scholarly journals Crystalline Morphology of Injection-Molded Polyacetal with Branched Structure

2005 ◽  
Vol 62 (3) ◽  
pp. 124-130 ◽  
Author(s):  
Kuniaki KAWAGUCHI ◽  
Yoshihisa TAJIMA
Keyword(s):  
Crystalline Morphology ◽  
Injection Molded ◽  
Branched Structure

scholarly journals Process Induced Skin-Core Morphology in Injection Molded Polyamide 66

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 894
Author(s):  
Yvonne Spoerer ◽  
René Androsch ◽  
Dieter Jehnichen ◽  
Ines Kuehnert
Keyword(s):  
Polarized Light ◽  
Skin Layer ◽  
Crystalline Morphology ◽  
Polyamide 66 ◽  
Thin Sections ◽  
X Ray ◽  
X Ray Scattering ◽  
Order Of Magnitude ◽  
Injection Molded ◽  
Ray Scattering

Polyamide 66 (PA 66) was injection-molded to obtain samples with a structure gradient between skin and core, as it was revealed by analysis of the semi-crystalline morphology using polarized-light optical microscopy (POM). Wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) were employed to characterize thin sections with a thickness in the order of magnitude of 50 µm, allowing detection of crystals of different perfection, as a function of the distance from the surface. It was found that the transparent and non-spherulitic skin layer contains rather imperfect α-crystals while the perfection of α-crystals continuously increases with extending distance from the surface. Since variation of the molding conditions allows tailoring the skin-core morphology, the present study was performed to suggest a reliable route to map the presence of specific semi-crystalline morphologies in such samples.

scholarly journals Effect of Mold Temperature on the Impact Behavior and Morphology of Injection Molded Foams Based on Polypropylene Polyethylene–Octene Copolymer Blends

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 894 ◽  
Author(s):  
Santiago Muñoz-Pascual ◽  
Eduardo Lopez-Gonzalez ◽  
Cristina Saiz-Arroyo ◽  
Miguel Angel Rodriguez-Perez
Keyword(s):  
Impact Resistance ◽  
Mold Temperature ◽  
Impact Behavior ◽  
Critical Parameters ◽  
Crystalline Morphology ◽  
Copolymer Blends ◽  
Opposite Trend ◽  
Izod Impact ◽  
Injection Molded ◽  
The Impact

In this work, an isotactic polypropylene (PP) and a polyethylene–octene copolymer (POE) have been blended and injection-molded, obtaining solids and foamed samples with a relative density of 0.76. Different mold temperature and injection temperature were used. The Izod impact strength was measured. For solids, higher mold temperature increased the impact resistance, whereas in foams, the opposite trend was observed. In order to understand the reasons of this behavior, the morphology of the elastomeric phase, the crystalline morphology and the cellular structure have been studied. The presence of the elastomer near the skin in the case of high mold temperature can explain the improvement produced with a high mold temperature in solids. For foams, aspects as the elastomer coarsening in the core of the sample or the presence of a thicker solid skin are the critical parameters that justify the improved behavior of the materials produced with a lower mold temperature.

Chromic Acid Etching of Polyethylene

1973 ◽  
Vol 31 ◽  
pp. 72-73
Author(s):  
J. D. Muzzy ◽  
R. D. Hester ◽  
J. L. Hubbard
Keyword(s):  
Chromic Acid ◽  
Low Cost ◽  
Acid Etching ◽  
Crystalline Morphology ◽  
Bulk Specimen ◽  
Morphological Studies ◽  
Perfect Form ◽  
Molecular Length ◽  
Lamellar Texture ◽  
Cost Studies

Polyethylene is one of the most important plastics produced today because of its good physical properties, ease of fabrication and low cost. Studies to improve the properties of polyethylene are leading to an understanding of its crystalline morphology. Polyethylene crystallized by evaporation from dilute solutions consists of thin crystals called lamellae. The polyethylene molecules are parallel to the thickness of the lamellae and are folded since the thickness of the lamellae is much less than the molecular length. This lamellar texture persists in less perfect form in polyethylene crystallized from the melt.Morphological studies of melt crystallized polyethylene have been limited due to the difficulty of isolating the microstructure from the bulk specimen without destroying or deforming it.

Influence of Process Parameters on the Morphologies of Micro-Injection Molded Polyformaldehyde Parts

2019 ◽  
Vol 34 (3) ◽  
pp. 367-375
Author(s):  
L.-X. Wang ◽  
D.-F. Wang ◽  
L. Jiang ◽  
N. Bian ◽  
Q. Li ◽  
...  
Keyword(s):  
Process Parameters ◽  
Influence Of Process Parameters ◽  
Injection Molded
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