Iranian Polymer Journal / Volume 7 Number 1 (1998) 5–13                                                                                                     ISSN: 1026-1265/1998

 

 

Laser Surface Modification of Polymers:

 

A Novel Technique for the Preparation of Blood

 

Compatible Materials‑(II) In Vitro Assay

 

H. Mirzadeh1, M. Khorasani1 and P. Sammes2

(1) Iran Polymer Institute, Tehran, I.R. Iran

(2) Department of Chemistry, Brunel University, Uxbridge, Middlesex UBH 3PH, UK

 

ABSTRACT

 

Surface modification of polydimethylsiloxane (PDMS) based vulcanizate by CO2‑pulsed laser was studied. The modified surfaces were characterized using a variety of techniques including scanning electron microscopy (SEM) combined with energy dispersive X‑ray analysis (EDXA), attenuated total reflectance infra‑red spectroscopy and the water drop contact angle analysis EDXA and SEM showed that all of the treated PDMS surfaces contained a higher ratio of O/Si than the base polydimethylsiloxane and the surface morphology of the treated samples were significantly changed. The friction coefficient of the modified silicone drastically decreased. Data from in vitro blood compatibility assessments indicated a significant reduction of platelet adhesion and aggregation for the modified surfaces and those platelets which were adherent remained unspread. The extent of platelet adhesion was correlated to the number of laser pulses.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 15–21                                                                                                   ISSN: 1026-1265/1998

 

 

Application of Conducting Polyaniline Membranes (II):

 

Separation of H2SO4/H3PO4 and HNO3/H2SO4 Using

 

Dialysis, Electrodialysis and Electrodynamic Methods

 

A. Mirmohseni and A. Saeedi

Polymer Technology Research Laboratory, Department of Applied Chemistry, Faculty of Chemistry

University of Tabriz, Tabriz, I.R. Iran

 

ABSTRACT

 

In the pursuit to exploit a new application for conducting electroactive polymers, polyaniline membrane has been successfully employed to separate two acidic mixtures (H2SO4/H3PO4 and HNO3/H2SO4). The ability of the membrane to electrochemical control of the selectivity factor, and the flux values have been demonstrated using three different methods of dialysis, electrodialysis and electrodynamic. Using dialysis method the acids have been separated. An electrical gradient (electrodialysis) has been applied across both sides of the membrane and separation is also achieved with the increase of the flux value but the selectivity factor slightly decreases. When the separation of acids is carried out using the new method of “electrodynamics”, in which an oxidative potential is applied directly to the polymer membrane, the selectivity factor increases significantly. This is a method that offers the possibility of selective and controllable transport and separation of acids.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 23–32                                                                                                   ISSN: 1026-1265/1998

 

 

Polymerization of 7,12‑Bis(2‑hydroxyethyl)benzo[k]-

 

fluoranthate with Aromatic Diacid Chlorides

 

S.E. Mallakpour and F. Rafiemanzelat

Organic/Polymer Chemistry Research Laboratory, College of Chemistry, Isfahan University of Technology, Isfahan 84156, I.R. Iran

 

ABSTRACT

 

7,12‑Bis(2‑hydroxyethyl)benzo[k]fluoranthate (BHBF) was prepared from benzyne intermediate in four steps. Polycondensation of BHBF with isophthaloyl dichloride and terephthaloyl dichloride was performed by solution as well as interfacial techniques. The solution polymerizations were performed in chloroform and in DMAc (N,N'‑dimethylacetamide)/chloroform system, in the presence of pyridine or triethylamine at room or refluxing temperature. The interfacial polymerizations were performed by DMAc/cyclohexane, an organic/ organic system, in the presence of pyridine or triethylamine at room temperature. The above polymerization reactions lead to the formation of novel aromatic polyesters having benzo[k]fluoranthene moieties in the main chain. The resulted polyesters show intense violet fluorescence property and were characterized by IR, 1H NMR, UV, DSC and the elemental analyses. The fluorescence excitation and emission spectra of the monomer BHBF and one of the polyesters (PS2) were also studied. Some physical properties of these novel polymers are also reported.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 33–40                                                                                                   ISSN: 1026-1265/1998

 

 

A Theoretical Study of Free Volume Effect on Phase Stability of

 

Hydrogen Bonded Polymer Mixtures by Lattice Fluid Theory

 

M. Taimoori1, H. Modarress1 and G. Mansoori2

(1) Faculty of Chemical Engineering, Amir Kabir University, Tehran, I.R. Iran

(2) Department of Chemical Engineering, The University of Illinois at Chicago, Chicago, Illinois 60607–7007, U.S.A

 

ABSTRACT

 

Strong intermolecular forces such as hydrogen bonds between repeating units of polymer molecules cause association of polymer chains and affect the phase behaviour of polymer‑polymer mixtures. In this work, the phase behaviour and miscibility regions of hydrogen bonded polymer mixtures are calculated by a new model based on the lattice fluid theory of mixtures. In this model, the compressibility or free volume effect of the mixture which is originated from empty lattice sites is considered by introducing a new correlation for the number of vacant sites. The spinodal curves are calculated for the mixtures and it is shown that as expected from the theory, higher compressibility causes lower stability and consequently the phase separation.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 41–46                                                                                                   ISSN: 1026-1265/1998

 

 

Phase Transfer Catalysis in Polycondensation Processes (XX):

 

Polyethers Containing an Oxetanic or Propylenic Spacer with

 

Potential Liquid Crystalline Properties

 

O. Catanescu1, N. Hurduc1, D. Scutaru1, I. Radu2 and C. Simionescu1

(1) “Gh. Asachi” Technical University, Department of Macromolecules, Bd. Copou 11A, 6600-Iasi, Romania

(2) “P. Poni” Institute of Macromolecular Chemistry, AL. Gr. Chica-Voda, 6600-Iasi, Romania

 

ABSTRACT

 

The present paper studies the influence of chains chemical structure on the ordering capacity of a series of copolyethers obtained from 3,3‑bis(chloromethyl)oxetane or 1,3‑dibromopropane and five types of bisphenols, as follows: 2,7‑dihydroxynaphthalene, 4,4'‑dihydroxyazobenzene, 4,4'‑dihydroxydiphenyl, 1,1‑bis(4'‑hydroxyphenyl)cyclohexane and 2,2‑bis (3'‑methyl‑4'-hydroxyphenyl)propane. The polymers are synthesized by phase transfer catalysis technique and characterized by 1H NMR, DSC and optical microscopy in polarized light. Theoretical conformational analysis, using a computer MMX‑88 programme, is performed, as well. The liquid crystalline polyethers behaviour is the most important property investigated. Only the polymers containing azobenzene and naphthalene units present a mesophase, but the transition temperatures are too high for a correct characterization.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 47–52                                                                                                   ISSN: 1026-1265/1998

 

 

Chemical Modification of Serum Globulins Recovered from

 

Slaughterhouse Waste and its Partial Characterization

 

C. Rose, T.P. Sastry, V. Madhavan and R. Rajaraman

Central Leather Research Institute, Madras 600 020, India

 

ABSTRACT

 

Bovine serum which is hitherto wasted was collected and the globulins were separated by polyethylene glycol precipitation. The globulins obtained were graft copolymerized with N,N'‑dimethylethyl methacrylate using potassium persulphate and sodium metabisulphite as a redox initiation system. The graft copolymer prepared was cross‑linked with glutaraldehyde and it was casted as a film. The film was characterized for the modification in the structure of protein, the thermal decomposition pattern, and for the mechanical properties. The infra‑red spectrum showed the grafting of polymer onto the protein, whereas, the thermogravimetric analysis results confirmed this process by exhibiting increased thermal stability of the graft.copolymer. Globulins separated were able to form films after graft copolymerization, and acquired some mechanical properties which were characterized by measuring the tensile strength and elongation at break.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 53–58                                                                                                   ISSN: 1026-1265/1998

 

 

Tensile Properties and Scanning Electron Microscopy

 

Examination of the Fracture Surface of Oil Palm

 

Wood Flour/Natural Rubber Composites

 

H. Ismail and H.I. Nurdin

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

 

ABSTRACT

 

Tensile properties and scanning electron microscopy examination of the fracture surface of oil palm wood flour/natural rubber composites have been studied. Tensile modulus of the composites increases with oil palm wood flour concentration, whereas, tensile strength and elongation at break show the opposite trend. The adhesion between oil palm wood flour and rubber matrix can be enhanced by the use of various bonding agents. The improvement in interfacial interaction between oil palm wood flour and rubber is substantiated by means of scanning electron microscopy.

 


Iranian Polymer Journal / Volume 7 Number 1 (1998) 59–65                                                                                                   ISSN: 1026-1265/1998

 

 

Branching in Radical Polymerization of Acrylamide

 

M.H. Rafíee Fanood

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

 

ABSTRACT

 

Acrylamide was polymerized at 40 and 80 °C in presence of 4,4'‑azobis‑4-cyanovaleric acid by radical polymerization, to high conversions. The polyacrylamides were isolated by precipitation in methanol. After drying, the limiting viscosity numbers, [h], and apparent molecular weights of polyacrylamides were determined viscometrically by several empirical equations, in distilled water and also by GPC. The dependence of limiting viscosity number on percentage conversion is discussed, and the significance of polymer branching at 40 and 80 °C is assessed.