Modification Of Polyvinyl Chloride Research Articles

Modification of polyvinyl chloride by organic molecule for the improvement of its thermal stability

Modification of polyvinyl chloride by organic molecule for the improvement of its thermal stability

Synergistic Modification of PVC with Nitrogen-Containing Heterocycle and Tung-Oil Based Derivative for Enhanced Heat Stabilization and Plasticization Behavior

The additives present in polyvinyl chloride (PVC) materials are the major source of organic by-products during PVC degradation. The thermal stabilizer and plasticizer are the main additives that endow PVC with the required properties during its processing. However, these two additives easily migrate when samples are obtained by physical mixing of the additives with PVC. This causes the reduction of PVC sample efficacy and the increase in the formation of organic by-products in the radiolysis process. In this work, two kinds of grafted PVC samples (tung-oil derivative grafted PVC and Atz grafted PVC, abbreviated as P-GT4 and P-AZ3) were synthesized by chemical grafting of 3-amino-1,2,4-triazole (Atz) and tung-oil derivative on PVC, respectively. These two PVC samples were then blended at different mass ratios to obtain hybrid PVC materials with excellent plasticization, thermal stability and migration resistance ability. Differential scanning calorimetry (DSC), discoloration, Congo red test and thermogravimetric analysis (TGA) showed that when the mass ratio of P-GT4 to P-AZ3 in the mixed PVC resin was 1:3, the resulting P1:3-GT4-AZ3 (P4) presented the best plasticization and thermal stability. The kinetics of thermal decomposition showed that the activation energy of P4 was much higher than that of the reference material [PVC/DOTP/CaSt2/ZnSt2, PVC/CZ41 for short] at mass loss α = 20% and 80%. In addition, the leaching test showed that P4 material possessed excellent migration resistance ability.

Heavy Metal Removal with NanoTiO2/Chitosan Modified Poly(Vinylidene Chloride)

Background: Heavy metal contamination of water resources has been identified as one of the most serious environmental issues. Chemical modification of hydrophobic polymer matrices is another approach for changing their surface properties for water treatment. The addition of nanoparticles to polymers alters surface characteristics such as adsorption capacity, adhesion, catalytic ability, and wettability to heavy metals in wastewater. Objective: Evaluation of the nanomodified polyvinyl chloride (PVC) polymer as a heavy metal adsorbent from wastewater. Methods: In the field of emission discharges from industries and domestic wastes that contain unknown inorganic pollutants by PVC using grafting chitosan/TiO2 nanocomposites. The characterization of different thin films was performed using TEM, XRD, and FTIR. The metal concentrations were measured by using inductively coupled plasma (ICP-OES). Results: Nanomodification of PVC was evaluated by infrared spectroscopy. The presence of chlorine in the PVC structure before and after the nanomodification is confirmed by the presence of a peak at 690 cm-1 attributed to the axial deformation of the C-Cl bond. The nanomodified PVC showed an ion exchange capacity of 1.27 mmol-1 , and efficiently removed the heavy metals from aqueous solutions. The heavy metal removal effectiveness (R) was improved by increasing the concentration of TiO2 nanoparticles. The amount adsorbed per gram of adsorbent (Qe) was computed and revealed that the amount of adsorption increased for nanomodified PVC thin film as compared to 100% PVC thin film. The nanomodified PVC thin film showed high stability for 4 cycles of use. This improvement has been attributed to the nanomodified PVC polymer's large surface area (ranging from 0.3 to 282 m2 /g). Conclusion: The modification of PVC with nanoparticles increases the cost of PVC thin film by 15%. However, it offers efficiency 3 times than the original PVC.

Preparation and properties of 4-aminobenzoic acid-modified polyvinyl chloride/titanium dioxide and PVC/TiO2 based nanocomposites membranes

In this work, polyvinyl chloride (PVC) and 4-aminobenzoic acid (4ABA) modified PVC and titanium dioxide (TiO2) nanocomposites were prepared by solution blending method. TiO2 was added to PVC (0.5 g) at 0.01, 0.03, 0.05 and 0.1 g. PVC matrix was modified using 4-aminobenzoic acid (4ABA). Fourier transform infrared (FTIR) spectroscopy was used to confirm the modification of PVC with 4ABA. Scanning electron microscopy (SEM) images depicted homogeneous morphology of modified PVC/TiO2 nanocomposites. XRD results confirmed the formation of PVC/TiO2 nanocomposites. Moreover, the thermal decomposition temperature T10 (10 Wt. % weight loss) of non-modified PVC was 189°C however, modified PVC nanocomposites membranes had 196°C with similar TiO2 content. Furthermore, modified PVC-TiO2 with 0.05 g loading showed homogenous morphology with higher hydrophilicity as determined by porosity, solvent content, and shrinkage ratio. Modified PVC/TiO2 membrane with a lower contact angle (32°) could be used for water purification purposes. These studies suggest that optimum modifier concentration improved the interaction between PVC and TiO2.

Influence of polystyrene modifier on features of polyvinylchloride plastics production

The main methods of physical modification of PVC materials is the combination with other polymers, including PS plastic, and the creation of polymer (nano) composites containing metal and silicate fillers. Modification of polyvinyl chloride by polystyrene plastic leads to obtain materials with reduced degree of plasticizer release out of matter volume, adjustable elastic-plastic characteristics, and enhanced physico - mechanical and thermal properties. Physical modification of vinyl chloride polymers by other polymers or nanoscale particles of inorganic nature enables predictable affect on the morphology of these materials and directed regulate their technological and performance properties.

Modification of polyvinylchloride by the silicates on the base of rice husk

As a modifying additive in PVC-compositions, silicates produced by means of rice husk processing are of practical interest. Rice husk ash obtained by burning at 350°C, along with synthetic and naturally occurring wollastonite, significantly reduce plasticizer’s migration from the PVC-composition due to their porosity. This is due to the fact that the part of hydroxyl components of the plasticizer EDOS has adsorbed on the surface or retained by the silicates pores. Along with that, Miwoll 10-97 ensures a greater decrease in plasticizer’s migration than synthetic calcium silicate on the base of rice husk ash. When all the researched silicates are modified by the rice husk and naturally occurring wollastonite, heat stability of PVC-compositions grows. This is preconditioned by the alkaline origin of the surface of filling compounds that allows their possible reaction with chlorine hydride released from PVC during thermal decomposition. Synthetic and naturally occurring wollastonite enhance strain-strength properties of PVC-compositions whereas silicates on the case of rice husk reduce these parameters.

Synthesis, characterization and in-vitro antimicrobial evaluation of thermally and photostable Schiff base-modified PVC/nanocomposites

Two Schiff base derivatives, 4-[(2, 5-dimethoxy phenylimino)-methyl] phenol, SB1 and 4-[(2-hydroxy benzylidine)-amino] phenol SB2, have been prepared and used as modifiers for polyvinyl chloride (PVC). Chemical modification of PVC was performed using these Schiff bases in presence of AgNO3 to obtain two modified PVC nanocomposite, PVC-SB1/AgNPs and PVC-SB2/AgNPs, and their chemical structures were confirmed by FTIR, 1H-NMR, 13C NMR and Mass spectroscopy. Scanning and transmission electron microscopy were performed for the modified polymer nanocomposites. The SEM and TEM micrographs of PVC-SB/AgNPs showed homogeneous surface polymeric matrix with uniform distribution of AgNPs, and their diameters are in the nanoscale. Moreover, thermal and photostabilities as well as mechanical properties of the modified polymer nanocomposites were also investigated. Moreover, mechanical properties of PVC-SB/AgNPs were also investigated. Antimicrobial activity of the modified PVC was evaluated against two Gram +ve bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram -ve bacteria (Escherichia coli and Pseudomonas aeruginosa) as well as Candida albicans as fungus.

Chemical modification of polyvinyl chloride with thiourea

The quasi-homogeneous (“synthesis in gel”) conditions for functionalization of polyvinyl chloride (PVC) with thiourea were experimentally selected. It was found that the best solvent for the formation of PVC gel is DMF, ensuring formation of the gel in the range of polymer concentrations from 10 to 30%. The composition of the products was characterized by elemental analysis data, the specific features of their structure were established by Fourier-transform IR spectroscopy and thermogravimetry. It was shown that thiourea reacted with PVC as an N-nucleophile to form thiocarbamoyl groups in the polymer structure. The maximum achieved total degree of functionalization was 0.31. The reaction was accompanied by cross-linking and partial dehydrochlorination.

Graft modification of polyvinyl chloride with epoxidized biomass-based monomers for preparing flexible polyvinyl chloride materials without plasticizer migration

Cardanol glycidyl ether, epoxidized acetylated castor oil methyl ester, and epoxidized soybean oil were grafted on polyvinyl chloride (PVC) chains to obtain flexible PVC materials. The structure and properties of graft modification of PVC materials were investigated. The glass transition temperature of graft modification of PVC with cardanol glycidyl ether, epoxidized acetylated castor oil methyl ester, and epoxidized soybean oil was 42.1 °C, 43.8 °C, and 37.9 °C, respectively. The mechanical properties illustrated that graft modification of PVC materials were more flexible than PVC. The extraction tests showed that the modified PVC materials presented no migration in n-hexane and can be used to prepare flexible PVC products with high requirements of durability. The internal plasticizing mechanism was also discussed according to the free volume theory.

Chemically recycled polyvinyl chloride as a bitumen modifier: synthesis, characterisation and performance evaluation

Polyvinyl chloride (PVC) is one of the most widely produced thermoplastic polymer, used in the manufacture of a variety of valuable short and long life products. Nevertheless, the increasing demand for PVC and current ineffective disposal methods have made it a potentially severe environmental hazard. The chemical recycling of PVC through hydrolytic or aminolytic routes has shown significant promise, however, their end applications have been limited as of now. This study is concerned with the chemical modification of PVC by amines into additives, and its ensuing use as a performance enhancing modifier for bitumen. In view of this, additives were firstly synthesised by the amination of PVC with two kinds of polyamines; triethylenetetramine (TETA) and ethylene diamine (ED) respectively. These were then chemically characterised by solid state Nuclear Magnetic resonance (NMR) and elemental analysis. Subsequently, the aminated PVC additives were blended with virgin asphalt binder and its effectiveness was evaluated in terms of moisture susceptibility and rheological properties. The results of the preliminary laboratory studies indicated that the binders modified with the additives showed significantly improved anti-stripping properties and overall rheological performance as compared to conventional binder. Overall, the usage of such waste PVC based additives as modifier for bituminous mixtures represents an innovative approach to deal with a relevant recycling problem while simultaneously recovering a value-added material.

Chemically Modified Polyvinyl Chloride for Removal of Thionine Dye (Lauth's Violet).

The chemical modification of hydrophobic polymer matrices is an alternative way to elchange their surface properties. The introduction of sulfonic groups in the polymer changes the surface properties such as adhesion, wettability, catalytic ability, and adsorption capacity. This work describes the production and application of chemically modified polyvinyl chloride (PVC) as adsorbent for dyes removal. Chemical modification of PVC was evaluated by infrared spectroscopy and elemental analysis, which indicated the presence of sulfonic groups on PVC. The chemically modified PVC (PVCDS) showed an ion exchange capacity of 1.03 mmol−1, and efficiently removed the thionine dye (Lauth’s violet) from aqueous solutions, reaching equilibrium in 30 min. The adsorption kinetics was better adjusted for a pseudo second order model. This result indicates that the adsorption of thionine onto PVCDS occurs by chemisorption. Among the models for the state of equilibrium, SIPS and Langmuir exhibited the best fit to the experimental results and PVCDS showed high adsorption capacities (370 mg−1). Thus, it is assumed that the system presents homogeneous characteristics to the distribution of active sites. The modification promoted the formation of surface characteristics favorable to the dye adsorption by the polymer.

Novel modified poly vinyl chloride blend membranes for removal of heavy metals from mixed ion feed sample

Herein, an attempt has been made to prepare a novel membrane with good efficiency for removal of heavy metal ions namely lead (Pb), cadmium (Cd) and chromium (Cr). 4-amino benzoic acid (ABA) was covalently grafted onto the poly vinyl chloride (PVC) backbone by CN bond to enhance the hydrophilicity. 1H NMR and ATR-IR spectroscopy analysis confirmed the chemical modification of PVC. Further the modified polymer was blended in different compositions with polysulfone (PSf) for optimization. Morphological changes that occurred in blend membranes, due to the incorporation of modified PVC was studied by AFM and SEM techniques. The effect on hydrophilicity and performance of blends owing to incorporation of modified PVC was evaluated by water uptake, contact angle and flux studies. The density of functional groups in blends was analyzed by its ion-exchange capacity. Batch wise filtration of metal ions was carried out and the effect of pressure, feed pH and interference of ions was thoroughly investigated. Essentially, 100% rejection was obtained for all the metal ions in acidic pH with a productivity of 2.56l/m2h. The results were correlated with the results of commercially available NF 270 membrane under the same operating conditions.

An investigation on 4-aminobenzoic acid modified polyvinyl chloride/graphene oxide and PVC/graphene oxide based nanocomposite membranes

We synthesized graphene oxide (GO) using a modified Hummer’s method, and then blended it into polyvinyl chloride (PVC) and amino-functional PVC (PVC-4ABA) matrices. GO was added to 0.5 g PVC at 0.01, 0.05, 0.1 and 0.5 g. The PVC/GO matrix was modified using 4-aminobenzoic acid (4ABA) at 0.01, 0.05, 0.1 and 0.5 g per 0.5 g PVC. This gave four amino-functional PVC/GO series and one PVC/GO series nanocomposite membranes that were prepared by a solution blending route. The filler and the modifier (4ABA) content effect on the PVC membrane properties were investigated. Fourier transform infrared spectroscopy confirmed the GO functional groups and PVC modification with 4ABA. According to scanning electron microscopy, a unique two-way layered structure was observed for modified PVC and GO composites. XRD explained the conformation of PVC/GO and modified PVC/GO nanocomposites. GO crystallite size and its interlayer distance between sheets were also studied. The XRD peak at 2θ = 10.8° with interlayer spacing of 0.81 nm was calculated with the Bragg equation. GO particle size was calculated (Scherrer formula) as 7.78 nm. XRD results revealed fine interaction between modified PVC and GO compared with unmodified PVC composites. Glass transition temperature (Tg) of non-modified PVC/GO nanocomposite was 202℃, whereas modified nanocomposite with similar GO loading had Tg equal to 212℃. Higher filler content gave better hydrophilic membranes as determined by solvent content, porosity, and shrinkage ratio. PVC-4ABA-0.5/GO 0.5 membrane with a low contact angle (25°) is a fine option for water purification. The overall results suggest that the higher modifier concentrations developed better interaction between the nanofiller and PVC.

Buckypapers of 4,4′-oxydianiline-modified polyvinylchloride and functional nano-filler obtained by resin infusion method

This study provides information on the fabrication and characterization of polyvinylchloride (PVC) buckypaper composite using resin infusion method. PVC modified with 4,4′-oxydianiline (ODA) was infiltrated through buckypapers made of purified multi-walled carbon nanotubes (P-MWCNTs) and functionalized MWCNTs (F-MWCNTs). The increases in P-MWCNT and F-MWCNT contents were investigated on the physical properties of BP-PVC-ODA/PEG (polyethylene glycol)/P-MWCNT and BP-PVC-ODA/PEG/F-MWCNT buckypaper composites. Fourier transform infrared spectroscopy was used for the functional group confirmation which proved the PVC modification and functionality of MWCNTs. The scanning electron micrographs of BP-PVC-ODA/PEG/F-MWCNT showed that intercalation of cross-linked polymer with nanotube produced a polymer-coated F-MWCNT mesh. The maximum degradation temperature (T max) of functional composite BP-PVC-ODA/PEG/F-MWCNT 0.05 (484 °C) was higher than that of non-functional BP-PVC-ODA/PEG/P-MWCNT 0.05 (473 °C). The glass transition temperature (T g) of BP-PVC-ODA/PEG/F-MWCNT 0.05 was 225 °C, while BP-PVC-ODA/PEG/F-MWCNT 0.03 yielded a lower T g of 214 °C. Tensile strength of the functional buckypaper was also found to increase to 37.3 MPa with filler loading. According to X-ray diffraction, the amorphous character of buckypaper showed a trend towards crystal formation with filler loading. P-MWCNT-based buckypaper showed an electrical conductivity up to 4.12 × 10−1 S/cm; lower than the electrical conductivity of functional buckypaper (1.98 S/cm). The results demonstrated that the resin infusion technique was a successful method to achieve high performance buckypapers compared with F-MWCNTs.

Improvement in flux and antifouling properties of PVC ultrafiltration membranes by incorporation of zinc oxide (ZnO) nanoparticles

In this study, modification of polyvinyl chloride (PVC) ultrafiltration membranes with zinc oxide (ZnO) nanoparticle addition was taken into consideration. The ZnO at five different weights was added to the polymeric solution, and the membranes were fabricated by the phase inversion method using water as a nonsolvent and PEG 6 kDa as a pore former additive. The results showed that the pure water flux of the modified membranes increased up to 3 wt% ZnO addition, which was the optimized amount of the nanoparticle addition in this study. Also, at 3 wt% ZnO addition, flux recovery ratio reached from 69% to above 90%, indicated that the nanocomposite membranes were less susceptible to be fouled. BSA rejection of the membranes also enhanced up to 97% by 3 wt% ZnO addition. The membranes were further characterized by SEM images and remarkable changes in their morphologies were observed, and they became more porous with higher interconnectivity between the pores. Furthermore, EDAX analysis was applied to study ZnO dispersion in the membrane structure and except for 4 wt% ZnO addition which particles aggregation was noticeable, ZnO was dispersed finely in the membrane structure. In addition, the modified membranes had higher hydrophilicity and lower contact angle that was effective to obtain higher water flux.

Polyvinyl Chloride / Attapulgite / Micro-crystalline Cellulose (MCC) Composites Preparation and Analysis of the Role of MCC as a Compatibilizer

To improve the performance of polyvinyl chloride (PVC), composites incorporating polyvinyl chloride (PVC), attapulgite nanoparticles (ANPs), and microcrystalline cellulose (MCC) were successfully prepared. The composites had higher vicat softening temperatures (VSTs) and the MCC had a great influence on mechanical properties of the composites. When MCC was added from 0 to 5 per hundred parts of PVC (phr), the mechanical properties of the composites increased, but the mechanical properties of the composites decreased when the MCC was more than 5 phr. The tensile breaking stress, tensile strength, and impact strength were maximized with increases of 19.76 N (4.1%), 29.66 MPa (15.5%), and 13.8 MPa (7%) when 5 phr MCC was added. Infrared spectral analysis indicated that MCC and ANPs were present in the composites. Scanning electron microscopy showed that the composites system was distributed into two phases, which indicated that MCC in composites was dissolved in the PVC matrix, and some of MCC coated the surface of ANPs as a compatibilizer. Overall, this study provided a promising method for PVC modification to improve its performance.

Polyvinyl chloride modification with sodium salt of 2-thiobenzimidazole

Polymer analogous reaction has been used to partially substitute chlorine atoms of polyvinyl chloride with 2-thiobenzimidazole fragments. 13C NMR and IR spectroscopy studies have shown that the vinylene units are present in the modified polymer. The copolymer product has been used to prepare the membrane with proton conductivity of 1 × 10−2 to 0.04 S/cm at 25–195°C.

PVC modification with biobased poly(hydroxyalkanoates)

Supported by numerous calculated and empirical data, a miscibility between polyvinylchloride (PVC) and biobased poly(hydroxyalkanoates) (PHAs), PHAs along with its utilization in plasticization, toughening, and processing improvement is discussed in unplasticized and plasticized (semirigid to flexible) PVC compounds. The long-term thermal stability of PVC stabilized with BaZn salts is shown to be improved in the presence of PHAs and the short-term stability (initial color hold) slightly reduced. The biobased PHAs are also shown to improve UV stability of PVC by offsetting the yellowing of PVC and not causing additional photodegradation. The transparence and durability of PVC are found to be unaffected by the presence of minor phase of otherwise biodegradable PHA. The discussed PHAs offer a new, ecologically attractive, and simplified approach to PVC formulation in which multiple processing and modifying additives could be replaced with a single product, eliminating both undesirable additive interactions and the need to stabilize unstable ingredients. J. VINYL ADDIT. TECHNOL., 21:259–271, 2015. © 2014 Society of Plastics Engineers

Cell Adhesive and Antifouling Polyvinyl Chloride Surfaces Via Wet Chemical Modification

Polyvinyl chloride (PVC) is one of the most frequently used polymers for the manufacturing of medical devices. Limitations for its usage are based upon unfavorable surface properties of the polymer including its hydrophobicity and lack of functionalities in order to increase its versatility. To address this issue, wet chemical modification of PVC was performed through surface amination using the bifunctional compound ethylene diamine. The reaction was conducted in order to achieve maximum surface amination while leaving the bulk material unaffected. The initial activation step was characterized by means of various methods including contact angle measurements, colorimetric amine quantification, infrared spectroscopy, and gel permeation chromatography. Depth profiles were obtained by a confocal microscopic method using fluorescence labeling. Exclusive surface modification was thus confirmed. To demonstrate biological applications of the presented technique, two examples were chosen: The covalent immobilization of the cell adhesive Asp-Gly-Asp-Ser-peptide (RGD) onto PVC samples yielded a surface that strongly supported cellular adhesion and proliferation of fibroblasts. In contrast, the decoration of PVC with the hydrophilic polymer polyethylene glycol prevented cellular adhesion to a large extent. The impact of these modifications was demonstrated by cell culture experiments.

Research on Inorganic Material Modification of PVC

PVC Resin has a great deal of excellent performances. It is corrosion preventive, inflaming retarding, resistant to wear and is insulated and so on. At the same time, its price is very competitive. Therefore, PVC Resin is being widely applied in a lot of aspects, which include bars, tubular products, thin films, antiseptic materials, insulation materials as well as building materials, and so on. It is a thermoplastic plastic which is of great importance. However, PVC Resin has large brittleness; its heating stability is not good; the performances of shock resistance are low and the handling characteristics are not good. In order to further improve its performances, PVC Resin must be modified. This paper studies on the inorganic material modification of PVC. From the perspective of the industry of plastic, polyvinyl chloride (PVC) is a kind of thermoplastic plastic which is of great importance. The field of application of PVC is very diverse. It can be used in multiple scopes, which include tubular products, thin films, structural sections, insulation mate-rials as well as bars and so on. As for the volume of production, it is next only to polyethylene in worldwide output of resin, ranking the second place. Polyvinyl chloride has a great amount of ex-cellent performances. For example, it is not flammable, insulated, corrosion preventive, as well as resistant to wear and so on. The most outstanding advantages of PVC are that its price is extremely competitive, and that its tensile strength as well as bending strength is larger than the ordinary gen-eral purpose plastics. However, PVC Resin is polar non crystalline polymer. The molecular of PVC Resin have very strong interactions. The material is hard and brittle, and its shock strength is low. This shortage restrains its further development as well as its application. In order to overcome this shortage of PVC resin, it should be modified so that its ductility can be improved. This is also one of the key content that is currently studied on.