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Made available in DSpace on 2022-04-28T19:44:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Developing novel renewable (and preferably biodegradable) materials has become recurrent due to the growing concerns with environmental impacts of high volumes of plastic waste produced from oil-based sources over the past decades. This study aimed at developing bioplastics from a mixture of starch and xylan in variable ratios, and the combined effect of α-cellulose and holocellulose extracted from sugarcane bagasse added to the process. The disintegration of bioplastics was evaluated in both soil and composting. The ecotoxicity analyses with Saccharomyces cerevisiae, Bacillus subtilis and seeds of Cucumis sativus were conducted after disintegration. All formulations based on 5% (w/v) of total polysaccharides were dried at 30 °C and resulted in homogeneous and non-brittle bioplastics. The composting results showed that all bioplastic formulations disintegrated in 3 days, whereas the 25/75% (xylan/starch, w/w) formulation vanished in soil within 13 days. The ecotoxicity data showed no inhibition of microbial growth after biodegradation, yielding 100% of seed germination. Despite the positive influence of the bioplastic degradation on the root and hypocotyl growth, temporary inhibition of C. sativus tissues exposed to soil washing (10 days of disintegration) was observed. The study demonstrated that xylan/starch bioplastics result in non-ecotoxic biodegradable materials. Institute for Research in Bioenergy (IPBEN) University of São Paulo State (UNESP) Department of Materials Engineering São Carlos School of Engineering (EESC) University of São Paulo (USP) Department of Natural Sciences Mathematics and Education Agricultural Sciences Centre– Federal University of São Carlos (UFSCar), SP-330, km 174 Department of Biology Institute of Biosciences University of São Paulo State (UNESP), Av. 24-A, 1515, CP 199 Institute for Research in Bioenergy (IPBEN) University of São Paulo State (UNESP) Department of Biology Institute of Biosciences University of São Paulo State (UNESP), Av. 24-A, 1515, CP 199 FAPESP: 2017/22401-8 FAPESP: 2019/12997-6 FAPESP: 2019/16853-9

Vat photopolymerization is an additive manufacturing process that produces high-performance ceramic parts. A critical step in the process is the preparation of a suspension that meets the requirements of high ceramic loading and proper rheological behavior, since an increase in solid loading might compromise the suspension rheology, resulting in non-uniform layer recoating. This review examines the rheological behavior of ceramic suspensions for vat photopolymerization, discussing the influence of the suspension formulation (solid loading, ceramic particle size and size distribution, monomers, diluents, and dispersants) on rheological aspects such as viscosity, shear-thinning/thickening behavior, critical shear rate, yield stress, and thixotropy. It provides a summary of the best formulations, which achieved low viscosity ( 40 vol%), and reports the main trends and challenges of ceramic vat photopolymerization, suggesting general guidelines for the preparation of highly loaded photocurable ceramic suspensions with low viscosity.

We report herein the use of nanofibrillated cellulose (NFC) for development of enzyme assemblies in an oriented manner for biotransformation with in situ cofactor regeneration. This is achieved by developing fusion protein enzymes with cellulose-specific binding domains. Specifically, lactate dehydrogenase and NADH oxidase were fused with a cellulose binding domain, which enabled both enzyme recovery and assembling in essentially one single step by using NFC. Results showed that the binding capacity of the enzymes was as high as 0.9 μmol-enzyme/g-NFC. Compared to native parent free enzymes, NFC-enzyme assemblies improved the catalytic efficiency of the coupled reaction system by over 100%. The lifetime of enzymes was also improved by as high as 27 folds. The work demonstrates promising potential of using biocompatible and environmentally benign bio-based nanomaterials for construction of efficient catalysts for intensified bioprocessing and biotransformation applications.

This article addresses the development of biodegradable blends of poly (butylene succinate-co-adipate) (PBSA) and poly (e-caprolactone) (PCL) processed by reactive extrusion in the presence of titanium butoxide (TiOBu4) (TBT) in twin-screw equipment. The PBSA/PCL concentration was set to 60/40 (wt.%), and 0%, 0.1%, 0.3% and 0.5% of TBT were added to the polymer weight. FTIR analysis revealed slight changes around the carbonyl peak correlated to the generation of copolymers. The results of MFR showed an increase in viscosity for higher TBT concentrations, and tensile tests indicated improved yield stress and yield elongation from up to 0.3% TBT concentration, with similar Young modulus. The storage modulus was similar at room temperature for blends with and without TBT. The thermal properties showed insignificant changes among the formulations. The crystallization behavior seemed to be influenced by a chain scission and copolymer generation competition promoted by transesterification, and altered the microbial susceptibility to a certain extent. PLOM and SEM results showed a blend morphology evolution from a co-continuous-like to a co-continuous-to-dispersed-like when the TBT concentration increased. Overall, TBT was an effective transesterification catalyst for the generation of a cohesive morphology with good mechanical properties, with no loss of microbial susceptibility.

This paper addresses the recycling of an industrial waste of jute (Corchoruscapsularis) and polypropylene fibers from Tapetes Sao Carlos carpet manufacturer conducted through the manufacture of composite materials and use of polypropylene (PP), a compatibilizer (C), and nano-calcium carbonate (N). The components were mixed in a co-rotational twin-screw extruder and dumbbell-shaped specimens were produced by injection molding. A masterbatch was previously processed for improving N dispersion in the polymer matrix. The composites were exposed to accelerated aging and tested by tensile and contact angle measurements, and evaluated by visual appearance before and after accelerated aging. The morphological evaluation was conducted by scanning electron microscopy (SEM). The processing techniques used provided composites with 50 wt.% waste, good N dispersion, no thermal or mechanical degradation of fibers, and better mechanical properties than pure PP. The presence of industrial waste led to a 135 % improvement in the elastic modulus of PP matrix and decreased deformation at break from 435 % to 5 %.N acted as mechanical reinforcement and decreased wettability. 18 % and 16 % improvements were achieved in the elastic modulus of the matrix when N was incorporated through the masterbatch and by direct extrusion, respectively. The composite processed after the manufacture of the masterbatch and with no compatibilizer showed a 186 % improvement in the elastic modulus of the matrix, lowest wettability, and best average performance under accelerated aging. Accelerated aging promotes a small reduction in stiffness, but a drastic dropping in the elongation of the materials. The composites can potentially be used in several commercial applications due to their properties and processing flexibility, which are relevant from both sustainable and economic viewpoints.

The accumulation of plastic wastes in different environments has become a topic of major concern over the past decades; therefore, technologies and strategies aimed at mitigating the environmental impacts of petroleum products have gained worldwide relevance. In this scenario, the production of bioplastics mainly from polysaccharides such as starch is a growing strategy and a field of intense research. The use of plasticizers, the preparation of blends, and the reinforcement of bioplastics with lignocellulosic components have shown promising and environmentally safe alternatives for overcoming the limitations of bioplastics, mainly due to the availability, biodegradability, and biocompatibility of such resources. This review addresses the production of bioplastics composed of polysaccharides from plant biomass and its advantages and disadvantages.

Scaffolds of poly(ε-caprolactone) (PCL) and their biocomposites with 0, 1, 3, and 5 wt.% Biosilicate® were fabricated by the generative manufacturing process coupled with a vertical miniscrew extrusion head to application for restoration of bone tissue. Their morphological characterization indicated the designed 0°/90° architecture range of pore sizes and their interconnectivity is feasible for tissue engineering applications. Mechanical compression tests revealed an up to 57% increase in the stiffness of the scaffold structures with the addition of 1 to 5 wt.% Biosilicate® to the biocomposite. No toxicity was detected in the scaffolds tested by in vitro cell viability with MC3T3-E1 preosteoblast cell line. The results highlighted the potential application of scaffolds fabricated with poly(ε-caprolactone)/Biosilicate® to tissue engineering.

To design more sustainable products often means improving the sustainability of materials. Currently, sustainable innovation calls upon materials to not only minimize environmental impacts but also to become circular. That requires efforts to keep materials functional for longer, avoid early disposal, and re-entering the cycle via recycling and other feedback processes. Those emerging challenges for materials development and the Circular Economy (CE) are especially critical in the case of polymers. How to develop strategies to preserve the value of polymers remains a question that mobilizes both researchers and practitioners. Technology Roadmapping (TRM) is a tool traditionally used for planning innovation processes and has supported the development of sustainable materials and other sustainability-related projects. This study tests TRM’s potential to assist with the planning of new circular polymers solutions and proposes the Circular TRM method. This proposition results from the case study of the development of waste-based fiber-polymer materials and strategies for getting them into the market. Our case study demonstrates how it would be possible to differentiate the various polymer material technologies and determine the most circular strategy path.

Scaffolds of poly(ε-caprolactone) (PCL) and their biocomposites with 0, 1, 3, and 5 wt.% Biosilicate® were fabricated by the generative manufacturing process coupled with a vertical miniscrew extrusion head to application for restoration of bone tissue. Their morphological characterization indicated the designed 0°/90° architecture range of pore sizes and their interconnectivity is feasible for tissue engineering applications. Mechanical compression tests revealed an up to 57% increase in the stiffness of the scaffold structures with the addition of 1 to 5 wt.% Biosilicate® to the biocomposite. No toxicity was detected in the scaffolds tested by in vitro cell viability with MC3T3-E1 preosteoblast cell line. The results highlighted the potential application of scaffolds fabricated with poly(ε-caprolactone)/Biosilicate® to tissue engineering.

Embora diferentes segmentos do mercado de filmes polimericos possuam diferentes exigencias de desempe-nho, as propriedades dos filmes dependem da arquitetura molecular, microestrutura, orientacao molecular e cristalinidade, desenvolvidas em funcao do tipo de maquinario utilizado e das condicoes do processamento. Portanto, o conhecimento das microestruturas desenvolvidas e de grande interesse cientifico e tecnologico. Neste trabalho foi estudada a correlacao entre orientacao molecular, cristalinidade e propriedades de permea-bilidade, ao vapor de agua e ao oxigenio, de filmes biaxialmente orientados de polietileno linear de baixa densidade (PELBD), obtidos pelo processo de extrusao plana e estirados com diferentes razoes de estiramen-to. O estudo da orientacao molecular revelou a mudanca da estrutura morfologica das cadeias da fracao cris-talina dos filmes submetidos a maiores graus de estiramento. Resultados do grau de cristalinidade dos filmes de PELBD evidenciaram uma tendencia de aumento da cristalinidade com o aumento da orientacao das ca-deias polimericas, devido ao estiramento. Resultados de propriedades de barreira mostraram que o aumento do grau de estiramento possui efeito moderado na diminuicao da permeabilidade ao oxigenio e ao vapor de agua dos filmes PELBD, e que esse comportamento esta relacionado ao grau de estiramento e cristalinidade dos filmes. Palavras-chave: Polietileno linear de baixa densidade, Orientacao molecular, Permeabilidade, Cristalinidade.

The influence of nanofiller, plasticizer and hydroxyvalerate (HV) contents on the properties of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/clay nano-biocomposites is studied. Analyses by wide-angle X-ray diffraction and differential scanning calorimetry showed that both the organo-modified montmorillonite clay and acetyl tributyl citrate plasticizer facilitate the crystallization process of PHBV. Despite its nucleating effect, the nanoclay hampers the spherulite growth and leads to a reduction in the copolymer crystallinity, while the addition of plasticizer induces the formation of thicker spherulites. For all studied systems, it was shown that the variation of mechanical properties of these nano-biocomposites is strongly influenced by their changes in crystallinity. © 2013 Elsevier Ltd. All rights reserved.

Cellulose nanocrystals (CNC) were successfully grafted with a low molecular weight poly(butylene glutarate) through an “in situ” polymerization procedure. The grafting treatment decreased the CNC hydrophilic character and increased the onset of their thermal degradation by approximately 20°C, thus increasing the possibilities of CNC application. Composites of grafted and nongrafted CNC with a poly(butylene-adipate-co-terephthalate) (PBAT) matrix were prepared by melt extrusion. The CNC addition led to an increase of 50% of the tensile elastic modulus of the PBAT. In addition, dynamic mechanical thermal analysis showed that the composite with CNC retained its high modulus even at temperatures far above the glass transition temperature of PBAT. At 60°C the storage modulus of the composite with CNC was approximately 200% higher than that of the pure PBAT. Thus, in this work, nanocomposites of improved properties were obtained through a combination of “in situ” polymerization and melt extrusion. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

Bionanocomposite films of poly(ɛ-caprolactone) (PCL) and poly(butilene succinate-co-adipate) (PBSA) blends with cellulose nanocrystals (CNW) grafted with PCL chains (CNW-g-PCL) were prepared by solution casting and their thermal properties and crystallinity were studied. The CNW surface was modified with PCL chains by grafting “from” approaches, in an effort to improve their compatibility with the polymer blends. The grafting efficiency was evidenced by FTIR and TGA analysis. The acicular morphology of CNW-g-PCL was characterized by SEM. The TGA results showed an increase in the thermal stability of the CNW grafted with PCL chains. The PCL/PBSA blends showed higher thermal stability in comparison with the neat polymers and PCL/PBSA/CNW-g-PCL bionanocomposites. DSC results showed the CNW-g-PCL act as a nucleating agent in the bionanocomposites. Additionally, a better interaction of the CNW-g-PCL in the blends of 30/70 composition in comparison with the blends of 50/50 composition was characterized. The results obtained for aforementioned films prepared by solution casting encourage the production of such bionanocomposites by melt compounding (extrusion), aiming the achievement of new bionanocomposites materials with improved thermal and mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44493.

© 2016 Wiley Periodicals, Inc.Electrospun nanocomposites of poly(ε-caprolactone) (PCL) incorporated with PCL-grafted cellulose nanocrystals (PCL-g-CNC) were produced. PCL chains were grafted from cellulose nanocrystals (CNC) surface by ring-opening polymerization. Grafting was confirmed by infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The resulting PCL-g-CNC were then incorporated into a PCL matrix at various loadings. Homogeneous nanofibers with average diameter decreasing with the addition of PCL-g-CNC were observed by scanning electron microscopy (SEM). PCL-g-CNC domains incorporated into the PCL matrix were visualized by transmission electron microscopy (TEM). Thermal and mechanical properties of the mats were analyzed by differential scanning calorimetry (DSC), TGA and dynamic mechanical analysis (DMA). The addition of PCL-g-CNC into the PCL matrix caused changes in the thermal behavior and crystallinity of the electrospun fibers. Significant improvements in Young's modulus and in strain at break with increasing PCL-g-CNC loadings were found. These results highlighted the great potential of cellulose nanocrystals as a reinforcement phase in electrospun PCL mats, which can be used as biomedical materials.

Cellulose nanocrystals (CNC) were grafted with an aliphatic and an aromatic isocyanate (octadecyl and 4-phenylbutyl isocyanate) and composites of poly(butyleneadipate-co-terephthalate) – PBAT – with 5 and 10 wt% of modified and non-modified CNC were prepared through solvent casting. Rheological analysis confirmed that the degree of grafting contributed to CNC dispersion and allowed the formation of a percolated structure. The treated-CNC reinforced composites displayed improved mechanical properties, namely: an increase by 120% and 40% in the elastic modulus and the tensile strength, respectively. The best results were obtained with 4-phenylbutyl isocyanate-modified CNC, due to the π – π interactions between the phenyl rings grafted onto the CNC molecules and the aromatic rings of the polymeric chain, as indicated by Raman spectroscopy. To the best of our knowledge, it is the first time that the CNC incorporation is studied in a PBAT pure matrix.

This work describes the preparation of composites of polypropylene and organophilic bentonites based on Brazilian and Argentinean bentonites. During the processing of the samples in a twin screw microextruder, torque and pressures of the extruder were accompanied and the viscosity values were calculated. No significant changes in the torque, pressure and viscosity were found for composites prepared with different bentonites. The samples were characterized by XRD and TEM to evaluate the structure and dispersion of the organophilic bentonites. Composites with exfoliated, partially exfoliated and intercalated structures were obtained and correlations between the intrinsic properties of the sodium clays and organophilic bentonites and their influence on the composites were studied. The cation exchange capacity of the sodium bentonites and the swelling capacity of the organophilic bentonites were the most important properties to obtain exfoliated structures in composites. All bentonites showed the potential to obtain polymer nanocomposites, but the ones from Argentina displayed the best results.

Nanocomposites of an organic-modified montmorillonite (MMT) and polyamide 6 (PA6) with a residual monomer were produced by melt mixing in a torque rheometer. By wide angle X-rays diffraction (WAXD), intercalated/exfoliated structures were observed in the PA6/MMT nanocomposites with 3 and 5 wt. (%) of MMT; on the other hand, when 7 wt. (%) of MMT was added, a nanocomposite with exfoliated structures was obtained due to the predominant linking reactions between the residual monomer and the "nanoclays" organic surfactant. Solutions of these PA6/MMT nanocomposites at 15, 17 and 20 wt. (%) in formic acid were prepared. The 3 and 5 wt. (%) nanocomposites were successfully electrospun; however, electrospinning of the 7 wt. (%) nanocomposite was not possible. WAXD, scanning and transmission electron microscopy results showed that the 3 and 5 wt. (%) nanofibers with average diameter between 80-250 nm had exfoliated structures. These results indicate that the high elongational forces developed during the electrospinning process changed the initial intercalated/exfoliated structure of the nanocomposites to an exfoliated one.

Two ethylene-vinyl acetate (EVA) resins with 19% (EVA19) and 28% (EVA28) of vinyl groups were used as compatibilizers for nanocomposites of high-density polyethylene (HDPE) and nanoclays. Two nanoclays were also used, one with a nonpolar surfactant (C15A) and another with a polar surfactant (C30B). The HDPE/EVA19/C15A formed an intercalated structure, while the HDPE/EVA28/C30B had surfactant loss. Blown films of these compositions were produced. A two-phase morphology made of HDPE and EVA/nanoclay particles was observed, which was responsible for the increase in water vapor and oxygen permeability rates of the films. The elastic modulus E along the transverse direction of the films was higher than along the machine direction due to preserved orientation given by the spiral die; the lamellae orientation was measured by small-angle X-rays diffraction. The highest E was observed in the HDPE/EVA19/C15A film due to stronger interactions. The long period of the HDPE lamellas was not affected by the presence of the EVA and nanoclay. A model was proposed to explain the improvement in elastic modulus due to the processing conditions and components' interactions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Intercalated polypropylene (PP)/clay nanocomposites were produced by twin screw extrusion; afterwards, the optical monitoring of their injection molding was done using a laser sensor. The transmitted light intensity as a function of molding time was measured. The mold and melt temperatures, packing pressure and flow rate were changed. The nanocomposite had higher induction times than the PP, that is, scattering structures were detected later in the nanocomposite than in the PP, which was attributed to a retardation effect promoted by the clay on the PP crystallization growth rate. The morphologies of the injection molded samples were analyzed by polarized light optical microscopy, differential scanning calorimetry and transmission electron microscopy. The nanocomposite samples showed a second core, a thicker skin layer, highly oriented nanoclay's tactoids in the skin region and average spherulites' sizes smaller than the PP. The final light intensity I f was correlated with the spherulites' sizes: high values of I f represented samples with large spherulites. The PP sample had average spherulites' sizes larger than the Nano samples. However, the surging of a second core with large spherulites in the Nano samples changed the expected pattern: the PP samples showed I f lower than the Nano samples. POLYM. ENG. SCI., 50:1326-1339, 2010. © 2010 Society of Plastics Engineers.

The use of a compatibilizer to improve the interactions between poly(trimethylene terephthalate) (PTT) and an organically treated montmorillonite (MMT) clay was studied. Nanocomposites, with and without compatibilizer, were obtained using a torque rheometer; their nanostructures were analyzed by wide angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), steady state and dynamic rheological measurements, and Fourier transform infrared analysis (FT-IR). Only intercalated structures were obtained when no compatibilizer was added, independent of the mixing method (one or two steps); when the compatibilizer was added, however, intercalated and exfoliated structures were obtained, depending on the masterbatch composition. When the PTT was not present in the masterbatch, two-phase exfoliated structures were obtained, with a disperse phase composed of nanoclay's lamellas and reticulated compatibilizer and a matrix phase composed of PTT. The compatibilizer cured due to the presence of the nanoclay's surfactant; a mechanism of cure was proposed in which the epoxide rings of the compatibilizer reacted with the hydroxyl groups of the nanoclay's surfactant, forming ether cross-linkages. It was also concluded that in order to obtain one-phase exfoliated structures the two steps mixing method using a masterbatch composition of 50 wt% of PTT, 25 wt% of compatibilizer, and 25 wt% of nanoclay gave the best results; after further dilution in the PTT, an exfoliated nanocomposite with a final concentration of 5 wt% of compatibilizer and 5 wt% of nanoclay was obtained. Copyright © 2008 John Wiley & Sons, Ltd.

Poly(vinyl alcohol) (PVOH) was obtained from the alkaline hydrolysis of poly(vinyl acetate) (PVAc). Nonwoven membranes (mats) of PVOH nanofibers were produced by electrospinning of solutions of PVOH in water with and without aluminum chloride. The concentration of the PVOH/water solution was 12.4% w/v. The morphology of the mats was analyzed by scanning electron microscopy (SEM). The thermal properties and the degree of crystallinity of the nanofibers were measured by differential scanning calorimetry (DSC); the crystal structure of the mats was evaluated by wide-angle X-ray diffraction. The best nanofibers were obtained by electrospinning the PVOH/water solution with aluminum chloride (45% w/v) in which an electrical field of 3.0 kV/cm was applied. It was observed that the addition of the aluminum chloride and the increase in the applied electrical field decreased the number-average nanofibers diameters. The mats without aluminum chloride had higher melting temperatures and higher degrees of crystallinity than the mats with the salt. The crystal structure of the mats was found to be monoclinic; however, the mats were neither highly oriented nor have a high degree of crystallinity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The influence of matrix viscosity and polarity on ethylene-vinyl acetate copolymer (EVA) nanocomposites was studied. Five different EVA grades, with different melt flow indexes (MFIs) and/or vinyl acetate (VA) contents, were mixed with two montmorillonite (MMT) nanoclays: pristine and modified with a polar surfactant, producing 75/25 w/w% masterbatches which were subsequently diluted in the EVA matrix to obtain 5 wt% MMT nanocomposites. Although the same VA content, WAXS results, rheological measurements and TEM analysis showed that the lower the EVA viscosity, the greater the tendency to obtain exfoliated and well dispersed nanocomposites with the organically modified clay. On the other hand, the high viscosity EVA nanocomposites showed that the (001) organoclay diffraction peak was shifted to higher values of 2θ, suggesting lamellae collapsing. TGA and FTIR measurements were used to probe the thermal degradation of organoclay; furthermore, it was not possible to identify, by the techniques used, any reaction between the VA groups and hydroxyl surfactant groups. Thus, it was inferred that the organic surfactant was removed (or ejected) from the clay galleries as a consequence of huge shear tensions developed during processing of the masterbatches/nanocomposites with high viscosity EVA matrices. Copyright © 2009 John Wiley & Sons, Ltd.

The Amazon Rain Forest has attracted worldwide attention due its large scale services to climate and also due to the green house gas emissions arising from deforestation. Contributing to the later and detrimental to the former, timber logging in the region has very low efficiency (only 16% in the production chain). Such timber extraction, often referred to as selective logging, has been claimed as a sustainable extractive industry, because the forest is said to restore itself through regenerative growth. But forest regeneration in the Amazon occurs naturally only in a very limited scale, resulting that large scale, low efficiency logging poses a big treat to the functional integrity of the biome, supplying to the market only a fraction of what it could if done differently. So, instead of extracting big centennial logs from the forests, the Amazonian Phoenix project proposes that large expanses of degraded lands be reforested using pioneer plants species from the forest itself. These plants have the capacity to heal gaps in the canopy, being able to grow and produce woody biomass in very extreme conditions. The idea is to mimic the regenerative dynamics of the natural ecosystem in short cycle agrosilvicultural production areas, utilizing a variety of technologies to transform raw fibers from these fast growth native plants into a variety of materials with high aggregated value. This communication presents the research on natural fibers by the Polymeric Composites Group within the Amazonian Phoenix Project. Sustainable technologies employing materials with good and responsible ecological footprints are important and necessary stimulus for a change in the destructive economical activities present in the Amazon frontiers. The relatively well established wood polymer composites technology, for example, is a good candidate solution. Two research and development fields are proposed: the first one considers production systems with simple and cheap machinery, to facilitate technology assimilation by rural communities in the Amazon. The second one aims at developing composite materials with advanced production technology, like profile and sheet extrusion and injection molding. The source of the fibers would be both the short cycle agrosilviculture with softwood species, on already deforested lands, and the hardwood residues from operating sawmills. Preliminary results show that softwood fibers act as potentially important reinforcement for synthetic plastics.

In this work, high density polyethylene (HDPE) was mixed in a twin screw extruder with organophilic treated clay, Cloisite 20A, and a compatibility agent, a HDPE grafted with maleic anhydride (PEMA). The screw profile was changed from a less dispersive (Profile 1) to a high dispersive configuration (Profile 2). A masterbatch procedure was used to obtain a final organoclay concentration of 5 wt.%. Both profiles allowed the intercalation of the HDPE into the clay, increasing the clay’s gallery distance to 3.7 nm. However, the samples produced with Profile 2 (Nano 2 samples) were more elastic and had a more stable structure than the samples produced with Profile 1. Therefore, two kind of blown films of Nano 2 samples were made: FN1 and FN2. The last one was blown at a higher screw velocity than the FN1. Both films had an increase of 95% in the elastic modulus and a reduction of 60% and 45% in O2 and water vapor permeability rates, respectively, compared to the film of pure HDPE. However, the FN2 structure was more unstable than the FN1 structure. It was concluded that both screw profiles gave the same level of HDPE intercalation in the clay; however, the more dispersive profile produced more time-stable and elastic structures. The increase in the elongation rate during the film blowing process produced also more time-stable morphologies; however, this higher orientation created matrix/filler interfacial defects. 2008 Elsevier Ltd. All rights reserved.

The crystalline uniaxial molecular orienta- tion of two liquid crystalline polymers (LCPs), Vec- tra 1 A950, and Rodrun 1 LC5000, blended with poly(ethyl- ene terephthalate) (PET) was obtained from wide angle X-ray pole figures. The blends films were produced by extrusion using a twin screw extruder with a slit die. The molecular orientation was evaluated along the transverse section of the films and as a function of the blends composi- tion. The influence of a compatibilizer agent on the LCPs orientation was also analyzed. It was found that the orienta- tion of both LCPs in the pure LCP films was high, highest in the draw direction but variable along the transverse sec- tion of the extruded films; in this last case, it was higher at the position where the shear rate was maximum. However, a drastic orientation decrease in both LCP's phases was observed in the films made of PET/LCPs blends. The maxi- mum orientation effects were observed for the blend with 5 wt % of LCP content and also at the position where the shear rate was the highest. The Vectra 1 A950 LCP, as a pure material and in the blend with PET, orient more effectively than the Rodrun 1 LC5000 LCP in the films produced at the same processing conditions. The results showed that the use of a compatibilizer agent decreased the LCP orientation and were in accordance with previous studies using polar

Oriented β-phase films were obtained by utilizing two different techniques: conventional uniaxial drawing at 80 °C of predominantly α-phase films, and by drawing almost exclusively β-phase films obtained by crystallization at 60 °C from dimethylformamide (DMF) solution with subsequent pressing. Wide angle X-ray diffraction (WAXD) and pole figure plots showed that with the conventional drawing technique films oriented at a ratio (R) of 5 still contained about 20% of phase α, a crystallinity degree of 40% and β-phase crystallographic c-axis orientation factor of 0.655. Drawing at 90 °C and with R = 4 of originally β-phase films results in exclusively β-phase films with crystallinity degree of 45% and orientation factor of 0.885. Crystalline phase, crystallinity degree, and crystallographic c-axis orientation factor of both phases were also determined for α-phase oriented films obtained by drawing α-phase films at 140 °C. For films drawn at 140 °C the α to β phase transition drops to about 22%. Reduction in crystallinity degree with increasing R is more pronounced at draw temperature of 140 °C compared with 80 °C. Moreover, for both phases the c-axis orientation parallel to the draw direction is higher at draw temperature of 140 °C than at 80 °C. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2793–2801, 2007

This study investigates the antibacterial properties of the natural oil from Copaifera multijuga which was embedded in bio-based materials, to be used in active packaging applications. For this purpose, the naturally extracted copaiba oil was first characterized by gas chromatography and thermogravimetry. Its antibacterial properties were evaluated and confirmed against gram-positive bacteria (Bacillus subtilis). The copaiba oil was incorporated into two bio-based materials: (i) paper and (ii) poly(lactic acid), PLA, films. This incorporation was made following two strategies: either at the surface, thanks to a coating process, or in the bulk, through impregnation (paper samples) or by film casting (PLA films). The antibacterial tests confirmed activity against B. subtilis in paper with a copaiba oil content of approximately 20 wt%. For the PLA films, the same amount showed satisfactory results against the same bacteria. To the best of our knowledge, it is the first time that copaiba oil has been incorporated on paper sheets and plastic films, with the confirmation of the maintenance of the effective antibacterial properties. The materials developed in this work through simple procedures have great perspective to be used as biodegradable packaging with bactericide effect, to improve the shelf life of food products.

The change of the processing parameters of a blown film operation alters the mechanical and optical properties of the films. This work studied the influence of some of these parameters on the properties of blown films made of blends of linear low-density polyethylene (LLDPE) and LDPE. Correlations between the crystalline biaxial orientations of these films and the mechanical properties were found. The crystalline biaxial orientation was measured by IR following the Krishnaswamy approach. The a axis of the unit cell was oriented along the machine direction (MD) at all LDPE concentrations, and it was not affected by the blow-up ratio (BUR). In contrast, the b axis changed its orientation from orthogonal to MD to along the transverse direction (TD), and it was affected by the BUR. Finally, the c axis changed its orientation from equiplanar between the MD and TD to along the thickness of the film, and it was influenced by the BUR. The decrease of the tensile mechanical properties along the MD with the increase in the amount of LDPE in the blends was attributed to the tilting of the c axis toward the film thickness. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3161–3167, 2006

The polarized infrared (IR) spectroscopy technique was used to evaluate the surface uniaxial molecular orientation of films of poly(ethylene terephthalate) (PET), two thermotropic liquid crystalline polymers (LCPs), Vectra®A950 and Rodrun®LC5000, and their blends obtained by extrusion. The molecular orientation of the LCP and of the crystalline and amorphous PET phases in the draw direction was evaluated along the transverse section of the films and as a function of the blend composition. A compatibilizer agent was used to improve the interfacial adhesion between the PET and LCPs. The results showed that the surface molecular orientation of both LCPs was very high along the draw direction. However, when blended, the orientation of the LCP phase decreased drastically, it was dependent of its content and varied along the transverse section of the extruded films. The maximum orientation was observed in the blend with 5 wt % LCP content and at the position where the shear rate was maxima. The LCP Vectra®A950 showed higher orientation than the Rodrun®LC5000, as a pure material and as blended. For the PET phases, an alignment of the amorphous phase in the draw direction due to the presence of LCP and compatibilizer agent was observed. The crystalline phase of PET, however, showed no significant orientation in the draw direction. The compatibilizer agent proved efficient for both PET/LCP systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2241–2248, 2006

The biaxial molecular orientation of blown films made of blends of linear low density polyethylene (LLDPE) with low density polyethylene (LDPE) was characterized by two different methods: complete pole figures obtained by wide angle X-rays diffraction (WAXD) and polarized infrared spectroscopy (IR) using the Krishnaswamy approach. The molecular orientation of the blends amorphous phase was also evaluated by polarized IR. The crystallinity of the blown films was determined by WAXD. A good correlation between the X-ray pole figures and the polarized IR results was obtained. At all blends compositions, it was shown that the a-axis of the polyethylene orthorhombic cell was preferentially oriented along the machine direction, the orientation degree along this direction increasing with the increase of the LDPE amount in the blends. The b-axis changed its preferential orientation from film thickness in the 100/0 LLDPE/LDPE film to along the transverse direction with increasing LDPE in the blends. The c-axis changed its orientation from orthogonal to normal direction in the 100/0 LLDPE/LDPE film to along the film thickness with increasing LDPE in the blends. Polarized IR characterization showed a negligible orientation of the amorphous phase. The amount of crystallinity was dependent on blend composition decreasing with the increase of LDPE content in the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2760–2767, 2006