Novel biodegradable form stable phase change materials: Blends of poly(ethylene oxide) and gelatinized potato starch

2010 ◽  
pp. NA-NA ◽  
Author(s):  
Kinga Pielichowska ◽  
Krzysztof Pielichowski
Keyword(s):  
Ethylene Oxide ◽  
Phase Change ◽  
Phase Change Materials ◽  
Potato Starch ◽  
Stable Phase ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Investigation of the Aqueous Dissolution of Semicrystalline Poly(Ethylene Oxide) Using Infrared Chemical Imaging: The Effects of Molecular Weight and Crystallinity

2005 ◽  
Vol 59 (8) ◽  
pp. 976-985 ◽  
Author(s):  
Carrie Coutts-Lendon ◽  
Jack L. Koenig
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Phase Change ◽  
Power Law ◽  
Bulk Polymer ◽  
Solvent Front ◽  
Poly Ethylene Oxide ◽  
Polymer Dissolution ◽  
Poly Ethylene ◽  
Polymer Solvent

Fourier transform infrared (FT-IR) imaging was used to successfully explore several factors influencing the dissolution of poly(ethylene oxide). The effect of the degree of crystallinity on the rate of dissolution of mid-range molecular weight PEO was negligible over the temperature ranges studied. The influence of molecular weight on polymer dissolution was found to be much greater than the changes in morphology. An examination of the polymer and solvent images and absorbance profiles, compared with the results of the bulk polymer/solvent boundary movement, confirmed this relationship. An investigation of the bulk polymer/solvent boundary using a crystalline-sensitive polymer band showed the crystalline to amorphous phase change occurred over a short distance. Moreover, solvent diffusion ahead of the bulk polymer/solvent front was minimal, most likely a result of the required phase change, which in turn regulated the degree of solvent ingress. Modeling of the dissolution was performed using the Peppas (power law) model. Physical parameters of the dissolution process were obtained from fitting the release profiles to the power law (fraction released = k × tn, where k is the dissolution rate constant and n is the release exponent). Results indicated the model worked well to describe dissolution at all molecular weights. By varying the number of data points input to the model and then comparing the generated graphs, it becomes clear that not only does the dissolution slow down over the course of the experiment, but an increase in molecular weight enhances this effect. The effect of different types of drug on the rate of polymer dissolution was also studied. The dissolution of neat polymer was compared to the dissolution of polymer containing 10% (by weight) of theophylline, etophylline, or testosterone. The general trend of all the dissolution curves was the same, with the addition of etophylline and testosterone tracing almost the same route in terms of movement of the bulk polymer/solvent front.

scholarly journals Applications of Sustainable Polymer-Based Phase Change Materials in Mortars Composed by Different Binders

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3502 ◽  
Author(s):  
Mariaenrica Frigione ◽  
Mariateresa Lettieri ◽  
Antonella Sarcinella ◽  
José Luìs Barroso de Aguiar
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Stable Phase ◽  
Hydraulic Lime ◽  
Cheap Method ◽  
Stone Cutting ◽  
Poly Ethylene ◽  
Thermal Energy Storage Systems ◽  
Change Material ◽  
Compressive Mode

Eco-sustainable, low toxic and low flammable poly-ethylene glycol (PEG) was forced into flakes of the porous Lecce stone (LS), collected as stone cutting wastes, employing a very simple cheap method, to produce a “form-stable” phase change material (PCM). The experimental PCM was included in mortars based on different binders (hydraulic lime, gypsum and cement) in two compositions. The main thermal and mechanical characteristics of the produced mortars were evaluated in order to assess the effects due to the incorporation of the PEG-based PCM. The mortars containing the PEG-based PCM were found to be suitable as thermal energy storage systems, still displaying the characteristics melting and crystallization peaks of PEG polymer, even if the related enthalpies measured on the mortars were appreciably reduced respect to pure PEG. The general reduction in mechanical properties (in flexural and compressive mode) measured on all the mortars, brought about by the presence of PEG-based PCM, was overcome by producing mortars possessing a greater amount of binder. The proposed LS/PEG composite can be considered, therefore, as a promising PCM system for the different mortars analyzed, provided that an optimal composition is identified for each binder.

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

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