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Porous Polymers for Hydrogen Production
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Porous Polymer Science and Applications, 2022
Certain pore production methods use polymerization chemistry, while others use macromolecular structural chemistry, and some use both. Several new approaches to synthesize macromolecules and create unique macromolecular architectures are constantly being discovered due to the ever-expanding toolset of polymerization processes. The macromolecule interactions with its surrounding are influenced by its structural chemistry. The Flory–Huggins interaction parameter has been used to explain these interactions, which is associated with the disparity in the solubility factors assigned to the polymer and solvent. The chemical group attraction constants have been used to link the solubility parameter to the macromolecular structure of the polymer. The final size-scale of the resultant pore is usually intrinsically linked to the pore creation methodology. The most frequent methods for pore formation in polymers are listed here.
POSS-Based Polymer Nanocomposite Fibers and Nanofibers: A Review on Recent Developments
Published in Mangala Joshi, Nanotechnology in Textiles, 2020
Mangala Joshi, Anasuya Roy, B. S. Butola
Incorporation of nanofillers in polymeric systems to fabricate useful polymer nanocomposites has been a popular approach in the last three decades for imparting functional attributes to polymers. Among different nanomaterials, polyhedral oligomeric silsesquioxane (POSS), with its versatile chemistry and unique properties, has made its mark among the topmost nanomaterials for research following its commercialization. Applied material scientists from around the globe have been fascinated by the endless tailoring possibilities that POSS offers owing to the reactive site of the molecule, where virtually any functional group or moieties can be chemically attached. Therefore, POSS-based polymeric nanocomposites have varied applications. This chapter presents an overview of the research work done on POSS-based polymeric nanocomposites. The synthesis and structural chemistry of POSS have been discussed for better scientific understanding of the properties imparted. A comprehensive section has been included on POSS-containing nanocomposites in forms other than fibers and nanofibers. However, the focus of this review article is on POSS nanocomposite filaments and nanofibers that represent an important form of polymer nanocomposites.
Introduction
Published in Ashutosh Kumar Dubey, Amartya Mukhopadhyay, Bikramjit Basu, Interdisciplinary Engineering Sciences, 2020
Ashutosh Kumar Dubey, Amartya Mukhopadhyay, Bikramjit Basu
It may be worthwhile to mention that traditionally each of the above-mentioned science disciplines is further compartmentalized into multiple sub-disciplines. For example, chemical sciences can be divided into physical chemistry, inorganic chemistry, organic chemistry, solid-state and structural chemistry, electrochemistry, etc. Physical sciences can be divided into condensed matter physics, high energy physics, mechanics, and so on. Similarly, biological sciences have sub-disciplines such as neurosciences, biochemistry, cell and molecular biology, genetics, and so on. Engineering science has also very well-defined sub-disciplines such as materials, mechanical, chemical, electrical, civil, instrumentation, manufacturing, and others (see Figure 1.2).
A new uranyl carboxylate constructed from a semi-rigid tetracarboxylic acid ligand containing two iminodiacetic acid moieties and four methyl groups
Published in Journal of Coordination Chemistry, 2021
Zhong Wang, Xiaomin Hou, Si-Fu Tang
Carboxylate ligands are the most investigated for construction of UOFs [9]. By varying of the synthetic conditions (M/L molar ratio, pH, solvent, temperature, etc.), many carboxylate based UOFs with diverse crystal structures have been constructed [10]. Auxiliary ligands (such as 4,4′-bipy (4,4′-bipyridine), 2,2′-bipy (2,2′-bipyridine), 1,10-phen (1,10-phenanthroline), etc.) [11] and metal nodes (such as NaI, KI, CuII, ZnII, and PbII) [12, 13] have been introduced to alter and enrich the crystal structures. Additionally, ligand rigidity also has a large effect on the crystal structure of UOFs. For rigid ligands, the coordination is limited by their rigidity and their crystal structures can be predicted somewhat due to reticular chemistry. In contrast, flexible and semi-rigid ligands have more freedom to coordinate with uranium ions and display more structural versatility, leading to difficulty in structural prediction [14–17]. It is therefore desirable to have a deep investigation on the structural chemistry of UOFs.
Green and eco-friendly mica/Fe3O4 as an efficient nanocatalyst for the multicomponent synthesis of 2-amino-4H-chromene derivatives
Published in Green Chemistry Letters and Reviews, 2021
Ali Maleki, Zoleikha Hajizadeh, Kobra Valadi
Newly, the clay minerals with their environmental compatibility, low cost, high selectivity, reusability and operational simplicity features have received considerable attention in different industries and fundamental researches [15]. Also, they have good potential to be used as a substrate for the preparation of nanocomposite [16]. Clay minerals are divided into different types based on their crystal and structural chemistry. The structure of mica sheets, as a subset of clay mineral, composed of two layers of silica tetrahedrons and one central dioctahedral or trioctahedral layer of alumina [17]. According to mica’s accessibility, eco-friendly character, elasticity, insolubility in acid and alkali solution resistance, it was very much considered for the synthesis of nanocomposites. Also, mica by including large sheets can be modified by different metal oxides such as TiO2, ZrO2, SnO2, Cr2O3, Fe2O3 and Al2O3 with epitaxial growth [18].
Berthelot’s Pathway from Synthesis to Thermochemistry
Published in Ambix, 2019
One of Berthelot’s arguments against structural chemistry was pragmatic. On what basis should one of these notations lay claim to representing the whole truth? Each of them is acceptable as a mere convention. The same applies to atomic weights: one of several systems must be chosen, each as valuable as the others. So Berthelot did not oppose the atomic notation dogmatically; he found the system of “equivalents” more practical in organic chemistry because he thought it led to simpler formulae. Furthermore, he used a system of notation that he regarded as closer to the experimental facts, reflecting the synthesis process. For instance, “tribenzoicin” (glyceryl tribenzoate) is an ether (i.e., an ester) obtained from glycerin and benzoic acid, which he named its generators. He represented it as follows: