HET acid based oligoesters – TGA/FTIR studies

One of the important reactive halogenated dicarboxylic acids used in the synthesis of flame retardant unsaturated polyester resins is 1,4,5,6,7,7-hexachlorobicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid (HET acid). In the present investigation four different oligoesters are synthesized using HET acid as the diacid component and 1,2-ethane diol, 1,2-propane diol, 1,3-propane diol and 1,4-butane diol as the aliphatic diols. Melt condensation technique in vacuum is used for the synthesis of the oligoesters. The number average molecular weights of the oligoesters are determined using end group analysis. The degree of polymerization is estimated to be 3–5. The structural characterization is done using FTIR and NMR (1H and 13C) techniques. In the present investigation, TGA-FTIR studies for the different oligoesters are carried out in nitrogen atmosphere. The materials are heated from ambient to 600 °C at a heating rate of 20 °C/min. The main volatile products identified are CO, HCl, H2O, CO2, hexachlorocyclopentadiene and HET acid/anhydride. The evolution profile of these materials with respect to the structure of the oligoesters is discussed in detail and presented. The importance of β-hydrogens in the diol component and the plausible mechanism for the flame retardant behavior of these oligoesters are presented

Thermal Degradation Studies on PMMA–HET Acid Based Oligoesters Blends

Imparting thermal stability to polymethyl methacrylate (PMMA) without affecting its optical clarity is attempted by incorporating HET acid based oligoesters. Pure PMMA and PMMA containing five and 20 wt% of four different oligoesters are separately prepared using bulk polymerization. The thermal properties of the materials studied using DSC, TG, TG–FTIR and Pyr–GC–MS are presented. The main volatile degradation products identified are CO, HCl, CO2, H2O, hexachlorocyclopentadiene, hexachloroendomethylene tetrahydrophthalic acid/anhydride and methyl methacrylate. A detailed mechanism for the influence of the degradation products of HET acid based oligoesters on the thermal degradation of PMMA is also presented

Physicochemical Properties of Irradiation Modified Starch Extrudates

Corn starch samples containing 0, 25, 50 and 70% amylose irradiated with -y -radiation dosages of 0 (native) , 5 , 10, 20 (containing 0, 2.5 or 5% potassium persulfate , hydrogen peroxide or eerie ammonium nitrate) or 30 kGy were extrusion cooked using a C. W. Brabender single-screw extruder at a barrel temperature of 140 °C, a screw speed of 140 rpm and 18% moisture content. Increasing irradiation dosages from 0 to 30 kGy gave consistently increased expansion ratios from 2.9 to 7.9 for 25% amylose starches and from 6.5 to 14.5 for 50% amylose starches, while the expansion ra tios consistently decreased from 6.0 to 2.1 for 0% amylose starches. The expansion ratios for 70% amylose starches remained more or less constant at 10 irrespective of irradiation dosage. Expansion ratios of all the 20 kGy irradiated starch samples treated with chemical agents, however, decreased to 5 or below. The patterns of bulk densities and expansion ratios of the products were generally similar. Increasing irradiation dosages caused darkening of the product color. The water solubility increased from \u3c l% for native starches to almost 100% for certain irradiated starches processed with chemical additives. Overall, increasing amylose contents of the starches appeared to be resistant to changes that otherwise occurred due to irradiation modifications and chemical treatments. Molecular weights and iodine binding capacities of starches were significantly reduced with irradiation dosages and chemical treatments

Effect of Graphite Filler on the Physiochemical Properties of Graphite Reinforced Thermoset Rooflite – Unsaturated Polyester Resin Composites

Received: 24.01.24. Revised: 09.02.24. Accepted: 09.02.24. Available online: 29.02.24.The authors would like the thank the Principal, and Head of the department of Chemistry, Government Arts college, Udumalpet 642 126, for allowing us to conduct the experi-ments. We extend our thanks to Dr. R. Venckatesh, Depart-ment of Chemistry, Government Arts college, Udumalpet 642 126 for helping us in the IR spectral studies of the sam-ples. The Authors wish to thank DST FIST DST-FIST-2018 (SR/FST/COLLEGE-417/2018) (TPN-2011) laboratory of the department for providing assistance to this research.The crystallinity index of the studied composite materials increased due to the enhanced interaction between the resin matrix and graphite filler.Agglomeration due to higher concentration of graphite filler lowers the interfacial contact and affects the mechanical characteristics of the composites.The glass transition temperature increases with the addition of graphite.When the percentage of graphite in composites is raised, the limiting oxygen index revealed that the composites are self-extinguishing.The synthetic composites exhibit a consistent swelling behavior in response to different chemical environments.It is well known that many polymers are insulators with poor mechanical properties, which limit their use in fuel cell applications. Physicochemical properties of the polymers can be improved by adding conductive fillers. Carbon-based materials like graphite, which provides excellent mechanical strength and thermal conductivity to the polymer matrices, is of special interest because of its abundance, low cost and light weight when compared to other carbon allotropes. In the present work we describe the physicochemical properties of rooflite unsaturated polyester resin/graphite composites. Rooflite resin and three of its composites containing 1%, 3% and 5% of graphite by weight (C-2, C-3, and C-4, respectively) were synthesized and characterized by FTIR spectral data. XRD showed two peaks at 2 = 27.37°and 55.40° with d spacing value of 3.2559 nm and 1.6571 nm, respectively, indicating the change in degree of crystallinity of the composite. The calculated crystallinity for the resin is 7.3%, and for C-2, C-3 and C-4 its values are 12.1%, 14.3%, 17.1%, respectively, evidencing the interactions between the graphite and polymer matrix. The composites showed fractured surfaces and porous rough structure with randomly distributed vascularized cavities. Agglomeration occurs, when the concentration of graphite increases. The glass transition temperature for the pure resin is 65.9 °C and increases when the resin is filled with graphite. Thermogravimetric analysis (TGA) of the composites showed no marked difference between Tmax and Tfinal, and LOI values of C-3 and C-4 are above 21%, making them self-extinguishable materials that could be used for making bipolar plates. The chemical resistance investigation against water, NaCl, NaOH, acetic acid, and toluene showed more resistance to acid than alkali solutions. These rooflite resin/graphite composites could be further studied to explore the possibility of making bipolar plates, which are an essential component of fuel cells

The long-term effects of CVDs on economic development: the case of Bangalore

The aim of this paper is to demonstrate the economic and health burden of Cardiovascular diseases (CVDs) in the context of Bangalore during the period 2010-2013. A data set containing in excess of 1 million historic records corresponding to all-cause mortality was obtained from the central repository data register. After a data quality assessment, a dataset of n=183,893 was obtained. Spatial analysis was carried out to highlight the hotspots of CVD. Potential Years of Life Lost due to CVD and Present Value of Lifetime Earnings were computed. CVDs were responsible for 25% of the total of potential years of life lost. The potential value of lifetime earnings highlighted a loss in excess of 8 billion INR over the four years. CVD poses a tremendous challenge for socio-economic development, and there is an urgent need for a strategic action to promote CVD prevention and enable a sustainable development for the economy

Editorial: Why should we read Dalit literature?

http://journals.sagepub.com/toc/jcla/0/0Numéro spécial papier publié en 2019International audienc

From proteomics to discovery of first-in-class ST2 inhibitors active in vivo

Soluble cytokine receptors function as decoy receptors to attenuate cytokine-mediated signaling and modulate downstream cellular responses. Dysregulated overproduction of soluble receptors can be pathological, such as soluble ST2 (sST2), a prognostic biomarker in cardiovascular diseases, ulcerative colitis, and graft-versus-host disease (GVHD). Although intervention using an ST2 antibody improves survival in murine GVHD models, sST2 is a challenging target for drug development because it binds to IL-33 via an extensive interaction interface. Here, we report the discovery of small-molecule ST2 inhibitors through a combination of high-throughput screening and computational analysis. After in vitro and in vivo toxicity assessment, 3 compounds were selected for evaluation in 2 experimental GVHD models. We show that the most effective compound, iST2-1, reduces plasma sST2 levels, alleviates disease symptoms, improves survival, and maintains graft-versus-leukemia activity. Our data suggest that iST2-1 warrants further optimization to develop treatment for inflammatory diseases mediated by sST2

The International Collaboration for Research methods Development in Oncology (CReDO) workshops: shaping the future of global oncology research

Low-income and middle-income countries (LMICs) have a disproportionately high burden of cancer and cancer mortality. The unique barriers to optimum cancer care in these regions necessitate context-specific research. The conduct of research in LMICs has several challenges, not least of which is a paucity of formal training in research methods. Building capacity by training early career researchers is essential to improve research output and cancer outcomes in LMICs. The International Collaboration for Research methods Development in Oncology (CReDO) workshop is an initiative by the Tata Memorial Centre and the National Cancer Grid of India to address gaps in research training and increase capacity in oncology research. Since 2015, there have been five CReDO workshops, which have trained more than 250 oncologists from India and other countries in clinical research methods and protocol development. Participants from all oncology and allied fields were represented at these workshops. Protocols developed included clinical trials, comparative effectiveness studies, health services research, and observational studies, and many of these protocols were particularly relevant to cancer management in LMICs. A follow-up of these participants in 2020 elicited an 88% response rate and showed that 42% of participants had made progress with their CReDO protocols, and 73% had initiated other research protocols and published papers. In this Policy Review, we describe the challenges to research in LMICs, as well as the evolution, structure, and impact of CReDO and other similar workshops on global oncology research