Iranian Polymer Journal / Volume 5 Number 3 (1996) 145–151                                                                                               ISSN: 1026-1265/1996

 

 

Synthesis of Benzofuro(2,3‑b)benzofuran‑2,9‑dicarboxylic Acid:

 

A Potential Monomer

 

A. Banihashemi and B. Pourabbas

Chemistry Department, Faculty of Sciences, Shiraz University, Shiraz, I.R. Iran

 

ABSTRACT

 

Glyoxal bisulphite reacts with p‑cresol in the presence of sulphuric acid to produce 2,9‑dimethyl(5a,10b)dihydrobenzofuro(2,3‑b) benzofuran, and later upon oxidation with potassium permanganate produces benzofuro(2,3‑b)benzofuran‑2,9‑dicarboxylic acid, a potential monomer. Characterization was accomplished by 1H-NMR, IR, mass spectroscopy and elemental analysis. The diacid was participated in a polyamidation reaction with 1,4‑phenylene diamine. Characterization of the prepared polyamide by TGA and DSC shows a relatively high thermal stability.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 153–164                                                                                               ISSN: 1026-1265/1996

 

 

Effect of Processing Methods and Conditions on Properties of

 

Conductive Carbon-Polyolefins Composite

 

V. Haddadi‑Asl and T. Mohammadi

School of Chemical Engineering and Industrial Chemistry, University of New South Wales Sydney, NSW 2052, Australia

 

ABSTRACT

 

Conductive polymer composite materials are fabricated by mixing high density polyethylene and polypropylene with conductive fillers. To overcome the deterioration in the mechanical properties of carbon‑polymer composites with high carbon loading, ethylene‑propylene rubber is blended into the composites. Electrical, mechanical and permeation properties of the composite materials are studied. The present investigation has revealed that the conductivity of carbon black filled conductive plastic composite with or without graphite fibre is strongly dependent on the state of dispersion, mixing and processing conditions and interaction with the polymeric matrix.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 165–173                                                                                               ISSN: 1026-1265/1996

 

 

Dielectric Characterization of Composites Based on Coated

 

Conducting Fibres Embedded in Epoxy Matrix

 

M. Safari‑Ardi

Department of Polymeric and Textile Materials, Chalmers University of Technology, 412 96 Gothenburg, Sweden

 

ABSTRACT

 

The dielectric properties of composites consisting of an epoxy matrix loaded with coated copper fibres or coated carbon fibres have been studied over the frequency range 100 Hz to 1 MHz. The fibres are coated with an insulating material in order to prevent continuous conducting paths from being formed in the composite. The dielectric behaviour of these composites is quite similar to that of heterogeneous dielectrics where interfacial polarization is important. High values of the real part of the dielectric permittivity (one hundred to five hundred relative to eo) are obtained throughout the frequency range. The imaginary parts of the permittivity are very high at low frequencies (of the order of 106 at 100 Hz) for carbon fibre loaded epoxy, but decrease by three orders of magnitude at 1 MHz.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 175–181                                                                                               ISSN: 1026-1265/1996

 

 

Polyurethanes (I). Product of Polyaddition of

 

Bis(4‑hydroxyethylenethio)diphenyl Ether with Methylene

 

Bis(4‑phenyl isocyanate)

 

D. Wdowicka and W. Podkoskielny

Department of Organic Chemistry and Technology, Maria Curie-Slodowska University, Lublin 20-614, Poland

 

ABSTRACT

 

New polyurethanes are synthesized by polyaddition reaction of bis(4hydroxyethylenethio)diphenyl ether with methylene bis(4‑phenyl isocyanate) in optimal established conditions. Good results are obtained using a nonreactive solvent such as benzene, dibutyltin dilaurate as a catalyst, cat 15% wt concentration of monomers and conducting the process at 80‑90 ºC for 1.5‑2 h. Basic physicochemical properties of the polyurethane obtained are defined. The thermal behaviour of the polymers is evaluated by means of thermogravimetry and differential scanning calorimetry. The structure of synthesized polyurethane is determined by elemental analysis, FT‑infrared and 1H NMR spectroscopies and X‑ray analysis. Polyurethanes with 20 and 50% molar 1,6‑hexamethylenediol in relation to bis(4‑hydroxyethylenethio)diphenyl ether are obtained under the same conditions established earlier as optimal for synthesis of these polymers from the above mentioned compounds.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 183–191                                                                                               ISSN: 1026-1265/1996

 

 

Synthesis and Hydrolysis of Modified Polyvinyl Alcohols

 

Containing Ibuprofen Pendant Groups

 

S. Davaran and A.A. Entezami

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

 

ABSTRACT

 

Polyvinyl alcohol is used as a carrier polymer for attachment of non‑steroidal anti‑inflammatory drugs such as ibuprofen via hydrolitically labile ester bonds. For this purpose, methods have been developed for the modification of polyvinyl alcohol with difunctional compounds such as chloroethanol, chloroacetic acid, and salicylaldehyde so that one of their functional groups is attached to polyvinyl alcohol and the other remain active for further reaction with drug functional groups. Poly(hydroxyethylvinyl alcohol), poly(vinylchloroacetate), and poly(vinylsalicylaldehyde acetal) were prepared and reacted with ibuprofen to produce polymer‑drug conjugates. In vitro heterogeneous hydrolysis of the polymers was studied at physiological conditions. Poly(vinylsalicylaldehyde acetal) containing ibuprofen groups was more reactive towards hydrolysis. Ibuprofen was released by hydrolysis of ester bond without the cleavage of cyclic acetal.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 193–198                                                                                               ISSN: 1026-1265/1996

 

 

Phase‑Transfer in Synthesis of Ylidic Polymers by

 

Polycondensation Processes

 

G. Surpateanu1, P. Decock1, N. Avarvari2, D. Scutaru3 and N. Hurduc3

(1) Department of Chemistry, “Littoral” University, 59379 Dunkerque, Cedex, France

(2) Department of Organic Chemistry, “Al. I. Cuza” University, Jassy, Romania

(3) Department of Organic Chemistry and Macromolecules, “Gh. Asachi” Technical University, Jassy, Romania

 

ABSTRACT

 

The paper presents the synthesis and characterization of an ylidic polymer derived from monosubstituted carbanion of the dipyridylium ylide and 3,3‑bis‑(iodomethyl)oxetane, obtained by interphase‑transfer polycondensation reaction. The synthesized polymers are characterized by elemental analysis and 1H-NMR, 13C NMR and IR spectroscopy. The polymers obtained have low molecular weights, probably due to steric hindrances, chains polarity and interphase‑transfer process.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 199–205                                                                                               ISSN: 1026-1265/1996

 

 

The Utilization of Waste Latex Products in

 

Styrene‑Butadiene Rubber

 

R.S. George and R. Joseph

Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology

Cochin 682 022, India

 

ABSTRACT

 

Waste latex products are converted to a processable material by a novel economical process developed in our laboratory. It contains rubber hydrocarbon of very high quality and is lightly cross‑linked. Styrene‑butadiene rubber is mixed with latex reclaim in different proportions. The mechanical properties are found to be improved up to 60 percent replacement of styrene‑butadiene rubber by latex reclaim. The curing of styrene‑butadiene rubber is found to be accelerated by the addition of latex reclaim. The processability study shows that the blends can be processed similar to SBR/NR blends.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 207–212                                                                                               ISSN: 1026-1265/1996

 

 

Effect of a Multifunctional Additive on Curing Characteristics

 

and Mechanical Properties of Carbon Blacks Filled Natural

 

Rubber Compounds

 

H. Ismail and Z. Ahmad

School of Industrial Technology, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

 

ABSTRACT

 

The effects of a multifunctional additive on curing characteristics and mechanical properties of N330 and N220 carbon blacks filled natural rubber compounds have been studied. The mechanical properties of vulcanizates with carbon blacks have been enhanced by incorporating a multifunctional additive. The amounts of 2 phr and 3 phr of the additive are found to be the optimum loading for 50 phr of N330 and N220 carbon blacks, respectively. The optimum loading is also found to correspond approximately to the amount needed for a monolayer coverage of the carbon black surface. As for natural rubber and carbon black of N330 type mixes, the rate and state of cure in natural rubber and N220 type of carbon black mixes are dependent on the multifunctional additive loading as well.

 


Iranian Polymer Journal / Volume 5 Number 3 (1996) 213–218                                                                                               ISSN: 1026-1265/1996

 

 

Kinetics of Dehydrochlorination of PVC by n‑Butylamine,

 

Diethylamine and Triethylamine

 

S.M. Yousaf, A. Qureshi and Z. Ahmad

Department of Chemistry, Quaid-Azam University, Islamabad 45320, Pakistan

 

ABSTRACT

 

Kinetics of dehydrochlorination of poly(vinylchloride) by n‑butylamine, diethylamine and triethylamine in cyclohexanone have been studied by measuring the amount of amine consumed at different time intervals. Initial rate constants for the process of dehydrochlorination were determined to be 3.92×10–3, 6.93×10–3 and 6.28×10–3 mol–1min–1 at 50 ºC for each amine, respectively. The corresponding activation energies for the same reactions are found to be 52.45, 24.67 and 34.25 kJmol–1. This trend is in agreement with the basic behaviour of these amines. The reaction has been found to be bimolecular and it proceeds by E2 mechanism.