Investigation of chemi-crystallization and free volume changes of high-density polyethylene weathered in a subtropical humid zone

2016 ◽  
Vol 65 (12) ◽  
pp. 1474-1481 ◽  
Author(s):  
Jian Xiong ◽  
Kai Ni ◽  
Xia Liao ◽  
Jingjun Zhu ◽  
Zhu An ◽  
...  
Keyword(s):  
Free Volume ◽  
High Density Polyethylene ◽  
High Density ◽  
Volume Changes ◽  
Humid Zone

Electrical, Thermal and Positron Lifetime Spectroscopy Studies on Multi-Walled Carbon Nanotube Reinforced High Density Polyethylene/Carbon Black Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 59-62 ◽  
Author(s):  
T. Jeevananda ◽  
O.G. Palanna ◽  
Joong Hee Lee ◽  
Siddaramaiah ◽  
C. Ranganathaiah
Keyword(s):  
Thermal Properties ◽  
Carbon Nanotube ◽  
Carbon Black ◽  
Free Volume ◽  
High Density Polyethylene ◽  
High Density ◽  
Hybrid Nanocomposites ◽  
Positive Temperature ◽  
Multi Walled Carbon Nanotube ◽  
Positron Lifetime Spectroscopy

The present study investigates the effect of the carboxylated multi-walled carbon nanotube (0~3 wt %) content on the electrical and thermal properties of high density polyethylene/carbon black/carboxylated multi-walled carbon nanotube (HDPE/CB/c-MWNT) hybrid nanocomposites. The room temperature electrical resistivity and positive temperature coefficient (PTC) intensity of the nanocomposites significantly improved with the addition of c-MWNT. However, the heat of fusion decreases as the amount of c-MWNT increases. Further, the microstructural parameters such as the fractional free volume (Fv) and free volume hole size (Vf) of the nanocomposites shows appreciable changes around the percolation threshold. Secondly, the PALS results seem to correlate well with the electrical and thermal properties of the composites.

Effect of confinement on glass dynamics and free volume in immiscible polystyrene/high-density polyethylene blends

2015 ◽  
Vol 64 (7) ◽  
pp. 892-899 ◽  
Author(s):  
Lingyun Wu ◽  
Jingjun Zhu ◽  
Xia Liao ◽  
Kai Ni ◽  
Qiongwen Zhang ◽  
...  
Keyword(s):  
Free Volume ◽  
High Density Polyethylene ◽  
High Density ◽  
Polyethylene Blends ◽  
Glass Dynamics

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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