Iranian polymer journal
No. 1407, 2005

Water-soluble polymers have gained a great importance in oil and gas producing industry because they are widely used in many technological processes and operations including drilling of wells. Among them, iron containing ones are not so numerous but they also attract much attention due to such interesting properties as tendency to swelling, complexation capacity, magnetic susceptibility, etc.. In this work, studies are made on the possibilities of obtaining new water-soluble iron-containing polymers based on acrylic acid (AA) and propylene oxide (PO) which are significant industrial products. Thus, the new water- soluble iron-containing copolymers have been synthesized by using the neutralization and radical copolymerization reactions. Iron content in these copolymers has been determined by using atomic absorption spectroscopy. Magnetic measurements by Faraday method have confirmed showed that the obtained copolymers are ordinary paramagnetics and the existing iron in them has an oxidation state of +3. Potentially they find application as insulating agents upon drilling of oil and gas wells and as magnetic indicators.

Acontinuous process for the polymerization of acrylamide and hydrolysis of functional groups in alkaline condition has been carried out. It was found that acrylamide may be polymerized and hydrolyzed in a single consequential step, whereby, both degrees of polymerization and hydrolysis can be carefully controlled. The hydrolysis of polyacrylamide up to 10 and 60% degrees was facilitated in suitable amount of different alkalines. The degree of hydrolysis of samples was determined by a back titration method. We have found that sodium carbonate as an hydrolyzing agent, also acts as a retarder and its addition to polymerization solution reduces the rate of polymerization reaction. The measured molecular weight of samples shows that we have reached a high molecular weight (about 12 million) and excellent water solubility. Another interesting result obtained is that the copolymer solutions showed a non-newtonian shear thinning behaviour. On the other hand, the associative behaviour is observed between the samples.

In this paper, the adaptive kinetic network model for describing the rheological propertiesof structured fluids has been made, which can be used to predict the change of the viscosity and entanglement density for molten low-density polyethylene (LDPE) in parallel superposition vibration force field upon steady shear flow. Recently, our new capillary dynamic rheometer has been developed, which is based on the capillary rheometer with invariable speed, and its equipment''s physical model has good agreement with the pulsating extrusion process of round-section die in the condition of electromagnetic dynamic extrusion, and one of the key technologies is that the mechanical vibration force field caused by an electromagnetic field is introduced into the whole plasticating and extrusion process. Through comparing theoretical result with transient experimental data, the theoretical viscosity values and experimental values are reasonably in good agreement, and the changing amplitude of the viscosity increases with the vibration frequency or amplitude increasing, and the effects of vibration frequency or amplitude on the experimental viscosity and the theoretical viscosity are also accordant. Therefore, the precision of our extended kinetic network model for polymer melt in parallel superposition vibration force field upon steady shear flow is reasonable. Lastly, the change of entanglement density for polymer melt in vibration shear field is studied. As a result, when the vibration frequency or amplitude increases, the entanglement density decrease obviously, while the decreasing amplitude of the 1 entanglement density and the change amplitude of the viscosity increase.

In this work, we have synthesized poly vinyl(alcohol-co-3-chloropropionate), (PVA-co- PV3CPr) by reaction between 3-chloropropionic acid and polyvinyl alcohol (PVA) in presence dicyclohexyl carbodiimide (DCCI) and (dimethylamino)pyridine (DMAP). Then 1,4-phenylene diamine was added and poly[vinylpropionate-co-3-(N-p-aminoaniline) propionate], (PVPr-co-P3NPAAPr) was prepared. This polymer dissolved in solution of chloroform/toluene containing polyvinylpyrolidone. Then sufficient fresh aniline was added to the solution and stirred at temperature 0-5oC. To continue, we added solution of ammonium persulphate, p-toluenesuphonic acid in water drop by drop by a dropping funnel. The solution was diluted with warm DMF and filtered under vacuum and then precipitated to ice methanol and produced polyvinylpropionate-graft-polyaniline, (PVPr-g-PANi). This polymer was doped in NMP or warm DMF solution with camphorsulphonic acid (CSA), p-toluenesulphonic acid (PTSA), dodecylbenzene sulphonic acid (DBSA) ormethansulphonic acid (MSA) and then produced their films by casting method. The electrical conducting charges versus dopants concentration, doping time and doping temperature were determined. Electropolymerization carried out by coating (PVPr-co-P3NPAAPr) on surface GC disk electrode, then grew graft copolymer (PVPr-g-PANi) inpresence of fresh aniline and acidic solution. Electrical conductivity of copolymer havebeen studied by a four-probe method and conductivity of 4.6 × 10-2 S/cm was achieved.

Accelerated ultraviolet weathering of unplasticized poly(vinyl chloride) (UPVC) filled composites with different filler contents of oil palm empty fruit bunch (EFB) was studied. The unfilled and filled composites samples were manufactured by dryblending PVC, EFB fillers and other additives in a heavy-duty laboratory mixer. The dryblended compounds were then two-roll milled and hot pressed into samples. The composites samples were exposed to cyclic ultraviolet fluorescent lamps/condensation for 504 h of accelerated weathering. Each assessment consisted of SEM analysis, impact and flexural testing, visual inspection and FTIR analysis. The experimental results indicated that EFB fillers accelerated photo-oxidative degradation of the UPVC matrix. Although filled composites exhibited greater discolouration than unfilled composites, their impact and flexural properties changed only slightly after accelerated weathering.

Epoxy resins are considered as one of the most important classes of thermosetting polymers for many industrial applications, but unfortunately they are characterized by a relatively low toughness. In this respect, many efforts have been made to improve the toughness of cured epoxy resins by the introduction of rigid particles, reactive rubbers, interpenetrating polymer networks and thermoplastics within the matrix. In this work, hydroxyl-terminated polybutadiene (HTPB) as a modifier, firstly, was crosslinked by variable content of divinylbenzene (DVB) in the presence of epoxy resin (ER) and then the modified matrix was cured with 1-methylimidazole as a curing agent. Infrared spectra showed the existence of a chemical reaction between modified HTPB (MHTPB) and the ER. Most of the tensile properties attained a peak at an approximately 20 phr (part per hundred rubber) DVB content, where the toughening reached its maximum. For both notched and un-notched specimens, a two-fold increase in izod impact strength was obtained by the addition of just 20 phr DVB compared to the neat resin. On the addition of DVB, the Izod impact strength varied from 0.54 to 0.71 kJ/m2 for notched specimens and from 1.43 to 6.66 kJ/m2 for un-notched specimens. Whereas, KIC varied from 1.35 to 2.59 MPa.m1/2 with increasing DVB content. By SEM analysis the average diameter was found to be about 5 μm (corresponding to maximum of toughness) for modified rubber particles. The overall results have shown that it is possible to obtain an excellent impact strength and good mechanical properties with the use of MHTPB as a tougheningagent for the epoxy resins.

Chitosan microspheres have been prepared for insulin controlled release delivery. After preparation of insulin chitosan microspheres by emulsification-cross linking process, the effects of chitosan quantity (200-400 mg) and citric acid concentration as a cross-linking agent (70-140 mg) were studied on the morphology, particle size, loading efficiency, flow and release of insulin from the microspheres. Mean particle size was 35-44 μm, insulin loading and preparation efficiency of microspheres were between 4.7-6.8% w/w and 70%, respectively. In microspheres containing citric acid, drug release followed the Higuchi model while in its absence a non-Fickian mechanism was dominant. Citric acid had no effect on stability, particle size, production efficiency and flow of the microspheres while decreased the loading efficiency. Increasing the chitosan content, increased particle size and release parameters like T50% (time required to release 50% of drug) and MDT (mean dissolution time). The increase of citric acid, increased DE8% (dissolution efficiency up to 8 h) of insulin but decreased the T50% and MDT. The results showed that not only citric acid does not cause reduction of release rate of insulin from chitosan microspheres but in fact accelerates the release rate.

Zinc acrylate has been synthesized by reaction of zinc oxide and 3N aqueous solution of freshly distilled acrylic acid. Cobalt (II) acrylate was prepared by the reaction of sodium acrylate with cobalt (II) acetate in methanol medium. Both monomer salts have been polymerized in methanol solution using α,αí-azodiisobutyronitrile (AIBN) as initiator at 60oC. Thermal behaviour of these materials has been studied under programmed heating at 10oC per min under dynamic nitrogen atmosphere by using differential thermal analysis (DTA) and thermogravimetry (TG) and in vacuo using thermal volatilization analysis (TVA). The degradation products including the gaseous, volatile liquid and cold ring fraction (CRF) from TVA degradation were investigated by IR spectroscopy, mass spectrometry, and GC-MS techniques, the volatile product fraction having first been separated by subambient TVA. Quantitative measurements of the main product fractions have also been made. The decompositions of these materials show some similarities to the behaviour of the alkaline earth metal salts of respective acid, but there are also important differences. Carbon dioxide is the most important volatile product and, in addition, there are various other carbonyl containing products. More carbon dioxide, resulting from side group scission, is evolved from cobalt (II) polyacrylate than from zinc polyacrylate due to lower thermal stability of it.

Unmodified polyester fibres can only be dyed with disperse dyestuffs either with the aid of carriers at 100oC (no longer desirable due to environmental limitations), or at elevated temperatures (130oC for the exhaustion processes and 210oC for the thermosol processes). The economical production of wash-fast, light-fast and sublimation- fast, red and bluish-red dyeings on polyester fibres with azo disperse dyestuffs is not easily achievable. The aim of the present study was to synthesize new dyestuffs based on various 4-aminonaphthalimide derivatives in order to achieve the above mentioned goals. The use of various 4-aminonaphthalimide derivatives as diazo components and β-naphthol as the coupling component gave a series of bright red dyeings on polyester fibres. The use of N,N-diethyl-m-toluidine as a coupling component together with the same diazo components gave bright bluish-red dyeings on polyester fibres. Using Npropyl- 4-aminonaphthalimide as an azo component and p-amino acetophenone as a coupling component gave a yellowish-cream dyed polyester fibres. Spectrophotometric studies on polyester fibres, showed that the attained dyeings had good tinctorial strength and high colour build up on polyester fibres. The dyeings also gave perfect wash fastnesses, very good to excellent sublimation fastnesses and very good light fasstnesses.