Synthesis,characterization and application of novel polyacrylamide‐grafted barley

Polyacrylamide‐grafted barley (BAR‐g‐PAM) was synthesized by ceric ion‐based conventional method. The grafting of polyacrylamide chains on the polysaccharide backbone was confirmed through various physicochemical techniques such as intrinsic viscosity measurement, ¹³C‐NMR spectra, FTIR spectroscopy, elemental analysis, scanning electron microscopy morphology, thermogravimetric analysis study, number‐average molecular weight, and aqueous solubility. Furthermore, flocculation efficacy of the graft copolymers was studied in coal fine suspension through “jar test” procedure, toward its possible application as a novel flocculant for treatment of coal washery effluent. BAR‐g‐PAM is reported as a novel flocculant that can be used for bulk treatment of coal washery effluents. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41046.     

Selected Applications of Chitosan Composites

Chitosan is one of the emerging materials for various applications. The most intensive studies have focused on its use as a biomaterial and for biomedical, cosmetic, and packaging systems. The research on biodegradable food packaging systems over conventional non-biodegradable packaging systems has gained much importance in the last decade. The deacetylation of chitin, a polysaccharide mainly obtained from crustaceans and shrimp shells, yields chitosan. The deacetylation process of chitin leads to the generation of primary amino groups. The functional activity of chitosan is generally owed to this amino group, which imparts inherent antioxidant and antimicrobial activity to the chitosan. Further, since chitosan is a naturally derived polymer, it is biodegradable and safe for human consumption. Food-focused researchers are exploiting the properties of chitosan to develop biodegradable food packaging systems. However, the properties of packaging systems using chitosan can be improved by adding different additives or blending chitosan with other polymers. In this review, we report on the different properties of chitosan that make it suitable for food packaging applications, various methods to develop chitosan-based packaging films, and finally, the applications of chitosan in developing multifunctional food packaging materials. Here we present a short overview of the chitosan-based nanocomposites, beginning with principal properties, selected preparation techniques, and finally, selected current research.     

Layered Titanium Carbide-Mediated Fast Shape Switching and Excellent Thermal and Electrical Transport in Shape-Memory-Polymer Composites for Smart Technologies: MAX Versus MXene

Stimuli-responsive materials can frequently tune between their temporary and original shapes, and have the potential for artificial intelligence-based technologies in robotics, aerospace, biomedical, engineering, security, etc. Shape memory polymers (SMPs) are promising for these technologies but their inadequate thermal and electrical characteristics causing slow shape recovery limit their practical applications. Herein, for the first time, comprehensively and precisely the shape memory polyurethane (PU), a promising SMP, via a variety of novel layered titanium carbides fillers, namely, Ti₂AlC (MAX₁), Ti₃AlC₂ (MAX₂), and Ti₃C₂ (MXene), is engineered. The resultant PU-composites show 30–50% faster shape recovery in different environments, 20–25% greater extent of shape recovery in the load-constrained environment, 100–125% higher thermal conductivity, and 700–16 000× higher electrical current. Importantly, the reinforcement of even a small amount of MAX and MXene (such as 0.25 wt%) has largely boosted the performance of PU. Considering ease of processability and performance enhancement factors, the MAX-phase fillers may be preferred over MXene-phase fillers for next-generation composites development. Employing PU composite component as both heat-sensor and actuator, a unique heat detector/fire alarm device that works successfully in simulated heat and fire environments is demonstrated. This work is crucial for enabling futuristic technologies.