Introduction to the Study of Mechanical Properties of Terpolymer PP/EPDM Mixtures

Thermoplastic elastomers (TPEs), based in PP (Polypropylene) / EPDM (Ethylene Propylene Diene Monomer) have as purpose improving PP resistance and impact, aiming to a more comprehensive use in automotive market, among edifications, construction and packaging sectors, due to their recyclability properties. PP is a commodity, with a high melting point, high mechanical resistance and low density, posing a balance between physical and mechanical properties; in addition, it shows an easy processing, at low cost. In order to minimize this deficiency, EPDM, an impact modifier, can be used. Nevertheless, most of polymeric blends are incompatible and immiscible, i.e., show a mutual and limited solubility and in most of cases, a high interfacial tension. However, there is a relatively low interfacial tension (force which acts on transformation of a continuous structure in a dispersion) between PP and EPDM (approximately 0.3 mN.m-1), reducing the rate of breakup and facilitating the build-up of a continuous structure. This work aims to the study of compatibility of PP and EPDM blends and variation of mechanical properties, emphasizing that many properties of thermoplastic elastomers can be processed according with conventional thermoplastics methods: herein, PP/EPDM blends, 90/10, 80/20, 70/30 and 50/50 were characterized according to: Mechanical essays, Differential Scanning Calorimetry, Thermogravimetric Analyses, Melt Flow Index, Izod Impact Strength and Dynamic mechanical Analyses

Effect of Ionizing Radiation Applied to PLA Used as Compatibilizing Agent in Reinforced eGG Shell PBAT/PLA Bio-Based Composites

Bio-filler from eggshells as reinforcement of bio-based polymers are based on their benefits as adequate strength and stiffness, besides friendly, degradable and renewable environment. Eggshell is an agricultural waste considered as garbage, contributing to pollution; nevertheless, it can be transformed into bio-calcium carbonate, acquiring new values. As biodegradable polymers, there were chosen PLA (poly-lactic-acid) and PBAT (butylene adipate co-terephthalate), thermoplastics capable to be processed via conventional methods. PLA is a linear, aliphatic thermoplastic polyester, high in strength and modulus, but brittle. PBAT is a synthetic polymer, very flexible, based on fossil resources with high elongation at break, but low strength. It will be required the use of compatibilizers, for reducing interfacial tension exhibited by PLA/PBAT immiscible blend, considering their extreme glass transition temperatures: 62 o C for PLA and – 30 o C for PBAT. Herein it was used ionizing radiation for inducing compatibilization by free radicals, improving dispersion and adhesion of blend phases, without using chemical additives, at room temperature. PLA, acting as compatibilizer, was previously e-beam and gamma radiated, at 150 kGy. PBAT/PLA 50/50 blend with 15 phr of bio-filler from avian eggs 125 µm particle size and both compatibilizers were homogeneized in a co-rotating twin-screw extruder, within a temperature profile 120 to 145 o C, from hopper to die. Characterization involved: Differential Scanning Calorimeter, Thermogravimetric Analyses, Fourier Transform Infrared Spectroscopy, Wide Angle X-Ray Diffraction, Tensile Strength and Elongation at Break

Study of Bio-Based Foams Prepared from PBAT/PLA Reinforced with Bio-Calcium Carbonate and Compatibilized with Gamma Radiation

Foamed polymers are future materials, considered “green materials” due to their properties with very low consumption of raw materials; they can be used to ameliorate appearance of structures besides contributing for thermal and acoustic insulation. Nevertheless, waste disposal has generated about 20–30% of total of solid volume in landfills besides prejudicing flora and fauna by uncontrolled disposal. The development of biodegradable polymers aims to solve this problem, considering that in 2012, bio-plastics market was evaluated in 1.4 million tons produced and in 2017 attained 6.2 million tons. Biodegradable polymers as poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are thermoplastics which can be processed using the most conventional polymer processing methods. PLA is high in strength and modulus but brittle, while PBAT is flexible and tough. In order to reduce interfacial tension exhibited by PLA/PBAT blends, it was used as compatibilizing agent 5 phr of PLA previously gamma-radiated at 150 kGy. Ionizing radiation induces compatibilization by free radicals, improving the dispersion and adhesion of blend phases, without using chemical additives and at room temperature. As a reinforcement agent, calcium carbonate from avian eggshell waste was used, at 10 ph of micro particles, 125 μm. Admixtures were further processed in a single-screw extruder, using CO2 as physical blowing agent (PBA). Property investigations were performed by DSC, TGA, XRD, SEM, FTIR, and mechanical essays

Consumo alimentar e perfil antropométrico de tenistas amadores e profissionais Food intake and anthropometric profile of amateur and professionals tennis players

INTRODUÇÃO: O perfil antropométrico e o consumo alimentar exercem grande influência no desempenho esportivo; entretanto, essas informações sobre tenistas brasileiros ainda são escassas. OBJETIVO: Descrever e comparar o consumo alimentar e o perfil antropométrico de tenistas amadores (AM) e profissionais (PRO). MÉTODOS: Foram avaliados 24 tenistas, com a seguinte distribuição: profissionais (PRO; n = 9) e amadores (AM; n = 15). Os atletas foram avaliados quanto a variáveis antropométricas (peso, estatura, circunferências e dobras cutâneas) e a composição corporal foi estimada por três diferentes protocolos. As dietas foram avaliadas a partir de três diários alimentares. RESULTADOS: Não houve diferença significativa no perfil antropométrico dos atletas PRO em relação aos AM (peso: 69,5 ± 9,8kg e 66,0 ± 5,0kg; estatura: 177,9 ± 4,3cm e 175,6 ± 2,7cm, IMC: 23,5 ± 1,4kg/m² e 22,6 ± 0,8kg/m² e gordura corporal: 13,0 ± 5,5% e 13,7 ± 2,4%, respectivamente). Observou-se significativo déficit energético entre a estimativa da necessidade energética e a ingestão energética relatada. O consumo de carboidratos apresentou-se no limite mínimo sugerido (AM: 6,3 ± 0,5g/kg/dia e PRO: 6,5 ± 0,7g/kg/dia), enquanto a ingestão de proteínas mostrou-se superior às recomendações disponíveis na literatura (AM: 2,4 ± 0,2g/kg/dia e PRO: 2,3 ± 0,3g/kg/dia). Com relação aos minerais, a principal preocupação foi a baixa ingestão de cálcio (AM: 798,1 ± 786,3mg/dia e PRO: 766,9 ± 602,4mg/dia). CONCLUSÃO: Não foram observadas diferenças significativas no perfil antropométrico e no consumo alimentar entre os atletas AM e PRO. Os desvios observados no consumo alimentar reforçam a necessidade de orientação/planejamento nutricional, a fim de atender às demandas específicas da modalidade, visando maximizar o desempenho.<br>The anthropometric profile and food intake play a key role in sports performance; however, there is little information available regarding Brazilian tennis players. AIM: the present study aimed to evaluate the food intake and the anthropometric profile of professional and amateur tennis players. METHODS: twenty-four tennis players were distributed in two groups: professionals (PRO; n = 9) and amateurs (AM; n = 15). The athletes were evaluated on their anthropometric measurements (body weight, height, circumferences and skin folders). Body fat was estimated from three different equations. Food intake was determined by a 3-day food diary. RESULTS: there were no significant differences from anthropometric profile between PRO and AM (body weight: 69.5 ± 9.8 kg and 66.0 ± 5.0 kg; height: 177.9 ± 4.3 cm and 175.6 ± 2.7 cm, BMI: 23.5 ± 1.4 kg/m² and 22.6 ± 0.8 kg/m² and body fat: 13.0 ± 5.5% and 13.7 ± 2.4%, respectively). Significant difference between the energy expenditure and estimation and reported energy intake was observed. Both groups showed low carbohydrate (AM: 6.3 ± 0.5 g/kg/day and PRO: 6.5 ± 0.7 g/kg/day) and high protein intake AM: 2.4 ± 0.2 g/kg/day and PRO: 2.3 ± 0.3 g/kg/day) compared to the current recommendations. Very low calcium intake was observed (AM: 798.1 ± 786.3 mg/day and PRO: 766.9 ± 602.4 mg/day). CONCLUSION: no significant differences were detected for food intake pattern and anthropometric profile between PRO and AM. The results presented herein reinforce the relevance of nutritional planning in order to achieve specific demands of tennis and maximize performance