Morphological and structural-rheological relationship in epiclon-based polyimide/hydroxypropylcellulose blend systems

Cosutchi, Andreea Irina; Hulubei, Camelia; Stoica, Iuliana; Ioan, Silvia

doi:10.1007/s10965-009-9342-3

Cited by 35 publications

(19 citation statements)

References 29 publications

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“…Polymers have been synthesized by the classical two‐step method (Scheme ), involving a PAA precursor subsequently cyclized into PI form [24]. The chemical structure of the resulted PIs is presented in Scheme .…”

Section: Resultsmentioning

confidence: 99%

“…In previous investigations [21–23], we have synthesized different polyimide structures based on cycloaliphatic dianhydrides, such as homo‐ and co‐polyimides. We have also studied some special properties of various polyimide‐based blend systems, related to morphological and structural‐rheological aspects [24], blood compatibility [25], or different novel approaches for patterning such type of polymers [26].…”

Section: Introductionmentioning

confidence: 99%

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Origin of dielectric response and conductivity of some alicyclic polyimides

Ioan¹,

Hulubei²,

Popovici³

et al. 2012

Polymer Engineering & Sci

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High‐performance alicyclic‐containing polyimides for advanced applications, derived from 5‐(2,5‐dioxotetrahydrofurfuryl)‐3‐methyl‐3‐cyclohexene‐1,2‐dicarboxylic acid anhydride or bicyclo[2.2.2]oct‐7‐ene‐2,3,5,6‐ tetracarboxylic dianhydride and two flexible aromatic diamines, were synthesized by a classical two‐step polycondensation reaction. The dielectric spectra behavior over wide frequency and temperature ranges of 1 Hz‐1 MHz and –150°C÷+250°C, respectively, was investigated according to chemical and micro‐structural aspects. The dielectric constants have low values and are dependent on dianhydride flexibility and diamine links, in relation with the charge–transfer complex (CTC) and free volume, and, consequently, with packing of the polymer chains and polarizable groups per volume units. All polyimide films develop two relaxation processes, i.e., γ and β relaxation, involving different enthalpy and entropy contributions induced by their chemical structures. Frequency–temperature‐dependent conductivity showed that conductivity increased with frequency and also that energy bandgap representation could be suitable for explaining the temperature influence on AC‐conductivity. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Origin of dielectric response and conductivity of some alicyclic polyimides

Ioan¹,

Hulubei²,

Popovici³

et al. 2012

Polymer Engineering & Sci

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“…By addition of PAA in the system the dimensions of the large bands increase because the hydrogen bonds might lead to the stretching of the HPC serpentine fibers. The effect is accentuated as the content of PAA is increased -situation sustained by AFM images [72,73]. The imidization process does not affect the aspect of the final surface texture, as presented in Figure 20.…”

Section: Patterning Pi Surface With Sheared Lc Matrixmentioning

confidence: 81%

“…A new approach for patterning polyimide, starting from its precursor, consists in using a lyotropic liquid crystal template, , namely hydroxypropyl cellulose (HPC), which under shear conditions exhibits a banded texture [72,73] (Figure 17). Besides the specific interactions, such as the hydrogen bonds between Epiclon-based PAA corresponding to PI4 and the LC component, a slight cross-linking produced in the precursor structure by UV irradiation can be applied to stabilize the resulting morphology.…”

Section: Patterning Pi Surface With Sheared Lc Matrixmentioning

confidence: 99%

Semi-Alicyclic Polyimides: Insights into Optical Properties and Morphology Patterning Approaches for Advanced Technologies

Barzic¹,

Stoica²,

Hulubei³

2012

High Performance Polymers - Polyimides Based - From Chemistry to Applications

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“…[7,8] HPC, produced by modification of alkali cellulose, is an odorless and tasteless, white to slightly off-white, fibrous or granular, free-flowing powder. Introduction of methoxy and hydroxypropyl groups onto the cellulose backbone confers to the molecule special properties.…”

Section: Introductionmentioning

confidence: 99%

On the Effects of UV Radiation on the Release Ability of Glucose Embedded in Hydroxypropyl Cellulose Films

Barzic

Nechifor

Stoica³

et al. 2016

Journal of Macromolecular Science, Part B

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New drug delivery systems based on hydroxypropyl cellulose (HPC) and different percents of glucose were prepared and characterized to check their suitability as UV resistant patches. The spectral absorption properties of the HPC and HPC-glucose blends before and after UV irradiation were analyzed. The surface polarity and hydrophilicity were correlated with the morphology of the films and analyzed with respect to the UV exposure time and the embedded amount of glucose. The effects of UV radiation on in vitro evaluation of glucose release from the HPC films are reported. The mechanism involved in the drug release process, evaluated using the Korsmeyer-Peppas equation, was dependent on the introduced amount of glucose and less on the UV exposure time. A more polar, smoother, and less dense surface releases the glucose over larger periods of time, making the system with lower percents of glucose more adequate for the pursued purpose.

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Morphological and structural-rheological relationship in epiclon-based polyimide/hydroxypropylcellulose blend systems

Cited by 35 publications

References 29 publications

Origin of dielectric response and conductivity of some alicyclic polyimides

Origin of dielectric response and conductivity of some alicyclic polyimides

Semi-Alicyclic Polyimides: Insights into Optical Properties and Morphology Patterning Approaches for Advanced Technologies

On the Effects of UV Radiation on the Release Ability of Glucose Embedded in Hydroxypropyl Cellulose Films

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