Polymerization kinetics under confinement

Reddy, Chaganti Srinivasa; Arinstein, Arkadii; Zussman, Eyal

doi:10.1039/c0py00285b

Cited by 13 publications

(17 citation statements)

References 23 publications

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“…In their study, lower sensitivity of the instrument and slower acquisition rate of the FT-IR did not provide sufficient information at the early stage of polymerization. Nevertheless, our trend agrees qualitatively with related studies involving the rate of reaction under confinement/constraint; for example, a recent study reported a decrease in the rate of reaction when the polymerization was confined inside a core-shell nanofiber [33]. The authors attributed this decrease to the obstruction of the cluster growth caused by steric restrictions, and the separation of the reacting area due to the formed clusters.…”

Section: Resultssupporting

confidence: 92%

Simultaneous measurement of polymerization stress and curing kinetics for photo-polymerized composites with high filler contents

et al. 2014

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Objectives Photopolymerized composites are used in a broad range of applications with their performance largely directed by reaction kinetics and contraction accompanying polymerization. The present study was to demonstrate an instrument capable of simultaneously collecting multiple kinetics parameters for a wide range of photopolymerizable systems: degree of conversion (DC), reaction exotherm, and polymerization stress (PS). Methods Our system consisted of a cantilever beam-based instrument (tensometer) that has been optimized to capture a large range of stress generated by lightly-filled to highly-filled composites. The sample configuration allows the tensometer to be coupled to a fast near infrared (NIR) spectrometer collecting spectra in transmission mode. Results Using our instrument design, simultaneous measurements of PS and DC are performed, for the first time, on a commercial composite with ≈ 80 % (by mass) silica particle fillers. The in situ NIR spectrometer collects more than 10 spectra per second, allowing for thorough characterization of reaction kinetics. With increased instrument sensitivity coupled with the ability to collect real time reaction kinetics information, we show that the external constraint imposed by the cantilever beam during polymerization could affect the rate of cure and final degree of polymerization. Significance The present simultaneous measurement technique is expected to provide new insights into kinetics and property relationships for photopolymerized composites with high filler content such as dental restorative composites.

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Section: Resultssupporting

confidence: 92%

Simultaneous measurement of polymerization stress and curing kinetics for photo-polymerized composites with high filler contents

et al. 2014

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“…An aluminum foil sheet was placed 11 cm beneath the spinneret exit for the collection of non‐woven fibrous scaffolds. PCL/BPAEDMA electrospun fibrous compound scaffolds were placed on aluminum foil sheets supported on a metal disc at a distance of 15 cm from two horizontal 20W high‐pressure mercury lamps and then BPAEDMA in the compound fibers was cured by UV radiation for 10 min as reported earlier …”

Section: Methodsmentioning

confidence: 99%

“…In addition, these elements are both non‐toxic and non‐immunogenic, which are two essential requirements for biocompatible implantable materials. Photopolymerization of this oligomer leads to the formation of flexible elastomeric hydrogel films and nanofibers . Assessment of the tissue engineering capacities of the described compound fiber scaffolds embedded with rabbit cardiac cells, demonstrated their low stiffness and balanced hydrophobic properties were suitable for cell adhesion and proliferation of cardiac cells.…”

Section: Introductionmentioning

confidence: 99%

Polycaprolactone/oligomer compound scaffolds for cardiac tissue engineering

Reddy

Venugopal

Ramakrishna

et al. 2013

J Biomedical Materials Res

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Polycaprolactone (PCL), a synthetic biocompatible and biodegradable polymer generally used as a scaffold material for tissue engineering applications. The high stiffness and hydrophobicity of the PCL fiber mesh does not provide significant cell attachment and proliferation in cardiac tissue engineering. Towards this goal, the study focused on a compound of PCL and oligomer hydrogel [Bisphenol A ethoxylated dimethacrylate (BPAEDMA)] processed into electrospun nanofibrous scaffolds. The composition, morphology and mechanical properties of the compound scaffolds, composed of varying ratios of PCL and hydrogel were characterized by scanning electron microscopy, infrared spectroscopy and dynamic mechanical analyzer. The elastic modulus of PCL/BPAEDMA nanofibrous scaffolds was shown to be varying the BPAEDMA weight fraction and was decreased by increasing the BPAEDMA weight fraction. Compound fiber meshes containing 75 wt % BPAEDMA oligomer hydrogel exhibited lower modulus (3.55 MPa) and contact angle of 25(o) . Rabbit cardiac cells cultured for 10 days on these PCL/BPAEDMA compound nanofibrous scaffolds remained viable and expressed cardiac troponin and alpha-actinin proteins for the normal functioning of myocardium. Cell adhesion and proliferations were significantly increased on compound fiber meshes containing 75 wt % BPAEDMA, when compared with other nanofibrous scaffolds. The results observed that the produced PCL/BPAEDMA compound nanofibrous scaffolds promote cell adhesion, proliferation and normal functioning of cardiac cells to clinically beneficial levels, relevant for cardiac tissue engineering.

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“…Core/shell nano‐/microfibers have been prepared by using coaxial electrospinning with a core/shell nozzle attached to a double‐compartment syringe . It was also found that the single‐nozzle electrospinning of emulsion solutions can produce core/shell fibers, for example, poly(ethylene oxide)‐fluorescein isothiocyanate‐core/poly(ethylene glycol‐ block ‐ l ‐lactic acid)‐shell, polyaniline‐core/polycarbonate‐shell, polyaniline‐core/polystyrene‐shell, polyaniline‐core/poly(methyl methacrylate)‐shell, polyaniline‐core/poly(ethylene oxide)‐shell, and poly(methyl methacrylate)‐core/polyacrylonitrile‐shell fibers .…”

Section: Introductionmentioning

confidence: 99%

“…a double-compartment syringe. [1][2][3][4] It was also found that the single-nozzle electrospinning of emulsion solutions can produce core/shell fi bers, for example, poly(ethylene oxide)fl uorescein isothiocyanate-core/poly(ethylene glycol-block -L -lactic acid)-shell, [ 5 ] polyaniline-core/polycarbonate-shell, [ 6 ] polyaniline-core/polystyrene-shell, [ 6 ] polyaniline-core/ poly(methyl methacrylate)-shell, [ 6 ] polyaniline-core/ poly(ethylene oxide)-shell, [ 6 ] and poly(methyl methacrylate)core/polyacrylonitrile-shell fi bers. [ 7 ] Upon the formation of a core/shell fl uid jet during electrospinning, the jet is immediately subject to capillary instabilities imposed at both the air/shell interface and the core/shell interface.…”

mentioning

confidence: 99%

The Enhanced Encapsulation Capacity of Polyhedral Oligomeric Silsesquioxane‐based Copolymers for the Fabrication of Electrospun Core/Shell Fibers

Bauer

Zeng

Liu

et al. 2014

Macromol. Rapid Commun.

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This paper reports the use of polyhedral oligomeric silsesquioxane (POSS)-based copolymers to stabilize the core/shell interface for the facile fabrication of electrospun core/shell fibers. For the poly[(propylmethacryl-heptaisobutyl-polyhedral oligomeric silsesquioxane)-co-(methyl methacrylate)] (POSS-MMA)/poly(ε-caprolactone) (PCL) system, the bicontinuity of hybrid core/shell fibers can be tuned by controlling the phase separation of POSS-MMA/PCL in electrospinning solutions and therefore the size of PCL-in-POSS-MMA emulsion droplets. Our results demonstrate the enhanced encapsulation capacity of POSS-MMA copolymers as shell materials. Taking advantage of the rapid advancement of POSS-based copolymer synthesis, this study can potentially be generalized to guide the fabrication of various other POSS-based core/shell nano-/microstructures by using single-nozzle electrospinning or coaxial electrospinning.

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Polymerization kinetics under confinement

Cited by 13 publications

References 23 publications

Simultaneous measurement of polymerization stress and curing kinetics for photo-polymerized composites with high filler contents

Simultaneous measurement of polymerization stress and curing kinetics for photo-polymerized composites with high filler contents

Polycaprolactone/oligomer compound scaffolds for cardiac tissue engineering

The Enhanced Encapsulation Capacity of Polyhedral Oligomeric Silsesquioxane‐based Copolymers for the Fabrication of Electrospun Core/Shell Fibers

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