An investigation of the relationships between processing conditions, microstructure and mechanical properties of an injection moulded semi-crystalline thermoplastic

Bowman, Jeremy; Harris, N.; Bevis, M.

doi:10.1007/bf00541032

Cited by 49 publications

(24 citation statements)

References 14 publications

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“…4,14,18 At higher melt temperature, less material is crystallised during the filling and packing stages, and more spherulitic material is present. The injection/cavity pressure will affect the microstructure, depending on the sensitivity of the freezing point to pressure.…”

Section: Resultsmentioning

confidence: 99%

Morphology of microinjection moulded polyoxymethylene

Kamal

Chu

Derdouri

et al. 2010

Plastics, Rubber and Composites

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Morphology of microinjection moulded polyoxymethyleneA microinjection moulding machine was used to obtain micromouldings of polyoxymethylene, in order to study morphology development during the process. The method of design of experiments was used to investigate statistically the effects of processing variables on the microstructural features of the mouldings. The morphological features were identified by microtoming the samples in both transverse and longitudinal (flow) directions and observing the microtomed sections under a polarised light microscope. Morphology evolution along the flow direction was followed by microtoming the specimens along the centre plane longitudinally and sequentially. A five-layer skin core structure was identified for micromoulded polyoxymethylene. The development of the structure was explained, based on mechanisms which were similar to those proposed for conventional injection moulding. Injection speed was found to be the most significant factor affecting morphological features of the final moulding. Moreover, the average plunger velocity, which is directly related to the cavity filling flow rate, was found to have good correlation with skin layer thickness. The distributions of crystalline polymorphs were observed and explained, in light of the distributions of the flow and thermal patterns in the mould. Morphology evolution along the flow direction reflected the distribution of pressure, temperature and velocity of the polymer melt during the microinjection moulding process. The results provided some indications regarding micromoulding mould design.

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Section: Resultsmentioning

confidence: 99%

Morphology of microinjection moulded polyoxymethylene

Kamal

Chu

Derdouri

et al. 2010

Plastics, Rubber and Composites

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show abstract

“…The bars were moulded under a range of barrel temperatures, injection pressures and mould temperatures, and the earlier publication (19) anotates the moulding conditions, the etching procedure and the wide range of morphologies produced. For microhardness studies, the ASTM tensile bars were cut as shown in figure 3, to reveal a surface .,":,.!.…”

Section: Specimens and Specimen Preparationmentioning

confidence: 99%

“…An earlier publication (19) introduced the relationships between injection moulding variables, microstructural variations throughout a component, and the mechanical properties of a component injection moulded from the semicrystalline plastic TPX; the microhardness test was used in this work as a further method of identifying microstructural variations throughout the components. We now expand upon the results of the Vickers microhardness testing of the above mentioned injection moulded TPX ASTM bars.…”

Section: Introductionmentioning

confidence: 99%

The evaluation of the structure and hardness of processed plastics by the Vickers microhardness test

Bowman

Bevis

1977

Colloid Polymer Sci

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“…As shown in the Appendix, unit normal n to any plane diffracting to a point on a ring with azimuthal angle 4 is given as follows (neglecting here the small deflections due to refraction): n = (cos 8 sin 4 cos a + sin 8 sin a)el + (cos 8 sin 4 sin a -sin 8 cos a)e2 + cos 8 cos 4 e3 (9) in terms of the orthogonal unit vectors el, e2, e3 defined in Figure 4.…”

Section: Grazing Incidence X-ray Diffractionmentioning

confidence: 99%

Method for studying orientation variations near surfaces in semicrystalline polymers

Buckley

Taylor

1984

J of Applied Polymer Sci

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SynopsisThe method of grazing incidence X-ray diffraction provides a convenient means of examining crystal orientation close to the surface of a semicrystalline polymer. Since the sampled depth is governed by the choice of X-radiation (via its absorption coefficient) and the angle of incidence, it is under the control of the experimenter. The method was tested and shown to be valid by applying it to a crossply laminated film of oriented polyethylene, of thickness 50 pm, in which the different crystal orientations on opposite faces of the film were known. Further experiments, with two polyethylene films of 20 pm and 40 pm thickness each extruded with differing rates of cooling on each surface, demonstrated the ability of the method to resolve spatial variations of orientation on this scale arising during manufacture.

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An investigation of the relationships between processing conditions, microstructure and mechanical properties of an injection moulded semi-crystalline thermoplastic

Cited by 49 publications

References 14 publications

Morphology of microinjection moulded polyoxymethylene

Morphology of microinjection moulded polyoxymethylene

The evaluation of the structure and hardness of processed plastics by the Vickers microhardness test

Method for studying orientation variations near surfaces in semicrystalline polymers

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