An evaluation of the melt crystallisation behaviour of injection-moulded high-density polyethylene (HDPE) based on a solidification kinetics analysis

2017 ◽  
Vol 46 (5) ◽  
pp. 200-211 ◽  
Author(s):  
Bin Yang ◽  
Lei Hu ◽  
Gui-Jing Li ◽  
Chuan-Ru Zhang ◽  
Ji-Bin Miao ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
High Density ◽  
Kinetics Analysis ◽  
Crystallisation Behaviour ◽  
Solidification Kinetics ◽  
Melt Crystallisation

Study on the solidification kinetics of high-density polyethylene during thin-walled injection molding process

2012 ◽  
Vol 32 (6-7) ◽  
pp. 355-363 ◽  
Author(s):  
Shuang-quan Deng ◽  
Bin Yang ◽  
Ji-bin Miao ◽  
Ru Xia ◽  
Jia-sheng Qian ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Density Polyethylene ◽  
Polymeric Materials ◽  
High Density ◽  
Injection Molding Process ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Molding Process ◽  
Solidification Kinetics ◽  
Thin Walled

Abstract In this work, the effect of the initial and secondary temperature differences on the solidification behaviors of high-density polyethylene (HDPE) during the thin-walled injection molding (TWIM) was intensively investigated. Simulated temperature profiles using the enthalpy transformation methodology were compared with an in situ temperature measurement, and reasonable agreement was achieved between calculations and measurements. Two-dimensional wide-angle X-ray diffraction characterization shows that the formation of oriented crystal structures was considerably affected by the thermal gradient within the injection-molded article. The present study can be practically significant to the optimization of the cooling parameters during the TWIM of crystalline polymers as well as to the further study on the relationship among “processing-structure-property” of polymeric materials.

scholarly journals Non-Isothermal Crystallisation Kinetics of Carbon Black- Graphene-Based Multimodal-Polyethylene Nanocomposites

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 110 ◽  
Author(s):  
Ibrahim Ahmad ◽  
Hyun-Kyung Kim ◽  
Suleyman Deveci ◽  
R. Kumar
Keyword(s):  
Carbon Black ◽  
High Density Polyethylene ◽  
Crystal Surface ◽  
Nucleating Agent ◽  
High Density ◽  
Crystallisation Kinetics ◽  
Crystallisation Behaviour ◽  
Graphene Content ◽  
Isothermal Crystallisation ◽  
Kinetics Of

The effect of carbon black (CB) and microwave-induced plasma graphene (g) on the crystallisation kinetics of the multimodal high-density polyethylene was studied under non-isothermal conditions. The non-isothermal crystallisation behaviour of the multimodal-high-density polyethylene (HDPE), containing up to 5 wt.% graphene, was compared with that of neat multimodal-HDPE and its carbon black based nanocomposites. The results suggested that the non-isothermal crystallisation behaviour of polyethylene (PE)-g nanocomposites relied significantly on both the graphene content and the cooling rate. The addition of graphene caused a change in the mechanism of the nucleation and the crystal growth of the multimodal-HDPE, while carbon black was shown to have little effect. Combined Avrami and Ozawa equations were shown to be effective in describing the non-isothermal crystallisation behaviour of the neat multimodal-HDPE and its nanocomposites. The mean activation energy barrier (ΔE), required for the transportation of the molecular chains from the melt state to the growing crystal surface, gradually diminished as the graphene content increased, which is attributable to the nucleating agent effect of graphene platelets. On the contrary, the synergistic effect resulting from the PE-CB nanocomposite decreased the ΔE of the neat multimodal-HDPE significantly at the lowest carbon black content.

Composition and Surface Topography Effects on Apatite-Forming Ability of Ceramic-Polymer Composites

2003 ◽  
Vol 774 ◽  
Author(s):  
Susan M. Rea ◽  
Serena M. Best ◽  
William Bonfield
Keyword(s):  
Surface Topography ◽  
High Density Polyethylene ◽  
High Density ◽  
Apatite Layer ◽  
Biologically Active ◽  
Human Blood Plasma ◽  
Apatite Formation ◽  
Polyethylene Matrix ◽  
Composite Surface ◽  
X Ray

AbstractHAPEXTM (40 vol% hydroxyapatite in a high-density polyethylene matrix) and AWPEX (40 vol% apatite-wollastonite glass ceramic in a high density polyethylene matrix) are composites designed to provide bioactivity and to match the mechanical properties of human cortical bone. HAPEXTM has had clinical success in middle ear and orbital implants, and there is great potential for further orthopaedic applications of these materials. However, more detailed in vitro investigations must be performed to better understand the biological interactions of the composites and so the bioactivity of each material was assessed in this study. Specifically, the effects of controlled surface topography and ceramic filler composition on apatite layer formation in acellular simulated body fluid (SBF) with ion concentration similar to those of human blood plasma were examined. Samples were prepared as 1 cm × 1 cm × 1 mm tiles with polished, roughened, or parallel-grooved surface finishes, and were incubated in 20 ml of SBF at 36.5 °C for 1, 3, 7, or 14 days. The formation of a biologically active apatite layer on the composite surface after immersion was demonstrated by thin-film x-ray diffraction (TF-XRD), environmental scanning electron microscopy (ESEM) imaging and energy dispersive x-ray (EDX) analysis. Variations in sample weight and solution pH over the period of incubation were also recorded. Significant differences were found between the two materials tested, with greater bioactivity in AWPEX than HAPEXTM overall. Results also indicate that within each material the surface topography is highly important, with rougher samples correlated to earlier apatite formation.

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