Skip to main content

Research Repository

Advanced Search

All Outputs (41)

Modeling non-linear rheology of PLLA: comparison of Giesekus and Rolie-Poly constitutive models (2020)
Journal Article
Stępień, M., Choong, G. Y., De Focatiis, D. S., & Figiel, Ł. (2020). Modeling non-linear rheology of PLLA: comparison of Giesekus and Rolie-Poly constitutive models. International Journal of Biobased Plastics, 2(1), 13-28. https://doi.org/10.1080/24759651.2020.1808367

Rheological models for biobased plastics can assist in predicting optimum processing parameters in industrial forming processes for biobased plastics and their composites such as film blowing, or injection stretch-blow molding in the packaging indust... Read More about Modeling non-linear rheology of PLLA: comparison of Giesekus and Rolie-Poly constitutive models.

A phenomenological constitutive model for the viscoelastic deformation of elastomers (2020)
Journal Article
Annarasa, V., Popov, A. A., & De Focatiis, D. S. A. (2020). A phenomenological constitutive model for the viscoelastic deformation of elastomers. Mechanics of Time-Dependent Materials, https://doi.org/10.1007/s11043-020-09452-2

This study proposes a one-dimensional constitutive model for elastomeric materials based on recent observations regarding the separation of elastic and viscous contributions in uniaxial cyclic tensile experiments on EPDM rubber. The focus is on captu... Read More about A phenomenological constitutive model for the viscoelastic deformation of elastomers.

Intrinsic dependence of ice adhesion strength on surface roughness (2020)
Journal Article
Memon, H., Liu, J., De Focatiis, D. S., Choi, K.-S., & Hou, X. (2020). Intrinsic dependence of ice adhesion strength on surface roughness. Surface and Coatings Technology, 385, Article 125382. https://doi.org/10.1016/j.surfcoat.2020.125382

The roles of surface roughness on icephobicity including ice adhesion strength have been long debated in icephobicity studies. However, the direct/systematic influence of surface roughness on ice adhesion strength while keeping other surface characte... Read More about Intrinsic dependence of ice adhesion strength on surface roughness.

A novel criterion for the prediction of meso-scale defects in textile preforming (2019)
Journal Article
Matveev, M. Y., Endruweit, A., De Focatiis, D. S., Long, A. C., & Warrior, N. A. (2019). A novel criterion for the prediction of meso-scale defects in textile preforming. Composite Structures, 226, Article 111263. https://doi.org/10.1016/j.compstruct.2019.111263

© 2019 The Authors In numerical simulations of reinforcement preforming, fabrics are often modelled using continuum approaches with homogenised material properties in order to reduce the computational costs. To predict the occurrence of meso-scale de... Read More about A novel criterion for the prediction of meso-scale defects in textile preforming.

The development of a novel technique for small ring specimen tensile testing (2018)
Journal Article
Kazakeviciute, J., Rouse, J., De Focatiis, D., & Hyde, C. (2019). The development of a novel technique for small ring specimen tensile testing. Theoretical and Applied Fracture Mechanics, 99, 131-139. https://doi.org/10.1016/j.tafmec.2018.11.016

The wide scale use of small specimens in routine testing programs could significantly reduce material resource requirements (factors of 10 are easily achievable). This is a major benefit to situations where there is not enough material to manufacture... Read More about The development of a novel technique for small ring specimen tensile testing.

Frictional behaviour of non-crimp fabrics (NCFs) in contact with a forming tool (2018)
Journal Article
Avgoulas, E. I., Mulvihill, D. M., Endruweit, A., Sutcliffe, M. P., Warrior, N. A., De Focatiis, D. S., & Long, A. C. (2018). Frictional behaviour of non-crimp fabrics (NCFs) in contact with a forming tool. Tribology International, 121, 71-77. https://doi.org/10.1016/j.triboint.2018.01.026

Microscopic observation and analysis are used to examine the role that contact conditions play in determining the frictional behaviour of non-crimp fabrics (NCFs). The true fibre contact length is measured over a range of normal pressures. For the NC... Read More about Frictional behaviour of non-crimp fabrics (NCFs) in contact with a forming tool.

The Roles of Blending and of Molecular Weight Distribution on Craze Initiation (2017)
Journal Article
Sánchez-Valencia, A., Smerdova, O., Hutchings, L. R., & De Focatiis, D. S. A. (2017). The Roles of Blending and of Molecular Weight Distribution on Craze Initiation. Macromolecules, 50(23), 9507-9514. https://doi.org/10.1021/acs.macromol.7b01289

Craze initiation stress was measured in three-point bending isochronal creep tests on a series of entangled bimodal blends of polystyrenes of narrow dispersity, on three polystyrenes of broad dispersity, and on four blends of polystyrenes of broad di... Read More about The Roles of Blending and of Molecular Weight Distribution on Craze Initiation.

Can a combination of poly(ethylene glycol) and dense phase carbon dioxide improve processing of polylactide? A high pressure rheology investigation (2017)
Journal Article
Pepper, K., Masson, T., De Focatiis, D. S., & Howdle, S. M. (in press). Can a combination of poly(ethylene glycol) and dense phase carbon dioxide improve processing of polylactide? A high pressure rheology investigation. Journal of Supercritical Fluids, 133(1), https://doi.org/10.1016/j.supflu.2017.10.014

High temperature melts or use of organic solvents are not practicable approaches for encapsulating protein based or thermally labile drugs into degradable polymers. Here, we demonstrate that poly(ethylene glycol) (PEG) in combination with supercritic... Read More about Can a combination of poly(ethylene glycol) and dense phase carbon dioxide improve processing of polylactide? A high pressure rheology investigation.

Compression moulding of composites with hybrid fibre architectures (2016)
Journal Article
Corbridge, D., Harper, L. T., De Focatiis, D. S., & Warrior, N. (2017). Compression moulding of composites with hybrid fibre architectures. Composites Part A: Applied Science and Manufacturing, 95, 87-99. https://doi.org/10.1016/j.compositesa.2016.12.018

Advanced Sheet Moulding Compounds (ASMC) and unidirectional (UD) prepregs have been co-compression moulded to form a hybrid composite material. In-mould flow influences the UD fibre architecture in two ways. When UD fibres are aligned transversely to... Read More about Compression moulding of composites with hybrid fibre architectures.

A model for the compressible, viscoelastic behavior of human amnion addressing tissue variability through a single parameter (2015)
Journal Article
Mauri, A., Ehret, A. E., De Focatiis, D. S., & Mazza, E. (2016). A model for the compressible, viscoelastic behavior of human amnion addressing tissue variability through a single parameter. Biomechanics and Modeling in Mechanobiology, 15(4), 1005-1017. https://doi.org/10.1007/s10237-015-0739-0

A viscoelastic, compressible model is proposed to rationalize the recently reported response of human amnion in multiaxial relaxation and creep experiments. The theory includes two viscoelastic contributions responsible for the sho... Read More about A model for the compressible, viscoelastic behavior of human amnion addressing tissue variability through a single parameter.

High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone) (2015)
Journal Article
Curia, S., De Focatiis, D. S., & Howdle, S. M. (2015). High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone). Polymer, 69, https://doi.org/10.1016/j.polymer.2015.05.026

High-pressure rheology has been used to assess the effects of supercritical carbon dioxide (scCO2) on the melting point (Tm) and viscosity of poly (ε-caprolactone) (PCL) over a range of temperatures and pressures up to 300 bar over a wide range of sh... Read More about High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone).

Time-dependent mechanical behavior of human amnion: Macroscopic and microscopic characterization (2014)
Journal Article
Mauri, A., Perrini, M., Ehret, A. E., De Focatiis, D. S., & Mazza, E. (2015). Time-dependent mechanical behavior of human amnion: Macroscopic and microscopic characterization. Acta Biomaterialia, 11, https://doi.org/10.1016/j.actbio.2014.09.012

Characterizing the mechanical response of the human amnion is essential to understand and to eventually prevent premature rupture of fetal membranes. In this study, a large set of macroscopic and microscopic mechanical tests have been carried out on... Read More about Time-dependent mechanical behavior of human amnion: Macroscopic and microscopic characterization.

The role of deformation history on stress relaxation and stress memory of filled rubber (2014)
Journal Article
Fernandes Arruebarrena, V. A., & De Focatiis, D. S. (2014). The role of deformation history on stress relaxation and stress memory of filled rubber. Polymer Testing, 40, https://doi.org/10.1016/j.polymertesting.2014.08.018

Although the magnitudes of inelastic and viscoelastic effects in filled rubbers are small relative to that of the elastic response, these effects are nevertheless critical in applications such as gaskets, seals and dampers. This study investigates th... Read More about The role of deformation history on stress relaxation and stress memory of filled rubber.

A novel nethod of extraction of blend component structure from SANS measurements of homopolymer bimodal blends (2014)
Journal Article
Smerdova, O., Graham, R. S., Gasser, U., Hutchings, L. R., & De Focatiis, D. S. (2014). A novel nethod of extraction of blend component structure from SANS measurements of homopolymer bimodal blends. Macromolecular Chemistry and Physics, 215(9), https://doi.org/10.1002/macp.201300787

A new method is presented for the extraction of single chain form factors and inter-chain interference functions from a range of small angle neutron scattering (SANS) experiments on bimodal homopolymer blends. The method requires a minimum of three b... Read More about A novel nethod of extraction of blend component structure from SANS measurements of homopolymer bimodal blends.

A toolbox for parameter-free predictions of solid-state properties of monodisperse glassy polymers with frozen-in molecular orientation (2012)
Journal Article
De Focatiis, D. S., & Buckley, C. P. (2012). A toolbox for parameter-free predictions of solid-state properties of monodisperse glassy polymers with frozen-in molecular orientation. Journal of Polymer Science Part B: Polymer Physics, 50(24), https://doi.org/10.1002/polb.23196

A toolbox that allows designers to predict the properties of oriented glassy polymers using only existing material constants is constructed from a constitutive model applicable to both polymer solids and polymer melts. Two solid-state properties of p... Read More about A toolbox for parameter-free predictions of solid-state properties of monodisperse glassy polymers with frozen-in molecular orientation.

Large deformations in oriented polymer glasses: experimental study and a new glass-melt constitutive model (2010)
Journal Article
De Focatiis, D. S., Embery, J., & Buckley, C. (2010). Large deformations in oriented polymer glasses: experimental study and a new glass-melt constitutive model. Journal of Polymer Science Part B: Polymer Physics, 48(13), https://doi.org/10.1002/polb.22028

An experimental study was made of the effects of prior molecular orientation on large tensile deformations of polystyrene in the glassy state. A new hybrid glass-melt constitutive model is proposed for describing and understanding the results, achiev... Read More about Large deformations in oriented polymer glasses: experimental study and a new glass-melt constitutive model.

Processing and properties of PLA-HA nanocomposites: The effect of particle morphology and dispersants
Presentation / Conference Contribution
Tomczynska, M. M., Ward, M., Choong, G. Y. H., Walton, K., De Focatiis, D. S. A., Grant, D. M., Irvine, D. J., & Parsons, A. J. (2016, July). Processing and properties of PLA-HA nanocomposites: The effect of particle morphology and dispersants. Presented at 32nd International Conference of the Polymer Processing Society (PPS-32), Lyon, France

Biodegradable polylactic acid nanocomposites for orthopaedic implants require optimum particle dispersion and high molecular weight in load bearing applications. Novel coated hydroxyapatite nanoparticles can offer new opportunities for enhanced dispe... Read More about Processing and properties of PLA-HA nanocomposites: The effect of particle morphology and dispersants.

Compounding and rheometry of PLA nanocomposites with coated and uncoated hydroxyapatite nanoplatelets
Presentation / Conference Contribution
Tomczynska, M. M., Choong, G. Y., De Focatiis, D. S., Grant, D. M., & Parsons, A. J. (2015, September). Compounding and rheometry of PLA nanocomposites with coated and uncoated hydroxyapatite nanoplatelets. Presented at The Polymer Processing Society Conference 2015, Graz, Austria

Polylactic acid and novel nanoplatelets of hydroxyapatite (HANP) were compounded in a laboratory scale twin-screw extruder and injection moulded to shape. The effect of HANP loading content, between 1 wt% and 10 wt%, and of HANP surface coating with... Read More about Compounding and rheometry of PLA nanocomposites with coated and uncoated hydroxyapatite nanoplatelets.

Rheological techniques for determining degradation of polylactic acid in bioresorbable medical polymer systems
Presentation / Conference Contribution
Choong, G. Y., Parsons, A. J., Grant, D. M., & De Focatiis, D. S. A. (2014, June). Rheological techniques for determining degradation of polylactic acid in bioresorbable medical polymer systems. Presented at PROCEEDINGS OF PPS-30: The 30th International Conference of the Polymer Processing Society – Conference Papers, Cleveland, Ohio, USA

AIP Publishing LLC. A method developed in the 1980s for the conversion of linear rheological data to molar mab distribution is revisited in the context of degradable polymers. The method is first applied using linear rheology for a linear polystyrene... Read More about Rheological techniques for determining degradation of polylactic acid in bioresorbable medical polymer systems.