Iranian Polymer Journal / Volume 8 Number 2 (1999) 73–81                                                                                                   ISSN: 1026-1265/1999

 

 

Modification of Some Mechanical Properties of Cedar Wood by

 

Radiation Induced In-situ Copolymerization of Allyl Glycidyl

 

Ether with Acrylonitrile and Methyl Methacrylate

 

D. Şolpan and O. Güven

Hacettepe University, Department of Chemistry, 06532, Beytepe, Ankara, Turkey

 

ABSTRACT

 

Acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether (AGE), AGE+AN, AGE+MMA monomer and monomer mixtures were used to conserve and consolidate the wood. The fine structure of wood-polymer (copolymer) composites were investigated by scanning electron microscopy (SEM). The copolymer obtained from AGE+MMA monomer mixture showed the optimum compatibility. Compressive strength and Brinell hardness number (BHN) measurements of the wood-polymer(copolymer) composites indicated that their mechanical stability is increased. The increase in the compressive strength that is in perpendicular to the fibres in the highest conversion, is 197% in cedar wood in the presence of P(AGE/MMA). It is found that the mechanical stability of the woods that imply AGE+AN and AGE+MMA copolymers is higher than the others. There was almost no change in the mechanical stability and BHN after 28 days of the ageing process.

Iranian Polymer Journal / Volume 8 Number 2 (1999) 83–90                                                                                                   ISSN: 1026-1265/1999

 

 

Kinetic Investigation and Characterization of Styrene-

 

Butyl Acrylate Solution Copolymerization

 

F. Ziaee and M. Nekoomanesh

Iran Polymer Institute, P.O. Box 14965/115, Tehran, I.R. Iran

 

ABSTRACT

 

An investigation on the kinetics of free radical solution copolymerization of styrene with butyl acrylate using benzoyl peroxide and toluene, was made at 80 °C using fixed initiator and solvent concentrations. Sequence distribution of styrene and butyl acrylate and determination of copolymer composition by 1H NMR and 13C NMR are reported. By interpretation of the 13C NMR spectra of the homopolymers and copolymers, assignment of the carbonyl and quarternary carbon atom resonances has been made. It has been then possible to make a quantitative estimation of the compositional triad distributions in the copolymers. The results are found to be in relatively good agreement with calculated triad sequences.

 

 

 

Iranian Polymer Journal / Volume 8 Number 2 (1999) 91–98                                                                                                   ISSN: 1026-1265/1999

 

 

Effect of Process Variables on the Quality of NR Latex Condoms

 

J. Maret1, N.M. Mathew1, J. Francis2, and J. Sahayadasan3

(1) Rubber Research Institute of India, Kottayam 686 009, India

(2) Cochin University of Science and Technology, Cochin 682 022, India

(3) Hindustan Latex Limited, Thiruvananthapuram 695 005, India

 

ABSTRACT

 

The influence of process variables such as ball milling time, concentration and temperature of mould cleaning, temperature, and time of prevulcanization and final vulcanization on the quality of condoms and the pinhole rejection rate have been studied. It was found that an optimum ball milling time of 72 h improve condom properties and reduce pinhole rejection rate. Optimum concentration of mould cleaning soap solution is in the range of 0.5-0.7 % and its temperature 60 °C. Time and temperature of prevulcanization and final vulcanization are interrelated in determining the final product properties.

Iranian Polymer Journal / Volume 8 Number 2 (1999) 99–113                                                                                                 ISSN: 1026-1265/1999

 

 

Physically-based Adaptive Control of Cavity Pressure

 

in Injection Moulding Process: Packing Phase

 

M. Rafizadeh1, W.I. Patterson2 and M.R. Kamal2

(1) Polymer Engineering Department, Amir Kabir University of Technology, Tehran, I.R.Iran

(2) Chemical Engineering Department, McGill University, Montreal, Canada

 

ABSTRACT

 

Cavity pressure plays an important role in determining the quality of injection moulded article.  However, the non-linear and time varying behaviour of the process causes difficulties in implementing efficient control systems, since these generally employ linear time invariant design strategies. Conversely, advanced control methods, such as self-tuning, do not provide physical information about the process. A physically-based adaptive controller has been developed for cavity pressure control during the packing phase.  Experimental results indicate that this control yields accurate results for the injection moulding of polyethylene.  Different control algorithms with different tuning criteria, were implemented on a microcomputer to control the cavity pressure.  The results also show that this method is superior to the classical empirical control approach.

Iranian Polymer Journal / Volume 8 Number 2 (1999) 115–121                                                                                               ISSN: 1026-1265/1999

 

 

A Novel Synthesis and Characterization of 4-Acetyl-

 

aminobenzene-p-styrene Sulphonate and its Polymer

 

as Prodrug in Controlled Release Technique

 

A. Khazaei1, A. Mashak2 and E. Mehdipour1

(1) Department of Chemistry, Faculty of Science, Bu-Ali Sina University, Hamadan, I.R. Iran

(2) Department of Chemistry, Faculty of Science, University of Lorestan, Khoramabad, I.R. Iran

 

ABSTRACT

 

Controlled drug release is one of the most important methods which is used to increase therapeutic effects. It decreases the side effects of drug and, therefore, it has attracted the interest of different research groups over the past two decades. The application of polymers has been also extended in this field. In this research the method employed is the chemically controlled release of 4-hydroxyphenyl acetamide (acetaminophen) as a drug. In this system the drug is chemically bonded to the polymer carrier backbone. Release of the drug occurs by hydrolytic degradation of the appropriate bonds. First, the monomer, 4-acetylaminobenzene p-styrene sulphonate was synthesized, then the obtained product was characterized by 1H NMR and IR spectroscopies. After monomer attachment to the drug, the monomer drug product was polymerized. Finally, the releaseability of the polymer was tested in buffer solution with pH=7 at temperatures of 37 and 40 °C. The latter studies were carried out by UV-spectroscopy. This test shows that the polymer is able to release drug and this ability is a function of temperature.

Iranian Polymer Journal / Volume 8 Number 2 (1999) 123–129                                                                                               ISSN: 1026-1265/1999

 

 

Biodegradable Polyglycol Succinates Used as Disposables

 

R. Sariri1 and A. Ghannadzadeh2

(1) Department of Biology, Gilan University, Rasht, I.R.Iran

(2) Department of Chemistry, Gilan University, Rasht, I.R.Iran

 

ABSTRACT

 

The rapid development in the field of disposable polymers has brought about the important problem of their wastes and disposals. Although recycling is one way of using these wastes, but in some cases such as blood storage bags, the danger of contamination is a problem. Polyglycol succinates have been known for a long term for their use as biodegradable materials. It has been found that, in addition to their bioabsorbable character, polyglycol succinates are particularly well tolerated by the tissues in which they are implanted. Polyglycol succinates possess very good mechanical properties and they are insensitive to moisture. It was suggested that they can be used as biodegradable disposables due to their high mechanical properties as well as the ability to be adsorbed to the soil by the action of micro-organisms. A group of biodegradable polyesters, polyglycol succinates, were synthesized using polycondensation reaction with different diols. The biodegradation rate of these polymers was studied on thin films prepared from the polymer solution. The effects of different physical and chemical variables on the rate of their bioabsorption were also studied. Among all variables, it was shown that the pH of the soil and the chemical structure of the monomers used in the synthesis were the most important of all.

Iranian Polymer Journal / Volume 8 Number 2 (1999) 131–136                                                                                               ISSN: 1026-1265/1999

 

 

Determination of Active Centre Concentration for

 

Polymerization of Propylene Using High

 

Activity Ziegler Natta Catalyst

 

P.J.Tait1 and G. Zohuri2

(1) Department of Chemistry, University of Manchester Institute of Science and Technology, Manchester, UK.

(2) Department of Chemistry, University of Mashhad, I.R. Iran

 

ABSTRACT

 

Suspension polymerizations were carried out at 1 atm of propylene in pentamethyl heptane using Mg(OC2H5)/di-n-butylphthalate/TiCI4-AIEt3/di-phenyldimethoxy silane catalyst system. Active centre concentration (C*) was determined by quenching and radio-tagging methods using tritiated methanol and carbon monoxide, respectively. Effect of external donor on the C* was studied. An investigation in the effect of temperature ( 50-80 °C) on C*, and propagation rate coefficient, kp, was carried out using the catalyst system. The optimum values of C* were achieved at 65-70 °C. The maximum rate of polymerization as well as the kp values increased steadily with increasing temperature. The preliminary investigation involved the time needed for the tritiated methanol and carbon monoxide to react with the active centres to stop the polymerization quickly and completely. The amount of carbon monoxide and alcohol which were able to stop the polymerization was also etermined. In the present work a five-fold of tritiated alcohol concentration to alkylaluminium was used.