Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends

Abstract

IntroductionBlending of polymers is an interesting route for producing new materials, basically due to economics aspects [1]. The miscibility between the polymers is a very important factor in the development of polymer blends [1,2]. Considering the low entropy associated to the polymers mixture, ΔS m , the miscibility between the components of a polymer blend is mainly driven by the enthalpy of mixing, ΔH m . Thus, effects that decrease ΔH m will favor to the miscibility due to the decrease of the Gibbs energy of mixture, ΔG m . In the light of this, attractive interactions among side groups or polymer segments are, in most of the cases, responsible for polymer-polymer miscibility. Different techniques have been used for evaluating the miscibility, for example, thermal analysis through determination of the glass transition temperature (T g ) [3][4][5], microscopy (Optical Microscopy -OM, Scanning Electronic Microscopy -SEM, Atomic Force Microscopy -AFM, Transmission Electronic Microscopy -TEM, and so on) [5][6][7][8] and spectroscopy (Fourier Transform Infrared -FTIR-Image, Raman-Image, Nuclear Magnetic Resonance -NMR, and so on) [9][10][11][12]. The presence of an amorphous (or slightly crystalline) component affects the crystallization process of the other polymer component significantly. When a given system is miscible, the equilibrium melting temperature (T m 0 ) is expected to be lower Abstract. The main purposes were evaluating the influence of different starches on the miscibility with Poly(ethylene oxide) (PEO) and their effects on the spherulite growth rate. Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends consisting of different w/w ratios (100/0, 95/05, 90/10, 80/20, 70/30, 65/35 and 60/40) was investigated. This analysis was based on the depression in the equilibrium melting temperature (T m 0 ). By treating the data of thermal analysis (Differential Scanning Calorimetry -DSC) with Nishi-Wang equation, a positive value (0.68) was found for the interaction parameter of PEO/cationic starch. For PEO/hydrophobic starch blends, a negative value (-0.63) was obtained for the interaction parameter. The results suggested that PEO/cationic starch system should be immiscible. However, the system PEO/hydrophobic starch was considered to be miscible in the whole range of studied compositions. Through optical microscopy analysis, it was concluded that the spherulite growth rate is significantly affected by changing the amount and the type of starch as well. Keywords

Cationation of starch with an aminating reagent based on triethylamine and epichlorohydrin

“…2, B) suggest the presence of C-O-H. The absorption at 1020 cm -1 in both spectra results from the O-C vibrations of the pyranose form [13,14].…”

Hyperbranched poly(glycidol)/poly(ethylene oxide) crosslinked hydrogel for tissue engineering scaffold using e‐beams

“…Tm decreased slightly from 55.5°C to 53.4°C as the content of HPG increased from 0 to 30%. This decrease might have been caused by the disordered state of the polymer chain, which is usually observed in miscible blends . The glass transition temperature ( T g ) of a matrix polymer generally decreases in the presence of low molecular miscible additives owing to the increase in free volume.…”

“…This decrease might have been caused by the disordered state of the polymer chain, which is usually observed in miscible blends. 40 The glass transition temperature (T g ) of a matrix polymer generally decreases in the presence of low molecular miscible additives owing to the increase in free volume. However, the T g of HPG/PEO blends appearing in a range of 257.98C to 259.18C showed the opposite behavior.…”

Preparation and Characteristics of Cationic Starches

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