Disordering of phospholipid headgroups induced by a small amount of polyethylene oxide

2012 ◽  
Vol 51 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Andrey Filippov ◽  
Bulat Munavirov ◽  
Bulat Gizatullin ◽  
Oleg N. Antzutkin
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.


2020 ◽  
Vol 1010 ◽  
pp. 638-644
Author(s):  
Mohd Pisal Mohd Hanif ◽  
Abd Jalil Jalilah ◽  
Mohd Fadzil Hanim Anisah ◽  
Arumugam Tilagavathy

Biopolymer-based conductive polymer composites (CPCs) would open up various possibilities in biomedical applications owing to ease of processing, renewable resource and environmentally friendly. However, low mechanical properties are a major issue for their applications. In this study, the investigated the conductivity of chitosan/ PEO blend films filled with carbonized wood fiber (CWF) prepared by solution casting. The effect of CWF was also investigated on tensile properties and their morphological surfaces. The tensile results from different ratios of chitosan/PEO blend films without CWF show that the tensile strength and modulus increased with the increase of chitosan content and chitosan/PEO blend film with 70/30 ratio exhibited the best combination of tensile strength and flexibility. However, a reduction of tensile strength was observed when CWF amount was increased while the modulus of the tensile shows an increment. The film also exhibited higher electrical conductivity as compared to low chitosan ratio. The addition of CWF greatly enhanced the conductivity three-fold from 10-10 to 10-6 S/cm. The electrical conductivity continued to increase with the increase of CWF up to 30wt%. The surface morphology by Scanning Electron Microscopy (SEM) exhibits the absence of phase separation for the blends indicating good miscibility between the PEO and chitosan. Incorporation of CWF into the blend films at 5wt% showed agglomeration. However, the increase of CWF created larger agglomerations that formed conductive pathways resulting in improved conductivity. FTIR analysis suggested that intermolecular interactions occurred between chitosan and PEO while CWF interacts more with the protons of PEO.


2013 ◽  
Vol 11 (4) ◽  
pp. 371-383 ◽  
Author(s):  
Yong-Lei Wang ◽  
Rochelle S. Lawrence ◽  
Zhong-Yuan Lu ◽  
Aatto Laaksonen

2009 ◽  
Vol 151 ◽  
pp. 67-71 ◽  
Author(s):  
Wai Kit Li ◽  
Y.W. Wong

Electrospinning is an efficient technique for the fabrication of polymer nanofibers. The charges inside the polymer jet tend to repel each other so as to stretch and reduce the diameter of the polymer fibers. By rotating the collector at a fast angular speed, nanofibers with specific orientation can be obtained. In this study, nanofibers of Polyethylene oxide (PEO) with carbon black were prepared by electrospinning. PEO was dissolved in a mixture of water and ethanol. PEO is known as an electrolytic polymer. With the blending of carbon black powders, its electrical properties along the fiber direction were investigated. The fiber morphology and characteristics were studied by SEM and polarized FTIR.


2021 ◽  
pp. 50740
Author(s):  
Rosario Ramírez ◽  
Ma. Guadalupe Olayo ◽  
J. Cuauhtemoc Palacios ◽  
Fernando G. Flores ◽  
Maribel González Torres ◽  
...  

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 278 ◽  
Author(s):  
Jinghui Hu ◽  
Weiqiang Tang ◽  
Yonghui Li ◽  
Jiyu He ◽  
Xiaoyan Guo ◽  
...  

A new energetic curing reagent, Glycidyl azide polymer grafted tetrafunctional isocyanate (N100-g-GAP) was synthesized and characterized by FT-IR and GPC approaches. Polytriazole polyethylene oxide-tetrahydrofuran (PTPET) elastomer was prepared by N100-g-GAP and alkynyl terminated polyethylene oxide-tetrahydrofuran (ATPET). The resulting PTPET elastomer was fully characterized by TGA, DMA, FTIR and mechanical test. The above analysis indicates that PTPET elastomers using N100-g-GAP as curing reagent have the potential for use in propellants. The overall formulation test of the composite propellants shows that this curing system can effectively enhance mechanical strength and bring a significant improvement in the interface interaction between the RDX & AP particles and binder matrix.


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