Degradation of agar films in a humid tropical climate: Thermal, mechanical, morphological and structural changes

Freile‐Pelegrín, Yolanda; Madera‐Santana, Tomás J.; Robledo, Daniel; Véleva, L.; Quintana, P.; Azamar, J.A.

doi:10.1016/j.polymdegradstab.2006.11.005

Cited by 129 publications

(51 citation statements)

References 22 publications

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“…It can be observed that a peak centered at around 20º showed an orderly structure with a high degree of crystallinity when compared with agarose films with high ChCl/Urea content. The characteristic features of the pristine agarose film peak in this study were similar to previous reports by other researchers (Freile-Pelegrín et al 2007). This is probably due to the slow drying during film casting, providing the opportunity for highly ordered lamellae to be formed.…”

Section: Crystallographic Propertiessupporting

confidence: 90%

Plasticizing Effect of Choline Chloride/Urea Eutectic-Based Ionic Liquid on Physicochemical Properties of Agarose Films

Shamsuri¹,

Daik²

2012

BioResources

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Agarose films were formed with the addition of 30 to 70 wt% choline chloride/urea eutectic-based ionic liquid (ChCl/Urea). The ChCl/Urea was prepared through complexation at a 1:2 mole ratio. The films were prepared by dissolving ChCl/Urea in distilled water followed by dispersion of the agarose at 95 °C. The solution was gelled at room temperature, and the formed gel was dried in an oven overnight at 70 °C. Mechanical testing indicated that the agarose film containing 60 wt% ChCl/Urea had higher tensile extension and tensile strain at break compared to the pristine agarose film. The addition of ChCl/Urea also reduced the glass transition temperature (T g ) of agarose films. Crosssection SEM images of the agarose films showed that surface roughness disappeared with the incorporation of ChCl/Urea. FTIR spectra confirmed the presence of intermolecular hydrogen bonding between agarose and ChCl/Urea. XRD patterns demonstrated that an amorphous phase was obtained when ChCl/Urea was added. Agarose films containing more ChCl/Urea exhibited higher transparency, as measured by a UV-Vis spectrometer. In summary, the physicochemical properties of agarose films were evidently affected by the incorporation of the ChCl/Urea as a plasticizing agent.

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Section: Crystallographic Propertiessupporting

confidence: 90%

Plasticizing Effect of Choline Chloride/Urea Eutectic-Based Ionic Liquid on Physicochemical Properties of Agarose Films

Shamsuri¹,

Daik²

2012

BioResources

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“…Figure 5 shows the typical X-ray diffraction patterns obtained for the sample Agar[C 2 mim][C 2 SO 4 ] measured at room temperature. The diffractogram of agar matrix (not shown here) revealed an ordered structure due to the presence of a very accentuated peak at 18.6° 2# and a slight shoulder at 14.3° 2#, similarly to the results of 19.9 and 13.83°, respectively, reported for pristine agar films [30]. The deconvolution of the diffraction profile ( Figure 5) in different Gaussian lines reveals very broad components on the fully disordered part of the sample and the three narrower bands are attributed to the ordered regions.…”

Section: Thermal Behaviour Of Electrolytessupporting

confidence: 86%

Investigation of polymer electrolyte based on agar and ionic liquids

Leones¹,

Sentanin²,

Rodrigues³

et al. 2012

Express Polym. Lett.

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Abstract. The possibility to use natural polymer as ionic conducting matrix was investigated in this study. Samples of agarbased electrolytes with different ionic liquids were prepared and characterized by physical and chemical analyses. Samples of solvent-free electrolytes were prepared and characterized by ionic conductivity measurements, thermal analysis, electrochemical stability, X-ray diffraction, scanning electron microscopy and Fourier Transform infrared spectroscopy. Electrolyte samples are thermally stable up to approximately 190°C. All the materials synthesized are semicrystalline. The electrochemical stability domain of all samples is about 2.0 V versus Li/Li + . The preliminary studies carried out with electrochromic devices (ECDs) incorporating optimized compositions have confirmed that these materials may perform as satisfactory multifunctional component layers in the field of 'smart windows', as well as ECD-based devices.

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“…Agar has a wide variety of uses in industry. For example, it has been used in the food area (processed cheese, ice cream, bread and soft candy) due to its ability to form hard gels at very low concentration [20,21].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Chitosan/Agar Blends: Rheological and Thermal Studies

El-Hefian

Nasef

Yahaya

et al. 2010

J. Chil. Chem. Soc.

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In this work, a number of mixture aqueous solutions of chitosan/agar (CS/AG) at different ratios (considering chitosan as the main component) were prepared. The rheological properties i.e. shearing viscosity and shear stress of the blend solutions as a function of shear rate as well as the thermal properties of the blend films were investigated. Among the parameters studied were temperature, shearing time and storage time. Results showed that almost Newtonian behavior was observed at temperatures from 40 o C to 55 o C for the ratios 100/0, 90/10, 80/20 and 70/30. However, the proportions 60/40 and 50/50 showed a clear shear thinning behavior (pseudoplastic non-Newtonian behavior). It was also found that all the blend solutions obeyed the Arrhenius equation. In addition, the effect of shearing time on the shearing viscosity of all blends did not show any significant differences at all shearing times applied in this study except the proportion 50/50 wherein decreasing in shearing viscosity and shear stress was observed as the shearing time increased. Furthermore, different behaviors were observed for the blend solutions when the period of storage was extended to three weeks. The FTIR results and the differential scanning calorimetery (DSC) curves showed that the interaction between chitosan and agar can occur.

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Degradation of agar films in a humid tropical climate: Thermal, mechanical, morphological and structural changes

Cited by 129 publications

References 22 publications

Plasticizing Effect of Choline Chloride/Urea Eutectic-Based Ionic Liquid on Physicochemical Properties of Agarose Films

Plasticizing Effect of Choline Chloride/Urea Eutectic-Based Ionic Liquid on Physicochemical Properties of Agarose Films

Investigation of polymer electrolyte based on agar and ionic liquids

Preparation and Characterization of Chitosan/Agar Blends: Rheological and Thermal Studies

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