Polymer Science and Rubber Technology

Low-protein content natural rubber latex was produced by using a nonionic surfactant-polyethylene glycol (PEG). Extractable protein content of natural rubber latex was found to decrease with PEG treatment and reduction increased with increase in the molecular weight of PEG. The low-protein latex samples were characterized by tensile testing, Fourier transform infrared and thermogravimetric analysis. The results have shown 35% reduction in the extractable protein content, without any compromise on the mechanical properties of the latex; however, thermal stability of low-protein latex was found to be reduced marginally with PEG treatment. V

Improvement of mechanical and chemical properties can be achieved by melt blending of thermoplastic polyurethane (TPU) with polyolefins (PO's). Since TPU and PO's are completely immiscible polymers, property enhancement cannot be attained. Effect of incorporation of polypropylene copolymer (PPCP), TPU-g-MA, TPU-g-AA as compatibiliser on the miscibility of the blends and effect of mica filler to enhance the mechanical properties were studied. A single screw extruder was used to manufacture blends by melt mixing. The results of mechanical and morphological properties show that the blend of thermoplastic polyurethane (TPU)/PO's with suitable compatibiliser and mica gives excellent performance in all aspects.

Blends of Nylon-66/ABS were prepared in various proportions. ABS was chemically modified using ethylene glycol, ethylene diamine and acrylamide. Butadiene region of ABS acted as site for modification reactions, irradiated by UV using UV initiator in UV reactor. m-ABS were characterized using FTIR confirming chemical functionalization. m-ABS blended with Nylon-66 and results compared with original ABS/N-66 blends. Physical, mechanical, chemical, electrical and thermal properties were characterized, and properties of modified blends were superior to conventional blends. Functional groups increases polarity of polymer enhancing miscibility of blends. SEM photographs gives evidence for miscibility of blends.

Melt blending of thermoplastic polyurethane (TPU) with polyolefins (PO's) can lower the cost and improve mechanical and chemical properties. Since TPU and PO's are completely immiscible polymers, property enhancement cannot be attained. Effect of incorporation of polypropylene copolymer (PPCP), TPU-g-MA, TPU-g-AA as compatibiliser on the miscibility of the blends and effect of clay filler on the mechanical properties were studied. Blends were produced by melt mixing using a single screw extruder. Mechanical and morphological properties were studied. The results show that the blend of thermoplastic polyurethane (TPU)/PO's with suitable compatibiliser and clay gives excellent performance in all aspects.

Improvement of mechanical and chemical properties can be achieved by melt blending of thermoplastic polyurethane (TPU) with polyolefins (PO's). Since TPU and PO's are completely immiscible polymers, property enhancement cannot be attained. Effect of incorporation of polypropylene copolymer (PPCP), TPU-g-MA, TPU-g-AA as compatibiliser on the miscibility of the blends and effect of mica filler to enhance the mechanical properties were studied. A single screw extruder was used to manufacture blends by melt mixing. The results of mechanical and morphological properties show that the blend of thermoplastic polyurethane (TPU)/PO's with suitable compatibiliser and mica gives excellent performance in all aspects.

Изучены возможности оценки изменений свойств подшипниковой стали в процессе термообработки с применением визуализации с помощью динамических спектрограмм (сонограмм), которые отображают изменения спектральных характеристик акустических сигналов по временной координате. В качестве образцов были взяты кольца упорных подшипников из стали марки ШХ15, новые и бывшие в эксплуатации. Проведено исследование изменения спектральных характеристик стальных образцов по акустическому отклику на точечное ударное воздействие в зависимости от изменений прочностных свойств и микроструктуры, генерируемых в образцах посредством отпуска с выдержкой при температурах в диапазоне от 360 до 560 °С. Анализ и сравнение сигналов акустического отклика выполнялись с применением программного спектроанализатора. Показана информативность применяемой методики для определения изменений состояния стальных образцов после термообработки. Анализ динамических спектрограмм путем визуального сопоставления участков сонограмм при различных значениях размера окна Хеннинга позволил выявить наиболее индикативные спектральные признаки-сдвиг частот резонансных гармоник и изменение декремента затухания. Обнаружена четкая зависимость сдвига частот и изменения декремента затухания основных резонансных гармоник от температуры отпуска закаленных образцов из стали марки ШХ15. При повторной закалке отпущенных образцов наблюдаются обратные изменения частот резонансных гармоник и декремента затухания. Изменения указанных индикативных спектральных характеристик соответствуют изменениям твердости и микроструктуры стали. Данная методика может быть использована при разработке экспресс-методов неразрушающего контроля для оценки изменений состояния стальных конструктивных элементов и контроля качества термообработки.

Background: The impact of diet on blood pressure and the age-related changes in blood pressure have been difficult to detect within one population. We designed this analysis to study the association of major dietary factors with blood pressure and with age-related changes in blood pressure in a representative sample of the US population.

The lush flora bestowed around us by the nature, is invariably valuable beyond measure on account of the medicinal value they posses. Over the period of time the medical arenas are witnessing a gradual transition from dependence on the chemical drugs to natural compositions as they prove to be effective and devoid of side effects 1,2. A series of research, has been directed towards the formulation of such functional biomaterial, setting a stage to the biomedical revolution. Chitosan is a cationic aminopolysaccharide of randomly distributed β-linked D-glucosamine and N-acetyl-Dglucosamine (NAG), derived from the chitin by means of deacetylation 3,4. The commercial and laboratory chitosan products are not completely deacetylated and tend to be copolymers of N-acetyl glucosamine (NAG) and N-glucosamine 3-5. The ratio of these two repeating units depends upon the source and method of preparation of chitosan but glucosamine unit predominates 6,7. The cationic nature of the chitosan enhances the activity of inflammatory cells such as poly-morphonuclear leukocytes, macrophages and fibroblast without any toxic nature, thereby accelerating epithelisation and regeneration of normal skin 8. The protonated amine cluster in chitosan exerts the pronounced antimicrobial nature to the system, which gets bound to the bacterial membrane and disrupts the membrane permeability resulting in protein leaching which causes cell death 9. Additionally, chitosan mediated chelation of metal ions such as Ni, Zn, Cu, Fe, Mg necessary for the pathogen growth has also been suggested as a mode of antimicrobial activity 10. Based on the facts, such as biodegradability, non-cytotoxicity, healing art and antimicrobial nature makes the chitosan an illustrious nominee for pharmaceutical and biomedical application 11. The activities exerted by the bioactive chitosan can be modified by the incorporation of the other active ingredients likes therapeutical herbal species from the nature 12. Azadirachta indica (neem), which belongs to the family of Meliaceae, is a therapeutical herbal species used in Ayurveda and homoeopathic systems of medicine, by virtue of its antioxidant, antimutagenic, anti-inflammatory, antidiabetic and contraceptive properties 13,14. A. indica contains a numerous active ingredients, among them the active components are azadirachtin, nimbin, nimbidin which exerts the admirable properties to the herbal species 15,16. Generally, these compounds have higher molecular-mass with significant amount of oxygen resulting in complex structure. These oxygen active centres in the pharmacophore operate as a free radical scavenger that inhibits the oxidation reaction in the cell 16-18. The present work is based on the formulation of a hybrid system through the combination of two bioactive elements into a single matrix and evaluating the medicinal characteristics of the adduct. In this research, the bioactive elements viz. A. indica and hygienic chitosan have been united to cultivate a hybrid system with enhanced antimicrobial properties. As the germicidal chitosan degrades, the A. indica diffused out and enhancing the antimicrobial properties drastically. The A. indica extracts merged with a bioactive chitosan matrix

Acrylates are the esters, salts and conjugate bases of acrylic acid with its derivatives. They are made from acrylate monomer, which usually comprises of esters which contains vinyl groups, that is two carbon atoms that are double-bonded to each other, and directly attached to the carbonyl carbon of the ester group. Acrylates possess very diverse characteristic properties ranging from super-absorbency, transparency, flexibility, toughness and hardness, among others. These kinds of materials are used in sundry applications such as diapers, cosmetics, orthopedics, paints and coatings, adhesives, textiles, and many biomedical applications such as contact lenses and bone cements. This book chapter highlights the characteristic properties and applications of acrylates, its derivatives and copolymers.

No part of the work reported in this thesis has been presented for any other degree from any other institution. All the relevant corrections and modifications suggested by the audience during the pre-synopsis seminar and recommended by the Doctoral committee have been incorporated in the thesis.

This paper presents an experimental study to investigate the sustainable alternativeceiling boards using Palm Kernel Shell (PKS) and Balanite Shell (BS). The ceiling boards were prepared by mixing (BS/binder, PKS/binder and PKS/BS/binder) at different ratios of (20/80, 40/60, 60/40 and 80/20) and represented as samples (A1, A2, A3 and A4), (B1, B2, B3 and B4) and (C1, C2, C3 and C4) respectively. The samples werecast by flat press process in rectangular sheet shape mould of 187mm x 125 mm x 3mm. The samples were cut into specimen sizes of 30 mm x 40 mm and tested for dry shrinkage, water absorption, apparent porosity, bulk density,flaking, and hardness properties. Morphology of the samples were examined using SEM. Results of the analysis show that irrespective of the filler loadings the properties of PKS / binder particularly at 20/80 ratio (B1) displayed better dry shrinkage of 3.7 %; water absorption of 12.4 %; apparent porosity of 15 %; bulk density of 2.3 g/cm3; flaking of 0.05g...

Improvement of properties of polymeric materials through blending is a way to obtain products with highly adapted performance for specific applications. The present work reports the design and preparation of binary blend films of poly(ethylene-co-methacrylic acid) neutralized using sodium salt (EMAANa) and nano polyaniline doped with hydrochloric acid (nano PANI-HCl) or toluene sulfonic acid (nano PANI-TSA) with the aim of achieving improved thermal stability, DC conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of EMAANa. The binary blends were prepared by solution blending using a solvent mixture of toluene/1-butanol (90 : 10) at 65◦C. The hybrid materials were characterized and evaluated by FTIR, UV-Vis spectroscopy, XRD spectroscopy and thermogravimetric analysis (TGA). The electrical conductivity of the PANI and PANI/EMAANa blends was measured by four-probe method. The EMI shielding effectiveness was studied using a waveguide coupled to an Agilent...

Conducting polyaniline (PANI) in nano dimension was prepared in presence of aqueous hydrochloric acid (HCl) or toluene sulfonic acid (TSA) as doping agents and ammonium persulfate (APS) as oxidizing agent. Composites of the PANI and multi walled carbon nanotubes (MWCNT) were prepared by in situ polymerization technique at room temperature. The structural composition, morphology, thermal decomposition behavior and conductivity of PANI and the composites were investigated. Studies include Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD) pattern, uvvisible spectroscopy and thermogravimetric analysis (TGA). The electrical conductivity of the PANI-MWCNT composites as well as the pure PANI was measured by conventional four-probe method. The electrical conductivities of the two PANIs show that nano PANI-TSA has a higher conductivity (0.824 S/cm -1 ) compared to PANI-HCl (0.478 S/cm -1 ). PANI...

Improvement of properties of polymeric materials through blending is a way to obtain products with highly adapted performance for specific applications. The present work reports the design and preparation of binary blend films of poly(ethylene-co-methacrylic acid) neutralized using sodium salt (EMAANa) and nano polyaniline doped with hydrochloric acid (nano PANI-HCl) or toluene sulfonic acid (nano PANI-TSA) with the aim of achieving improved thermal stability, DC conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of EMAANa. The binary blends were prepared by solution blending using a solvent mixture of toluene/1-butanol (90 : 10) at 65 • C. The hybrid materials were characterized and evaluated by FTIR, UV-Vis spectroscopy, XRD spectroscopy and thermogravimetric analysis (TGA). The electrical conductivity of the PANI and PANI/EMAANa blends was measured by four-probe method. The EMI shielding effectiveness was studied using a waveguide coupled to an Agilent Synthesized Sweeper 8375A and a Hewlett-Packard spectrum analyzer 7000 in the X band frequency range (8-12 GHz). FTIR indicates a π-π and hydrogen bonding interaction between PANI and EMAANa, enabling the PANI to be adsorbed in the ionomer. The TGA of the blends show similar weight loss pattern with nano PANI-TSA/EMAANa exhibiting slightly lower weight loss below the decomposition temperature. The TGA results show that thermal stability of the blends is better compared to pure EMAANa. The results of measurements of electrical conductivity and EMI SE demonstrates that PANI was successfully blended into the EMAANa substrate.

This experiment focuses on the synthesis of Multifunctional Additives (MFA) from Castor seed oil (CO) and pure Oleic acid (OA) respectively. These multifunctional additives (CO-MFA and OA-MFA) were investigated as potential substitutes for process oil, activator, co-activator, and accelerator in the formulation of a natural rubber vulcanizate. During processing, the castor seed oil was characterized for acid value (AV), free fatty acid (FFA) and saponification value (SV) and subsequently reacted with 1, 6-hexane diamine to obtain a mixture of salts termed castor oil-based multifunctional additives (CO-MFA), similarly, a pure oleic acid was also reacted with 1, 6-hexane diamine to obtain a pure salt termed oleic acid-based multifunctional additive (OA-MFA). These compounds were investigated as substitutes for process oil/stearic acid, process oil/stearic acid/zinc oxide, process oil/MBT, and process oil/stearic acid/zinc oxide/MBT in the formulation and compounding of natural rubber ...