Introduction

Haward, R. N.; Young, R. J.

doi:10.1007/978-94-011-5850-3_1

Cited by 49 publications

(120 citation statements)

References 41 publications

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“…Starting from a dry condition, when they absorb water and swell, a part of the interchain interactions dissociate, making them partly rubbery. However, conventional constitutive models are either designed for rubbery elastomers [44–47], or for glassy solids [48]. The mixed nature of our polymer phases necessitates a model which can account for (a) the energetic contribution to stiffness (b) the interaction between polymer and water leading to sorption and (c) the poromechanical effects arising from fluid pressure.…”

Section: Introductionmentioning

confidence: 99%

Swelling equilibrium of dentin adhesive polymers formed on the water–adhesive phase boundary: Experiments and micromechanical model

Misra

Ranganathan

et al. 2014

Acta Biomaterialia

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During their application to the wet, oral environment, dentin adhesives can experience phase separation and composition change which can compromise the quality of the hybrid layer formed at the dentin-adhesive interface. The chemical composition of polymer phases formed in the hybrid layer can be represented using a ternary water-adhesive phase diagram. In this paper, these polymer phases have been characterized using a suite of mechanical tests and swelling experiments. The experimental results were evaluated using granular micromechanics based model that incorporates poro-mechanical effects and polymer-solvent thermodynamics. The variation of the model parameters and model-predicted polymer properties has been studied as a function of composition along the phase boundary. The resulting structure-property correlations provide insight into interactions occurring at the molecular level in the saturated polymer system. These correlations can be used for modeling the mechanical behavior of hybrid layer, and are expected to aid in the design and improvement of water-compatible dentin adhesive polymers.

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Section: Introductionmentioning

confidence: 99%

Swelling equilibrium of dentin adhesive polymers formed on the water–adhesive phase boundary: Experiments and micromechanical model

Misra

Ranganathan

et al. 2014

Acta Biomaterialia

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“…The mechanical response of glassy polymers is strongly rate-and temperature-dependent, accompanied by a possible presence of large inelastic strains, see Haward and Young (1997) for a review. The elasto-viscoplastic response stems from the inherent disordered micro-structure of the material that is formed by polymer chains in a frozen-in state.…”

Section: Introductionmentioning

confidence: 99%

Coupled thermoviscoplasticity of glassy polymers in the logarithmic strain space based on the free volume theory

Miehé

Diez

Göktepe

et al. 2011

International Journal of Solids and Structures

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a b s t r a c tThe paper outlines a constitutive model for finite thermo-visco-plastic behavior of amorphous glassy polymers and considers details of its numerical implementation. In contrast to existing kinematical approaches to finite plasticity of glassy polymers, the formulation applies a plastic metric theory based on an additive split of Lagrangian Hencky-type strains into elastic and plastic parts. The analogy between the proposed formulation in the logarithmic strain space and the geometrically linear theory of plasticity, makes this constitutive framework very transparent and attractive with regard to its numerical formulation. The characteristic strain hardening of the model is derived from a polymer network model. We consider the particularly simple eight chain model, but also comment on the recently developed microsphere model. The viscoplastic flow rule in the logarithmic strain space uses structures of the free volume flow theory, which provides a highly predictive modeling capacity at the onset of viscoplastic flow. The integration of this micromechanically motivated approach into a three-dimensional computational model is a key concern of this work. We outline details of the numerical implementation of this model, including elements such as geometric pre-and post-transformations to/from the logarithmic strain space, a thermomechanical operator split algorithm consisting of an isothermal mechanical predictor followed by a heat conduction corrector and finally, the consistent linearization of the local update algorithm for the dissipative variables as well as its relationship to the global tangent operator. The performance of the proposed formulation is demonstrated by means of a spectrum of numerical examples, which we compare with our experimental findings.

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“…These materials often exhibit ductile behavior and yield significantly prior to fracture in response to a large applied load. [12] By contrast, when cross-linked thermosetting polymers such as those formed via typical photopolymerizations are strained, eventual breaking of covalent bonds leads to the formation of nanosized cracks and ultimately failure at a relatively low elongation to break. [13,14] For a ductile thermoplastic material, multiple crazes appear in a comparatively large volume of the polymer, or shear deformation occurs without crazing, [15,16] and this is macroscopically evident after the yield point by a reduction in stress followed by the specimen necking at constant stress during the cold-drawing region, as the necked section is extended.…”

Section: Introductionmentioning

confidence: 99%

“…[17] The material’s ductility is dependent on complex factors including temperature relative to the glass transition ( T g ) or melting temperatures, testing rate, degree of crystallinity, chain alignment, chain length, chain branching and cross-linking, chain packing, intrinsic chain rigidity, and other intermolecular forces, among others. [3,12,16,18–20] …”

Section: Introductionmentioning

confidence: 99%

Photopolymerized Triazole‐Based Glassy Polymer Networks with Superior Tensile Toughness

Han

Baranek

Worrell

et al. 2018

Adv Funct Materials

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Photopolymerization is a ubiquitous, indispensable technique widely applied in applications from coatings, inks, and adhesives to thermosetting restorative materials for medical implants, and the fabrication of complex macro-scale, microscale, and nanoscale 3D architectures via additive manufacturing. However, due to the brittleness inherent in the dominant acrylate-based photopolymerized networks, a significant need exists for higher performance resin/oligomer formulations to create tough, defect-free, mechanically ductile, thermally and chemically resistant, high modulus network polymers with rapid photocuring kinetics. This study presents densely cross-linked triazole-based glassy photopolymers capable of achieving preeminent toughness of ≈70 MJ m−3 and 200% strain at ambient temperature, comparable to conventional tough thermoplastics. Formed either via photoinitiated copper(I)-catalyzed cycloaddition of monomers containing azide and alkyne groups (CuAAC) or via photoinitiated thiol-ene reactions from monomers containing triazole rings, these triazole-containing thermosets completely recover their original dimensions and mechanical behavior after repeated deformations of 50% strain in the glassy state over multiple thermal recovery–strain cycles.

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Introduction

Cited by 49 publications

References 41 publications

Swelling equilibrium of dentin adhesive polymers formed on the water–adhesive phase boundary: Experiments and micromechanical model

Swelling equilibrium of dentin adhesive polymers formed on the water–adhesive phase boundary: Experiments and micromechanical model

Coupled thermoviscoplasticity of glassy polymers in the logarithmic strain space based on the free volume theory

Photopolymerized Triazole‐Based Glassy Polymer Networks with Superior Tensile Toughness

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