The effect of crystallization conditions on the properties of polyoxymethylene

Plummer, C. J. G.; Menu, Patrick; Cudré‐Mauroux, N.; Kausch, H. H.

doi:10.1002/app.1995.070550314

Cited by 52 publications

(32 citation statements)

References 26 publications

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“…From the DSC endotherms, the lamellar thickness l of the samples was calculated on the basis of Gibbs–Thomson equation:

T_{m} = T_{m}^{0} (1 - \frac{2 σ_{e}}{Δ h_{0} l})

where T m 0 is the equilibrium melting temperature, Δ h 0 is thermodynamic enthalpy of fusion per unit volume of the crystalline phase, and σ e is the free surface energy of the end faces lamellar that is associated with the crystallization process. The values of T m 0 , Δ h 0 , and σ e for POM assumed in the previous equation for calculating the lamellar thickness were 200 °C, 380 × 10 6 J/m 3 , and 0.125 J/m 2 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of polyoxymethylene‐copolymer/hydroxyapatite nanocomposites for long‐term bone implants

Pielichowska

Szczygielska

Spasowka

2011

Polymers for Advanced Techs

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In this work, new polyoxymethylene (POM)/hydroxyapatite (HAp) nanocomposites for long‐term bone implants have been obtained via extrusion and injection molding processes and characterized by differential scanning calorimetry (DSC), temperature‐modulated DSC (TMDSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), wide‐angle X‐ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and tensile mechanical and in vitro stability tests. Based on the DSC results, it was found that the degree of crystallinity increases for POM/0.5% HAp sample and decreases for POM/1.0% HAp and POM/2.5% HAp. SEM and TEM observations for POM/HAp nanocomposites indicated that the dispersion of HAp in the polymer matrix was uniform and the diameter of the HAp particles was less than 100 nm for most of them. Young's modulus increases with increasing HAp concentration, whereby elongation at break decreases. On the contrary, HAp concentration does not have a significant influence on the tensile strength. TG results show that for POM/0.5% HAp, POM/1.0% HAp, and POM/2.5% HAp, thermal stability slightly increases in comparison to pure POM, whereas for POM/5.0 HAp and POM/10.0% HAp, lower thermal stability was observed. In vitro data reveal that with an increase of HAp content, bioactivity of nanocomposites increases; a good in vitro chemical stability of POM and POM nanocomposites was confirmed. Copyright © 2011 John Wiley & Sons, Ltd.

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“…From the DSC endotherms, the lamellar thickness l of the samples was calculated on the basis of Gibbs–Thomson equation:

T_{m} = T_{m}^{0} (1 - \frac{2 σ_{e}}{Δ h_{0} l})

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of polyoxymethylene‐copolymer/hydroxyapatite nanocomposites for long‐term bone implants

Pielichowska

Szczygielska

Spasowka

2011

Polymers for Advanced Techs

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“…At the next stage, the lamellar thickness l of the samples was calculated using Gibbs‐Thomson equation41, 42: where T

_{italicm}^{0}

is the equilibrium melting temperature, Δ h 0 is thermodynamic enthalpy of fusion per unit volume of the crystalline phase, and σ e is the free surface energy of the end faces lamellar that is associated with the crystallization process. The values of T

_{italicm}^{0}

, Δ h 0 , and σ e for POM assumed in the above equation for calculating the lamellar thickness were 200°C,43 380 × 10 6 J m −3 ,44 and 0.125 J m −2 ,45 respectively.…”

Section: Resultsmentioning

confidence: 99%

Polyoxymethylene‐homopolymer/hydroxyapatite nanocomposites for biomedical applications

Pielichowska

2011

J of Applied Polymer Sci

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In this article, new polyoxymethylene (POM)/hydroxyapatite (HAp) nanocomposites for bone long-term implants have been obtained and characterized by using FTIR, WAXD, SEM, TG, DSC, tensile tests, and in vitro evaluation. Characteristic bands both for extended chain crystals (ECC) and folded chain crystals (FCC) were observed in FTIR profiles for both pure POM and POM in POM/HAp nanocomposites. From WAXD analysis it has been found that the addition of HAp does not change the hexagonal system of POM in POM/HAp nanocomposites. Moreover, degree of crystallinity of POM increases with an increase of HAp content up to 1.0% and next decreases with an increase HAp content. It indicates that HAp nanoparticles up to 1.0% content act as effective nucleating sites. Mechanical tests revealed that Young's modulus increases, whereby, elongation at break and tensile strength decrease with increasing hydroxyapatite concentration. Results of in vitro investigations show that an increase of HAp content in POM nanocomposites facilitates formation of apatite layer on the sample surface and improves in vitro stability POM/HAp nanocomposites.

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“…The applications of a semicrystalline polymer are often limited by the high level of crystallinity, accompanied by brittleness and low-impact resistance [1,2]. However, this problem can be overcome by blending the thermoplastic with an elastomeric modifier, which in turn will also improve the polymer's toughness.…”

Section: Polymer Toughnessmentioning

confidence: 99%

Thermomechanical Analysis and Processing of Polymer Blends

Siengchin

2014

Characterization of Polymer Blends

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IntroductionCombinations of standard polymers can help in the development of new materials; indeed, the blending of polymers represents a technological approach to providing materials with a full set of desirable and specific properties. During the past few decades there has been a growing interest in polymer blends for the following reasons:The quest for new materials. The successful use of these blends in the automotive industry and various other engineering applications. Improved processing capabilities, product uniformity, and the ability to make quick changes to the formulations.The reasonable performances of polymer blends has attracted economic interest in a variety of industries. The method by which polymer blends are characterized is very important from the point of their utility and added value. Such characterization may also help to provide an understanding of the behavior of any new materials developed using these polymers, including polymer blends. The characterization of polymer blends is also very important if the user industries need to define suitable quality aspects in order to obtain products that are of consistent quality. This would be especially important when the quality criteria depend on the proposed application of the blend. A careful examination of the various properties of a polymer blend not only provides details of its chemical composition and constituents, but would also be valuable for predicting the types of possible application. Knowledge of the blend structure and of its observed properties would also be helpful when developing appropriate modifications of polymer blends for various applications. Accordingly, the main aim of this chapter is to provide a systematic examination of the toughness characteristics of polymer blends, using novel methods. Additional aims are to show that the concepts of latex and online 393

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The effect of crystallization conditions on the properties of polyoxymethylene

Cited by 52 publications

References 26 publications

Preparation and characterization of polyoxymethylene‐copolymer/hydroxyapatite nanocomposites for long‐term bone implants

Preparation and characterization of polyoxymethylene‐copolymer/hydroxyapatite nanocomposites for long‐term bone implants

Polyoxymethylene‐homopolymer/hydroxyapatite nanocomposites for biomedical applications

Thermomechanical Analysis and Processing of Polymer Blends

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