http://nopr.niscair.res.in/handle/123456789/3446 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/4222 Title: Free radical cross-linking copolymerization of acrylamide and <i>N,N</i>^/ methylene-bis-acrylamide by using Fe(III)/thiourea and Ce(IV)/thiourea redox initiator systems <br/> <br/>Authors: Debnath, Bidyut; Bit, Goutam; Saha, Swapan K <br/> <br/>Abstract: Acrylamide (AM) and <i>N,N</i>^/ methylene-bis-acrylamide (Bis) copolymerization in water has been investigated at a total monomer concentration (AM + Bis) of 0.4 M. Extent of conversion of monomer into polymer was measured as a function of the reaction time upto the onset of macrogelation (gelation observed visually). The critical conversion at the gel point shows a minimum at ~5.7 mol% Bis concentration for Fe(III)/thiourea (TU) redox system whereas for Ce(IV)/TU redox system it occurs at ~2.6 mol% Bis concentration. It was found that polymer formed after gel points with different Bis% were not soluble in water, acetic acid, toluene or chloroform. In the copolymerization reaction involving Fe(III)/TU redox initiator system, no induction period is observed at 50°C. In the case of Ce(IV)/TU redox initiator system, however, a significant induction period is observed at 40°C, which depends upon the Bis% in the monomer mixture. Unlike Fe(III)/TU, the reaction takes only a few minutes to complete for Ce(IV)/TU redox initiator system after the induction period is over. <br/> <br/>Page(s): 196-199 http://nopr.niscair.res.in/handle/123456789/4221 Title: Utilization of aleuritic acid free gummy mass - an industrial by-product for making particle board <br/> <br/>Authors: Sao, K P; Pandey, S K <br/> <br/>Abstract: Aleuritic acid free gummy mass, a by-product obtained during the preparation of aleuritic acid from lac resin has been used in conjunction with lac resin for making medium density particle board from the particles of arhar (<i style="">Cajanus cajan</i>) plant stalk. The proportion of gummy mass and lac in the binder composition has been optimized. Influence of various parameters such as the amount of binder, time and temperature of hot press and particle size on the impact strength of the particle board was studied. The other mechanical properties namely water absorption, thickness swelling, modulus of rupture, tensile strength perpendicular to surface of board, and screw withdrawal forces of the particle board of dimensions 120x120x12 mm indicate that these boards can be used for interior applications. <br/> <br/>Page(s): 192-195 http://nopr.niscair.res.in/handle/123456789/4220 Title: [Cu(NH₃)₄]²⁺ SnP as a catalyst <br/> <br/>Authors: G, Chithra P; Tharayil, Nisha J; B, Beena <br/> <br/>Abstract: The complex cation [Cu(NH₃)₄]²⁺ has been sorbed onto tin phosphate (SnP) support and the product has been characterized by elemental analysis. The catalytic activity of the [Cu(NH₃)₄]²⁺ sorbed SnP support has been studied through the decomposition of hydrogen peroxide. The kinetic data and calculated energy of activation show that the new catalyst system exhibits good catalytic activity. <br/> <br/>Page(s): 188-191 http://nopr.niscair.res.in/handle/123456789/4219 Title: Comparative study on hydrogen peroxide bleaching of soda-organosolv and Kraft rice straw pulps <br/> <br/>Authors: Ziaie-Shirkolaee, Y <br/> <br/>Abstract: Rice straw was cooked with three levels of alkali content (12, 14 and 16%) in cooking liquor by soda-organosolv (ethanol, diethylene glycol, dimethyl formamide) process. The effect of alkali addition on yield, kappa number, brightness and viscosity of organosolv unbleached pulps was studied. The TCF bleachability of these organosolv pulps and kraft pulp was carried out using a simple three stage peroxide bleaching sequence without oxygen pre-bleaching. All tested pulps were bleached under identical conditions during each stage. After full peroxide bleaching sequences of three alkali-organosolv pulps, some similarity in behaviour of brightness and peroxide consumption for each alkali percentage was observed. The final brightness of 63-70% ISO was attained for all tested pulps. The chemical charge required to reach this level of brightness varied for different pulps (despite the equal initial content of the residual lignin), which was directly related to starting brightness values. The high bleached yield for organosolv pulps (approximately, in range of 90–91% o.d.p) indicates to the limited organosolv carbohydrate degradation during peroxide bleaching. The strength properties of bleached organosolv pulps were higher than kraft pulp. No relation was found between improvement in brightness and lignin removal during hydrogen peroxide bleaching. <br/> <br/>Page(s): 181-187