Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 242–247                                                    ISSN: 1017-6020/1995

 

 

A Differential Thermal Analysis Study of

 

Fluoroelastomer Vulcanization

 

D.S. Ogunniyi1 and C. Hepburn2

(1) Department of Chemistry, University of Ilorin, Ilorin, Nigeria

(2) Institute of Polymer Technology, University of Technology, Loughborough LE11 3TU, UK

 

ABSTRACT

 

The reaction taking place during the cure of a rubber compound are often complex and not easily understood. Also, the curing temperature of a compound is often determined in an empirical manner. This paper discusses the differential thermal analysis (DTA) method which has been used to determine the curing temperature range of a fluoroelastomer compound. The same technique was used to determine the post-curing temperature of fluoroelastomer vulcanizate. The DTA results were used to prepare vulcanizates which were found to possess good tensile properties; however, the results were not sufficient to propose a mechanism of crosslink formation.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 248–255                                                    ISSN: 1017-6020/1995

 

 

Poly(hydroxamic acid) Chelating Resin: The Synthesis and Uses

 

R. Khodadadi, S.A. Fakhri and A.A. Entezami

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

 

ABSTRACT

 

Two methods for the synthesis of poly(hydroxamic acid) chelating ion exchange resins: (A) from copoly(acrylamide‑divinylbenzene) by treatment with hydroxylamine hydrochloride in the presence of potassium hydroxide, and (B) acrylhydroxamic acid with divinylbenzene by free radical solution polymerization are described. Sorption capacities of Fe(III), Cu(II), Co(II) and Pb(II) ions are pH dependent and the selectivity towards these metal ions is in following order: Fe(II)>Cu(II)>Pb(II)>Co(II). The ability of the above resins to extract and separate these metal ions are reported. The hydroxamic acid capacity of the products from two methods is also compared.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 256–261                                                    ISSN: 1017-6020/1995

 

 

The Effect of a Cationic Surfactant on the Processing and

 

Mechanical Properties of Styrene Butadiene Rubber

 

H. Ismail1 and P.K. Freakley2

(1) School of Industrial Technology, University Sains Malaysia, 11800 Minden, Penang, Malaysia

(2) Rubber Process Engineering Center (RUPEC), IPTME, Loughborough University of Technology

Loughborough, Leics., LE11 1TU, UK

 

ABSTRACT

 

The effect of a multi‑functional additive (MFA), such as N‑tallow‑1,3‑diamine salt of a carboxylic acid on the mechanical properties of styrene butadiene rubber (SBR) peroxide system is studied. The addition of the MFA is found to improve the mechanical properties of SBR/peroxide system. Carbon black dispersion measurement using scanning electron microscopy and internal mixer power trace show that the MFA improves carbon black dispersion by acceleration of the incorporation of mixing. The MFA is also found to confer higher crosslink density.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 262–267                                                    ISSN: 1017-6020/1995

 

 

A Densimetric Study of the Redox Polymerization of

 

N‑Vinylpyrrolidone in Aqueous Medium

 

M.T. Taghizadeh and M.T. Salehi

Chemical Kinetic Laboratory, Faculty of Chemistry, Tabriz University, Tabriz, I.R. Iran

 

ABSTRACT

 

The kinetics of the polymerization of N‑vinylpyrrolidone (NVP) in aqueous solution by density measurements using hydrogen peroxide/ascorbic acid as a redox couple is studied at 35.00±0.01 °C under the influence of atmospheric oxygen. The following rate expression: rp[NVP]1.0 [H2O2]1.0 [ascorbic acid]°, is observed and a suitable mechanism is suggested. The overall energy of activation is found to be 41.7 kJ/mol, within the temperature range 25‑45 °C. The results of densimetric measurements are confirmed by iodometry method.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 268–273                                                    ISSN: 1017-6020/1995

 

 

Phase Transfer Agent‑Aided Free Radical Polymerization of

 

Butylacrylate

 

C. Mihailescu and V. Bulacovschi

Department of Macromolecular, Technical University of Iassi, Iassi, Romania

 

ABSTRACT

 

Polymerization of butylacrylate under phase transfer conditions in different organic solvent/water mixtures is studied. The kinetic approach points to the influence of the nature of the organic solvent as well as that of the volume ratio between aqueous and organic phase. The overall activation energy of the polymerization is calculated to be 70.3 kJ/mol and transfer constants CM and CI are found to be 3.98 x 10–5 and 2.036 x 10–4, respectively.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 274–282                                                    ISSN: 1017-6020/1995

 

 

Thermogravimetry of Poly(b‑hydroxybutyrate) and its Blends

 

with Polypropylene and Poly(methyl methacrylate)

 

J. Rychly1, K. Csomorova1, I. Janigova1, R. Broska1 and D. Bakos2

(1) Polymer Institute, Slovak Academy of Science, Dubravska Cesta 9, Bratislava, Slovak Republic

(2) Faculty of Chemical Technology, Department of Printing Art and Applied Photochemistry

Radlinskeho 9, 81237 Bratislava, Slovak Republic

 

ABSTRACT

 

Decomposition of biologically prepared poly(b‑hydroxybutyrate) into volatile products is slightly affected when non-isothermal experiments are carried out in air instead of nitrogen. The process of decomposition of PHB into volatile products is influenced by molecular mass of the polymer within the range 8,390–539,000, with medium molecular masses being the most stable. A melt behaviour of PHB is demonstrated by a gradual change of endotherms of melting of PHB which splits into three peaks with simultaneous shift of temperature of their maximum to lower values. It is ascertained that residual amounts of PHB decomposition affect the subsequent decomposition of PP, PE and PMMA into volatiles, the effect on polypropylene being the most pronounced. A significant back effect of second polymer on decomposition of PHB in its blends is observed for the case of poly(methyl methacrylate).

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 284–292                                                    ISSN: 1017-6020/1995

 

 

Ultraviolet Stabilizer with Dibenzyl Structure

 

E. Scortanu, J. Bestiuc and A.A. Caraculacu

Institute of Macromolecular Chemistry “Petru. Poni”, Romanian Academy, Jassy 6600, Romania

 

ABSTRACT

 

The 2‑hydroxyphenyl benzotriazoles are typical UV absorbing compounds that can diminish the photodegradation of polymers. Here the synthesis of two benzotriazole compounds is described. A model compound is synthesized from 2‑nitro4‑toluidine and an original benzotriazole derivative of 3,3'‑dinitro‑4,4'‑diaminodibenzyl. Each step of the three‑step process used is described in detail and the compounds thereby obtained are characterized by elemental analyses, IR, UV and 1H NMR spectra and the melting points.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 294–298                                                    ISSN: 1017-6020/1995

 

 

Vinylcarbo‑cyclosiloxane Reaction with Si-H-organodisiloxanes

 

L. Sacarescu, N. Luchian, M. Marcu, R. Ardeleanu and G. Sacarescu

Institute of Macromolecular Chemistry “Petru Poni”, 6600 Iassi, Romania

 

ABSTRACT

 

New cyclo‑linear organosiloxanes are prepared through the hydrosilylation reaction of vinylcarbo‑cyclosiloxane with organomethyl(H)disiloxanes using chloroplatinic acid as catalyst. These products are characterized by IR, 1H NMR spectroscopy, molecular weight, elemental analysis which confirm the predicted chemical structures.

 


Iranian Journal of Polymer Science and Technology / Volume 4 Number 4 (1995) 300–303                                                    ISSN: 1017-6020/1995

 

 

The Investigation of the Effect of Epoxide Resins Thermal

 

Destruction Products on Epoxide Compounds Electrical Ageing

 

R.M. Aliguliyev and E.A.M. Efendiev

Azerbaijan Research Institute of Olefins (AzNIIOLEFIN) Baku, Republic of Azerbaijan

 

ABSTRACT

 

Thermal destruction of epoxide diane resin is conducted in inert media at 300 °C for 180 min. Then the alcohol extract of the thermodestruction light products is obtained. After the ethyl alcohol distillation, the product is obtained in the quantity of 18 wt% on the starting resin. Using the method of infrared spectroscopy, it is established that the obtained resin product of thermodestruction is a mixture of complex dioles. The effect of 0.5‑2 wt% of this product as the additive on the electrical ageing of epoxide compounds is studied. It is established that the additive has the stabilizing effect on the ageing of epoxide compound. After the introduction of 2% of the additive the rate of the decrease of electrical strength of these compounds lessens 1.5 times, and the lifetime increases 3 times on the starting compounds.