Author
A. Mahammad Ibrahim
Bio: A. Mahammad Ibrahim is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Glass transition & Viscosity. The author has an hindex of 2, co-authored 5 publications receiving 12 citations.
Topics: Glass transition, Viscosity, Copolymer, Monomer, Nucleophile
Papers
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TL;DR: Aliphatic-aromatic co-polyureas have been prepared using 1.4-bis (isocyanatomethyl)-2,5-dimethylbenzene and 1.5-bis(isocynatmethyl)2,4-dimethylamine with various diamines as discussed by the authors.
7 citations
2 citations
1 citations
TL;DR: In this paper, the authors synthesize alternating copolymers by the reaction of nucleophilic monomers M N with electrophilic monomer M E, which are characterized by spectral and other methods.
1 citations
TL;DR: In this article, the glass transition temperatures of polyurethanes derived from 1,4-butylene and ethylene glycols were determined using dilatometric techniques and they ranged from −12 to −48°C.
Abstract: The present paper deals with the single step syntheses of a few aliphatic polyurethanes using some simple glycols like ethylene, propylene, 1,3- and 1,4-butylene glycols and two different bis(chloromethyl) compounds viz., 1,4-bis(chloromethyl)-2,5-dimethyl benzene (I), and 1,5-bis(chloromethyl)-2,4-dimethyl benzene (II). The glass transition temperatures, Tg, of these polymers were determined using dilatometric techniques and they ranged from −12 to −48°C. The polyurethanes derived from 1,4-butylene and ethylene glycols were amorphous gums with Tg well below −30°C.
1 citations
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TL;DR: A series of elastomers based on polyurea chemistry is synthesized by crosslinking amino-terminated polyethers with a triisocyanate using an appropriate solvent, which slowed down the reactivity of the amino groups as mentioned in this paper.
Abstract: A series of elastomers based on polyurea chemistry is synthesized by crosslinking amino-terminated polyethers with a triisocyanate using an appropriate solvent, which slowed down the reactivity of the amino groups. Control of the reactivity allows the shaping of the material, and films of defined thickness can be achieved for mechanical testing. The strength of the final network can be tuned by the crosslinking density of the network chemical constitution. The resulting materials show a good thermal stability and promising mechanical enhancement.
73 citations
TL;DR: In this paper, a series of norm-defying hydrocolloid emulsifiers is reported for the challenging task of outstanding long-term retention of volatile cryogenic phase change materials (cryoPCM) in high-payload capsules.
24 citations
TL;DR: The approach presented allows for programing the release of payloads by co-encapsulating inexpensive salts inside nanocontainers without the help of stimuli-responsive materials.
Abstract: The encapsulation of payloads in micro- to nano-scale capsules allows protection of the payload from the surrounding environment and control of its release profile Herein, we program the release of hydrophilic payloads from nanocontainers by co-encapsulating simple inorganic salts for adjusting the osmotic pressure The latter either leads to a burst release at high concentrations of co-encapsulated salts or a sustained release at lower concentrations Osmotic pressure causes swelling of the nanocapsule's shell and therefore sustained release profiles can be adjusted by crosslinking it The approach presented allows for programing the release of payloads by co-encapsulating inexpensive salts inside nanocontainers without the help of stimuli-responsive materials
18 citations
TL;DR: In this paper, a series of aromatic/aliphatic co-polyureas have been synthesized from 4,4-diphenylmethane diisocyanate (MDI), m-phenylene diamine (m-PDA), and 1,6-diaminohexane (HDA) in DMAc by a two-stage solution polymerization route.
Abstract: In the present work, a series of aromatic/aliphatic co-polyureas have been synthesized from 4,4-diphenylmethane diisocyanate (MDI), m-phenylene diamine (m-PDA), and 1,6-diaminohexane (HDA) in DMAc by a two-stage solution polymerization route. Characterizations of the polyurea products have been carried out by 1H-nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopic techniques. Thermal properties of the polyurea samples have been investigated by differential scanning calorimetry and thermogravimetric analysis. The mechanical properties of the polyurea samples have been measured. The results show that the polyurea samples with the expected structure have been synthesized. The results of DSC analysis show the glass transition temperatures of the co-polyurea samples decrease with the increase of HDA content, and fit the Fox equation well. TGA data of the polyurea samples indicate that thermal stability of the aromatic polyurea is better than that of the co-polyureas. The thermal degradation activation energies of the co-polyureas are ∼60–70 kJ/mol. The results of mechanical measurement show that the initial modulus and tensile strength of the co-polyurea samples decrease with the increase of HDA content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
17 citations
TL;DR: In this article, the effects of hydrogen bonding in a given polymer system or blend will be predicted, as well as what structural features will promote such interaction, for the design of polymer blends and laminates where compatibility is normally difficult to achieve.
Abstract: Although a great deal is known about the effects of hydrogen bonding in solid polymer systems, there has been little effort to organize this information. AS a result, it is still difficult to predict what the effects of hydrogen bonding in a given polymer system or blend will be, as well as what structural features will promote such interaction. Availability of predictive capability would be particularly valuable for the design of polymer blends and laminates where compatibility is normally difficult to achieve.
17 citations