The effect of spherulite size on the fracture morphology of polypropylene

Way, Jerome; Atkinson, J. R.; Nutting, Jack

doi:10.1007/bf00550954

Cited by 174 publications

(86 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…22 The SEM micrograph of Figure 10 shows a crack that has propagated along the weak spherulite boundary regions. The detrimental effect of large spherulites and weak boundaries, as noted here for low molecular weight PEO and its composites with PPTA-anion molecules, is consistent with findings that, in another crystalline polymer, isotactic polypropylene, there is a transition from ductile to brittle behavior 23 and a decrease in fracture toughness 21 as the spherulite size is increased.…”

Section: Effects Of the Peo Molecular Weightsupporting

confidence: 87%

Molecular composites of poly(p-phenylene terephthalamide) anion and poly(ethylene oxide): Mechanical properties

Tsou

Sauer

Hara

2000

J. Polym. Sci. B Polym. Phys.

View full text Add to dashboard Cite

Section: Effects Of the Peo Molecular Weightsupporting

confidence: 87%

Molecular composites of poly(p-phenylene terephthalamide) anion and poly(ethylene oxide): Mechanical properties

Tsou

Sauer

Hara

2000

J. Polym. Sci. B Polym. Phys.

View full text Add to dashboard Cite

“…In nylon 6/clay nanocomposites, it has been shown that the clay layers affected the formation of the lamellae [42], spherulites [40], crystallization rate [43], and also the crystalline phase [44]. It was proposed by many authors that an increase in crystallinity or spherulite size in polymeric materials could decrease impact strength, strain-to-fracture, and yield stress [45,46]. They also observed that reducing the spherulite size through the use of a nucleating agent or reinforcement did not improve the toughness [46].…”

Section: Crystallization and Crystal Structurementioning

confidence: 98%

Micro- and nano-scale deformation behavior of nylon 66-based binary and ternary nanocomposites

Dasari

Yang

et al. 2006

Composites Science and Technology

103

View full text Add to dashboard Cite

“…Probably it is this ordering that has given rise to the high Young's modulus, shear and tensile yield strengths in the transcrystalline material. However, in the transcrystalline material there will be, as with large, well-developed spherulites [9], little interconnecting material between crystallites, thus aiding the propagation of cracks in these areas. This is reflected in the low strain to failure in the transcrystalline material, and also in its low failure energy.…”

mentioning

confidence: 98%

Direct study of the structure and properties of transcrystalline layers

Folkes

Hardwick

1987

J Mater Sci Lett

View full text Add to dashboard Cite

When a fibre is embedded into a thermoplastic melt it may act as a nucleant for the growth of spherulites. If there are many nucleation sites along a fibre's surface, then the resulting spherulite growth will be restricted in the lateral direction, so that a columnar layer, known as transcrystallinity [1] will develop and enclose the fibre.The presence of anisotropic layers, such as transcrystallinity, has significant implications for the performance of fibre-filled thermoplastics composites. Several workers [2][3][4][5] have examined this topic in composites, without fully characterizing the mechanical properties of the transcrystalline layer. As it is very difficult to establish the properties of such layers in situ in a fibre-reinforced composite, it was decided that the best approach for characterizing the microstructure and properties of the transcrystalline layer would be to study it in isolation, as a two-dimensional analogue.A way of creating such a two-dimensional analogue would be to prepare totally fiat transcrystalline sheets of material. One method of achieving this could be by sandwiching thin layers of a suitable polymer, such as polypropylene, between sheets of a nucleating material, such as poly(ethylene terephthalate) in the form of a Melinex sheet. It should then be possible under suitable thermal conditions to obtain transcrystallinity in isolation. For comparison purposes one could also make polypropylene sheets of a differing microstructure by appropriate modifications to the thermal conditions employed during the manufacture of the sheet.For our studies, the polypropylene chosen was the I.C.I. grade GW522M, which has been previously shown [6] to be capable of displaying thick (up to 150#m) and regular transcrystallinity against poly-(ethylene terephthalate) when in the form of Terylene fibres. A typical thickness of a transcrystalline zone is of the order of 50 to 75/~m, so our aim was to produce polypropylene sheets 100 to 150 #m thick.Accordingly, a tape of polypropylene, of 100 to 150/~m thick, was first extruded using a Plasticiser Ltd Fibrillator. Secondly, the tape was sandwiched between two sheets of Melinex, which was then held, in compression, between two glass plates. This arrangement was then kept in an oven held at 200°C for 30 min.In order to produce transcrystallinity, the system was transferred to a separate oven held at 120°C for a further 10 min, after which the tape was quenched in cold water. In addition, a fine spherulitic sheet was prepared by directly quenching the molten tape in cold water.For the microstructural studies, the two types of polypropylene sheet were microtomed, in cross- section. For this purpose, the sheets were stacked together, as six to eight small pieces on to a cold stage, and then cut into 20 to 40/~m thick sections using a steel blade. They were subsequently examined "edge on" under crossed-polars using a Reichert Zetopan microscope. Fig. 1 shows a particularly well-developed transcrystalline morphology, where two transcrystalline layers have gro...

show abstract

The effect of spherulite size on the fracture morphology of polypropylene

Cited by 174 publications

References 6 publications

Molecular composites of poly(p-phenylene terephthalamide) anion and poly(ethylene oxide): Mechanical properties

Molecular composites of poly(p-phenylene terephthalamide) anion and poly(ethylene oxide): Mechanical properties

Micro- and nano-scale deformation behavior of nylon 66-based binary and ternary nanocomposites

Direct study of the structure and properties of transcrystalline layers

Contact Info

Product

Resources

About