The present study portrays the investigations on the optimization of the K2CO3-catalyzed synthesis of sucrose–coconut fatty acids esters. Determination of the hydroxyl value (HV) and the saponification value (SV), as well as Fourier transform infrared (FTIR) analysis, provided an understanding of the progress of transesterification, as a function of temperature (120–140 °C), holding period (30–150 min), catalyst concentration (1%–4%), molar ratio of sucrose to fatty acid methyl esters (FAME) (M = 0.364–6), and molecular weight of fatty acids. Bimolecular second-order kinetic model based on equal transesterification opportunity for all hydroxyl groups of sucrose/partial esters and that based on preferential transesterification of 6 −OH of the glucose unit in constant volume batch reactor were developed using integral and differential methods. The dependence of selective and nonselective kinetic models on the number and nature of hydroxyl groups in the sucrose were investigated. The changes in viscosity of sucrose ester solutions in dimethyl formamide (DMF) solvent were interpreted on the basis of solvent–ester/ester–ester interactions, hydrogen-bond density, and formation of mixed partial esters.

In this study, hydrous (Zn3B6O12·3.5H2O) and anhydrous (ZnB2O4) forms of zinc borates were synthesized at 150 and 175°C under moderate pressure conditions (85 and 150 psi, respectively). Synthesized zinc borates were controllably incorporated (1, 5, and 10 wt%) in epoxy resin to prepare their nanocomposites. The flame‐retardant and mechanical properties of these nanocomposites were determined and compared in terms of their flame spread testing, smoke density, limiting oxygen index, and flexural strength. Superior properties in terms of flame retardancy were observed for epoxy composites containing hydrous filler as compared to anhydrous zinc borates. Although flexural strength was observed to be decreased with increasing filler concentration, the marked drop is lower for composites with hydrous zinc borate as compared to the anhydrous one. The variations in flame‐retardant and mechanical properties of composites with both types of fillers are related to their morphological (field emission scanning electron microscopy), X‐ray diffraction (XRD) analysis, Fourier Transform Infrared (FTIR), differential scanning calorimetry, and thermogravimetry analysis and explained with condensed phase mechanism.

In this study, we propose a simple low-cost emulsion-based method to fabricate porous poly­(dimethylsiloxane) (PDMS) adhesive films, with a focus on their possible application as wound dressings. In this method, water is added to PDMS to form an emulsion. On film-casting the emulsion and curing it at 120 °C, evaporation of water droplets and PDMS cross-linking result in randomly distributed pores/voids in the bulk of the PDMS film. A huge advantage of the proposed method over conventional approaches is its simplicity owing to the use of water as a porogen. Two variants of the fabrication approach were considered: direct film-casting of emulsion and film-casting of the solvent-mediated emulsion with additional degassing. Films prepared using the first approach demonstrated that the bulk porosity induces significant roughness at their surface. Such films do not make good contact with the substrate, resulting in poor adhesion. Coating the films with a thin viscoelastic layer of PDMS, while retaining the bulk structure, improves the contact of the film with the substrate. These bi-layer films demonstrated remarkable enhancement in adhesion. The second approach involves adding ethyl acetate as a solvent and degassing the emulsion before film-casting, which results in a more controlled porosity and lower roughness at the surface. Compared to the porous films synthesized using the former protocol, these films have a relatively improved contact with the cover plate, resulting in enhanced adhesion. Lastly, through falling weight impact measurements, it was shown that the porous films, in comparison to their nonporous counterpart, were more effective in absorbing the accidental impact shock, which makes them potentially useful in healthcare applications.

In the present study, the adhesive and viscoelastic properties of polydimethylsiloxane (PDMS) based nanocomposite pressure sensitive adhesives (PSAs) with embedded electrospun polyacrylonitrile (PAN) and polyvinyl alcohol (PVA) nanofibers as fillers were investigated.