Effect of the degree of clay delamination on the phase morphology, surface chemical aspects, and properties of hydrolyzable polyurethanes for periodontal regeneration

Pereira, Iaci Miranda; Carvalho, Sandhra M.; Pereira, Marivalda M.; Leite, M. Fátima; Oréfice, Rodrigo Lambert

doi:10.1002/app.30404

Cited by 11 publications

(5 citation statements)

References 35 publications

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“…The carbonyl hydrogen‐bonding index,

{H B I}_{(C = O)}^{(%)}

, and the amine hydrogen‐bonding index,

{H B I}_{(- N H)}^{(%)}

, were determined using Eqs . and , respectively

{H B I}_{(c = o)}^{(%)} = \frac{A_{1700} + A_{1640}}{A_{1700} + A_{1640} + A_{1724} + A_{1660}} \times 100,

where A 1724 , A 1700 , A 1660 and A 1640 are the absorption band areas of free urethane, bonded urethane, free urea and bonded urea, respectively , and

{H B I}_{(- N H)}^{(%)} = \frac{{N H}_{b o n d e d}}{{N H}_{b o n d e d} + {N H}_{f r e e}} \times 100,

where NH bonded and NH free are the absorption band areas for bonded –NH groups (∼3,326 cm −1 ) and free –NH groups (∼3,446 cm −1 ), respectively.…”

Section: Resultsmentioning

confidence: 99%

Influence of aqueous dispersions in place of organic solvents during the synthesis of shape memory polyurethanes on their structure and properties

Martins

Pereira

Hoehne

et al. 2016

Polymer Engineering & Sci

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In this work, the effect of synthesizing shape memory polyurethanes in aqueous dispersions instead of in organic solvents on the structure and properties of the obtained polymers was investigated. Shape memory polyurethanes based on polycaprolactone diol and isophorone diisocyanate were synthesized by two routes: (1) aqueous dispersion (PU/SM WATER ) and (2) dissolution in THF (PU/SM THF ). The samples were analyzed by infrared spectroscopy (FTIR), X-ray diffraction (XRD), static light scattering (SLS), atomic force microscopy (AFM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and mechanical tests. The aqueous dispersion method led to the production of polyurethanes with a higher degree of phase separation and a higher degree of crystallinity. The morphology of the obtained polyurethanes demonstrated that PU/SM WATER displays a structure with better defined phase separated domains. The polyurethanes exhibited similar average molar masses, soft segment glass transitions (T gs ) and mechanical properties. The lower degrees of phase separation and crystallinity of the PU/SM THF led to lower values for the shape memory properties (shape recovery ratio (R r )). The observed changes in the structure of the polyurethanes due to the replacement of organic solvent by an aqueous dispersion during their syntheses confirmed the preparation of shape memory polyurethanes with enhanced shape memory properties. POLYM. ENG. SCI.,

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“…The carbonyl hydrogen‐bonding index,

{H B I}_{(C = O)}^{(%)}

, and the amine hydrogen‐bonding index,

{H B I}_{(- N H)}^{(%)}

, were determined using Eqs . and , respectively

{H B I}_{(c = o)}^{(%)} = \frac{A_{1700} + A_{1640}}{A_{1700} + A_{1640} + A_{1724} + A_{1660}} \times 100,

where A 1724 , A 1700 , A 1660 and A 1640 are the absorption band areas of free urethane, bonded urethane, free urea and bonded urea, respectively , and

{H B I}_{(- N H)}^{(%)} = \frac{{N H}_{b o n d e d}}{{N H}_{b o n d e d} + {N H}_{f r e e}} \times 100,

where NH bonded and NH free are the absorption band areas for bonded –NH groups (∼3,326 cm −1 ) and free –NH groups (∼3,446 cm −1 ), respectively.…”

Section: Resultsmentioning

confidence: 99%

Influence of aqueous dispersions in place of organic solvents during the synthesis of shape memory polyurethanes on their structure and properties

Martins

Pereira

Hoehne

et al. 2016

Polymer Engineering & Sci

View full text Add to dashboard Cite

show abstract

“…:

{H B I}_{(- N H)}^{(%)} = \frac{{N H}_{b o n d e d}}{{N H}_{b o n d e d} + {N H}_{f r e e}} \times 100

where NH bonded and NH free are the respective areas of the FTIR absorption band relative to the hydrogen bonded NH groups (∼3300 cm −1 ) and the nonhydrogen bonded groups, that is, free (∼3500 cm −1 ).

{H B I}_{(c = o)}^{(%)} = \frac{A_{1700} + A_{1640}}{A_{1735} + A_{1724} + A_{1700} + A_{1660} + A_{1640}} \times 100

where A 1735 , A 1724 , A 1700 , A 1660 , and A 1640 are the respective absorption band areas of the carbonyl groups of the PCL, free urethane, hydrogen‐bonded urethane, free urea, and hydrogen‐bonded urea

{H B I}_{(c = o)}^{(%)} = \frac{A_{1700}}{A_{1735} + A_{1724} + A_{1630}} \times 100

where A 1735 , A 1724 , A 1700 , and A 1630 are the resp...…”

Section: Resultsmentioning

confidence: 99%

The effect of the incorporation of polystyrene‐based chain extenders on the properties of the shape memory polyurethanes

Martins

Pereira

Diniz

et al. 2016

J of Applied Polymer Sci

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In this work, the idea of modulating the shape memory properties of polyurethanes by changing their macromolecular architecture through the incorporation of polystyrene-based moieties was investigated. To study these effects, poly(styrene-co-maleic anhydride) (SMA) was incorporated during the synthesis of PU as a potential chain extender. Two sample groups were produced: (i) PU, produced with hydrazine as a chain extender and (ii) PU SMA , produced with the addition of SMA instead of hydrazine. The results suggest that the SMA incorporation in the PU SMA chains occurred by the reaction between NCO groups of the PU and maleic anhydride (MA) of the SMA. The presence of SMA was useful in modulating the structure of PU by reducing the soft segment crystallinity and molar mass. These changes in the structure and macromolecular architecture due to the presence of SMA moieties in PU chains led to pronounced improvements in strength, toughness, and the shape recovery ratio. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44471.

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“…Otherwise, an increase in scattering (mainly for lower values of q) was observed when clay nanoparticles were introduced into PU (Figure 4(b)) as an evidence of the presence of these nanoentities that have a higher electron density than the pure polymer. It was demonstrated previously [43] that clay nanoparticles can interact with hard segments of polyurethane through the formation of hydrogen bonds to change the course of the phase separation process. Additionally, the polar clay surface can also interact with the poly(ethylene glycol)-based soft segments of the polymer, changing the morphology of the polyurethane.…”

Section: Resultsmentioning

confidence: 99%

Montmorillonite Clay-Based Polyurethane Nanocomposite As Local Triamcinolone Acetonide Delivery System

Pinto

Silva-Cunha

Pianetti

et al. 2011

Journal of Nanomaterials

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Biodegradable polyurethane was synthesized by preparing aqueous polyurethane dispersion having poly(caprolactone) and poly(ethylene glycol) as soft segments. Montmorillonite particles were delaminated within the waterborne polyurethane to produce a nanocomposite. The triamcinolone acetonide (TA), an important corticoid drug, was dispersed into the nanocomposite followed by a drying step to produce an implantable drug delivery system. Infrared (FTIR) results demonstrated that the original chemical structure of the TA was preserved after incorporation into the nanocomposite. Wide angle (WAXS) and small angle X-ray scattering (SAXS) results suggested that TA and clay do not dramatically change the morphology phase of the polymer although they can interact with each other. The presence of montmorillonite particles in the nanocomposite reduced the rate of TA release as compared to the pure polyurethane and enhanced the mechanical properties of the polymer. The overall results indicate that montmorillonite clay-based polyurethane nanocomposite could be potentially applied as local TA delivery system.

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Effect of the degree of clay delamination on the phase morphology, surface chemical aspects, and properties of hydrolyzable polyurethanes for periodontal regeneration

Cited by 11 publications

References 35 publications

Influence of aqueous dispersions in place of organic solvents during the synthesis of shape memory polyurethanes on their structure and properties

Influence of aqueous dispersions in place of organic solvents during the synthesis of shape memory polyurethanes on their structure and properties

The effect of the incorporation of polystyrene‐based chain extenders on the properties of the shape memory polyurethanes

Montmorillonite Clay-Based Polyurethane Nanocomposite As Local Triamcinolone Acetonide Delivery System

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