R. Arun Prasath

Synthesis and characterization of metal-containing polyurethanes and polyurethane-ureas

Abstract Metal-containing polyurethanes containing ionic linkages in the main chain were synthesized by the polyaddition reaction of hexamethylene diisocyanate (HMDI) or toluylene 2,4-diisocyanate (TDI) with 1:1 mixtures of divalent metal salts of mono(hydroxybutyl)phthalate [M(HBP)2] and digol [DG]. Similarly polyurethane-ureas were synthesized by reacting the diisocyanates with 1:1 mixtures of hexamethylene bis(ω,N-hydroxyethyl-urea) (HBHEU) and M(HBP)2. The polymers were characterized by elemental analysis, thermogravimetric analysis, solubility, visocity and spectral studies.

Synthesis and characterization of homopolymer of 3,5-dimethylphenyl methacrylate and its copolymers with glycidyl methacrylate

Abstract The acrylic monomer, 3,5-dimethylphenyl methacrylate was synthesized by reacting 3,5-dimethylphenol dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in the presence of triethylamine. The homopolymer and various copolymers with glycidyl methacrylate were synthesized using free radical polymerization in EMK solution at 70±1 °C using benzoyl peroxide as initiator. The copolymers were characterized by FT-IR, 1 H -NMR and 13 C -NMR techniques. The molecular weights ( M n and M w ) and polydispersity indices were determined using gel permeation chromatography. The glass transition temperatures were determined by differential scanning calorimetry. Thermogravimetric analysis were performed in air. The solubilities of the polymers were tested in various polar and non-polar solvents. Copolymer compositions were determined using 1 H -NMR spectra. The monomer reactivity ratios were determined by application of conventional linearisation methods such as Fineman–Ross, Kelen–Tudos and extended Kelen–Tudos.

STUDIES ON ZINC-CONTAINING POLYURETHANES AND POLYURETHANE-UREAS

ABSTRACT Zinc salt of mono(hydroxypentyl)phthalate [Zn[HPP]2] was synthesized by reacting 1,5-pentane diol, phthalic anhydride and zinc acetate. Zinc containing polyurethanes having ionic linkages in the main chain were synthesized by the polyaddition reaction of hexamethylene diisocyanate (HMDI) or toluylene 2,4-diisocyanate (TDI) with Zn[HPP]2, using di-n-butyltin dilaurate (DBTDL) as catalyst. Four different bisureas were prepared by reacting ethanolamine or propanolamine with HMDI or TDI. Zinc containing polyurethane-ureas were synthesized by reacting HMDI or TDI with 1:1 mixtures of Zn[HPP]2 and each of the bisureas. Zn[HPP]2 and the polymers were characterized by solubility, viscosity study, elemental analysis, FT-IR,1H-NMR,13C-NMR spectroscopy and thermogravimetric analysis (TGA).

SYNTHESIS AND CHARACTERIZATION OF HOMO- AND COPOLYMER OF 2-(N-PHTHALIMIDO)ETHYL METHACRYLATE AND STYRENE

2-(N-Phthalimido)ethanol (NPE) was prepared by reacting phthalic anhydride with ethanolamine in dimethy formamide medium. The NPE thus obtained was reacted with methacryloyl chloride in the presence of triethylamine to form the monomer, 2-(N-Phthalimido)ethyl methacrylate (NPEMA). Free radical polymerization technique was used to synthesize the homopolymers and copolymers of different composition of NPEMA and styrene in 2-butanone solution at 70ˆC ± 1ˆC using benzoyl peroxide as initiator. The monomer and the polymers were characterized by IR and 1H-NMR techniques. The molecular weights (M¯ w and M¯ n) and polydispersity index of the polymers were determined using gel permeation chromatography. Thermogravimetric analysis of the polymers were carried out in air. The solubility of the polymers were also studied. The composition of the copolymers was inferred from the 1H-NMR data obtained. The reactivity ratios of the monomers were determined by the application of FinemanRoss and Kelen-Tüdös methods.

7SYNTHESIS AND CHARACTERIZATION OF POLYURETHANES AND POLYURETHANE-UREAS BASED ON ZINC SALT OF MONO(HYDROXYBUTYL)PHTHALATE

Zinc salt of mono(hydroxybutyl)phthalate [Zn(HBP)2] was synthesized by the reaction of 1,4-butanediol, phthalic anhydride and zinc acetate. Polyurethanes containing zinc ions in the main chain were synthesized by reacting hexamethylene diisocynate (HMDI) or toluylene 2,4-diisocyanate (TDI) with Zn(HBP)2 using di-n-butyltindilaurate (DBTDL) as catalyst. Four different bisureas were prepared by reacting ethanolamine or 2-amino-2-methylpropanol with HMDI or TDI. Zinc containing polyurethane-ureas were synthesized by reacting HMDI or TDI with 1:1 mixture of Zn(HBP)2 and each of the bisureas. Zn(HBP)2 and the polymers were characterized by solubility study, elemental analysis, IR and 1H-NMR spectroscopy, and thermogravimetric analysis.

A high speed proficient power reduction method using clustering based flip flop merging

In todays electronic scenario, low power has grasped attention. The ought for low power has been a main epitome whereby the power dissipation is one of the constraint as with performance and area. In the past, the major apprehension of the VLSI designer are its area, performance, cost, reliability but now, the power obsessive is mainly due to clocking for the circuit that incorporate deeply scaled CMOS technology. Eliminating redundant inverter in merging out one bit flip flops into multi bit causes optimization in wirelength which would probably result in reduction of power. Its been a successful power saving methodology whose dynamic power of clock and total flip flop area is effectively encapsulated. In this paper, an agglomerative clustering algorithm is utilized to obtain nearest clustering for merging flip flops. The multi bit technique is introduced in fir circuit to lessen power as well as area. This satisfies with the above given constraints. According to the experimental results, our algorithm considerably reduces clock power by 21.98% and it is found that total gate count is reduced from 264 to 148 which increases the speed thus reducing the delay.