Dynamic mechanical and impact properties of polypropylene/EPDM blends

Karger‐Kocsis, J.; Кулезнев, В. Н.

doi:10.1016/0032-3861(82)90054-4

Cited by 109 publications

(46 citation statements)

References 18 publications

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“…Equation (1) indicates that the equilibrium particle size R* becomes small when and -j become large and when p, EDK, a, and Q D become small. It was reported that the particle size of dispersed phase varies with the melt viscosity of the dispersed phase and the PP matrix.6 Thus it can be presumed that the changes of PEP particle size shown in Figures l(a) and (b) would result from the complications of the factors described above.…”

Section: Influence Of Structure Of Pep On Annealing Effect Of Binary mentioning

confidence: 97%

Annealing of polypropylene/poly(ethylene‐co‐propylene) blend. II. Influence of the structure and properties of poly(ethylene‐co‐propylene) and blended polyethylene on impact strength

Ito

Mitani

Mizutani

1985

J of Applied Polymer Sci

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SynopsisThe effect of annealing on the impact strength of PP/poly(ethylene-co-propylene) (PEP) and PP/PEP/PE blends was studied with regard to the structure of PEP and the polyethylene crystallinity. The tensile impact strength of annealed blends was remarkably affected by the PEP structure such as molecular weight and comonomer composition and the annealing temperature, while the brittle temperature was scarcely affected. For the PP/PEP/PE blends, annealing at temperatures above the melting point of PE lowers the tensile impact strength in a similar manner as the PP/crystalline PEP blend. These phenomena were explained on the basis of the deformation mechanism presented in the previous article, that is, a thicker interfacial layer of PP and PEP forms by means of annealing to increase the energy needed to deform the interface. By using a scanning electron microscope, the transition layer was observed at the interface between amorphous PEP and PE in the PP/amorphous PEP/PE blend after etching with nitric acid. The formation of a thicker transition layer between amorphous PEP and PE and a sizeable increase in PE particle size by annealing was observed. The phenomena should be correlated with the impact sensitivity, especially tensile impact strength, in the PP/crystalline PEP and PP/amorphous PEP/PE blends. A reasonable explanation of the microstructure in PP/PEP blends has been developed in terms of comonomer composition and melting property of PEP.

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Section: Influence Of Structure Of Pep On Annealing Effect Of Binary mentioning

confidence: 97%

Annealing of polypropylene/poly(ethylene‐co‐propylene) blend. II. Influence of the structure and properties of poly(ethylene‐co‐propylene) and blended polyethylene on impact strength

Ito

Mitani

Mizutani

1985

J of Applied Polymer Sci

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“…Karger-Kocsis e Kuleznev 44 , em 1982, encontraram uma relação linear entre o "damping" e a resistência ao impacto em blendas de polipropileno e EPDM.…”

Section: Correlação Entre a Curva De "Damping" E As Propriedades Mecâunclassified

Comportamento dinâmico-mecânico e relaxações em polímeros e blendas poliméricas

Cassu

Felisberti

2005

Quím. Nova

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Recebido em 3/11/03; aceito em 26/8/04; publicado na web em 2/2/05 DYNAMIC MECHANICAL BEHAVIOR AND RELAXATIONS IN POLYMERS AND POLYMERIC BLENDS. Dynamic mechanical analysis (DMA) is widely used in materials characterization. In this work, we briefly introduce the main concepts related to this technique such as, linear and non-linear viscoelasticity, relaxation time, response of material when it is submitted to a sinusoidal or other periodic stress. Moreover, the main applications of this technique in polymers and polymer blends are also presented. The discussion includes: phase behavior, crystallization; spectrum of relaxation as a function of frequency or temperature; correlation between the material damping and its acoustic and mechanical properties.Keywords: DMA; polymer; polymer blends. INTRODUÇÃOA análise dinâmico-mecânica (DMA) ou análise termodinâmico-mecânica (DMTA) tem como um dos principais objetivos relacionar as propriedades macroscópicas, tais como as propriedades mecâni-cas, às relaxações moleculares associadas a mudanças conformacionais e a deformações microscópicas geradas a partir de rearranjos moleculares 1 .As propriedades mecânicas dos materiais são avaliadas a partir de uma solicitação, na forma de uma deformação ou na aplicação de uma tensão, com o monitoramento da resposta do material, expressa como tensão ou como deformação, respectivamente. Ensaios mecâ-nicos são classificados como estáticos, uma vez que se aplica ao material uma tensão ou deformação constante, ou a taxas constantes. Estes experimentos são destrutivos, já que uma de suas finalidades é a determinação de propriedades limite do material.A análise dinâmico-mecânica consiste, de modo geral, em se aplicar uma tensão ou deformação mecânica oscilatória, normalmente senoidal, de baixa amplitude a um sólido ou líquido viscoso, medindo-se a deformação sofrida por este ou a tensão resultante, respectivamente, sob variação de freqüência ou de temperatura 2 .O comportamento mecânico ou dinâmico-mecânico de um material será governado por sua viscoelasticidade, que será função do tipo de ensaio e de solicitação aplicados. Dependendo da resposta ao estímulo mecânico, o material pode ser classificado como elástico ou viscoso. Para um sólido perfeitamente elástico ou Hookiano a deformação é proporcional à tensão aplicada e vice-versa, segundo a lei de Hooke. Um material viscoso ideal obedece à lei de Newton, que estabelece que a tensão e a taxa de cisalhamento estão relacionadas através de uma característica intrínseca que é a viscosidade 1,2 . Materiais poliméricos apresentam comportamento mecânico intermediário ao elástico e ao viscoso, sendo denominados viscoelásticos. A contribuição elástica e viscosa para o comportamento mecânico do polímero depende da temperatura e da escala de tempo do experimento.O comportamento viscoelástico de materiais poliméricos pode ser compreendido mais facilmente a partir de ensaios mecânicos.Resultados típicos de ensaios de fluência são mostrados na Figura 1, e se relacionam a testes realizados sob cisalha...

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“…According to Karger-Kocsis and Kuleznev 26 a linear relationship can be expected between notched impact strength and tanδ curves. In fact the relation is not linear because it is the sum of at least two separated events: first, the increase in the amount of elastomer and so the impact absorption levels (which was accounted for by Karger-Kocsis 26 ) and second, more important of them all, triggering the toughening mechanisms. The later is more sensitive to changes in morphology and interparticle distance 27 , the former is strongly related to the elastomer content.…”

Section: Dynamic-mechanical Thermal Analysis (Dmta)mentioning

confidence: 99%

Mechanical and morphological characterization of polypropylene toughened with olefinic elastomer

2000

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The effect of incorporating (C2-C8) ethylene-octene elastomer on the mechanical properties and morphology of polypropylene copolymers has been investigated employing two types of PP copolymer, with and without nucleating agent. The results were compared to the ones presented by a commercial PP heterophase (reactor impact modified PP/EPR). The addition of the elastomer increases the toughness of the blends but reduces their stiffness. PP blends in the low elastomer content region (< 20%) show low values of the Izod impact strength and both, elastomer content and impact strength, are directly proportional to the area under the β damping peak or its maximum intensity of the elastomer. The morphology is a continuous pattern of segregate elastomeric particles with average particle size in the range of 0.27 µm to 0.39 µm. The average particle size and particle size distribution plotted in log-normal distribution curves, increases slightly with the increase in the elastomer content. The reactor modified PP heterophase has a broader particle size distribution and an average particle size of 0.56 µm, at the lower limit but inside the range for good impact performance, as observed.

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Dynamic mechanical and impact properties of polypropylene/EPDM blends

Cited by 109 publications

References 18 publications

Annealing of polypropylene/poly(ethylene‐co‐propylene) blend. II. Influence of the structure and properties of poly(ethylene‐co‐propylene) and blended polyethylene on impact strength

Annealing of polypropylene/poly(ethylene‐co‐propylene) blend. II. Influence of the structure and properties of poly(ethylene‐co‐propylene) and blended polyethylene on impact strength

Comportamento dinâmico-mecânico e relaxações em polímeros e blendas poliméricas

Mechanical and morphological characterization of polypropylene toughened with olefinic elastomer

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