RESUMO Neste estudo, foram avaliadas blendas de polipropileno copolímero (PPCop)/polipropileno reciclado (PPRec), proveniente de baldes industriais pós-consumo, em três proporções diferentes (80:20; 60:40 e 40:60% em peso). As blendas foram avaliadas por índice de fluidez, reometria de torque e reologia em regime dinâmico-oscilatório. Os resultados de índice de fluidez indicaram que a mistura de material reciclado com o PPCop promove uma diminuição da massa molar, em comparação ao PPCop. Por reometria de torque, verificou-se que as blendas melhoraram a processabilidade em comparação ao PPCop. Além disso, as blendas apresentaram estabilidade ao longo do processamento, indicando ausência de degradação para as condições de processos utilizadas. Por meio dos ensaios em regime dinâmico-oscilatório, observou-se que, em baixas frequências (< 1 rad/s), o PPCop e as blendas (PPCop/PPRec) apresentam um comportamento de fluido Newtoniano, enquanto que, para frequências maiores que 1 rad/s, um comportamento de fluido pseudoplástico. Os valores dos pontos de intersecção (G’ = G”) das curvas de módulo de armazenamento (G’) e de módulo de perda (G’’), em função da frequência angular (ω), indicaram que as blendas apresentaram uma redução da massa molar, sendo mais pronunciada na composição contendo 60% de PPRec. Os resultados reológicos das blendas PPCop/PPRec foram de grande relevância, uma vez que permitem analisar o comportamento de blendas contendo material reciclado.

ABSTRACT In this study, blends of copolymer polypropylene (PPCop /recycled polypropylene (PPRec) from industrial containers after consumption were evaluated in three different ratios (80:20, 60:40 and 40:60 wt.%). The blends were evaluated by melt flow index, torque rheometry and rheology in a dynamic oscillatory regime. The results from the melt flow index indicated that the blending of recycled material with PPCop causes a decrease in the molecular weight as compared to PPCop. By torque rheometry, it was verified that the blends showed improved processability in relation to PPCop. Also, the blends showed stability throughout the processing, indicating absence of degradation due to the process conditions used. By the dynamic-oscillatory regime tests, it was observed that, at low frequencies (<1 rad/s), the PPCop and the blends (PPCop / PPRec) demonstrated a Newtonian fluid behavior, whereas, at frequencies greater than 1 rad/s, a pseudoplastic fluid behavior was observed. The values of the intersection points (G ‘= G”) of the storage modulus curves (G’) and loss modulus (G’), as a function of the angular frequency (ω) indicated that the blends showed a reduction of the molecular weight, which was more pronounced in the composition containing 60% PPRec. The rheological results of the PPCop / PPRec blends were of great relevance, since they allowed the analysis of the blends behavior containing recycled material.

Abstract Researches of polymer blends based on biological and biodegradable polymers appear as a viable alternative to develop environmentally friendly materials. Therefore, the aim of this research was to produce compounds made with biological polyethylene, i.e., Biopolyethylene, Bio-PE, added to the biodegradable Polycaprolactone (PCL) and functionalized by the copolymer of polyethylene grafted with acrylic acid (PEgAA), to obtain better mechanical properties and toughen Bio-PE. Compounds were processed in a co-rotating twin screw extruder and sample tests were injection molded. The compositions investigated were: Bio-PE/PCL at 90/10, 80/20 and 70/30 wt.% without compatibilizer and upon addition of 10 phr (parts per hundred of resin) of PEgAA. The blends were characterized by X-ray diffraction (XRD), impact strength, heat deflection temperature (HDT) and scanning electron microscopy (SEM). Through XRD, it was observed that addition of PCL and PEgAA did not significantly change Bio-PE diffraction patterns. Impact strength data showed that the blends presented a tougher behavior upon addition of PCL and PEgAA. The HDT of compatibilized blend with 20wt.% of PCL was slightly higher. SEM images of compatibilized blends showed lower average particle diameters as well as absence of coalescence and aggregates.

In this work, compounds based on two grades of polypropylene (PP), i.e., PP H503 or PP H103 with residues of Big bag fabrics (RBB) were processed in a corrotational twin screw extruder with RBB content ranging from 10% to 50% of the weight. Then, their thermal properties were investigated through Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG); mechanical by tensile and impact; thermomechanic by heat deflection temperature (HDT); and their morphology by Scanning Electron Microscopy (SEM). With the aim to add maximum RBB content without considerable damage to the properties of neat PPs, it was observed that addition of 10%, 30% and 50% of RBB did not significantly interfere in the PP matrices, being the compound PP + 30% RBB which one presented more successful properties, leading to reused compounds with higher performance and lower costs at same time.

RESUMO Este trabalho teve como objetivo avaliar o envelhecimento termo-oxidativo, nas propriedades mecânicas e de índice de amarelamento (YI), de blendas de poliestireno com borracha reciclada (SBRr), compatibilizadas. As blendas foram preparadas, inicialmente, em uma extrusora de rosca dupla corrotacional e, posteriormente, os grânulos extrudados foram moldados por injeção. Para efeito comparativo, o poliestireno de alto impacto comercial (HIPS) foi processado nas mesmas condições das blendas. Os resultados da caracterização do SBRr indicaram, em sua composição, cargas de sílica, carbonato de cálcio, talco e óxido de zinco, enquanto que, por termogravimetria, verificou-se duas etapas de decomposição térmica. Verificou-se que a resistência ao impacto diminuiu, significativamente, nos 15 dias iniciais do envelhecimento, e, subsequentemente, apresentou uma tendência de estabilização com pequenas oscilações. As propriedades de módulo de elasticidade, resistência e alongamento na ruptura sob tração apresentaram o mesmo comportamento da resistência ao impacto, redução acentuada nos 15 dias inicias, seguida de estabilização, com o decorrer do envelhecimento. Quando a blenda foi compatibilizada com 5% de estireno-butadieno-estireno (SBS), foram observadas as melhores propriedades, antes e após o envelhecimento, apresentando resistência ao impacto equiparáveis ao HIPS. A perda de massa das blendas indicou extração de componentes voláteis. Por índice de amarelamento (YI), observou-se, nas blendas, um aumento brusco nos 15 dias iniciais e, em seguida, estabilidade, com uma taxa de amarelamento praticamente constante. Até 30 dias de envelhecimento, o HIPS apresentou uma baixa taxa de amarelamento, e, posteriormente, ocorreu uma intensificação no YI. No geral, as blendas obtidas por mistura mecânica apresentaram comportamento similar ao HIPS. Porém, somente quando a blenda foi compatibilizada com SBS que o comportamento de impacto apresentou o mesmo patamar do HIPS.

ABSTRACT The objective of this study was to evaluate thermo-oxidative aging in the mechanical properties and yellowing index (YI) of polystyrene blends with compatibilized recycled rubber (SBRr). The blends were initially prepared in a co-rotating double screw extruder, after which the extruded granules were injection molded; high-impact polystyrene (HIPS) was processed under the same conditions for comparison. The SBRr characterization results revealed composition fillers of silica, calcium carbonate, talc, and zinc oxide, while thermogravimetry demonstrated two thermal decomposition stages. It was found that impact strength decreased significantly during the initial 15 days of aging and then showed a tendency to stabilize with small oscillations. Properties related to the modulus of elasticity, strength, and elongation at tensile rupture were similar to those of impact strength: a marked reduction in the initial 15 days followed by stabilization with aging. When a blend was compatibilized with 5% styrene-butadiene-styrene (SBS), optimal properties were observed before and after aging, indicating impact resistance comparable to HIPS. The blends’ loss of mass suggested volatile component extraction. In terms of the YI, the blends showed a sudden increase in the first 15 days of aging before stabilizing at a practically constant yellowing rate. Up to 30 days of aging, HIPS presented a low yellowing rate, after which point the YI intensified. In general, the blends obtained via mechanical mixing exhibited behavior similar to HIPS; for the blend compatibilized with SBS, however, the impact behavior was identical to that of HIPS.

Biodegradable Poly (ɛ-caprolactone) (PCL) was compounded with Brasgel PA (MMT) and Cloisite Na (CLNa), and compatibilized with maleic anhydride grafted poly(ɛ-caprolactone) (PCL-g-MA). No evidence of degradation was verified during processing, as well as particle aggregates were absent as displayed through scanning electron microscopy (SEM) images. Compatibilized compounds upon clay addition achieved higher thermal stability as visualized by thermogravimetry (TG). Montmorillonite clays acted as nucleant agent during PCL melt crystallization as evidenced by differential scanning calorimetry (DSC). Mechanical behavior of PCL was preserved, and all compounds presented Elongation higher than 350% meanwhile the heat distortion temperature (HDT) was increased by 20% in PCL compounds, which may have wider range of application and better performance.

Abstract In this work, blends based on environmentally friend polymers such as Biopolyethylene (Bio-PE), Polycaprolactone (PCL) and Polyethylene graft maleic anhydride (PEgMA) added as compatibilizer agent were produced by conventional extrusion, aiming to produce bio-blends with synergic properties at low processing cost, being at same time non-polluting and therefore contributing to the environment preservation. Differential scanning calorimetry (DSC) showed that blending does not significantly interfere on the melting and crystallization behaviors of neat polymers, suggesting being low miscibility compounds. Mechanical properties were observed changing with blend composition as the impact strength significantly increased reaching values higher than 130% when compared to neat Bio-PE. Scanning electron microscopy (SEM) images showed honeycomb morphology in Bio-PE/PCL blends, and the addition of PEgMA decreased the coalescence contributing to obtain more stable and synergic compounds. Bio-PE/PCL/PEgMA at 80/20/10 contents presented the best properties and may be used for packaging materials (food containers, film wrapping), and hygiene products.

Abstract The vulcanized rubber waste from the shoe industry causes environmental damage when it is incinerated or inappropriately discarded, turning this into a problem of major concern. Therefore, this study had as the main objective the Polystyrene (PS) toughening using different contents of white vulcanized styrene-butadiene rubber (SBRr) waste produced in the shoe industry. The mixtures were initially prepared in a co-rotational double screw extruder and, thereafter, the extruded granules were injection molded. Analyzed were the rheological, mechanical, thermomechanical properties and morphology of the produced blends. The rheological results showed a viscosity increase as the SBRr concentration was augmented, leading to a higher stability when compared to pure Polystyrene. Verified was an increase of impact resistance of 189% to the blend that contained 50% of SBR rather than pure Polystyrene. On the other hand, the traction properties, hardness Shore D, thermal deflection temperature (HDT) and Vicat softening temperature of the blends tended to decrease when compared to pure Polystyrene results. However, as this SBR waste is made up of a complex mixture of SBR, filler, processing additions, curing agents and stabilizers, it probably acted in the sense of not causing such a drastic reduction of the properties, even using a high concentration of SBRr waste. The morphologies obtained with the SEM method (Scanning Electronic Microscope) were quite different and typical of immiscible blends. The results show that it is possible to obtain a new material with good properties, valuing a discarded industrial waste and avoiding environment aggression.

RESUMO A Poli(ɛ-caprolactona) (PCL) é um termoplástico sintético biodegradável que tem sido foco de estudos em novos “polímeros verdes”, devido principalmente as suas boas propriedades mecânicas, o que a torna competitiva com outros polímeros convencionais e biopolímeros, tais como: Poli(ácido lático) (PLA), Poli(hidroxibutirato) (PHB). O objetivo deste trabalho foi a enxertia de grupos reativos anidrido maleico (MA) na PCL para a produção de um polímero funcional biodegradável. A síntese de enxertia do anidrido maleico na PCL ocorreu em um misturador interno de laboratório, utilizando concentrações de 2,5 e 5 % de MA e de 0,3 e 0,5% do iniciador peróxido de dicumila (DCP) em duas temperaturas de processo, 110oC e 160oC. A metodologia do planejamento fatorial 23 foi usada visando à otimização dos experimentos, assim como também para avaliar a eficiência das condições reacionais empregadas para a funcionalização da PCL. Os resultados indicaram que o anidrido maléico foi enxertado na PCL usando o iniciador peróxido de dicumila. A porcentagem de anidrido maléico grafitizado (%gMA) foi obtida por titulação e comprovada por Espectroscopia na região do Infravermelho por Transformada de Fourier (FTIR). Através dos resultados obtidos pode-se inferir que um maior teor (5,0%) de MA favoreceu positivamente a enxertia. No entanto, acima de determinada quantidade, possivelmente ocorre uma saturação do sistema e a tendência é a recombinação.

ABSTRACT Poly (ɛ-caprolactone) (PCL) is a biodegradable synthetic thermoplastic that has been the focus of studies on new "green polymers", due mainly to its good mechanical properties, which makes it competitive among other conventional polymers and biopolymers, such as, Poly(lactic acid) (PLA) and Poly(hydroxybutyrene) (PHB). The objective of this work was the grafting of maleic anhydride (MA) reactive groups in PCL for the production of a functional biodegradable polymer. The grafting synthesis of the maleic anhydride in the PCL occurred in an internal lab mixer, using concentrations of 2.5 and 5.0% MA and 0.3 and 0.5% of the dicumyl peroxide initiator (DCP) at two temperatures of process, 110°C and 160°C. The methodology of factorial planning 23 was used to optimize the experiments, as well as to evaluate the efficiency of the reaction conditions employed for PCL functionalization. The results indicated that maleic anhydride was grafted onto PCL using the dicumyl peroxide initiator. The percentage of graphitized maleic anhydride (% gMA) was obtained by titration and confirmed by Fourier Transform Infra-Red (FTIR). Through the obtained results it can be inferred that higher content (5.0%) of MA positively favored the grafting. However, over certain amount, a saturation of the system may occur and the tendency is for recombination.