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.

Biocompatibility of CaSiO3 /High-Density Polyethylene Composites Prepared by Hot-Pressing

2006 ◽  
Vol 309-311 ◽  
pp. 1161-1164 ◽  
Author(s):  
Miho Tanuma ◽  
Yoshikazu Kameshima ◽  
Akira Nakajima ◽  
Kiyoshi Okada ◽  
Shigeo Asai ◽  
...  
Keyword(s):  
Hot Pressing ◽  
High Density Polyethylene ◽  
Ceramic Powder ◽  
High Density ◽  
Apatite Formation ◽  
Composite Surface ◽  
Ceramic Particles ◽  
Fast Bone ◽  
The Matrix

We have reported that CaSiO3 ceramics show very fast bone-like apatite formation in simulated body fluid (SBF). However, CaSiO3 ceramics have disadvantages in their mechanical properties and shapability. It is therefore more effective to develop composites of CaSiO3 particles dispersed in a matrix of polymer or metal. Such composites are usually prepared by homogeneously blending the ceramic powder with the matrix component. This method is, however, ineffective for the preparation of biocompatible polymers or metals because only the surfaces containing accidentally-exposed ceramic particles play a role in generating apatite in SBF. It is therefore necessary to add a large volume of ceramic powder and also to abrade the surface to expose more of the ceramic particles. In this study, CaSiO3/high-density polyethylene (HDPE) composites were prepared by hot-pressing to introduce surface CaSiO3 particles and their biocompatibilities were evaluated under in vitro conditions using SBF. CaSiO3 powders were spread on a HDPE plate and hot-pressed at 140oC and 4.9-14.7 MPa for 2 min. The composite sample (about 10×10×1 mm3 in size) was immersed in 30ml SBF (sample/solution ratio of 2.5 g/l) at 36.5oC. After 14 days soaking, the apatite product particles covered most of the composite surface and formed apatite layers. Bone-like apatite particles were formed only on the surface regions containing exposed CaSiO3 particles but no apatite was formed on the CaSiO3 particles buried in the HDPE matrix. The results show that this surface deposition method is very effective in developing biocompatibility in the composites using very small amounts of CaSiO3 powder (about <1 %v) compared with results reported for hydroxyapatite and AW glass-ceramic powders (requiring about 40 %v). It is also found that the inhomogeneous state of the CaSiO3 particles in the surface of the present composites strongly influences their biocompatibility. It will be necessary to improve the homogeneity of CaSiO3 dispersion in the surface of the composites to achieve a more uniform surface apatite layer.

scholarly journals Enhanced Water Resistance of Recycled Newspaper/High Density Polyethylene Composite Laminates via Hydrophobic Modification of Newspaper Laminas

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 421
Author(s):  
Binwei Zheng ◽  
Weiwei Zhang ◽  
Litao Guan ◽  
Jin Gu ◽  
Dengyun Tu ◽  
...  
Keyword(s):  
Stearic Acid ◽  
Photoelectron Spectroscopy ◽  
Composite Laminates ◽  
High Density Polyethylene ◽  
Water Resistance ◽  
Laminated Composite ◽  
High Strength ◽  
High Water ◽  
High Density ◽  
X Ray

A high strength recycled newspaper (NP)/high density polyethylene (HDPE) laminated composite was developed using NP laminas as reinforcement and HDPE film as matrix. Herein, NP fiber was modified with stearic acid (SA) to enhance the water resistance of the NP laminas and NP/HDPE composite. The effects of heat treatment and SA concentration on the water resistance and tensile property of NP and composite samples were investigated. The chemical structure of the NP was characterized with X-ray diffractometer, X-ray photoelectron spectroscopy and attenuated total reflectance Fourier transform infrared spectra techniques. The surface and microstructure of the NP sheets were observed by scanning electron microscopy. An expected high-water resistance of NP sheets was achieved due to a chemical bonding that low surface energy SA were grafted onto the modified NP fibers. Results showed that the hydrophobicity of NP increased with increasing the stearic acid concentration. The water resistance of the composite laminates was depended on the hydrophobicity of the NP sheets. The lowest value of 2 h water absorption rate (3.3% ± 0.3%) and thickness swelling rate (2.2% ± 0.4%) of composite were obtained when the SA concentration was 0.15 M. In addition, the introduction of SA can not only enhance the water resistance of the composite laminates, but also reduce the loss of tensile strength in wet conditions, which shows potential in outdoor applications.

Improvement of the Properties of Polyethylene with Chlorinated Polyethylene (CPE)

2003 ◽  
Vol 11 (2) ◽  
pp. 115-122
Author(s):  
Kálmán Marossy ◽  
Pál Bárczy
Keyword(s):  
High Density Polyethylene ◽  
Industrial Applications ◽  
Mechanical Tests ◽  
High Density ◽  
Structural Units ◽  
Chlorinated Polyethylene ◽  
X Ray ◽  
Dynamic Mechanical ◽  
X Ray Scattering ◽  
Multiphase Systems

Blends of high density polyethylene (HDPE) and chlorinated polyethylene (CPE) have been tested across the whole concentration range. Polyethylene is used to modify the properties of CPE in the elastomer industry, but modification of the properties of polyethylene with CPE is still not usual. Conventional mechanical tests and dynamic mechanical tests were carried out. The blends were found to be multiphase systems of excellent technological compatibility. Between 10 and 15% by weight CPE increased the modulus of polyethylene. X-ray scattering studies showed that the blends contained structural units not present either in the polyethylene or in the CPE. The blends were melt processable and may have industrial applications, too.

Enhanced dispersion of carbon nanotubes in high density polyethylene matrix using secondary nanofiller and compatibilizer

2015 ◽  
Vol 16 (1) ◽  
pp. 129-137 ◽  
Author(s):  
M. E. Ali Mohsin ◽  
Agus Arsad ◽  
Syed K. H. Gulrez ◽  
Zurina Muhamad ◽  
H. Fouad ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Density Polyethylene ◽  
High Density ◽  
Polyethylene Matrix

Surface Spectroscopic Signatures of Mechanical Deformation in High-Density Polyethylene (HDPE)

2018 ◽  
Vol 72 (7) ◽  
pp. 1057-1068 ◽  
Author(s):  
Shawn C. Averett ◽  
Steven K. Stanley ◽  
Joshua J. Hanson ◽  
Stacey J. Smith ◽  
James E. Patterson
Keyword(s):  
High Density Polyethylene ◽  
Cold Drawing ◽  
Mechanical Deformation ◽  
Sum Frequency Generation ◽  
High Density ◽  
X Ray ◽  
Sum Frequency ◽  
Surface Normal ◽  
Methylene Groups ◽  
Spectroscopic Signatures

High-density polyethylene (HDPE) has been extensively studied, both as a model for semi-crystalline polymers and because of its own industrial utility. During cold drawing, crystalline regions of HDPE are known to break up and align with the direction of tensile load. Structural changes due to deformation should also manifest at the surface of the polymer, but until now, a detailed molecular understanding of how the surface responds to mechanical deformation has been lacking. This work establishes a precedent for using vibrational sum-frequency generation (VSFG) spectroscopy to investigate changes in the molecular-level structure of the surface of HDPE after cold drawing. X-ray diffraction (XRD) was used to confirm that the observed surface behavior corresponds to the expected bulk response. Before tensile loading, the VSFG spectra indicate that there is significant variability in the surface structure and tilt of the methylene groups away from the surface normal. After deformation, the VSFG spectroscopic signatures are notably different. These changes suggest that hydrocarbon chains at the surface of visibly necked HDPE are aligned with the direction of loading, while the associated methylene groups are oriented with the local C2 v symmetry axis roughly parallel to the surface normal. Small amounts of unaltered material are also found at the surface of necked HDPE, with the relative amount of unaltered material decreasing as the amount of deformation increases. Aspects of the nonresonant SFG response in the transition zone between necked and undeformed polymer provide additional insight into the deformation process and may provide the first indication of mechanical deformation. Nonlinear surface spectroscopy can thus be used as a noninvasive and nondestructive tool to probe the stress history of a HPDE sample in situations where X-ray techniques are not available or not applicable. Vibrational sum-frequency generation thus has great potential as a platform for material state awareness (MSA) and should be considered as part of a broader suite of tools for such applications.

Fabrication and characterization of microwave cured high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube composites

2019 ◽  
Vol 53 (15) ◽  
pp. 2091-2104 ◽  
Author(s):  
Gaurav Arora ◽  
Himanshu Pathak ◽  
Sunny Zafar
Keyword(s):  
Carbon Nanotube ◽  
High Density Polyethylene ◽  
High Density ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Scanning Electron

Carbon nanotubes have been used as reinforcements in polymers due to their high elasticity, flexibility, and thermal conductivity. In this study, pellets of high-density polyethylene +20 wt% carbon nanotube and polypropylene +20 wt% carbon nanotube were cured using microwave energy. X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, uniaxial tensile test, and scanning electron microscopy was used to study morphology, thermal stability, and mechanical performance of the microwave-cured composites. X-ray diffraction analysis confirmed the bonding between the polymer and carbon nanotube as the peaks shifted and intensified. From the thermal study, it was observed that melting point of the composites is affected by microwave curing and the crystallinity of high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube changed by 57.67% and 47.28%, respectively. Results of the uniaxial tensile test indicated that Young’s modulus of microwave cured high-density polyethylene/carbon nanotube and polypropylene/carbon nanotube composites were improved by 295% and 787.8%, respectively. Scanning electron microscopic fractography shows the stretching of polymer over-lapped on carbon nanotubes in the direction of the applied load.

Structural evolution of melt-drawn transparent high-density polyethylene during heating and annealing: Synchrotron small-angle X-ray scattering study

2010 ◽  
Vol 46 (9) ◽  
pp. 1866-1877 ◽  
Author(s):  
Zhiyong Jiang ◽  
Yujing Tang ◽  
Jens Rieger ◽  
Hans-Friedrich Enderle ◽  
Dieter Lilge ◽  
...  
Keyword(s):  
Small Angle ◽  
High Density Polyethylene ◽  
Structural Evolution ◽  
High Density ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Ray Scattering

Stress-Induced Crystal-to-Crystal Transformations in High-Density Polyethylene-Layered Silicate Nanocomposites: A Spectroscopic Study

2005 ◽  
Vol 59 (9) ◽  
pp. 1148-1154 ◽  
Author(s):  
Spiros Tzavalas ◽  
Vasilis G. Gregoriou
Keyword(s):  
High Density Polyethylene ◽  
Mechanical Strain ◽  
Layered Silicate ◽  
High Density ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Polyethylene Matrix ◽  
Dsc Measurements ◽  
Infrared Measurements ◽  
Ft Ir

High-density polyethylene (HDPE)–clay nanocomposites have been prepared using the melt intercalation technique. Organically modified montmorillonite at various loadings (0.5–7%) was used as a nanoadditive. Fourier transform infrared spectroscopy (FT-IR) was utilized for the first time to monitor the stress-induced crystal-to-crystal transformations of the polyethylene matrix with respect to the clay loading as well as to the degree of mechanical strain. In addition, polarized infrared measurements revealed information on both the orientation and the stress-induced distortion of the crystals. It was concluded that the crystal-to-crystal transformations are hindered by the presence of the clay, which also prevented the crystals from orienting even at low clay loadings (1%). Finally, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements confirmed the presence of the stress-induced crystalline structures in agreement with the infrared measurements.

Structure Refinement of High-Density Polyethylene Using X-Ray Powder Diffraction Data and the Rietveld Method

1995 ◽  
Vol 39 ◽  
pp. 515-521
Author(s):  
Kenneth B. Schwartz ◽  
Robert B. Von Dreele
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
High Density Polyethylene ◽  
Rietveld Method ◽  
Structure Refinement ◽  
High Density ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Voigt Profile ◽  
Full Structure

A full structure analysis of a completely crystallized sample of high-density polyethylene (HDPE) has been achieved using x-ray powder diffraction data collected on a laboratory-based powder diffractometer. The structure refinement is performed using the Rietveld method and includes refinement of the carbon and hydrogen atomic positions and temperature factors. The C-C and C-H bond distances and the C-C-C bond angle along the polyethylene chain have been calculated from the refined atomic positions and are in very good agreement with previous experimental and modelling determinations. Evaluations of the pseudo-Voigt profile parameters for Lorentzian strain broadening and me Scherrer coefficient for Gaussian broadening yield reasonable values for microstrain and particle size for this sample. Refinement of the preferred orientation parameter indicates that the HDPE flakes consist of platy crystals or lamellae that are packed normal to the diffraction vector.

scholarly journals Lifetime assessment of high-density polyethylene–silica nanocomposites

2019 ◽  
Vol 9 ◽  
pp. 184798041984998 ◽  
Author(s):  
A Dorigato ◽  
LE Govaert ◽  
A Pegoretti
Keyword(s):  
Fumed Silica ◽  
High Density Polyethylene ◽  
Tensile Tests ◽  
Testing Temperature ◽  
High Density ◽  
Time To Failure ◽  
Creep Tests ◽  
Polyethylene Matrix ◽  
Significant Drop ◽  
Fumed Silica Nanoparticles

In this work, the effect of fumed silica on the long-term resistance of high-density polyethylene was investigated. Different amounts of functionalized fumed silica nanoparticles were dispersed in a high-density polyethylene matrix by melt compounding, and compression molded specimens were tested under tensile mode in the quasi-static ramp and creep conditions. In particular, tensile tests at different speeds and temperatures and the subsequent application of the modified Ree–Eyring model allowed the determination of an analytical expression correlating the strain rate with the yield stress and the testing temperature. It was demonstrated that the introduction of fumed silica led to a significant drop in the deformation rate, especially at elevated filler amounts. Creep tests showed that the nanofiller addition led to a progressive reduction of the critical deformation values. The application of this engineering approach evidenced how nanosilica introduction led to a systematic increase of the time-to-failure values, and good accordance between theoretical prediction and experimental measurements was found.

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