Study on thermal,spectroscopic and electrochemical behavior of some ferrocene-containing organometallic polyesteramides and their siloxane-based block copolymers

The thermal, spectroscopic and electrochemical behavior of some novel ferrocene-containing polyesteramides and their siloxane-based block copolymers are described in the present study. The thermal properties of the organometallic materials were investigated by thermogravimetric analysis (TGA) and compared with their terephthaloyl- and isophthaloyl-based organic analogues. The energies of activation of pyrolysis for the polymeric materials were calculated using Horowitz and Metzger method. The spectroscopic and electrochemical properties of the organometallic polymeric materials were examined by means of UV-visible (UV) and cyclic voltammetric (CV) studies. The interactions of these materials with ds.DNA (extracted from chicken blood) were also investigated.     

Nano-structured PMMA/aramid blends: self-assembly via competitive interactions

A new type of self-assembled PMMA/aramid nano-blends were developed from an aromatic polyamide obtained by condensing 4,4′-oxydianiline with isophthaloyl chloride. Physical interactions between the two polymers derived molecular self-assembly process, ensuing marvelous nano-structured blends. Exclusive nano-scale morphology generated in perfectly miscible PMMA/aramid blends was studied using FESEM. Moreover, the effect of blend nano-structure and N–H/C=O interactions between the components on T _g, thermal, tensile and crystalline behavior were investigated. Addition of aramid imparted mechanical and thermal stability to novel blends owing to the physical interlocking of PMMA and polyamide chains via hydrogen bonding. As a result 40- and 70-wt% aramid-containing blends demonstrated fine morphological profile complemented by the optimal mechanical reinforcement and high temperature resistance. In future new blends, holding excellent properties due to physical interaction between the components, can be exploited to acquire exceptional performance in various technological applications such as nano-devices.     

Scrutinization of Polystyrene Microsphere-grafted Multiwalled Carbon Nanotube and Silver Nanoparticle-based Hybrids: Morphology,Thermal Properties,and Antibacterial Activity

Polystyrene microsphere (emulsion polymerization) was grafted on pure multiwalled carbon nanotube and amine-modified multiwalled carbon nanotube. Silver nanoparticle was also decorated on nanotube using chemical reduction (dimethylformamide). Amine-modified multiwalled carbon nanotube secures better silver attachment on nanotube wall. Polystyrene/Ag–amine-modified multiwalled carbon nanotube depicted fine dispersion in polymer latex due to modification. The 10% decomposition temperature and maximum degradation temperature of polystyrene/Ag–amine-modified multiwalled carbon nanotube was increased to 352 and 424°C. Antibacterial properties of nanocomposite were studied against respiratory track demolishing Gram-positive Staphylococcus aureus bacteria and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Ag nanoparticle was found responsible to potential death rate of microbes.     

Review on Polymer/Halloysite Nanotube Nanocomposite

Halloysite nanotube (HNT) is a unique type of nanofiller, i.e., structurally much similar to nanoclay, whereas geometrically analogous to carbon nanotube. Due to nanosize, surface area, low cost, and natural availability, HNT offers up to date latent for polymeric nanocomposite. Polymer/HNT nanocomposites have been prepared using different techniques; however, melt mixing technique was widely used. Thermal stability, mechanical robustness, and nonflammability of polymer nanocomposite have been found to increase by HNT addition. Application areas discovered so far include materials for flame retardancy, stimuli-response, anticorrosion, dye removal, and drug delivery. Future research is desired to expand the potential of polymer/HNT nanocomposite.     

Post-translational Assembly of Protein Parts into Complex Devices by Using SpyTag/SpyCatcher Protein Ligase

Exploiting the innate modularity of proteins has allowed advances across the fields of synthetic biology and biotechnology. By using standardized protein components as building blocks, complex, multiprotein assemblies with sophisticated functions can be generated; feats previously not possible with strictly genetic-engineering approaches. The development of strategies for protein assembly is accelerating, pushing the boundaries of protein architecture. SpyTag and SpyCatcher protein ligase is a recent advance in this field that allows plug-and-play modularity by harnessing post-translational protein assembly. Herein, we review the latest applications of this powerful tool including novel enzyme assemblies, modularizing protein display, and the generation of antibody and antibody-like “devices” by using SpyTag/SpyCatcher technology.     

Novel poly(thiourea‐ether‐imide)s derived from 4,4′‐oxydiphenyl‐bis(thiourea): probing the possibility for high‐temperature applications

Our interest in the fabrication of high‐performance polyimides has led to thiourea‐substituted poly(thiourea‐ether‐imide)s (PTEIs) with good retention of thermal properties along with flame retardancy. A new aromatic monomer, 4,4′‐oxydiphenyl‐bis(thiourea) (ODPBT), was efficiently synthesized and polymerized with various dianhydrides (pyromellitic dianhydride, 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic dianhydride) via two‐stage chemical imidization to fabricate a series of PTEIs. The structural characterization of ODPBT and the polymers was carried out using Fourier transform infrared, ¹H NMR and ¹³C NMR spectral techniques along with crystallinity, organosolubility, inherent viscosity and gel permeation chromatographic measurements. PTEIs bearing C?S and ? O? moieties in the backbone demonstrated an amorphous nature and were readily soluble in various amide solvents. The novel polymers had inherent viscosities of 1.16–1.23 dL g^?1 and molecular weights of ca 90 783–96 927 g mol^?1. Their thermal stability was substantiated via 10% weight loss in the temperature range 516–530 °C under inert atmosphere. The polyimides had glass transition temperatures of 260–265 °C. Incorporation of thiourea functionalities into polymer backbones is demonstrated to be an effective way to enhance their thermal properties and flame retardancy. Thus, ODPBT can be considered as an excellent candidate for use in the synthesis of high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry     

AdDroid: Rule-Based Machine Learning Framework for Android Malware Analysis

Mobile Networks and Applications - Recent years have witnessed huge growth in Android malware development. Colossal reliance on Android applications for day to day working and their massive...     

Aflatoxins: Occurrence in red chilli and control by gamma irradiation

Chilli is one of the valuable spices commercialised globally, added as condiments in various cuisines and is easily susceptible to aflatoxin contamination (produced mainly by Aspergillus flavus) during pre- and post-harvesting stages. The important factors such as temperature, moisture content and humidity affect the growth of fungi producing aflatoxins. Chillies contaminated with aflatoxins could be carcinogenic and thus can pose a threat to the general population leading to the loss of international trade market. Therefore, to overcome this problem, there is a need for some effective and novel technologies such as gamma irradiation. Gamma irradiation minimises the toxicological effects of aflatoxins by inhibiting the growth as well as the proliferation of Aspergillus species. In this work, the natural occurrence of aflatoxins including the contribution of gamma irradiation on either eliminating or controlling the aflatoxins in red chilli is reviewed.     

Novel derivatives of 3D woven T-shaped composites with improved performance

Conventional 3D woven T-shaped preforms were modified for improving joint/ peel off strength of associated T-shaped polymeric composites. Preforms were modified at weaving level by preferred yarns orientations for better performance in associated composites. Major modifications studied are; the addition of supporting layer, single or double-crossing in joint layers and crossing along with supporting layer (in a single sample). Novel derivatives were compared with conventionally used (on-loom and off-loom) T-shaped 3D woven composites. Microscopic analysis was also carried out to analyze the orientation of yarns and analysis of samples from failure point after testing. By combined variation of crossing and supporting layers improvement of 47.37% in peel off strength and 70.37% in impact strength was observed. Modified T shapes can serve to be a good replacement for conventional T-shaped stiffener (used to avoid folding under loads) and in joints.