug-loaded nanotubes were incorporated in thermoplastic starch dispersion, forming the (bio)nanocomposites. The silver sulfadiazine-loaded halloysite and the (bio)nanocomposite were characterized by zeta potential, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy. The dressing properties of (bio)nanocomposites (water vapor permeability and mechanical stability) and their antimicrobial efficacy by Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were also evaluated. Physicochemical studies suggested the silver sulfadiazine-loaded halloysite complexation (zeta potential of −38.9 mV) and its interactions with the starch forming the nanocomposites. The silver sulfadiazine-loaded halloysite/starch-based (bio)nanocomposites possessed a homogeneous and organized structure. Also, they had mechanical properties to be used as a dressing (13.73 ± 3.09 MPa and 3.17 ± 1.28% of elongation at break), and its permeability (6.18 ± 0.43 (10−13) g.Pa−1.s−1.m−1) could be able to maintain the environmental moisture at the wound surface. Besides that, the (bio)nanocomposites acted against the studied bacteria, being a potential contact antimicrobial and biodegradable wound dressing. Finally, the developed (bio)nanocomposites are semi-occlusive and good candidates for dry wounds to be widely in vitro and in vivo tested as controlled silver sulfadiazine delivery dressing.

Research paper thumbnail of Eco‐friendly materials produced by blown‐film extrusion as potential active food packaging

Polymers for Advanced Technologies, 2020

Starch/polyester blends are potential substitutes for non‐degradable materials. Active food packa... more Starch/polyester blends are potential substitutes for non‐degradable materials. Active food packaging was produced by the blown‐extrusion of starch/poly (butylene adipate‐co‐terephthalate) (PBAT) blends added to α‐tocopherol (α‐TOC). The films showed adequate stability and processability by the blown‐extrusion method and were converted into an essentially amorphous and homogeneous material. The transparency and water vapor permeability of the films increased with the addition of α‐TOC. The antioxidant interfered in the organization of the polymeric matrix, which was confirmed by SEM images, resulting in lower tensile strength and elongation at break, with no interference due to the α‐TOC concentration. The inclusion of α‐TOC did not influence the thermal stability, and it increased the crystallinity of the samples. The formulation with the lowest concentrations of the antioxidant (T0.25) presented an almost complete release of α‐TOC, proving the efficiency of the films as active pac...

Research paper thumbnail of Citric acid as crosslinking agent in starch/xanthan gum hydrogels produced by extrusion and thermopressing

LWT, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Sepiolite as a promising nanoclay for nano-biocomposites based on starch and biodegradable polyester

Materials Science and Engineering: C, 2017

The effects of sepiolite addition (0, 1, 3 and 5wt%) were evaluated on dynamic-mechanical behavio... more The effects of sepiolite addition (0, 1, 3 and 5wt%) were evaluated on dynamic-mechanical behaviour, water uptake, thermal and optical properties of thermoplastic starch (TPS)/poly (butylene adipate-co-terephthalate) (PBAT) nano-biocomposites, with different TPS/PBAT (w/w) ratios and nanofiller contents. The results highlighted the improvement of the dynamic-mechanical behaviour with the addition of sepiolite, producing high performance materials. An increase of 25°C in the Tg of TPS was recorded by DMTA analysis at sepiolite content of 5wt%. The sepiolite influenced the crystallisation of nano-biocomposites, without causing interference in the crystal organisation, evidenced by DSC analysis. The addition of sepiolite nanoclay decreased the water adsorption rate and water adsorption capacity of the corresponding nano-biocomposites. For such multiphase systems, the successful use of natural sepiolite brought a clear benefit, without the need of any modifications or additional processes to produce advanced nano-biocomposites.

Research paper thumbnail of Influence of microcrystalline cellulose in thermoplastic starch/polyester blown films

Polímeros, 2017

This work investigated the influence of microcrystalline cellulose (MCC) in thermoplastic starch/... more This work investigated the influence of microcrystalline cellulose (MCC) in thermoplastic starch/poly (butylene adipate-co-terephthalate) films produced by blown extrusion, using different MCC contents (4, 7 and 10 g.100 g-1). The films were characterised for their mechanical, structural and barrier properties. Increasing fibres concentration reduced the tensile strength (6.9 to 4.6 MPa), the elongation at break (568 to 147%) and weight loss in water (12.8 to 11.1%) of the films. The rigidity of the films increased from 19.8 MPa (without MCC) to 79.2 MPa in the samples with 10 g.100 g-1 of MCC. SEM images showed the occurrence of some agglomerates in this sample. The water vapour permeability of the films was not affected by the presence of MCC. The production of starch/PBAT/MCC films by blown extrusion was successful; however some adjustments are necessary to improve the dispersion of the particles at the polymeric matrix.

Research paper thumbnail of Oat fibers modification by reactive extrusion with alkaline hydrogen peroxide

Polímeros, 2016

The modification of lignocellulosic fibers can enhance their interaction with other materials and... more The modification of lignocellulosic fibers can enhance their interaction with other materials and alkaline hydrogen peroxide (AHP) is a reagent widely used to promote such modification. This work aimed to modify oat hulls fibers by reactive extrusion using AHP (7 g 100 g-1 of hulls). The modified oat hulls displayed performances comparable to those observed by other researchers using conventional AHP method (without extrusion). The AHP treated oat hulls showed increased luminosity compared to the extruded ones. Fourier transform infrared spectroscopy showed differences between the modified and unmodified structures. The removal of surface compounds resulted in a more open morphology, with greater surface area and greater porosity. Reactive extrusion can be an alternative method for fiber modification with several advantages, such as short processing time and no wastewater generation.

Research paper thumbnail of Blendas de amido termoplástico e poliéster : estudo da influência de compatibilizantes e agentes de reforço

A producao de materiais biodegradaveis tem sido o foco de inumeras pesquisas atualmente. Como for... more A producao de materiais biodegradaveis tem sido o foco de inumeras pesquisas atualmente. Como forma de superar as limitacoes do amido termoplastico, propoe-se a producao de blendas deste com polimeros de melhor desempenho. Nesse sentido, blendas de amido/poli (adipato co-tereftalato de butileno) (PBAT) adicionadas dos acidos citrico, malico ou tartarico em concentracoes de 0,375; 0,75 e 1,5 g.100g-1, foram produzidas por extrusao reativa em uma unica etapa. A inclusao dos acidos orgânicos aumentou a resistencia a tracao e reduziu a permeabilidade ao vapor de agua dos filmes, em funcao de sua atuacao como compatibilizantes. O acido tartarico (TA) mostrou resultados promissores e representa uma alternativa ainda nao abordada por outros autores. Com isso, sua influencia nas blendas foi investigada por meio de um planejamento de misturas. Diferentes e concomitantes papeis foram observados para o TA, desde a compatibilizacao das blendas, com a reducao da tensao interfacial e obtencao de materiais mais homogeneos, ate a hidrolise parcial das cadeias de amido, causando enfraquecimento dos materiais quando utilizado em elevadas proporcoes (>1.5 g.100g-1). Analises de infravermelho (FT-IR) e ressonância magnetica nuclear (13C CPMAS NMR) apontaram para a ocorrencia de reacoes de esterificacao / transesterificacao promovidas pelo acido tartarico, sendo esse seu principal mecanismo de acao como compatibilizante, o que e refletido nas demais propriedades dos materiais. De acordo com a tecnica da Desejabilidade, a formulacao mais desejada, isto e, a que produziu filmes mais resistentes, continha proporcao intermediaria de acido tartarico (0.8 g.100g-1). Sacolas plasticas biodegradaveis produzidas utilizando-se a proporcao otimizada entre os componentes (amido, PBAT, glicerol e TA) foram aprovadas em todos os ensaios constantes na norma ABNT NBR 14937:2010, o que indica que este material e adequado para o uso comercial. Em uma segunda etapa, com o objetivo de avaliar o efeito reforcador da nanoargila sepiolita, blendas de amido/PBAT, contendo 1, 3 e 5 g.100g-1 deste nanosilicato, foram produzidas utilizando-se duas proporcoes entre as fases polimericas (50:50 e 80:20 amido termoplastico (TPS)/PBAT, respectivamente). A analise das imagens de microscopia eletronica de varredura e dos espectros de difracao de raios-x evidenciaram que a sepiolita apresentou-se bem dispersa e nao alterou a morfologia e o perfil cristalino das blendas, mas aumentou significativamente o torque registrado durante o processamento dos materiais, como consequencia da reducao da mobilidade molecular. Ainda, foi observado um efeito reforcador significativo (aumento do modulo de Young e resistencia a tracao), principalmente para as formulacoes contendo 80:20 TPS/PBAT, uma vez que a sepiolita parece estar concentrada na fase de TPS, devido a sua maior compatibilidade molecular. Por fim, a inclusao de 5 g.100g-1 de sepiolita na matriz com proporcao 50:50 TPS/PBAT levou a um aumento de 25°C na temperatura de transicao vitrea (Tg) relativa a fase de amido, sem…

Research paper thumbnail of Poly(lactic acid)/thermoplastic starch sheets: effect of adipate esters on the morphological, mechanical and barrier properties

Polímeros, 2016

Blends of poly(lactic acid) (PLA) and thermoplastic starch (TPS) plasticized with adipate esters ... more Blends of poly(lactic acid) (PLA) and thermoplastic starch (TPS) plasticized with adipate esters (diisodecyl adipate and diethyl adipate) having different molecular weight were used to produce sheets. The calendering-extrusion process at a pilot scale was used, and the mechanical, barrier, and morphological characterization of the obtained materials were performed. The increase in the TPS content affected the mechanical properties of the sheets by increasing the elongation and decreasing the rigidity. TPS conferred a more hydrophilic character to the sheets, as observed from the water vapor permeability results. The sheets plasticized with diisodecyl adipate (DIA), having a higher molecular weight, had better mechanical and barrier properties than diethyl adipate (DEA) plasticized sheets, indicating that DIA was more effective as plasticizer. Micrographs obtained by confocal laser microscopy and scanning electron microscopy showed different morphologies when different proportions of PLA and TPS were used (dispersed or co-continuous structures), which were strongly associated with the mechanical and barrier properties.

Research paper thumbnail of Mixture design applied for the development of films based on starch, polyvinyl alcohol, and glycerol

Journal of Applied Polymer Science, 2015

ABSTRACTStarch and polyvinyl alcohol (PVA) are biodegradable materials with potentiality to repla... more ABSTRACTStarch 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...

Research paper thumbnail of Biodegradable bags for the production of plant seedlings

Polímeros, 2014

The production of plant seedlings has traditionally used polyethylene bags, which are thrown out ... more The production of plant seedlings has traditionally used polyethylene bags, which are thrown out in the soil or burned after transplant because the large amount of organic material attached to the bags makes recycling difficult. Additionally, when a seedling is taken from the bag for transplant, there is the risk of root damage, which compromises the plant's development. In this study, we developed biodegradable bags to be used in seedling production, and we verify their influence on the development of Brazilian ginseng (Pfaffia glomerata (Spreng) Pedersen), when the plant is planted without being removed from the bag. Both black and white biodegradable bags remained intact throughout the seedling production period (60 days). After being transplanted into containers (240 days), they were completely biodegraded, and there was no significant difference between the dry mass of these plants and that of plants that were transplanted without the bags. The plants that were cultivated without being removed from the polyethylene bags had root development difficulties, and the wrapping showed no signs of degradation. The use of biodegradable films is an alternative for the production of bags for seedlings, as these can then be transplanted directly into the soil without removing the bag, reducing the risk of damage to the roots during the moment of transplant.

Research paper thumbnail of Efeito de embalagem biodegradável de amido no armazenamento de queijo processado

Semina: Ciências Agrárias, 2006

Efeito de embalagem biodegradável de amido no armazenamento de queijo processado Recebido para pu... more Efeito de embalagem biodegradável de amido no armazenamento de queijo processado Recebido para publicação 18/02/05 Aprovado em 31/08/05 Efeito de embalagem biodegradável de amido no armazenamento de queijo processado

Research paper thumbnail of Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Polímeros, 2013

Blends of starch/polyester have been of great interest in the development of biodegradable packag... more Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability) was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate) (PBAT) blown films produced via a one-step reactive extrusion using tartaric acid (TA) as a compatibiliser. Maximum results for all the properties were set as more desirable, with an optimal formulation being obtained which contained (55:45) starch/PBAT (88.2 wt. (%)), glycerol (11.0 wt. (%)) and TA (0.8 wt. (%)). Biodegradable plastic bags were produced using the film with this formulation, and analysed according to the standard method of the Associação Brasileira de Normas Técnicas (ABNT). The bags exhibited a 45% failure rate in free-falling dart impact tests, a 10% of failure rate in dynamic load tests and no failure in static load tests. These results meet the specifications set by the standard. Thus, the biodegradable plastic bags fabricated with an optimised formulation could be useful as an alternative to those made from non-biodegradable materials if the nominal capacity declared for this material is considered.

Research paper thumbnail of Physical and structural characterisation of starch/polyester blends with tartaric acid

Materials Science and Engineering: C, 2014

Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. Th... more Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. The effects of TA, glycerol and starch + PBAT on the mechanical, optical and structural properties of the films were evaluated, with formulations based in a constrained mixture design. Tartaric acid acts as a compatibiliser and promotes the acid hydrolysis of starch chains. These two functions explain the observed film resistance and opacity. TA reduced the weight loss in water. Scanning electron microscopy (SEM) images showed that TA reduces the interfacial tension between the polymeric phases, resulting in more homogeneous films. Nuclear magnetic resonance (13 C CPMAS) and Fourier transform infrared spectroscopy (FT-IR) suggest that tartaric acid is able to react with the hydroxyl groups of the starch by esterification/transesterification reactions, confirming its role as a compatibiliser. The addition of TA results in materials with better properties that are suitable for use in food packaging.

Research paper thumbnail of Microcrystalline Cellulose as Reinforcement in Thermoplastic Starch/Poly(butylene adipate-co-terephthalate) Films

Journal of Polymers and the Environment, 2014

Lignocellulosic fibers or their derivatives may be used to reinforce packaging materials. The aim... more Lignocellulosic fibers or their derivatives may be used to reinforce packaging materials. The aim of this study was to assess the effect of adding microcrystalline cellulose (MCC) on the microstructure and properties of thermoplastic starch (TPS)/poly(butylene adipate-co-terephthalate) (PBAT) films. MCC concentrations of 0, 1, 3 and 5 g 100 g-1 TPS/PBAT were added to mixtures containing 56 g 100 g-1 of TPS and 44 g 100 g-1 of PBAT. The morphology of the film changed slightly and the storage modulus increased when MCC was added at the concentration of 3 g 100 g-1 TPS/PBAT. No differences were observed in the Fourier transform infrared spectra and in the crystallinity of the films without and with 3 g MCC 100 g-1 TPS/PBAT. The tensile strength (medium value 6.52 MPa), elongation at break (medium value 723.83 %) and water vapor permeability (WVP; medium value 5.68 9 10-11 g m-1 s-1 Pa-1) of the films with and without MCC showed no significant differences. The films with 3 and 5 g MCC 100 g-1 TPS/PBAT were stiffer than control film. The low interaction of MCC with the polymer matrix (mainly with PBAT), the processing technique, and the low concentration of MCC may have contributed to these results.

Research paper thumbnail of Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

Polímeros, 2012

Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate) (PBAT) c... more Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate) (PBAT) containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic) did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

Research paper thumbnail of Study of the compatibilizer effect in the properties of starch / polyester blends

Polímeros Ciência e Tecnologia, 2013

The mechanical, viscoelastic and structural properties of starch/ poly (butylene adipate co-terep... more The mechanical, viscoelastic and structural properties of starch/ poly (butylene adipate co-terephthalate) (PBAT) blown films produced by reactive extrusion were evaluated using citric acid (CA) and maleic anhydride (MA) as compatibilizers. Scanning electron microscopy images showed more homogeneous structure when CA and MA were included in the formulation. The tensile strength (MPa) was improved with the inclusion of the highest proportion of both compatibilizers (1.5 %wt). A larger elastic component with values between 0.42-0.45 for the degree of solidity (1-c 1) was observed for the intermediate concentration of compatibilizers. A high level of glycerol (10 %wt) results in films with increased % elongation. Three partially miscible phases were observed in the blends. Biodegradable films of starch/PBAT with better properties could be produced by one-step reactive extrusion using CA and/or MA as compatibilizers.

Research paper thumbnail of Production and Characterization of Starch/PVA Blends with Bioactive Compounds from Malt Bagasse

Macromolecular Symposia

Starch is an abundant and renewable material for producing biodegradable films and, to improve th... more Starch is an abundant and renewable material for producing biodegradable films and, to improve their mechanical performance is usually blended with polymers of better performance, as poly(vinyl alcohol) (PVA). Malt bagasse or brewer spent grain is a by‐product of brewing, mostly used as animal feed, and has bioactive compounds with proven antioxidant properties. On this basis, this work aims to produce starch‐PVA blends incorporated with malt bagasse extracts of two different types of beer, Pilsen, and Weiss. The inclusion of the Weiss (WMB) and Pilsen (PMB) malt bagasse extracts has no significant influence on the water solubility of the films. FEG‐SEM images present no tendency to phase separation at the sample surfaces, with a higher roughness of samples containing PMB extracts and improved homogeneity with the presence of WMB extracts. The inclusion of the bioactive extracts, regardless of concentration, has preserved the resistance and flexibility of the blends. Thermogravimetr...

Research paper thumbnail of Application and characterisation of industrial brewing by‐products in biodegradable starch‐based expanded composites

International Journal of Food Science & Technology

SummaryConcern headed under waste management promotes the development and application of biodegra... more SummaryConcern headed under waste management promotes the development and application of biodegradable materials. Naturally occurring lignocellulosic fibres, such as malt bagasse (MB), are often low‐cost industrial by‐products with attractive properties. This work focused on extruding starch‐based expanded composites, containing two different brewing residues, Pilsen malt bagasse (PMB) and Weiss malt bagasse (WMB). Their mechanical, thermal and structural properties were evaluated. The expansion index was higher in the WMB10 extruded composite (25.73 ± 4.75), also evident in the SEM‐FEG images which show more quantity and uniformity of pores. WMB5 and WMB10 resulted in a 50% decrease in composite water solubility relative to the Control. The hardness (N) of the samples was reduced by using MB fibres of both types, producing a less stiff and brittle material, which contributes to a potential application as alternative biodegradable packaging for non‐biodegradable materials based on e...

Research paper thumbnail of Halloysite/cellulose derivatives‐based bionanocomposites for controlled naproxen delivery

Journal of Applied Polymer Science, 2021

Bionanocomposites are biocompatible, biodegradable, low‐toxicity materials inorganic/biopolymer‐b... more Bionanocomposites are biocompatible, biodegradable, low‐toxicity materials inorganic/biopolymer‐based, carrying drugs for controlled delivery. The development of novel materials aiming to improve drug efficacy and reduce its toxicity is a continuous focus of the pharmaceutical industry. In this work, we report the development of an innovative controlled naproxen delivery system. The bionanocomposites are composed of naproxen‐loaded halloysite and ethylcellulose/hydroxypropylmethylcellulose blends produced by the spray drying technique. Chemical modification in the halloysite nanotubes was performed, aiming to improve the ionic interactions with the naproxen. The bionanocomposites drug‐load efficiency and interactions were characterized by physicochemical analysis. We also evaluated the naproxen release and its transport mechanism. Results show an efficient drug loading into halloysite, varying from 70% to 90%. Moreover, the naproxen release was delayed up to four times (compared wit...

Research paper thumbnail of Starch-based biodegradable active packaging with Euphorbia umbellata (PAX) Bruyns bioactive extract

Journal of Packaging Technology and Research, 2021

Research paper thumbnail of Antimicrobial dressing of silver sulfadiazine-loaded halloysite/cassava starch-based (bio)nanocomposites

Journal of Biomaterials Applications, 2021

(Bio)nanocomposites have been studied for biomedical applications, including the treatment of wou... more (Bio)nanocomposites have been studied for biomedical applications, including the treatment of wounds. However, wound infection is one of the main problems of wound care management, and the use of wound dressings with antibacterial agents is essential. This work focused on developing and characterizing silver sulfadiazine-loaded halloysite/cassava starch-based (bio)nanocomposites potentially suitable as antimicrobial dressing. Silver sulfadiazine was complexed inside the halloysite nanotubes lumen, and the drug-loaded nanotubes were incorporated in thermoplastic starch dispersion, forming the (bio)nanocomposites. The silver sulfadiazine-loaded halloysite and the (bio)nanocomposite were characterized by zeta potential, scanning electron microscopy, X-ray diffraction, and infrared spectroscopy. The dressing properties of (bio)nanocomposites (water vapor permeability and mechanical stability) and their antimicrobial efficacy by Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were also evaluated. Physicochemical studies suggested the silver sulfadiazine-loaded halloysite complexation (zeta potential of −38.9 mV) and its interactions with the starch forming the nanocomposites. The silver sulfadiazine-loaded halloysite/starch-based (bio)nanocomposites possessed a homogeneous and organized structure. Also, they had mechanical properties to be used as a dressing (13.73 ± 3.09 MPa and 3.17 ± 1.28% of elongation at break), and its permeability (6.18 ± 0.43 (10−13) g.Pa−1.s−1.m−1) could be able to maintain the environmental moisture at the wound surface. Besides that, the (bio)nanocomposites acted against the studied bacteria, being a potential contact antimicrobial and biodegradable wound dressing. Finally, the developed (bio)nanocomposites are semi-occlusive and good candidates for dry wounds to be widely in vitro and in vivo tested as controlled silver sulfadiazine delivery dressing.

Research paper thumbnail of Eco‐friendly materials produced by blown‐film extrusion as potential active food packaging

Polymers for Advanced Technologies, 2020

Starch/polyester blends are potential substitutes for non‐degradable materials. Active food packa... more Starch/polyester blends are potential substitutes for non‐degradable materials. Active food packaging was produced by the blown‐extrusion of starch/poly (butylene adipate‐co‐terephthalate) (PBAT) blends added to α‐tocopherol (α‐TOC). The films showed adequate stability and processability by the blown‐extrusion method and were converted into an essentially amorphous and homogeneous material. The transparency and water vapor permeability of the films increased with the addition of α‐TOC. The antioxidant interfered in the organization of the polymeric matrix, which was confirmed by SEM images, resulting in lower tensile strength and elongation at break, with no interference due to the α‐TOC concentration. The inclusion of α‐TOC did not influence the thermal stability, and it increased the crystallinity of the samples. The formulation with the lowest concentrations of the antioxidant (T0.25) presented an almost complete release of α‐TOC, proving the efficiency of the films as active pac...

Research paper thumbnail of Citric acid as crosslinking agent in starch/xanthan gum hydrogels produced by extrusion and thermopressing

LWT, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Sepiolite as a promising nanoclay for nano-biocomposites based on starch and biodegradable polyester

Materials Science and Engineering: C, 2017

The effects of sepiolite addition (0, 1, 3 and 5wt%) were evaluated on dynamic-mechanical behavio... more The effects of sepiolite addition (0, 1, 3 and 5wt%) were evaluated on dynamic-mechanical behaviour, water uptake, thermal and optical properties of thermoplastic starch (TPS)/poly (butylene adipate-co-terephthalate) (PBAT) nano-biocomposites, with different TPS/PBAT (w/w) ratios and nanofiller contents. The results highlighted the improvement of the dynamic-mechanical behaviour with the addition of sepiolite, producing high performance materials. An increase of 25°C in the Tg of TPS was recorded by DMTA analysis at sepiolite content of 5wt%. The sepiolite influenced the crystallisation of nano-biocomposites, without causing interference in the crystal organisation, evidenced by DSC analysis. The addition of sepiolite nanoclay decreased the water adsorption rate and water adsorption capacity of the corresponding nano-biocomposites. For such multiphase systems, the successful use of natural sepiolite brought a clear benefit, without the need of any modifications or additional processes to produce advanced nano-biocomposites.

Research paper thumbnail of Influence of microcrystalline cellulose in thermoplastic starch/polyester blown films

Polímeros, 2017

This work investigated the influence of microcrystalline cellulose (MCC) in thermoplastic starch/... more This work investigated the influence of microcrystalline cellulose (MCC) in thermoplastic starch/poly (butylene adipate-co-terephthalate) films produced by blown extrusion, using different MCC contents (4, 7 and 10 g.100 g-1). The films were characterised for their mechanical, structural and barrier properties. Increasing fibres concentration reduced the tensile strength (6.9 to 4.6 MPa), the elongation at break (568 to 147%) and weight loss in water (12.8 to 11.1%) of the films. The rigidity of the films increased from 19.8 MPa (without MCC) to 79.2 MPa in the samples with 10 g.100 g-1 of MCC. SEM images showed the occurrence of some agglomerates in this sample. The water vapour permeability of the films was not affected by the presence of MCC. The production of starch/PBAT/MCC films by blown extrusion was successful; however some adjustments are necessary to improve the dispersion of the particles at the polymeric matrix.

Research paper thumbnail of Oat fibers modification by reactive extrusion with alkaline hydrogen peroxide

Polímeros, 2016

The modification of lignocellulosic fibers can enhance their interaction with other materials and... more The modification of lignocellulosic fibers can enhance their interaction with other materials and alkaline hydrogen peroxide (AHP) is a reagent widely used to promote such modification. This work aimed to modify oat hulls fibers by reactive extrusion using AHP (7 g 100 g-1 of hulls). The modified oat hulls displayed performances comparable to those observed by other researchers using conventional AHP method (without extrusion). The AHP treated oat hulls showed increased luminosity compared to the extruded ones. Fourier transform infrared spectroscopy showed differences between the modified and unmodified structures. The removal of surface compounds resulted in a more open morphology, with greater surface area and greater porosity. Reactive extrusion can be an alternative method for fiber modification with several advantages, such as short processing time and no wastewater generation.

Research paper thumbnail of Blendas de amido termoplástico e poliéster : estudo da influência de compatibilizantes e agentes de reforço

A producao de materiais biodegradaveis tem sido o foco de inumeras pesquisas atualmente. Como for... more A producao de materiais biodegradaveis tem sido o foco de inumeras pesquisas atualmente. Como forma de superar as limitacoes do amido termoplastico, propoe-se a producao de blendas deste com polimeros de melhor desempenho. Nesse sentido, blendas de amido/poli (adipato co-tereftalato de butileno) (PBAT) adicionadas dos acidos citrico, malico ou tartarico em concentracoes de 0,375; 0,75 e 1,5 g.100g-1, foram produzidas por extrusao reativa em uma unica etapa. A inclusao dos acidos orgânicos aumentou a resistencia a tracao e reduziu a permeabilidade ao vapor de agua dos filmes, em funcao de sua atuacao como compatibilizantes. O acido tartarico (TA) mostrou resultados promissores e representa uma alternativa ainda nao abordada por outros autores. Com isso, sua influencia nas blendas foi investigada por meio de um planejamento de misturas. Diferentes e concomitantes papeis foram observados para o TA, desde a compatibilizacao das blendas, com a reducao da tensao interfacial e obtencao de materiais mais homogeneos, ate a hidrolise parcial das cadeias de amido, causando enfraquecimento dos materiais quando utilizado em elevadas proporcoes (>1.5 g.100g-1). Analises de infravermelho (FT-IR) e ressonância magnetica nuclear (13C CPMAS NMR) apontaram para a ocorrencia de reacoes de esterificacao / transesterificacao promovidas pelo acido tartarico, sendo esse seu principal mecanismo de acao como compatibilizante, o que e refletido nas demais propriedades dos materiais. De acordo com a tecnica da Desejabilidade, a formulacao mais desejada, isto e, a que produziu filmes mais resistentes, continha proporcao intermediaria de acido tartarico (0.8 g.100g-1). Sacolas plasticas biodegradaveis produzidas utilizando-se a proporcao otimizada entre os componentes (amido, PBAT, glicerol e TA) foram aprovadas em todos os ensaios constantes na norma ABNT NBR 14937:2010, o que indica que este material e adequado para o uso comercial. Em uma segunda etapa, com o objetivo de avaliar o efeito reforcador da nanoargila sepiolita, blendas de amido/PBAT, contendo 1, 3 e 5 g.100g-1 deste nanosilicato, foram produzidas utilizando-se duas proporcoes entre as fases polimericas (50:50 e 80:20 amido termoplastico (TPS)/PBAT, respectivamente). A analise das imagens de microscopia eletronica de varredura e dos espectros de difracao de raios-x evidenciaram que a sepiolita apresentou-se bem dispersa e nao alterou a morfologia e o perfil cristalino das blendas, mas aumentou significativamente o torque registrado durante o processamento dos materiais, como consequencia da reducao da mobilidade molecular. Ainda, foi observado um efeito reforcador significativo (aumento do modulo de Young e resistencia a tracao), principalmente para as formulacoes contendo 80:20 TPS/PBAT, uma vez que a sepiolita parece estar concentrada na fase de TPS, devido a sua maior compatibilidade molecular. Por fim, a inclusao de 5 g.100g-1 de sepiolita na matriz com proporcao 50:50 TPS/PBAT levou a um aumento de 25°C na temperatura de transicao vitrea (Tg) relativa a fase de amido, sem…

Research paper thumbnail of Poly(lactic acid)/thermoplastic starch sheets: effect of adipate esters on the morphological, mechanical and barrier properties

Polímeros, 2016

Blends of poly(lactic acid) (PLA) and thermoplastic starch (TPS) plasticized with adipate esters ... more Blends of poly(lactic acid) (PLA) and thermoplastic starch (TPS) plasticized with adipate esters (diisodecyl adipate and diethyl adipate) having different molecular weight were used to produce sheets. The calendering-extrusion process at a pilot scale was used, and the mechanical, barrier, and morphological characterization of the obtained materials were performed. The increase in the TPS content affected the mechanical properties of the sheets by increasing the elongation and decreasing the rigidity. TPS conferred a more hydrophilic character to the sheets, as observed from the water vapor permeability results. The sheets plasticized with diisodecyl adipate (DIA), having a higher molecular weight, had better mechanical and barrier properties than diethyl adipate (DEA) plasticized sheets, indicating that DIA was more effective as plasticizer. Micrographs obtained by confocal laser microscopy and scanning electron microscopy showed different morphologies when different proportions of PLA and TPS were used (dispersed or co-continuous structures), which were strongly associated with the mechanical and barrier properties.

Research paper thumbnail of Mixture design applied for the development of films based on starch, polyvinyl alcohol, and glycerol

Journal of Applied Polymer Science, 2015

ABSTRACTStarch and polyvinyl alcohol (PVA) are biodegradable materials with potentiality to repla... more ABSTRACTStarch 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...

Research paper thumbnail of Biodegradable bags for the production of plant seedlings

Polímeros, 2014

The production of plant seedlings has traditionally used polyethylene bags, which are thrown out ... more The production of plant seedlings has traditionally used polyethylene bags, which are thrown out in the soil or burned after transplant because the large amount of organic material attached to the bags makes recycling difficult. Additionally, when a seedling is taken from the bag for transplant, there is the risk of root damage, which compromises the plant's development. In this study, we developed biodegradable bags to be used in seedling production, and we verify their influence on the development of Brazilian ginseng (Pfaffia glomerata (Spreng) Pedersen), when the plant is planted without being removed from the bag. Both black and white biodegradable bags remained intact throughout the seedling production period (60 days). After being transplanted into containers (240 days), they were completely biodegraded, and there was no significant difference between the dry mass of these plants and that of plants that were transplanted without the bags. The plants that were cultivated without being removed from the polyethylene bags had root development difficulties, and the wrapping showed no signs of degradation. The use of biodegradable films is an alternative for the production of bags for seedlings, as these can then be transplanted directly into the soil without removing the bag, reducing the risk of damage to the roots during the moment of transplant.

Research paper thumbnail of Efeito de embalagem biodegradável de amido no armazenamento de queijo processado

Semina: Ciências Agrárias, 2006

Efeito de embalagem biodegradável de amido no armazenamento de queijo processado Recebido para pu... more Efeito de embalagem biodegradável de amido no armazenamento de queijo processado Recebido para publicação 18/02/05 Aprovado em 31/08/05 Efeito de embalagem biodegradável de amido no armazenamento de queijo processado

Research paper thumbnail of Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

Polímeros, 2013

Blends of starch/polyester have been of great interest in the development of biodegradable packag... more Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability) was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate) (PBAT) blown films produced via a one-step reactive extrusion using tartaric acid (TA) as a compatibiliser. Maximum results for all the properties were set as more desirable, with an optimal formulation being obtained which contained (55:45) starch/PBAT (88.2 wt. (%)), glycerol (11.0 wt. (%)) and TA (0.8 wt. (%)). Biodegradable plastic bags were produced using the film with this formulation, and analysed according to the standard method of the Associação Brasileira de Normas Técnicas (ABNT). The bags exhibited a 45% failure rate in free-falling dart impact tests, a 10% of failure rate in dynamic load tests and no failure in static load tests. These results meet the specifications set by the standard. Thus, the biodegradable plastic bags fabricated with an optimised formulation could be useful as an alternative to those made from non-biodegradable materials if the nominal capacity declared for this material is considered.

Research paper thumbnail of Physical and structural characterisation of starch/polyester blends with tartaric acid

Materials Science and Engineering: C, 2014

Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. Th... more Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. The effects of TA, glycerol and starch + PBAT on the mechanical, optical and structural properties of the films were evaluated, with formulations based in a constrained mixture design. Tartaric acid acts as a compatibiliser and promotes the acid hydrolysis of starch chains. These two functions explain the observed film resistance and opacity. TA reduced the weight loss in water. Scanning electron microscopy (SEM) images showed that TA reduces the interfacial tension between the polymeric phases, resulting in more homogeneous films. Nuclear magnetic resonance (13 C CPMAS) and Fourier transform infrared spectroscopy (FT-IR) suggest that tartaric acid is able to react with the hydroxyl groups of the starch by esterification/transesterification reactions, confirming its role as a compatibiliser. The addition of TA results in materials with better properties that are suitable for use in food packaging.

Research paper thumbnail of Microcrystalline Cellulose as Reinforcement in Thermoplastic Starch/Poly(butylene adipate-co-terephthalate) Films

Journal of Polymers and the Environment, 2014

Lignocellulosic fibers or their derivatives may be used to reinforce packaging materials. The aim... more Lignocellulosic fibers or their derivatives may be used to reinforce packaging materials. The aim of this study was to assess the effect of adding microcrystalline cellulose (MCC) on the microstructure and properties of thermoplastic starch (TPS)/poly(butylene adipate-co-terephthalate) (PBAT) films. MCC concentrations of 0, 1, 3 and 5 g 100 g-1 TPS/PBAT were added to mixtures containing 56 g 100 g-1 of TPS and 44 g 100 g-1 of PBAT. The morphology of the film changed slightly and the storage modulus increased when MCC was added at the concentration of 3 g 100 g-1 TPS/PBAT. No differences were observed in the Fourier transform infrared spectra and in the crystallinity of the films without and with 3 g MCC 100 g-1 TPS/PBAT. The tensile strength (medium value 6.52 MPa), elongation at break (medium value 723.83 %) and water vapor permeability (WVP; medium value 5.68 9 10-11 g m-1 s-1 Pa-1) of the films with and without MCC showed no significant differences. The films with 3 and 5 g MCC 100 g-1 TPS/PBAT were stiffer than control film. The low interaction of MCC with the polymer matrix (mainly with PBAT), the processing technique, and the low concentration of MCC may have contributed to these results.

Research paper thumbnail of Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

Polímeros, 2012

Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate) (PBAT) c... more Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate) (PBAT) containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic) did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

Research paper thumbnail of Study of the compatibilizer effect in the properties of starch / polyester blends

Polímeros Ciência e Tecnologia, 2013

The mechanical, viscoelastic and structural properties of starch/ poly (butylene adipate co-terep... more The mechanical, viscoelastic and structural properties of starch/ poly (butylene adipate co-terephthalate) (PBAT) blown films produced by reactive extrusion were evaluated using citric acid (CA) and maleic anhydride (MA) as compatibilizers. Scanning electron microscopy images showed more homogeneous structure when CA and MA were included in the formulation. The tensile strength (MPa) was improved with the inclusion of the highest proportion of both compatibilizers (1.5 %wt). A larger elastic component with values between 0.42-0.45 for the degree of solidity (1-c 1) was observed for the intermediate concentration of compatibilizers. A high level of glycerol (10 %wt) results in films with increased % elongation. Three partially miscible phases were observed in the blends. Biodegradable films of starch/PBAT with better properties could be produced by one-step reactive extrusion using CA and/or MA as compatibilizers.