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Solid-State Electrolytes for Lithium-Ion Batteries
Published in Prasanth Raghavan, Fatima M. J. Jabeen, Ceramic and Specialty Electrolytes for Energy Storage Devices, 2021
Jabeen Fatima M. J., P. P. Abhijith, N. S. Jishnu, Das Akhila, Neethu T.M. Balakrishnan, Jou-Hyeon Ahn, Prasanth Raghavan
Crystallinity is the degree of long-range order in a material and has a significant impact on the material properties. The crystallization of polymers is a process associated with the partial alignment of their molecular chains. Polymers can crystallize upon cooling from the melt or solvent evaporation, corresponding to the different filming technologies used to fabricate polymer electrolytes. The properties of polymers are determined not only by the degree of crystallinity but also by the size and orientation of the molecular chains. The degree of crystallinity can be estimated by different analytical methods including density measurements, DSC, X-ray diffraction (XRD), infrared spectroscopy, and nuclear magnetic resonance. In addition, the distribution of crystalline and amorphous regions can be visualized with microscopic techniques, such as polarized light microscopy and transmission electron microscopy [25].
Advanced Applications of Spray Drying
Published in Nan Fu, Jie Xiao, Meng Wai Woo, Xiao Dong Chen, Frontiers in Spray Drying, 2020
Nan Fu, Jie Xiao, Meng Wai Woo, Xiao Dong Chen
To better interpret the subsequent discussion, it is important to clearly define what in-situ crystallization control means, depending on the material of interest. For this purpose, broadly, spray dried materials can be classified into easy to crystallize and difficult to crystallize materials. Most spray dried food powders are typically difficult to crystallize during spray drying. This is mainly because of the rapid solidification that quenches the solute into the amorphous form, preventing effective crystallization. Some examples of difficult to crystallize materials are lactose, sucrose, starches, coffee powder, etc. For such materials, the control of crystallization mainly pertains to generating partial crystallinity; the focus is on controlling the percentage of solids within the powder in the crystalline form (or the relative percentage between batches of powder). While there is continuous scientific interest in controlling or increasing the percentage of crystallization within such typically amorphous powder, partial crystallinity may not be beneficial for commercial production of these powders. This is because partial crystallinity may actually provide the seed for undesired phase changes during the long-term storage of the typically amorphous powder. Generating partial crystallinity, however, has been widely adopted in the spray drying of whey powder to control the stickiness of the powder. In the spray drying of whey powder, the feed solution is typically allowed to undergo cooling crystallization so that part of the lactose is crystallized prior to spray drying.
Crystalline Polymers
Published in Timothy P. Lodge, Paul C. Hiemenz, Polymer Chemistry, 2020
Timothy P. Lodge, Paul C. Hiemenz
The world's most popular synthetic polymer, in terms of volume produced per year, is polyethylene; polyethylene can crystallize. Other high-volume polymers such as isotactic polypropylene, poly(hexamethylene adipamide) (Nylon 6,6), and poly(ethylene terephthalate) crystallize, as do many specialty materials, such as poly(tetrafluoroethylene) (Teflon®) and poly(p-phenylene terephthalamide) (Kevlar®). In general, crystallinity conveys enhanced mechanical strength, greater resistance to degradation, and better barrier properties.
Effects of stabilising overfeed on the properties of draw textured polyester yarns
Published in The Journal of The Textile Institute, 2023
Bibekanada Basu, Subhankar Maity
DSC studies reveal that the glass transition temperature, crystallisation temperature and melting point of the control sample and all textured samples remain unchanged. The glass transition, crystallisation and melting temperature of the samples are observed at about 80 °C, 216 °C and 255 °C, respectively. However, the area under the melting peak of the samples increases as SOF% increases, as shown in Figure 7 and Table 1. The area of the melting peak denotes the heat energy required for melting the crystalline phase of the material. Higher will be the area under the peak, higher will be the crystallinity of the material (Schick, 2009). The DSC analysis reveals that the higher will be SOF%, higher will be crystallinity of the samples after texturing treatment. Improved crystallinity gives a better dimensional stability to the material. Therefore, it can be concluded that the higher will be the SOF% better will be dimensional stability of the yarn and fabrics made out of that yarns.
Characterization of the crystallographic properties of bamboo plants, natural and viscose fibers by X-ray diffraction method
Published in The Journal of The Textile Institute, 2021
Bahrum Prang Rocky, Amanda J. Thompson
The CI is a very important distinct property that determines the uniqueness of a polymer or a fiber. It is a challenging and complex process to determine the CIs of cellulosic polymer materials (Ju et al., 2015; Park et al., 2010). Most of the polymers have a certain degree of crystallinity; only a very few of them have a CI of 100%. The CI of polymers generally ranges from 10–80% (Carraher, 2003; Ju et al., 2015). The CI of natural fibers was reported between 30 and 90% (Sanjay et al., 2018). Unlike amorphous polymers, polymers with a certain CI have a definite melting point and glass transition temperature, and they display clear X-ray diffraction (XRD) patterns. The crystallinity can be modified or changed through production processes or by treatments (Carraher, 2003; Odian, 2004). The polymer structure or orientation and the intermolecular forces are two major factors responsible for crystal formation in polymers. The greater the secondary attraction forces, the higher the degree of ordering and therefore the crystallinity of a polymer (Carraher, 2003; Mohamed & Hassabo, 2015; Odian, 2004).
Proceeding toward the development of poly(ɛ-caprolactone)/cellulose microfibrils electrospun biocomposites using a novel ternary solvent system
Published in The Journal of The Textile Institute, 2020
Mohsen Zolfagharlou Kouhi, Tayebeh Behzad, Laleh Ghasemi-Mobarakeh, Alireza Allafchian, Zahra Moazzami Goudarzi, Mohammad Saeid Enayati
Viscosity and conductivity of PCL solution was increased after the addition of CMF into the polymer solution (Table 2): the higher amounts of CMF, the higher viscosity and conductivity of the polymer solution. The viscosity increase can be attributed to the limited movements of PCL chains due to the presence of nanoparticles and low interaction between nanoparticles and solute (Wutticharoenmongkol, Sanchavanakit, Pavasant, & Supaphol, 2006). In terms of conductivity rising, it can be explained from two points of view. From one hand, it has been reported that conductivity directly varies by crystallinity (Mark, 2007). Therefore, it is anticipated that by the incorporation of crystalline CMF into the PCL solution, the conductivity will be grown. On another hand, the negative charges from sulfate ester groups on the surface of CMFs grafted from sulfuric acid present during the bleaching stage of CMF isolation (Peresin et al., 2010) increase the conductivity of the solution.