Dielectric properties of castor oil cross-linked polyurethane

Oprea, Stefan; Potolinca, Otilia; Oprea, Veronica

doi:10.1177/0954008310378403

Cited by 14 publications

(12 citation statements)

References 29 publications

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“…We have previously described the detailed two‐step polymerization procedure for the synthesis of the pyridine‐based polyurethane elastomers . The composition and the designation of the samples are shown in Table .…”

Section: Methodsmentioning

confidence: 99%

Biodegradation of pyridine‐based polyether polyurethanes by the Alternaria tenuissima fungus

Oprea¹,

Potolinca²,

Gradinariu

et al. 2017

J of Applied Polymer Sci

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The scope of the present work is to study the biodegradability behavior of several novel heterocyclic poly(ether urethanes) when their hard segments are subjected to exposure to the Alternaria tenuissima fungus. The heterocyclic poly(ether urethanes) were chain-extended with various pyridine derivatives that had different functional groups placed in different positions on the pyridine rings. Different ratios of the reactive components were also used. The measurements obtained by the use of the attenuated total reflectance-Fourier transform infrared spectroscopy revealed the different structural changes that occurred after exposure to fungi. The degradation process was analyzed through measurement of the mechanical properties and surface morphology evolution by scanning electron microscopy. The obtained results show that the nature and design of the functional groups on the pyridine ring determine the strength of the cohesion linkages that in turn influence different degradation behaviors under exposure to fungi. V C 2017Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46096.

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Section: Methodsmentioning

confidence: 99%

Biodegradation of pyridine‐based polyether polyurethanes by the Alternaria tenuissima fungus

Oprea¹,

Potolinca²,

Gradinariu

et al. 2017

J of Applied Polymer Sci

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“…The diversification of synthesis components is gradually shifting to the inclusion of natural raw materials to obtain PU materials with improved properties for specific applications. 6–10 Conventional PUs exhibit acceptable mechanical properties up to a relatively low temperature (80°C) and their thermal degradation begins at about 200°C. 11,12…”

Section: Introductionmentioning

confidence: 99%

Structure–properties relationship of the polyurethanes that contain Schiff base in the main chain

Oprea¹,

Potolinca²,

Oprea

et al. 2020

High Performance Polymers

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This article studies the diversification of useful properties of polyurethane (PU) structures by the inclusion of new components. PUs containing a Schiff base in the main chain were synthesized by using N, N′-bis(salicylidene)-1,3-propanediamine as a chain extender. Novel Schiff base PUs were synthesized via a two-step polymerization starting from a Schiff base derivative diol chain extender with different molar ratios or by cross-linking with various natural raw materials. The sought after structures was confirmed by Fourier transform infrared spectra that showed the disappearance of the signals of both the hydroxyl and isocyanate groups. The thermal properties of these PUs were investigated by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The initial degradation temperatures of the obtained PUs were found to be in the range of 300–350°C. Based on the results from DMA, the rigid structure of the Schiff base from the backbone of the PUs presented a higher storage modulus, results which may be connected to the physical cross-linking process of the macromolecules. Their optical properties were determined by fluorescence spectroscopy. The incorporation of Schiff base structures into the main PU chain generates new PU structures with improved thermomechanical properties, which includes possible bioactive Schiff base moieties, widening the range of practical applications for such polymers.

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“…Nowadays, the study on waterborne polyurethane (WPU) is fast developed, which is prompted by the environmental requirements . However, WPU have several shortcomings such as low resistance to moisture and polar solvents and low thermal stability.…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, the incorporation of polyhedral oligomeric silsesquioxane (POSS) into WPU matrix for the construction of organic/inorganic hybrid has been an attractive method to high‐performance materials. The nanoscale cage structure of POSS affords a molecular level control on the mechanical properties, surface performances, and biological function of the hybrids. Moreover, the high dielectric constant of the polar WPU material can also be depressed by the addition of POSS .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of waterborne polyurethane/polyhedral oligomeric silsesquioxane composites with low dielectric constants

Zhao

et al. 2019

Polymers for Advanced Techs

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A facile method was developed to synthesize a new type of polyhedral oligomeric silsesquioxane (POSS). It contained a single amine group and seven aliphatic moieties on its corners. FT-IR, 1 H-NMR, 13 C-NMR, 13 C-1 H COSY, and 1 H-1 H COSY confirmed that cages with eight corners were the main part of the product. This new POSS was used to modify the structure of hexamethylene diisocyanate trimer and then copolymerized with hexamethylene diisocyanate and poly (tetramethylene glycol) to get a serious of waterborne polyurethane (WPU)/POSS hybrid materials with low dielectric constants for microelectronics applications. The results showed that POSS particles were uniformly dispersed in the WPU dispersions. The WPU/POSS films did not show any macrophase separation, even when the POSS content was as high as 16%. As the POSS content increased from 0% to 16%, the tensile strength was increased from 2.3 to 7.3 MPa, the dielectric constant was decreased from about 2.9 to 2.0, and the thermal stability of the WPU/POSS was also improved.

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Dielectric properties of castor oil cross-linked polyurethane

Cited by 14 publications

References 29 publications

Biodegradation of pyridine‐based polyether polyurethanes by the Alternaria tenuissima fungus

Biodegradation of pyridine‐based polyether polyurethanes by the Alternaria tenuissima fungus

Structure–properties relationship of the polyurethanes that contain Schiff base in the main chain

Synthesis and characterization of waterborne polyurethane/polyhedral oligomeric silsesquioxane composites with low dielectric constants

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