Uniplanar oriented isotactic polypropylene: 3. Properties and morphology

Osawa, Satoshi; Porter, Roger S.; Ito, Masayoshi

doi:10.1016/0032-3861(94)90510-x

Cited by 19 publications

(10 citation statements)

References 32 publications

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“…We have shown that the spherulite is pancaked as deformation proceeds. 16 At a high CR, The modulus and strength of forged samples the layer structure is seen to be composed of a were measured by a conventional tensile tester at stacking of deformed spherulite planes. Takaroom temperature.…”

Section: 14mentioning

confidence: 99%

The application of multiple regression analysis to the property-structure-processing relationship on forging of isotactic polypropylene

Osawa

Mukai

Ogawa

et al. 1998

J. Appl. Polym. Sci.

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ABSTRACT:The property-structure-processing relationship on the forging of isotactic polypropylene (iPP) has been investigated by applying multiple regression analysis. The analysis showed that the optical and mechanical properties of forged iPP can be described quantitatively by phase structures and the compression draw ratio (CR). For optical clarity, appropriate variables to explain the property are the smectic fraction (X s ), the amorphous fraction ( X a ) and CR 01 . The increase in the smectic fraction and CR reduced the turbidity (for example, the increase in optical clarity) of the sample. The contribution of smectic phase estimated by the analysis was about one-third of the compression draw, as revealed by CR 01 . For mechanical properties, X s , X a , and CR 1/2were the appropriate variables. The existence of the smectic phase reduced the tensile mechanical properties. The effect of X s is 12 times higher in modulus than that in strength.

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Section: 14mentioning

confidence: 99%

The application of multiple regression analysis to the property-structure-processing relationship on forging of isotactic polypropylene

Osawa

Mukai

Ogawa

et al. 1998

J. Appl. Polym. Sci.

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“…Texture evolution of α‐iPP and related deformation mechanisms were studied in tension as well as in uniaxial15, 16 and plane‐strain compression17, 18 modes. Deformation mechanisms of crystallographic origin were found to be responsible for an alignment of the c axis along the direction of plastic flow.…”

Section: Introductionmentioning

confidence: 99%

Plastic deformation behavior of β phase isotactic polypropylene in plane‐strain compression at elevated temperatures

Łężak¹,

Bartczak²

2007

J Polym Sci B Polym Phys

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Isotactic polypropylene (iPP) rich in β crystal modification was deformed by plane‐strain compression at T = 55–100 °C. The evolution of phase structure, morphology, and orientation were studied by DSC, X‐Ray, and SEM. The most important deformation mechanisms found were interlamellar slip operating in the amorphous layers, resulting in numerous fine deformation bands and the crystallographic slip systems, including the (110)[001]β chain slip and (110)[$1{\bar {1}}0$]β transverse slip. Shear within deformation bands leads to β→α solid state phase transformation in contrast to β→smectic transformation observed at room temperature. Newly formed α crystallites deform with an advancing strain by crystallographic slip mechanism, primarily the (010)[001]α chain slip. As a result of deformation and phase transformation within deformation bands β lamellae are locally destroyed and fragmented into smaller crystals. Deformation to high strains, above e = 1, brings further heavy fragmentation of lamellae, followed by fast rotation of crystallites with chain axis towards the direction of flow FD. This process, together with still active crystallographic slip, leads to the final texture with molecular axis of both crystalline β and α phase oriented along FD. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 92–108, 2008

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“…As the overall crystallinity of the deformed samples is lowered only slightly in comparison with the undeformed iPP, the observed substantial damping of the β process with increasing strain should be interpreted in terms of a considerable change in the molecular packing of the amorphous phase resulting in reduced mobility. It was demonstrated for uniaxially compressed iPP30–32 that the density of the amorphous phase increased markedly with increasing strain, which indicated that the average intermolecular distance was smaller than the respective distance in the unoriented amorphous component.…”

Section: Resultsmentioning

confidence: 99%

Structure and properties of isotactic polypropylene oriented by rolling with side constraints

Bartczak

Morawiec

Gałęski

2002

J of Applied Polymer Sci

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ABSTRACT:The rolling of isotactic polypropylene (iPP) with a new method of rolling with side constraints (inside a channel) was studied. It was found that deformation processes by compression in a channel die and by rolling with side constraints proceed in very similar fashions (planestrain conditions) and result in materials of similar orientations and mechanical properties. The difference between the two processes is that rolling causes the destruction of the lamellar structure at a higher strain than compression. Dynamic mechanical measurements showed that rolling to a high strain produces not only a well-developed orientation of the crystalline component but also high orientation and transverse ordering of the amorphous phase, leading to its transverse anisotropy. iPP deformed by rolling with side constraints has tensile properties similar to those of iPP deformed by other methods, such as conventional rolling or plane-strain compression. The elastic modulus and ultimate strength measured along the rolling direction increase with an increasing deformation ratio. For samples deformed to a deformation ratio of 10.4, the ultimate strength reaches 340 MPa and can be further increased by postdeformation annealing. The oriented iPP also demonstrates extremely high impact toughness, especially in the direction of side constraints. Izod impact tests demonstrated that the material fracture on impact is very limited and that the impact strength exceeds 170 kJ/m 2 . In contrast to the tensile properties, there is an optimum deformation ratio around 5, for which the impact strength is the highest.

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Uniplanar oriented isotactic polypropylene: 3. Properties and morphology

Cited by 19 publications

References 32 publications

The application of multiple regression analysis to the property-structure-processing relationship on forging of isotactic polypropylene

The application of multiple regression analysis to the property-structure-processing relationship on forging of isotactic polypropylene

Plastic deformation behavior of β phase isotactic polypropylene in plane‐strain compression at elevated temperatures

Structure and properties of isotactic polypropylene oriented by rolling with side constraints

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