Abstract Objective: To assess the predictive value of selected growth phenotypes for neonatal morbidity and mortality in preterm infants < 30 weeks and to compare them with INTERGROWTH-21st (IG21). Methods: Retrospective analysis of data from the Brazilian Neonatal Research Network (BNRN) database for very low birth weight (VLBW) at 20 public tertiary-care university hospitals. Outcome: the composite neonatal morbidity and mortality (CNMM) consisted of in-hospital death, oxygen use at 36 weeks, intraventricular hemorrhage grade 3 or 4, and Bell stage 2 or 3 necrotizing enterocolitis. Selected growth phenotypes: small-for-gestational-age (SGA) defined as being < 3rd (SGA3) or 10th (SGA10) percentiles of BW, and large-for-gestational-age (LGA) as being > 97th percentile of BW. Stunting as being < 3rd percentile of the length and wasting as being < 3rd percentile of BMI. Single and multiple log-binomial regression models were fitted to estimate the relative risks of CNMM, comparing them to IG21. Results: 4,072 infants were included. The adjusted relative risks of CNMM associated with selected growth phenotypes were (BNRN/IG21): 1.45 (0.92–2.31)/1.60 (1.27–2.02) for SGA; 0.90 (0.55–1.47)/1.05 (0.55–1.99) for LGA; 1.65 (1.08–2.51)/1.58 (1.28–1.96) for stunting; and 1.48 (1.02–2.17) for wasting. Agreement between the two references was variable. The growth phenotypes had good specificity (>95%) and positive predictive value (70-90%), with poor sensitivity and low negative predictive value. Conclusion: The BNRN phenotypes at birth differed markedly from the IG21 standard and showed poor accuracy in predicting adverse neonatal outcomes.

Abstract In this study, green high-density polyethylene (GHDPE) composites with 5, 10 and 15% natural powdered cork (CP) with and without 5% maleic anhydride (PE-g-MA) were developed in order to evaluate the potential of these materials for civil construction applications. The composites were produced in a co-rotating twin-screw extruder and injection molded. An impedance tube was used to determine the acoustic behavior of the composites, which were then used as ceiling tiles in prototypes of provisional constructions in order to study ascertain their performance with respect to thermal comfort in the City of Teresina, PI - Brazil. Our data indicates that composites sound absorption coefficient values are good between 500 and 1200 Hz, especially for those with a higher percentage of cork, with the lowest absorption rate observed for composites containing PE-g-MA. The composites used in the prototypes provided a decrease in the internal temperature of the built structure.

The present work investigates the aquatic biodegradation of poly(3-hydroxybutyrate) (PHB)/nanoclay bionanocomposites containing PP-g-MA as compatibilizing agent. Both pristine and organically modified (Cloisite20A®) montmorillonite clay were used as fillers in different content (1 and 3 wt%). The bionanocomposites were prepared by melt intercalation in a single screw extruder. There after films (50x50x0.5mm) were prepared by compression and assessed by X-ray diffraction. Aquatic biodegradation of the films was appraised by visual inspection, optical microscopy, counting and identification of bacteria. Results proposed that the water of the Parnaíba River in the city of Teresina (Piauí, Brazil) has microorganisms (Pseudomonas putida and Pseudomonas aeruginosa) capable of degrading these bionanocomposite films, particularly the films with 3 wt% organoclay. Our data indicated the bacteria Pseudomonas aeruginosa degraded dexterously all the films. This work collaborates with the preservation of the environment and expands the use of bionanocomposites in expendable items with the development of films with properties favorable to biodegradation in aquatic environments. It is believed that PHB/clay/PP-g-MA films emerge as a promising alternative for the packaging industry.

This work developed ternary films based on Poly(Lactic Acid) (PLA), Cloisite 30B (C30B) and Oregano Essential Oil (OEO) as proposal to be applied in food packaging. The films thus manufactured were unscathed, with reduced surface defects. Their thickness and moisture content varied according to the composition and content of each component in the formulation. Optical micrographs indicated a homogeneous morphology, with good distribution of clay in the matrix. FTIR data confirms the incorporation of OEO into the films. TGA analysis indicated that the thermal stability of the films was not significantly affected by the incorporation of C30B and OEO. OEO incorporation did not promote an efficient antimicrobial action which is probably due to its retention by the clay. Further studies are needed to confirm this hypothesis. The combination between C30B and OEO in the PLA polymeric matrix is a promising proposal.

Abstract Polymer processing parameters may considerably affect final product characteristic as, if properly chosen, these parameters may lead to products with optimal properties. The aim of this work is to evaluate the rheological characteristics of poly(ethylene terephthalate) (PET) by torque rheometry, as well as to estimate its incipient degradation rate during processing in an internal laboratory mixer. In order to estimate the temperature coefficient of the viscosity (β), and the pseudoplasticity index (n) of PET, two sets of experiments need to be performed. In the first one, the polymer is processed at three different temperatures at a single rotor speed for 10 min, getting temperature coefficient of the viscosity equal to β = 0.053 °C-1. In the second set of experiments, the resin (PET) is processed at a single temperature at six different rotor speeds for the same time interval and the pseudoplasticity index was determined, n = 0.78. From the results obtained, it is possible to indicate the internal mixer as an equipment not only for mixing polymers or composites, but as a tool for determining important rheological variables for predicting degradative processes.

Abstract The use of polymer blends and composites based on fossil-based and bio-based polymers has become an important environmentally protective alternative for common use and disposable plastics applications such as packaging, bottles and trays. The disposal of these more degradable products, however, may also harm the environment and, therefore, recycling these systems becomes relevant. Recycling involves reprocessing which can significantly change the morphology and properties of polymeric products. Therefore, this study deals with the effects of reprocessing cycles on the properties and morphology of blends and nanocomposites based on fossil and bio-based polymers. The systems investigated were: a) neat polypropylene (PP), b) a polypropylene/poly(3-hydroxybutyrate) (PP/PHB) blend and c) PP/PHB/organoclay nanocomposite compatibilized with polypropylene-g-maleic anhydride (PP-g-MA) and erucamide. These materials were submitted to up to seven extrusion cycles in a single screw extruder operating at 60 rpm. Samples were taken after the first, third, fifth and seventh extrusion cycles and their tensile properties and morphology were determined. Scanning electron microscopy indicated that two phases were observed in the blend which showed spherical PHB domains. The addition of clay, PP-g-MA and erucamide improved the adhesion between the nanocomposites components. X-ray diffraction analysis showed that crystallinity tended to increase with the number of reprocessing cycles for all systems investigated up to the fifth cycle and then tended to decrease. A 10% crystallinity increase was observed for neat PP in the fifth cycle. In general, the tensile properties of all systems decreased with reprocessing and the highest losses were observed for the PP/PHB blend after seven processing cycles with 50% and 37% decreases in stress at break and elastic modulus, respectively. Impact strength of the PP matrix and of the PP/PHB blend tended to decrease with reprocessing, except for the nanocomposite which showed a slight increase especially after the seventh processing cycle in which an 18% increase in impact strength was observed.

Abstract This study aims to evaluate the effects of natural weathering in the city of Teresina, State of Piauí, Brazil, on the morphology and mechanical properties of eco-composites based on high-density green polyethylene, powdered cork and compatibilizer processed in a twin-screw extruder and injection molded. The analyses revealed that although weathering induced surface bleaching of eco-composites and cracking, these effects were not intense in the compatibilized samples. The tensile properties of the investigated materials were affected by abiotic degradation, which led to a reduction of the tensile strength and elastic deformation of the eco-composites, however, the incorporation of PEgMA was fundamental for the maintenance of mechanical performance after natural aging. In general, the results obtained were satisfactory for external applications of the compatibilized eco-composite with 15% cork in the proposed weathering range, which indicates its possible use in temporary constructions.

Abstract The rheological behavior of poly (butylene adipate-co-terephthalate) (PBAT) and its composites prepared with three different organoclays was investigated. Composites containing up to 7.5%, w/w organoclay, were prepared by two routes: (a) direct melt blending in an internal laboratory mixer with high intensity rotors and (b) concentrates (prepared in the internal mixer) with 50 %, by weight, of the organoclays diluted in a co-rotating twin screw extruder equipped with a high intensity mixing thread operating at a nominal speed of 480 rpm. The samples were characterized by both torque and parallel plate rheometry. Results indicate that nanodispersions in the clay layers were obtained during processing and that, like the pure matrix, at high shear rates, the organoclay compounds follow the power law, although with higher viscosity. It is believed that the interaction of the polymer with the organoclay is responsible for the increase in melt viscosity (observed by increases in torque and relaxation time) of the hybrid systems.

Abstract Blends of Polystyrene (PS) and Poly(ε-caprolactone) (PCL) were twin screw extruded, two PSs, with low and high melt flow rate (MFR) were used and their feasibility within PCL investigated by means of torque rheometry, mechanical tests, heat deflection temperature (HDT) and scanning electron microscopy (SEM); predictive models were utilized to evaluate interfacial adhesion in PS/PCL blends. Results show that no decreasing was verified in torque rheometry plots suggesting thermally stable blends; elastic modulus decreased and elongation at break increased in PS/PCL blends compared to neat PS. PS/PCL blends with low MFR PS and higher PCL amount are more thermodynamically stable. Higher HDT was verified in PS/PCL blends. The trends observed applying predictive models are indicative of poor adhesion between PCL and PS, agreeing with coalescence and phase segregation as verified in SEM images. PS/PCL systems with higher MFR PS presented the best results.

Polymeric syntactic foams are composites made from the mixture of Hollow Glass Microspheres (HGM) and polymer matrices. One of their main characteristics is their low density and the production of these composites using a matrix derived from renewable sources potentiates their development without neglecting sustainability. In this paper , the properties of High Density Polyethylene (HDPE)/HGM syntactic foams containing 1% and 5% w/w HGM and 5% w/w of a compatibilizer are assessed. The composites were prepared by two processing routes: single screw extruder and twin screw extruder. The morphology and mechanical properties (tensile and impact) of the syntactic foams thus manufactured were ascertained. Morphological analysis indicated that matrix/filler adhesion was poor for all samples and that the best HGM dispersions were obtained in twin screw extruded samples. Mechanical properties were affected by the processing route adopted and by the content of hollow glass microspheres added. Elastic modulus, tensile strength and strain were reduced by 20, 10 and 23%, respectively, in systems processed in a twin screw extruder. Impact strength was the exception, with an increase of more than 300%. Higher contents of hollow glass microspheres led to reductions in mechanical strength of the syntactic foams, varying from 5% for the elastic modulus to 50% for strain.

The population increase, urbanization and climatic change adversely affect the agricultural production have prompted actions to improve the means of production without affecting the environment. One of the actions to make the production of food more efficient and sustainable is the use of plastics in protection of crops, soils and packaging, for example. Therefore, the aim of this work was to develop flat extruded mulch films of poly (butylene adipate-co-terephthalate)/2.5 and 5.0% sugar cane residue/2.0% carnauba wax for application in soil cover and characterize them as to their chemical structure, morphology and transmittance. The FTIR results suggest that there was no chemical interaction between the components of the mulch films. SEM images and optical microscopy showed that the polymer matrix was able to cover sugarcane residues and that the carnauba wax dispersed well in the PBAT matrix. In addition, carnauba wax addition increased the transmittance of these mulch films.

RESUMO O Polietileno (PE) Verde é um polímero sintético que apresenta baixa energia superficial, que resulta em fraca propriedade de adesão. Esta baixa adesão, provoca alguns problemas relativos às aplicações práticas dos polímeros, como fraca aderência de tintas de impressão, revestimentos, adesivos e metais à superfície do polímero, entre outros. Uma maneira de alterar essa propriedade é por meio da aplicação de um tratamento por plasma. Neste sentido, o objetivo deste trabalho foi preparar, via extrusão plana, filmes de biocompósitos com matriz de PE Verde (PEPURO) e carga de argila Vermiculita Expandida (VMT) no teor de 1%. Os filmes foram tratados por plasma em duas condições distintas: sob atmosfera de Oxigênio (O2) (C1); e sob atmosfera correspondendo a mistura de Argônio/Hidrogênio (Ar/H2) e um posterior tratamento por plasma sob atmosfera de O2 (C2). Os resultados indicaram que os tratamentos a plasma e a incorporação de VMT aumentaram a hidrofilicidade dos filmes, sendo que a aplicação da condição 2 (C2) mostrou-se de maneira mais eficiente. O PEPURO não tratado apresentou redução significativa de resistência máxima a tração com a inserção de VMT, já com a aplicação dos tratamentos (C1 e C2) os valores de resistência foram superiores. Em relação à rugosidade foi possível verificar que a aplicação do plasma aumentou a rugosidade na superfície das amostras. Estes resultados indicaram que o aumento da hidrofilicidade e da rugosidade resultaram em um aumento significativo na interação de fluidos com a superfície e também melhora das características adesivas do polímero.

ABSTRACT Green Polyethylene (PE) is a synthetic polymer that has low surface energy, which results in poor adhesion properties. This factor causes some problems regarding the practical applications of polymers, such as poor adherence of printing inks, coatings, adhesives and metals to the surface of the polymer, among others. One way to alter this property is by applying a plasma treatment. In this sense, the objective of this work was to prepare, by flat extrusion, biocomposite films with Green PE matrix (PEPURO) and load of Expanded Vermiculite Clay (VMT) in the 1% content. The films were treated by plasma under two different conditions: under O2 atmosphere (C1); (Ar/H2) and a subsequent treatment by plasma under O2 (C2) atmosphere. The results indicated that the plasma treatments and the incorporation of VMT increased the hydrophilicity of the films, and the application of condition 2 (C2) was shown more efficiently. The untreated PEPURO presented a significant reduction of maximum tensile strength with the insertion of VMT, already with the application of treatments (C1 and C2) the resistance values were higher. In relation to the roughness it was possible to verify that the application of the plasma increased the surface roughness of the samples. These results indicated that increased hydrophilicity and roughness resulted in a significant increase in the interaction of fluids with the surface and also improvement of the adhesive characteristics of the polymer.

ABSTRACT During the last decades, a lot of research work focused on several biodegradable and biosourced polyesters for the purpose of reducing the non-degradable polymer wastes. These polyesters are particularly considered to be promising polymers for biomedical applications and short life-time products like packaging. As these packagings are rapidly discarded, especially the food ones, their accumulation becomes a serious environmental problem. In order to replace these materials with new ones that do not harm the environment, several studies are being carried out about these materials. However, it presents some limitations as its thermal instability in the molten state and high cost of production, being the incorporation of clay to the polymer matrix, forming bionanocomposites, a viable alternative since it improves the mechanical and thermal properties of the material when compared to the pure polymer, and may or may not reduce the total cost of production. Among commercially-available polyesters, polyhydroxyalkanoates (PHAs) are produced by various bacteria and known to be fully biodegradable. The aim of this study was to develop and to characterize bionanocomposites produced from the polymer matrix of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) - PHBV and natural vermiculite and organoclay. The melt intercalation technique was used for obtaining systems in the form of films. The FTIR results unveiled changes in the bionanocomposites structure with the addition of the clay, verifying the incorporation and overlap of bands of both the natural clay and the quaternary ammonium salt. Through the XRD technique, it was observed a greater disorganization in the systems compared to the pure polymer, suggesting a structure of a microcomposite for the systems with natural clay and tending to a greater exfoliation for the systems with organoclay vermiculite. From the micrographs by MO and MEV, the films presented a small number of clusters for the natural systems and a more uniform structure for the organophilic systems, thus corroborating with the XRD. In this way, it was evidenced that the systems with organoclay were the ones that presented better against the characteristics desired for its possible industrial application. Thus, elaborated bionanocomposites may be an alternative to the substitution of synthetic polymers in the industry, for example, in food packaging.

RESUMO A adição de fibras naturais a uma matriz de polímero biodegradável tem sido uma alternativa para obter compósitos com melhores propriedades térmicas e mecânicas. Tendo em vista que as propriedades dos compósitos possam ser influenciadas pelas condições de processamento, tipo e concentração da fase dispersa, este trabalho teve como objetivo obter compósitos a partir de uma blenda comercial constituída de Poli (butileno adipato co-tereftalato) - PBAT/ Amido (EB), de caráter biodegradável, e casca de arroz (CA). Inicialmente foram preparados compósitos com PBAT/Amido contendo 10,20 e 30% de (CA) utilizando extrusora de dupla rosca e misturador interno. Posteriormente, foram determinadas propriedades mecânicas e térmicas dos sistemas obtidos. Os resultados das propriedades mecânicas mostraram que o módulo elástico dos compósitos foi afetado pelo tipo de processamento empregado, os compósitos obtidos em extrusora apresentam maior módulo que os compósitos obtidos no misturador: 92% maior em compósitos com 10% de carga, e 38% maior em compósitos com 30% de carga. A resistência ao impacto diminuiu significativamente e a resistência a tração aumentou moderadamente com o teor de casca de arroz, independente do tipo de processamento utilizado. A resistência ao impacto de compósitos com 30% de carga é aproximadamente 33% da resistência ao impacto da blenda pura. Já na resistência a tração, observou-se um aumento de 25% nos compósitos com 30% de carga. Análises de MEV indicam que as partículas de carga foram adequadamente molhadas pela matriz e que a adesão carga/matriz é boa. A avaliação dos resultados obtidos com as análises de DSC indicou que a adição de CA nos compósitos extrusados altera a temperatura de cristalização, variando de 75ºC da amostra pura, para 101ºC para as amostras com casca de arroz, resultado atribuível ao efeito nucleante causado pela maior dispersão da carga neste tipo de processamento.

ABSTRACT The addition of natural fiber is a biodegradable polymer matrix has been an alternative for composites having enhanced thermal and mechanical properties. Considering that the properties of the composite can be influenced by the processing conditions, type and concentration of the dispersed phase, this study aimed to obtain composites from a commercial blend made of Poly (butylene adipate co-terephthalate) - PBAT / Starch (EB), of biodegradable character, and rice husk (CA). Initially composites were prepared PBAT / starch containing 10, 20 and 30% (CA) using a dual extruder and internal mixer screw. Subsequently, there were certain mechanical and thermal properties of the systems obtained. The results of mechanical properties showed that the elastic modulus of the composite was affected by the type of employee processing the composites obtained in the extruder have a higher modulus than the composite obtained in the mixer: 92% higher in composites with 10% load and 38% higher in composites with 30% filler. The impact resistance decreased significantly and the tensile strength increased moderately with rice husk content, regardless of the type of processing used. The impact resistance of composites with 30% load is approximately 33% the impact resistance of the pure blend. In the tensile strength, there was a 25% increase in the composite with 30% filler. SEM analyzes indicated that the filler particles were adequately wetted by the matrix and the adhesion load / matrix was good. The evaluation of the results obtained with the DSC analysis indicated that the addition of CA in the extruded composite alter the crystallization temperature ranging from 75 ° C pure sample to 101ºC for samples with rice husk, as a result attributable to the nucleating effect caused by the greater this type of load dispersion processing.

Resumo Este trabalho teve como objetivo preparar e avaliar filmes PHB/vermiculita natural e modificada nas quantidades em peso de 1%, 3% e 6% através dos métodos intercalação por fusão e intercalação por solução. Os bionanocompósitos obtidos pelo método intercalação por fusão foram preparados em uma extrusora monorosca e posteriormente os filmes foram moldados via compressão. Na preparação dos filmes por solução, os sistemas foram submetidos à agitação e aquecimento a 80 °C. Os sistemas foram avaliados por difração de raios-X e o comportamento de biodegradação foi avaliado de acordo com a norma ASTM G 160-03. O acompanhamento da biodegradação foi realizado por meio de inspeção visual e perda de massa. Observou-se que o percentual de argila e o método de obtenção dos filmes influenciaram na estrutura formada e na biodegradação dos sistemas.

Abstract This study aimed to prepare and to evaluate natural and modified PHB /vermiculite films in quantities of 1%, 3% and 6% by weight, through melt intercalation and solution intercalation methods. The bionanocomposites in the form of thin films, obtained by the melt intercalation method, were prepared in a single screw extruder and then molded via compression. In the preparation of the films by solution method, the systems were stirred and heated at 80 °C in the presence of the chloroform solvent. The systems were evaluated by X-ray diffraction and the degradation behavior was evaluated according to ASTM G 160-03, by visual inspection and through weight loss. It was observed that the percentage of clay and the method of obtaining of the films influenced in the structure and biodegradability of the systems.