Browsing by Author "El-Khodary, Esraa"

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Critical Review on Smart Chromic Clothing
(Journal of Design Sciences and Applied Arts, 2020) El-Khodary, Esraa; Gebaly, Bahira; Rafaat, Eman; AlSalmawy, Ahmed
Materials that can undergo a reversible color change, upon the application of an external stimulus, are technically known as chromic materials. Research into the application of such materials has been extensive due to the ability of color change to effectively convey important information and therefore have been used in the industry to fulfill certain applications. Since they have the capability to change their colour, they have been used in some hazardous applications, medical applications and some may serve pure artistic statement. Each of these chromic materials react to external stimuli in a very different way. Materials that display chromic properties are classified by the type of stimuli that induces their color change. This paper aims to introduce the different types of chromic materials used within the industry and to demonstrate how far they are known within the Egyptian community through surveys.
Effect of the melt-mixing condition on the physical property of poly(L-lactic acid)/poly(D-lactic acid) blends
(Journal of Applied Polymer Science, 2017) El-Khodary, Esraa; Fuku, Yoko; Yamamoto, Masaki; Yamane, Hideki
The effect of the mixing condition in a mill-type mixer on the thermal property and the crystal formation of the poly(L-lactide)/poly(D-lactide) blends is investigated. The blends melt-mixed at 200 and 210 8C under application of a high shear flow tend to show a single melting peak of the stereocomplex crystal (SC) in the differential scanning calorimetry first and second heating processes without indicating the trace of the melting of homo-chiral crystal. The mixing at an elevated temperature causes a serious thermal degradation. Further kneading of the blends at an elevated temperature higher than Tm of SC causes the transesterification between the same enatiomeric chains forming block copolymers of L- and D-chains. This block copolymer acts as a nucleating agent of SC and the compatibilizing agent between poly(L-lactide) and poly(D-lactide) and promotes the formation of SC. VC 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45489.
Physical Properties of Stereocomplex Type Poly (lactic acid) Biaxially Drawn Films
(The Society of Fiber Science and Technology, Japan, 2017) El-Khodary, Esraa; Fukui, Yoko; Yamamoto, Masaki; Yamane, Hideki
Equal amounts of PLLA and PDLA were melt-mixed in a mill type mixer at 190 ̊C and further extruded at 250 ̊C. The blend obtained was compression molded into films and biaxially drawn and annealed. The changes in various physical properties such as mechanical and thermal properties and the higher-order structure of the films in the biaxial drawing and annealing processes were investigated. The biaxially drawn films showed a broad crystalline WAXD reflection similarly to the uniaxially drawn PLLA/PDLA blend fibers and the application of annealing at 190 ̊C completely changed the reflections into those of SC. The higherorder structure was completely transferred into SC after annealing at an elevated temperature. The mechanical property was improved by the biaxial drawing and the annealing for short period of time, and the films showed an excellent thermal resistance. However the annealing for a long period deteriorated the mechanical property.