Iranian Polymer Journal / Volume 10 Number 2 (2001) 77–83                          ISSN: 1026-1265/2001

 

 

Redox Polymer Precursors: Removal of Blocking Groups

 

and Redox Properties

 

Saâd Moulay

Laboratoire de Chimie‑physique Moléculaire et Macromoléculaire, Institut de Chimie Industrielle,

Université de Blida, Route de Soumâa, B.P. 270, 09000 Blida, Algeria

 

ABSTRACT

 

Study of the removal of blocking groups in redox polymer precursors, poly(5‑vinyl‑1,3-benzodioxole) (polymer I) and poly(2,3‑dimethoxystyrene) (polymer II), was undertaken with different acidic reagents. Boron trichloride dodecyl mercaptan (RSH) system showed a better cleaving performance among the experimented reagents. Poly(4‑vinylcatechol), initially methanol‑soluble, became purple‑coloured with a defied insolubility under aerobic conditions. Intramolecular cross-linking is viewed as a possible explanation for the observed insolubility of the obtained resin; that is, either benzene rings of two moieties undergo an intramolecular Pummerer reaction. A mechanism of the deportation of the redox polymers seems to be substituent-dependent polymer precursors. Indeed, poly(3‑vinylcatechol) remained methanol‑soluble for months with a faint pink colour. Redox midpotentials of poly(3‑vinyl-catechol) were established to be 707 mV at 23 ºC, while that of catechol was found to be 764 mV under the same conditions.

 

 


Iranian Polymer Journal / Volume 10 Number 2 (2001) 85–90                          ISSN: 1026-1265/2001

 

 

Synthesis, Characterization and Flocculation Efficiency of

 

Poly(acrylamide‑co‑acrylic acid) in Tannery Waste-water

 

Achala Jha1, Sudha Agrawal1, Anuradha Mishra1 and Jaishankar P. Rai2

(1) Department of Chemistry, Institute of Engineering and Technology, Chhatrapati Shahu Ji Maharaj University,

Kanpur-208024, India

(2) Department of Plastics Technology, Harcourt Butler Technological Institute, Kanpur, India

 

ABSTRACT

 

Synthesis, characterization, thermal behaviour and flocculation efficiency of poly(acrylamide‑co‑acrylic acid) prepared in aqueous medium are studied. The copolymers are prepared at moderate acidic/basic pH levels and characterized by IR,
13C NMR, elemental analysis and differential scanning calorimetry. The copolymers prepared in alkaline medium show higher Tg and intrinsic viscosity value than those prepared in acidic medium. Flocculation efficiency of these copolymers is studied in tannery waste-water. The copolymers prepared at pH 10.0 are found to be a better flocculant than those prepared at pH 4.0. The flocculation efficiency of these copolymers increases with the decrease in acrylic acid content in the copolymer.

 


Iranian Polymer Journal / Volume 10 Number 2 (2001) 91–98                          ISSN: 1026-1265/2001

 

 

Theoretical Aspects of the Technology in Synthesis of Sodium

 

Carboxymethyl Cellulose from Various Raw Materials

 

Yavuz Ismail oglu Rustamov, Gusein Alesker oglu Karamamedov, Takhira Allakhveran gizi Samedova and Gulistan Tofig gizi Shakhbazova

Institute of Polymer Materials of Azerbaijan Academy of Sciences, Sumgait, Republic of Azerbaijan

 

ABSTRACT

 

Some peculiarities of the technology in synthesis of sodium salt of carboxymethyl cellulose from various cellulose containing raw materials have been considered and discussed. The wastes of cotton‑gin plants and their mixtures with viscose cellulose were used as raw materials. It has been predicted and experimentally confirmed that for preparation of product with high homogeneity on degree of substitution and molecular mass, the basic criterion is the rate of mass-diffusion of solid phase, providing approximately the same concentration of alkali exists in all points of cellulose raw materials during its treatment with aqueous solution of sodium alkali. The increase of mass-diffusion of raw materials by addition of microaccelerator has been predicted and experimentally proved. An adequate mathematical model of the relationship of the parameters of cellulose raw materials mass-diffusion and chemical reaction by taking into account the form coefficient of non‑globular particles has been developed and examined. The practical confirmation for results of theoretical investigations has been presented.


Iranian Polymer Journal / Volume 10 Number 2 (2001) 99–106                        ISSN: 1026-1265/2001

 

 

Living Radical Polymerization of Methylmethacrylate,

 

Methylacrylate and Their Block Copolymers with

 

Acrylonitrile by Atom Transfer Radical Polymerization

 

Mehdi Alipour, Bakhshali Massoumi, Kazem Dindar Safa and Ali-Akbar Entezami

Polymer Laboratory, Faculty of Chemistry, Tabriz University, Tabriz 51664, I.R. Iran

 

ABSTRACT

 

Free radical polymerization with reversible termination has recently generated the longest waiting entry into the field of living and/or controlled polymerization reactions. These methods are known as living radical polymerization and it is found that they proceed in easy conditions and result in narrow polydispersities. Thus, the possibility of living radical polymerization of methyl-methacrylate, methylacrylate and their block copolymers with acrylonitrile by atom transfer and with Cr(OAc)2 initiators have been studied. As a consequence, we have synthesized homopolymers with high molecular weights, low polydispersities up to 1.26. Homopolymers and copolymers obtained are characterized with FTIR and GPC.


Iranian Polymer Journal / Volume 10 Number 2 (2001) 107–114                      ISSN: 1026-1265/2001

 

 

Polymeric Azo Dyes Derived from 4-[4¢-(4-Dimethylamino-1-

 

phenylazo) phenyl]-1,2,4-triazolidine-3,5-dione and Diisocyanates

 

Shadpour E. Mallakpour and Hossein Nasr-Isfahani

Organic Polymer Chemistry Research Laboratory, College of Chemistry, Isfahan University of Technology,

Isfahan, 84156, I.R. Iran

 

ABSTRACT

 

4-[4¢-(4-Dimethylamino-1-phenylazo)phenyl]-1,2,4-triazolidine-3,5-dione 1 was reacted with excess amount of n-propylisocyanate in DMF (N,N-dimethylformamide) solution at room temperature. The reaction proceeded with moderate yield and involved reaction of both N–H of the urazole group. The resulting bis-urea derivative 2 was characterized by IR, 1H NMR, elemental analysis and UV-vis spectra and it was finally used as a model compound for the polymerization reaction. Solution polycondensation reactions of monomer 1 with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI) and tolylene-2,4-diisocyanate (TDI) were performed in DMF in the presence of pyridine as a catalyst and lead to the formation of novel aliphatic and aromatic azo-containing polyurea dyes which are soluble in polar solvents. These novel polyureas have inherent viscosities in a range of 0.15–0.27 dLg–1 in DMF at 25 ºC. Some structural characterization and physical properties of these novel polymers are reported.

 

 

 


Iranian Polymer Journal / Volume 10 Number 2 (2001) 115–123                      ISSN: 1026-1265/2001

 

 

Development of Optimized Rubber Compounds for the

 

Components of the Bead Section of a Low Aspect Ratio

 

Steel‑belted Radial Tire

 

Mir Hamid Reza Ghoreishy, Mohammad Karrabi and Mohammad Razavi Nouri

Department of Rubber Engineering and Processing, Iran Polymer Institute, P.O. Box 14185‑515, Tehran, I.R. Iran

 

ABSTRACT

 

This paper is devoted to the description of the development of optimized rubber compounds for the various parts of the bead section of low aspect ratio steel‑belted radial tires. Four main parts of the bead zone have been considered which are bead insulation, apex, chafer and pad. For each section, a series of compounds have been designed and then based on the measured physical and mechanical properties, they are modified until the pre‑defined properties have been achieved. It is shown that based on use of a blend of elastomers and novel combination of different compounding ingredients, optimized rubber compounds for the mentioned parts both from physical properties and economical points of view can be obtained. The use of the developed compounds in the manufacturing of a 175/70‑14 steel-belted tire and also the results of the indoor and outdoor tire tests generally confirm the validity of the designed rubber compounds.

 


Iranian Polymer Journal / Volume 10 Number 2 (2001) 125–132                      ISSN: 1026-1265/2001

 

 

Enzymatic Treatment of Wool Fabric: Effects of the Surfactants

 

Nahid Hemmati Nejad1, Shahla Salahshour Kordestani2, Farzaneh Vahabzadeh3

(1) Department of Textile Engineering, Amirkabir University of Technology

(2) Department of Medical Engineering, Amirkabir University of Technology

(3) Department of Chemical Engineering, Amirkabir University of Technology

 

ABSTRACT

 

By use of the commercial protease, the wool fabric has been treated enzymatically. The modified form of the Michaelis-Menten equation has been used and the maximal velocity and the half-saturation constant, V΄max and k΄m, were calculated. The effects of different types of surfactants (cationic ‘CAS’, non-ionic ‘NNS’, anionic ‘ANS’, amphoteric ‘AMS’) on the rate of enzymatic reaction were studied. By considering Lineweaver-Burk plot, K΄m and V΄max values are: 0.37, 2; 0.07, 5.15; 0.10, 5.98; 0.10, 2.89; μmol/min for CAS, NNS, ANS, AMS surfactants, respectively. In the absence of surfactant (WOS), the K΄m and V΄max values are:  0.059 and 4.52 μmol/min, respectively. The results obtained showed that the amount of released amino acid (raa) in presence of either ANS or NNS surfactant were higher than that in the absence of the named surfactants. In presence of CAS or AMS surfactants, the amount of raa, was decreased. With the use of surfactants results obtained from scanning electron microscopy on the treated fabrics and also from determination of one of the measurable physical properties (tensile strength), indicate that there is a good correlation between amount of raa and loss of the tensile strength of fabric. The measured kinetic parameters (K΄m and V΄max) were also changed accordingly. AMS showed to act more properly on the uniformity of the wool substrate as compared with that of the other tested surfactants. Moreover, as the catalytic specificity, the ratio of V΄max/K΄m, was determined.