Dynamic mechanical thermal analysis studies of polymer films prepared from aqueous dispersion

Lafferty, S.V.; Newton, JM; Podczeck, Fridrun

doi:10.1016/s0378-5173(01)00973-5

Cited by 18 publications

(11 citation statements)

References 11 publications

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“…This technique involved measurement of a sinusoidal strain induced by application of a sinusoidal mechanical force. The response was resolved into part which was in phase with the applied stress (elastic component) and that, which was out of phase with applied stress (viscous component) (34). Changes in these responses were studied as a function of temperature and frequency.…”

Section: Dynamic Mechanical Analysismentioning

confidence: 99%

Novel Film Modifiers to Alter the Physical Properties of Composite Ethylcellulose Films

2005

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Section: Dynamic Mechanical Analysismentioning

confidence: 99%

Novel Film Modifiers to Alter the Physical Properties of Composite Ethylcellulose Films

2005

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“…By increasing the temperature, the value of the E´ modulus starts to decrease from approximately 10 9 to 10 6 Pa, in the temperature range of -40 to 20 °C. Such variation is characteristic of phase transition, which, in the present case, can be attributed to T g [28,29]. Figure 5 shows the results of tanδ as a function of temperature.…”

Section: Samples With the Same Glycerol Contentmentioning

confidence: 53%

Conductivity and Thermal Analysis Studies of Solid Polymeric Electrolytes Based on Plasticized Hydroxyethyl Cellulose

2007

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Transparent film samples of hydroxyethyl cellulose (HEC) based on solid polymeric electrolytes (SPE) were prepared by the plasticization of HEC with glycerol and addition of lithium perchlorate salt. SPEs with different quantities of glycerol and LiClO 4 were studied by electrochemical impedance spectroscopy (EIS), Dynamic Mechanical Thermal Analysis (DMTA), TGA (Thermogravimetric Analysis) and DSC (Differential Scanning Calorimetry). The ionic conductivity measurements revealed that the sample containing [O]/[Li]=8 and 48% of glycerol showed the conductivity value of almost 10 -4 S/cm at room temperature. The TGA analysis of electrolytes with high plastizant and salt concentrations showed 25% weight loss after heating to 130 o C, which can be related to the liberation of absorbed water. Finally, DMTA measurements showed changes attributed to the glass transition (T g ) evidenced by the decrease in the elastic modulus value and peaks in the tanδ curves. These results demonstrated that HEC is a good material to be used as a matrix for new solid polymeric electrolytes.

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Section: Characterization Of Melt Extrudatesmentioning

confidence: 99%

“…These DMTA results indicate that PEO was partially miscible in the PEO/S100 (30/70) system after HME. This can highlight the importance of using DMTA as a sensitive analytical technique to detect the Tg(s) of the polymer blend and hence to give more accurate conclusions about the degree of miscibility between its components (Lafferty et al, 2002).Although PEO was present in lower concentration in PEO/S100 (30/70) system than the 50/50 one, the 30/70 ratio was less homogeneous after HME. This nonhomogeneity in PEO/S100 (30/70) system may be related to the insufficient plasticization of Eudragit ® S100 by PEO (30% w/w) particularly that HME was carried out significantly lower than its Tg.…”

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The Use of Binary Polymeric Networks in Stabilizing Polyethylene Oxide Solid Dispersions

Jones

Tian

Shu

et al. 2016

Journal of Pharmaceutical Sciences

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The objective of this study was to investigate the role of amorphous domain of polyethylene oxide (PEO), a semicrystalline polymer, on the stability of drug/PEO solid dispersion. Molecular dispersion of drugs within hydrophilic low molecular weights PEOs (solid solution) has been demonstrated as a viable approach to enhance the dissolution properties and hence the oral bioavailability of poorly soluble drugs. In this system, the drug molecules are dissolved within the amorphous domain of the polymer and a miscible amorphous drug/polymer combination can result in a decrease of the polymer crystallinity, and hence increasing its amorphous fraction. This may result in increasing the drug solubility in the polymer hence affecting the stability of drug/polymer solid dispersion system. PEO is a highly crystallisable semi-crystalline polymer in natural and a rapid decrease in the amorphous fraction of the polymer may occur immediately after hot-melt extrusion resulting a forced migration of amorphous drug into nearby amorphous region. Thus, the actual concentrations of the drug within PEO solid dispersion were much higher than the concentration that we intended. Therefore, we are proposing a novel method of stabilising the amorphous drug/PEO solid dispersion by stabilising the amorphous region of PEO using another amorphous polymer. Inclusion of a miscible polymer that can increase the glass transition (Tg) of PEO (antiplasticization) or/and form strong inter-polymer interactions was used to enhance the stability of the amorphous PEO. In this study, the effects of inter-polymer interactions and miscibility between PEO and an amorphous polymer of high Tg, Eudragit ® S100, on the stability of the amorphous PEO and consequently the PEO/drug celecoxib (CX) solid dispersion was studied. Hot-melt extrusion (HME) was used to prepare different ratios of binary polymer blends of PEO/S100 (70/30, 50/50 and 30/70 w/w) and ternary solid dispersion systems containing pre-defined drug loading within the PEO/S100 polymer blends. Results from differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) suggested a great miscibility between PEO and S100 polymer blends particularly in the 50/50 ratio. After immediately HME, single Tg was observed in all ternary systems that increase with increasing S100 amount (antiplasticization). The completely absence of PXRD crystalline Bragg's peaks also suggested the full amorphous CX/polymer solid dispersion has been produced. Upon storage, CX crystallized rapidly from the CX/PEO (30/70) system within 3 days at 40°C and 75% RH, whereas it remained stable without crystallization up to 4 weeks within CX/(PEO/S100) 30/(50/50) system. Interestingly, both the stability of the amorphous PEO and CX were greater in the ternary system containing the polymer blend at 50/50 ratio than other systems. Despite of the lower Tg of 30/(50/50) system than 30/(30/70) one, the former was more stable. This indicates that the antiplasticization effects by Eudragit ® S100 were not the ...

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Dynamic mechanical thermal analysis studies of polymer films prepared from aqueous dispersion

Cited by 18 publications

References 11 publications

Novel Film Modifiers to Alter the Physical Properties of Composite Ethylcellulose Films

Novel Film Modifiers to Alter the Physical Properties of Composite Ethylcellulose Films

Conductivity and Thermal Analysis Studies of Solid Polymeric Electrolytes Based on Plasticized Hydroxyethyl Cellulose

The Use of Binary Polymeric Networks in Stabilizing Polyethylene Oxide Solid Dispersions

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