Chemical Modification Of PVC Research Articles

Synthesis and characterization of functionalized modified PVC-chitosan as antimicrobial polymeric biomaterial

Amino acetic acid modified poly(vinyl chloride), MPVC, was obtained by chemical modification of PVC using glycine methyl ester. MPVC was used as a precursor to prepare some functionalized MPVC conjugates to be used in biomedical applications. MPVC-Cs was prepared by the chemical reaction of MPVC with chitosan as a natural polymer in absence and presence of epichlorohydrin (Ech) as a crosslinking agent. Further chemical modification was performed by the reaction of MPVC with Cs and salicylic acid in the absence in presence of Ech via one-pot reaction. The chemical structure of the formed MPVC, MPVC-Cs, MPVC-Cs/POH, MPVC-Cs/SA and MPVC-Cs/POH/SA was confirmed by the FTIR spectroscopic analysis, scanning electron microscopy, and thermogravimetric analysis (TGA). The antibacterial activity of the prepared MPVC and its conjugates was investigated against two Gram +ve bacteria (Staphylococcus aurous and Listeria monocytogenes) and (Escherichia coli and Salmonella typhi) as Gram −ve bacteria in addition to the Catondida albicans as yeast. Minimum inhibition concentration (MIC) was also determined for the prepared materials.

Modification of PVC with captopril and complexation reaction for preparing photostability and thermal stability of PVC

Many chemical changes have been made to poly(vinyl chloride) (PVC) in order to enhance its photo-stability features, the use of PVC in new applications, and the study of PVC-related phenomena. The chemical modification of PVC using captopril as a modifying agent is described in this paper. Infrared spectroscopy and energy dispersive X-ray analysis was used to characterize the modified polymer. Metal salts (HgCl2, CoCl2, ZnCl2, NiCl2, and CdCl2) were used to react with the modified film and form polymeric complexes. FTIR, weight loss percentage, AFM, EDX, and SEM approaches were used to analyze polymeric films that had been exposed to UV radiation for 300 hrs. The modified PVC complexes films have shown excellent stability against photo-degradation even after 300 h of irradiation by UV light. Thermogravimetry (TGA) was used to evaluate the thermal characteristics of the modified polymers, which demonstrated that the synthesized polymer complexation showed good thermal stability.

Enhancement of the photo-chemical properties and efficacy of the mixing technique in the preparation of Schiff base-Cu(II)/poly(vinyl chloride) compounds

A new Schiff base containing the 1,2,4-triazole ring system (L) was synthesized and confirmed by FTIR spectroscopy. The chemical modification of PVC with a new Schiff base (L) was synthesized to produce a homogenous blend (PVC-L). A homogenous blend (PVC-L) was added to copper chloride to produce PVC-L-Cu(II). The PVC films had been irradiated with ultraviolet light for a long period and confirmed by FTIR spectroscopy and weight loss; the surface morphology was inspected by scanning electron microscopy.

Impact of stabilizer on the environmental behavior of PVC films reinforced 1,2,4-triazole moiety.

A new Schiff base containing 1,2,4-triazole ring system (L) was synthesized and confirmed by 1HNMR, FTIR spectroscopy. The chemical modification of PVC with a new Schiff base (L) was synthesized to produce a homogenous blend (PVC-L). A homogenous blend (PVC-L) was added to copper chloride to produce PVC-L-Cu (II). The PVC films had been irradiated with ultraviolet light for a long period and confirmed by FTIR spectroscopy and weight loss; the surface morphology was inspected by scanning electron microscopy.

Chemical modification of PVC with Schiff Base Containing a Thiadiazole Moiety and its Influence on the Physicochemical and Morphological Properties

Chemical modification of PVC with Schiff Base Containing a Thiadiazole Moiety and its Influence on the Physicochemical and Morphological Properties

Chemical modification of PVC by different nucleophiles in solvent/non-solvent system at high temperature

Chemical modification of polyvinyl chloride by nucleophiles is a versatile method for preparation of new functional polymers. Modification of PVC was carried out using different nucleophiles (Nu) in ethylene glycol (EG)/N,N-dimethylformamide (DMF) (1:1 by volume) solution. OH−, N3−, and SCN− were examined as nucleophiles in this study. The FTIR spectrum confirmed substitution of Cl by nucleophiles and also the elimination of HCl in the modification reaction of PVC. The glass transition temperatures (Tgs) of modified-PVC samples were in the order N3− > SCN− > OH− and were equal to 87.6, 86.8 and 78.15 °C, respectively. The T5% (the temperature at which weight loss is 5%) of PVC was 266 °C, while after 1 h modification by OH− it reduced to 197 °C. After alkaline modification, the scanning electron microscopy (SEM) images not only showed an increase in surface roughness and porosity, but also revealed a relatively large drop in average particle size from 160 to 80 µm. Molecular weight and molecular weight distribution were determined by gel permeation chromatography (GPC). The GPC results showed that the number average molecular weight (Mn) and weight average molecular weight (Mw) were decreased from 79,950 and 176,360 g mol−1 in crude PVC to 45,370 and 99,930 g mol−1, respectively, after 1 h modification by OH−. Alkaline treatment also decreased the mechanical strength of PVC.

Synthesis and characterization of pH responsive poly(vinyl chloride)

The dye coated textile fabrics are very much useful in the MRI and bio-imaging applications due to its versatile fluorescence behavior. Based on this concept, in the present investigation the non bio degradable and hydrophobic PVC was chemically modified by two different dyes such as safranine and rose bengal. The chemical modification of PVC can be confirmed by FT-IR, UV–visible, fluorescence, DSC, TGA and SEM analysis. By the structural modification through dyes, PVC was converted into hydrophilic as well as bio-degradable polymer. Under strongly acidic pH, the dye modified PVC becomes water soluble one. The surface morphology analysis confirmed the formation of nano particles in the interface region of hydrophobic PVC and hydrophilic dye molecule and hence suitable for drug releasing applications. Ultrasonic velocity, compressibility and refractive index of the PVC before and after structural modification were determined and the results were critically compared.

Upgrading of poly(vinyl chloride) by chemical modifications using sodium sulfide

The recycling of poly(vinyl chloride) (PVC) is one of the most important issues in the treatment of waste plastics. To improve PVC recycling, it is necessary to develop new recycling techniques, including new techniques for the dechlorination of chlorine-containing polymers. It has been established that wet dechlorination of PVC in NaOH/ethylene glycol solution is more effective than dry dechlorination. In this study, the wet process was used, and the chemical modification of PVC by nucleophilic substitution was considered for upgrading waste PVC. Chlorine was substituted in solution by several nucleophilic reagents, thus changing the properties of PVC. The reaction of PVC in Na2S/ethylene glycol solution at 170°C resulted in the formation of a mixture comprising 32% elimination and 26% substitution products. The scanning electron microscopy/energy dispersive X-ray spectroscopy mappings and elementary analysis of PVC indicated that this chlorine-substitution process led to cross-linking by sulfur.

Chemical modification of PVC into polymer‐supported oxazolinones and triazoles

AbstractPVC (P1) was converted into polymer‐supported oxazolinone and triazole derivatives after sequential chemical assembly of the reactive groups onto PVC. First, poly(vinyl chloride‐co‐vinylaminoaniline) (P2) was prepared by the reaction of PVC with p‐phenylenediamine. The primary aromatic amino group in P2 was diazotized and reacted with hippuric acid to form the supported oxazolinone derivative (P3) which could be converted into supported triazole derivatives (P4)–(P6) on further interaction with substituted anilines. The involved ring opening and preferred cyclization reactions have been clearly addressed based on spectroscopic and elemental analyses of the products. Also the ability for metal uptake has been roughly tested through the interaction with Cu(II) ions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2304–2309, 2007

Bacterial adhesion to poly(vinyl chloride) films: Effect of chemical modification and water induced surface reconstruction

Escherichia coli (E. coli) and Staphyloccus aureus (S. aureus) bacteria adhesion to pure and modified poly(vinyl chloride) (PVC) was investigated through classical wettability measurements, captive bubble time dependent measurements, and static adhesion tests. Various chemical modifiers were studied, namely 4-mercaptophenol, 4-mercaptobenzylalcohol, 4-methoxybenzenethiol, 2-naphthalenethiol and 4-mercaptopyridine. The surface thermodynamics of the modified PVC films was investigated via the van Oss, Chaudhury and Good (vOCG) theory and an increase in the hydrophilic character was deduced from the increase of the contact angle of the air bubble in water with time of immersion. This is ascribed to a water induced surface reconstruction of the modified PVC surface. E. coli bacteria exhibit a hydrophilic character and strong adhesion, dependence on the nature of the PVC modifier as shown by the remaining attached bacteria. S. aureus which is hydrophobic showed no difference in its adhesion to pure or modified PVC. A slight increase in the adhesion of E. coli is observed with the water induced surface reconstruction. This work highlights the predominance of the hydrophilic/hydrophobic nature over the acid–base in the bacteria/polymer adhesion mechanism. It also provides, through chemical modification of PVC, a nice route to control the micro-organisms' adhesion to biomedical devices.

PVC modification with new functional groups. Influence of hydrogen bonds on reactivity, stiffness and specific volume

The chemical modification of PVC with new bifunctional thiol compounds is reported. Aliphatic as well as aromatic reactives were tested and the influence of protic and non-protic functionalities on reactivity was studied. The chemical structure of the polymers was analyzed using 1H NMR spectroscopy. The structural changes in the modified samples were monitored by means of density and T g determinations, which are a measure of interchain spacing and chain stiffness. While protic functionalities lead to polymers with strongly enhanced T g values indicating a considerable stiffening of the system due to physical interaction by hydrogen bonds, the softening-point temperature of PVC modified with non-protic substituents does not change very much. The interchain spacing of the polymer is not significantly altered by the presence of mobile hydrogen in the polymer.

Vinylamine polymer via chemical modification of PVC

Chemical modification of PVC using NaNO 2 in THF/DMSO(1:1) or DMF/DMSO(1:1) solutions has been achieved without appreciable discolouration. Transformation yields as high as 73% have been attained at room temperature with long reaction times. The modified polymer is not explosive under the conditions studied and has a CC unsaturation content of less than 10%. Interestingly, GPC analysis indicates that appreciable chain scission occurs and typically the molecular weight is reduced from 73700 to 12000 during chemical modification. Reduction of the resulting polymer with hydrazine hydrate in the presence of Pd(10%)–C catalyst gives a water-soluble vinylamine-derived polymer.

Synthesis and characterization of comb-like polymer PVC-poly(ethylene oxide)

A new series of amphiphilic graft-copolymers, composed of poly(vinyl chloride) (PVC) backbones and poly(ethylene oxide) side chains, was synthesized by chemical modification of PVC. The synthesis was based on the reaction between chlorine in PVC (polymerization degree 700) and sodium salt of polyethylene glycol (PEG). PEGs with molecular weights of 200 and 600 were used. The graft polymers were characterized by IR and gel permeation chromatography and the molecular parameters such as the average numbers of grafting chains on the PVC backbones were calculated as well as the grafting percent. The molecular weights of PEG were found to influence the rate of the grafting reaction and the final degree of conversion. The maximum grafting percentage of the resulted polymers after the purification was ca. 34%, regardless of the molecular weight of PEG. No gel was observed in the PVC-g-PEOs, in spite of the average numbers of grafting chains up to 32. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 475–479, 2000

Vinylchloride copolymers obtained by chemical modification of PVC

Vinylchloride copolymers obtained by chemical modification of PVC

PVC modification with bifunctional thiol compounds

The chemical modification of PVC with bifunctional thiol compounds is reported. Aliphatic as well as aromatic compounds were tested under different reaction conditions. The modified PVC's were studied by IR and H-NMR.

Chemical Modification of PVC with Phenolic Groups

Abstract The reaction of poly(vinyl chloride) with phenol was studied without catalysts at temperatures between 60 and 182°C. The reaction products were analyzed by NMR, IR and UV spectroscopy, elemental analysis, viscometry, osmometry, and OH groups determinations. The content of phenolic groups bound to polymer chain increased with the reaction temperature. At the same time, some scissions of macromolecular chains can occur.

Chemical modification of PVC

ABSTRACT The degradation of PVC at a processing temperature is mostly caused by its abnormal and unstable molecular structures. It has been pointed out that its allyl chloride structures play a significant role as the abnormal and unstable structures. Inasmuch as the allyl chloride structures are markedly more chemically active than the normal structure, the selective chemical treatments are applicable to the allyl chloride structures. The thermal stability of PVC can be remarkably improved by treating PVC with certain organo-aluminium compounds or protic solvents. Concretely, the results of analyzing the reaction mechanism with the low molecular model compounds of PVC or the tracer show that the selective stabilizing reaction on the allyl chloride structure takes place. On the other hand, the improvement of the mechanical properties of PVC, such as softening temperature, rigidity, anti-creep property, impact strength and tensile strength, is important for practical applications of PVC.