Polyvinyl Chloride Composites Research Articles

Thermal and three-body abrasion behaviors of alkali-treated eucalyptus fiber reinforced polyvinyl chloride composites

Wood-plastic composites (WPCs) have been widely used as exterior construction materials. The effect of alkali-treated (with NaOH concentrations of 1%, 3%, 5%, and 7%) eucalyptus fiber on the three-body abrasion behaviors of eucalyptus/polyvinyl chloride (PVC) composites was investigated. The results showed that the eucalyptus fiber treated with NaOH had a higher crystallinity and improved hardness and impact strength. The wear loss and rate of alkali-treated eucalyptus/PVC composites was noticeably decreased compared to the natural eucalyptus fiber. The scanning electron microscopy (SEM) examination on the worn surfaces revealed that the main wear mechanism of the eucalyptus/PVC composites was a combination of microcutting and microindentations.

Micro-structural and mechanical characterization of doum-palm leaves particulate reinforced PVC composite as piping materials

A doum palm particulate reinforced polyvinyl chloride (PVC) composite was developed with considerably low cost materials providing an overall light-weight and good mechanical properties for potential application as piping material. The specimen composite material was produced with the doum palm (leaves) particulate as reinforcement using compression molding. Results showed that density and elastic Modulus of the composite decreases and increases respectively with increasing weight fraction of the particulate reinforcement. The tensile strength increased to a maximum of 50 MPa and then decreased steadily. The composition with optimum mechanical property (50 MPa) was determined at 8, 62 and 30% formulation of doum palm particulates (reinforcement), PVC (matrix) and Kankara clay (filler) respectively with corresponding percentage water absorption of 0.72%, Young’s Modulus of 2 GPa, flexural strength of 84 MPa and density of 1.43 g/cm3. Fourier Transform Infrared (FTIR) analysis of the constituents showed identical bands within the range 4000–1000 cm−1 with renown research work. Scanning Electron Microscopy (SEM) result showed fairly uniform distribution of constituents’ phases. X-Ray Fluorescence (XRF) confirms the X-ray diffraction (XRD) result of the presence of minerals of kaolinite, quartz, rutile and illite in the kaolin clay. Comparison with conventional piping materials showed the composite offered a price savings per meter length of 86.6% and 35.9% when compared with carbon steel and PVC material.

Fabrication of multi-walled carbon-nanotube-grafted polyvinyl-chloride composites with high solar-thermal-conversion performance

The optical absorption properties of carbon nanotubes (CNTs) have attracted extensive research attention. Here we report the fabrication of sea-island structured polymer-based multi-walled CNT (MWNT) composite with high solar-thermal-conversion performance. MWNT-grafted 4-chloromethyl styrene (MWNTs-g-CMS) is prepared via esterification between carboxyl groups on the MWNT surface and the chloromethyl group of the CMS in the presence of a phase-transfer reagent in water. Covalent bonding between the CMS and the MWNTs is confirmed by Fourier transform infrared spectra. Thermogravimetric analysis of the MWNTs-g-CMS shows a mass percentage of the attached methyl styrene chains as high as 24.31 wt%. Subsequently, polymer-based MWNT-graft-polyvinyl-chloride (MWNTs-g-PVC) composite was prepared via an in-situ graft polymerization between the vinyl chloride and active styryl groups of the MWNTs-g-CMS. The MWNT grafting efficiencies in a series of MWNTs-g-PVC composites are 0.013–0.103%. The sea-island structure of the MWNTs-g-PVC composites and the fine dispersion of MWNTs in the island are verified by electron microscopy. The solar-thermal conversion performance of the MWNTs-g-PVC composites is studied. The composites exhibit excellent light-absorption properties that resemble a black body, and yield a higher solar-thermal conversion efficiency than the carboxylic MWNT (PVC/MWNTs-COOH) composites, which is attributed to the sea-island structure and the good dispersion of MWNTs in the islands.

Interfacial Adhesion and Mechanical Properties of PET Fabric/PVC Composites Enhanced by SiO₂/Tributyl Citrate Hybrid Sizing.

Poly(ethylene terephthalate) (PET) fabric-reinforced polyvinyl chloride (PVC) composites have a wide range of applications, but the interface bonding of PET fabric/PVC composites has remained a challenge. In this work, a new in-situ SiO2/tributyl citrate sizing agent was synthesized according to the principle of “similar compatibility.” The developed sizing agent was used as a PET surface modifier to enhance the interfacial performance of PET fabric/PVC composites. The morphology and structure of the PET filaments, the wettability and tensile properties of the PET fabric, the interfacial adhesion, and the tensile and tearing properties of the PET fabric/PVC composites were investigated. Experimental results showed that many SiO2 nanoparticles were scattered on the surface of the modified PET filaments. Moreover, the surface roughness of the modified PET filaments remarkably increased in comparison with that of the untreated PET filaments. The contact angle of the modified PET filaments was also smaller than that of the untreated ones. The peeling strength of the modified PET fabrics/PVC composites was 0.663 N/mm, which increased by 62.50% in comparison with the peeling strength of the untreated ones (0.408 N/mm). This work provides a new approach to the surface modification of PET and improves the properties of PET fabric/PVC composites.

The effects of polybenzimidazole and polyacrylic acid modified carbon black on the anti-UV-weathering and thermal properties of polyvinyl chloride composites

In this study, the effects of polybenzimidazole (PBI) and polyacrylic acid (PAA) modified carbon black (MCB) on the anti-UV-weathering and thermal properties of PVC composites were investigated. The optimal mass ratios of PBI and MCB to PVC are 0.1 wt% and 0.2 wt%, respectively, and the resultant 1PBI/2MCB/PVC composite membrane with a thickness of about 60 μm can block over 99% of UV light below 380 nm. The UV absorption mechanism was investigated by the optional band gap (Eg) and the fluorescence spectroscopy. The incorporation of PBI and MCB results in a decrease in Eg, from 4.96 eV for PVC membrane to 2.90 eV for 1PBI/2MCB/PVC composite membrane, and MCB can quench the fluorescence of PBI by photon-induced electron transfer to further protect PVC. The results of accelerated UV-weathering experiment indicate that the incorporation of PBI and MCB can improve the anti-UV-weathering property of PVC. The thermal degradation behaviors of PVC and its composite membranes in air and N2 atmosphere were also investigated. The highest char residue (13.7 wt%) is obtained in 1PBI/2MCB/PVC composite membrane at 800 °C in N2 atmosphere, with an increase of 73.4% compared with that of PVC membrane, which may be because PBI and MCB can synergistically accelerate the carbonization of PVC molecules to rapidly form stable char residue.

Artificial neural network modeling to evaluate polyvinylchloride composites’ properties

The mechanical properties of extruded Polyvinylchloride (PVC) composites cannot be easily predicted due to the nonlinear nature of the relationship between the composite’s composition and the resulting after-production properties. In the work presented herein, supervised artificial neural network (ANN) modeling is used to predict and optimize three properties (tensile strength, ductility and density) of PVC composites having different weight percentages of virgin PVC, CaCO3, plasticizers, and recycled PVC. Different ANN models, designed and analyzed through factorial design and analysis of variance methodology, were evaluated using an experimental dataset which was designed according to the mixture design of experiments approach. The results show that the constituents-mechanical properties relationship of PVC composites’ can be accurately estimated using several ANN models including Levenberg-Marquardt/6-[18-9]3-3/Radial basis and Levenberg-Marquardt/6-[9-18]3-3/Log sigmoid models. The results also show that the ANN modeling is capable of determining the optimal weight percentages of the different PVC composite constituents in order to achieve a required composite property.

Wear Properties of Wood-plastic Composites Pretreated with a Stearic Acid-palmitic Acid Mixture before Exposure to Degradative Water Conditions

Wood–plastic composites (WPCs) are experiencing rapid growth in terms of applications where they may be subject to degradation and wear. This paper investigated the effect of sorghum straw (SS) fiber, pretreated with a mixture of stearic and palmitic acids, on the wear behaviors of polyvinyl chloride (PVC) composites in alternated simulated sea water and acid rain aqueous conditions. The results showed that the water resistance of the SS/PVC composites improved noticeably after pretreatment with 0.80 wt% stearic and 0.50 wt% palmitic acid (0.8SA-0.5PA). The SS/PVC composites pretreated with 0.8SA-0.5PA exhibited high water (moisture) resistance, hardness, mechanical, thermal, and wear resistance properties. Exposure to degradative water worsened interfacial bonding, and degraded the matrix strength and heat resistance, which reduced the wear resistance of the SS/PVC composites. The wear mechanism of the SS/PVC composites after 12 d of soaking was abrasive wear.

Investigation of dielectric behavior of the PVC/BaTiO3composite in low-frequencies

Polyvinyl chloride (PVC) is widely used as insulator in electrical engineering especially as cable insulation sheaths. In order to improve the dielectric properties, polymers are mixed with ceramics. In this paper, PVC composites with different weight percentages 2 wt.%, 5 wt.%, 8 wt.% and 10 wt.% were prepared and investigated. Loss index ([Formula: see text]) and dielectric constant ([Formula: see text]) have been measured using an impedance analyzer RLC. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) have been used as characterization techniques. The incorporation of BaTiO3does not modify the crystallinity and the morphology of the PVC but reduces the space charges, therefore the dielectric losses. The frequency response analysis has been followed in the frequency ranges (20–140 Hz and 115–1 MHz). Relaxation frequencies have been evaluated in each frequency range. Experimental measurements have been validated using Cole–Cole’s model. Experimental results show well that BaTiO3as a filler improves the dielectric properties of PVC.

Wear Behavior of Alkali-Treated Sorghum Straw Fiber Reinforced Polyvinyl Chloride Composites in Corrosive Water Conditions

The application of wood-plastic composites is growing rapidly in the fields of corrosion and aging. The present study investigated the effect of alkali-treated (with NaOH concentrations of 0.5, 2.5, 4.5, and 6.5%) sorghum straw (SS) fiber on the wear resistance of polyvinyl chloride (PVC) composites under simulated seawater and acid rain conditions. The results showed that the wear resistance of the SS/PVC composites was noticeably improved by the addition of the alkali-treated SS fiber. SS fiber treated with 4.5% NaOH showed low polarity and hydrophilicity with high crystallinity and improved mechanical properties, which endowed the SS/PVC composites with high interfacial bonding and wear resistance. Exposure to simulated seawater and acid rain resulted in the deterioration of physical (including water repellency and hardness), mechanical, thermal, and wear-resistance properties of the composites; the wear mechanism of the SS/PVC composites after corrosion for 12 days was mainly abrasive wear.

Formaldehyde emission from PVC–wood composites containing MDF sanding dust

The main purpose of this work was to study the formaldehyde emission from wood plastic composites (WPCs) containing polyvinyl chloride (PVC), wood flour, and sanding dust of medium density fiberboard (MDF). Wood floor was replaced with 10, 15, and 20% MDF sanding dust (as a wood‐based panel waste), and the composites were manufactured by the extrusion method. Formaldehyde emission from WPCs was measured using two different methods: the desiccator method according to ISO 12460 and the flask method according to EN717‐3. Moreover, the physical and mechanical properties of the WPC samples were determined. The results indicated that the use of MDF sanding dust in formulation of WPCs leads to higher formaldehyde emission. The composites with higher content of MDF sanding dust exhibited higher formaldehyde emission. Although the PVC composites containing MDF sanding dust release formaldehyde, the formaldehyde emission values were very low. Therefore, these composites can be considered to be green composites and there is no concern in their indoor applications. J. VINYL ADDIT. TECHNOL., 25:159–164, 2019. © 2018 Society of Plastics Engineers

Electrical and Tensile Properties of Carbon Black Reinforced Polyvinyl Chloride Conductive Composites

Conductive polymer composites are becoming more important and useful in many electrical applications. This paper reports on the carbon black (CB) reinforced polyvinyl chloride (PVC) conductive composites. Conductive filler CB was reinforced with thermoplastic PVC by compression molding technique to make conductive composites. The particle size of CB was measured, as it affects the electrical conductivity of the composites. Different types of CB-PVC compression-molded composites were prepared, using CB contents from 5 to 30 wt %. The electrical and tensile properties of these composites were studied and compared. Improved electrical properties were obtained for all CB-PVC conductive polymer composites compared to virgin PVC composite. However, the tensile properties of the CB-PVC composites increased up to 15 wt % CB loading, and then decreased, and elongation at break decreased with increasing CB loading. The structure of the CB, PVC and CB-PVC composites were studied by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic analysis. ATR-FTIR spectra provide evidence of the formation of CB-PVC composites. The microstructural analyses showed a good dispersion of CB in PVC matrix.

Preparation and Characterization of PVC Matrix Composites with Biochemical Sludge

Biochemical sludge (BS), generated in the waste water treatment of paper mills, was pretreated by enzyme hydrolysis. The effect and action mechanism of the enzymatic treatment on the properties of polyvinyl chloride (PVC) matrix composites with BS were discussed. Results showed that when the filler content was 30 wt%, the tensile strength of the PVC composites filled with BS and its modified products which were pretreated by laccase, cellulase and hemicellulase can be increased by 38.64, 67.4, 63.5 and 66.3% than the PVC composite filled with calcium carbonate. When the dosage of filler was 40 wt%, the elastic modulus of PVC composites filled with BS and its above three modified products decreased by 53.3, 52.3, 50.0 and 46.3%, respectively. Meanwhile, the thermal stability of PVC composites can also be improved at the temperature of over 340 °C. It can be concluded that the enzyme pretreatment can improve the application performance of BS usage in PVC matrix composites.

Influence of UV Radiation on Mechanical Properties of PVC Composites Reinforced with Pineapple Fiber

Pineapple fiber reinforced polyvinyl chloride (PVC) composites (25-75% fiber by weight) were fabricated using compression molding technique and the mechanical properties such as tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM) and impact strength (IS) of the composites were evaluated. It was found that at 55% fiber content, the composite exhibited the best mechanical properties. The TS, TM, BS, BM and IS were found to be 48.8 MPa, 773 MPa, 75.6 MPa, 4.2 GPa, 21.4 KJ/m2 for 55% fiber composite. The composites were exposed to different intensities of ultraviolet (UV) radiation (25-200 UV dose) and found significant improvement in the mechanical properties up to 100 UV dose. At 100 UV dose, the value of TS, TM, BS, BM and IS of the composite were found to be 57.3 MPa, 932 MPa, 87.5 MPa, 5.2 GPa and 26.3 KJ/m2 respectively. Water uptake behaviours of the non-irradiated and UV irradiated composites were also observed. The interfacial property was examined by scanning electron microscopy (SEM).

Закономерности совмещения поливинилхлоридных композиций с дисперсиями углеродных нанотрубок

Закономерности совмещения поливинилхлоридных композиций с дисперсиями углеродных нанотрубок

Kinetics of thermal decomposition of PVC/fly ash composites

ABSTRACTIn this study, the kinetics and mechanisms of thermal degradation of Poly Vinyl Chloride (PVC) composites reinforced with class-F fly ash are studied experimentally and numerically using Flynn–Wall model. The addition of fly ash to the polymer matrix results in a decrease in the primary degradation temperature and an increase in the secondary degradation temperature. The metal oxides in the fly ash act as acid absorbers, which results in the destabilization of PVC during its dehydrochlorination process. However, they also react with the chlorine free radicals, which prevents the formation of HCl during degradation. In addition, it is observed that calcium and iron oxides, present in fly ash, are more reactive to the chlorine radicals rather than the silicon and aluminum oxides. The effect of fly ash chemical composition on the degradation of PVC composites was studied by comparing the thermal properties of composites containing two different classes of fly ashes, class-F and class-C, at similar levels. Thermal stability of the composites is found to be dependent on the chemical composition of fly ash. Higher dehydrochlorination rate is observed in the case of composites filled with class-F fly ash than those reinforced with class-C fly ash.

The irradiation surface treatment of UHMWPE fiber on the interfacial properties of PVC composite

Properties of ultrahigh molecular weight polyethylene (UHMWPE) fiber-reinforced composites depend largely on the interfacial bonding strength between fiber and matrix. In the present work, UHMWPE was irradiation treatment. The existence of functional groups introduced to the fiber surface and the changes of surface roughness were confirmed by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). To evaluate the possible applications of this surface modification of UHMWPE fiber (UF), we examined the mechanical properties as well as the friction and wear performance of thermoplastic polyvinyl chloride (PVC) composites and found that the mechanical properties of PVC composites were all significantly improved. Scanning electron microscope investigation of worn surfaces of PVC composites showed that surface-treated UF/neoprene/PVC (UF/NO/PVC) composite had the strongest interfacial adhesion.

Использование нанодобавок в поливинилхлоридных композициях строительного назначения

Использование нанодобавок в поливинилхлоридных композициях строительного назначения

Study of various thermal responses of PVC – CPVC Blends

Binary blends of Polyvinyl Chloride (PVC) / Chlorinated Polyvinyl Chloride (CPVC) were prepared using Haake Polylab extruder. The blends were then compression molded and their thermal properties were evaluated and compared. 7 different batches including virgin PVC and CPVC were prepared with varying PVC compositions from 10 to 90%. DMA results showed the immiscibility of blends above a certain composition. Colorimetry results give an insight into Yellowness index values of various blends with different compositions. Similarly, other improvements and optimization was observed and recorded for different batches while studying their thermal properties.

The core-double-shell microcapsules flame retardant: Synthesis and its application for polyvinyl chloride composites

The core-double-shell microcapsules flame retardant has been regarded as a promising additive for improving the fire safety of PVC. In this article, melamine–formaldehyde resin (MF)/silicon dioxide (SiO2)/zinc hydroxystannate (ZHS) microcapsule was prepared. The effect of synthetic parameters (such as pH, agitation speed, reaction time and reaction temperature) on the morphologies and sizes of the SiO2/ZHS microcapsules were investigated in details. MF/SiO2/ZHS microcapsule was introduced into PVC to prepare biofunctional composites with excellent fire resistance and smoke suppression. The flammability of PVC composites was characterized by limiting oxygen index (LOI), smoke density (SDR), cone calorimeter test. The results showed that the sample containing 16.4% MF/SiO2/ZHS microcapsule (the mass ratio of MF:SiO2:ZHS = 2.5:2:8) achieved the maximal LOI value of 35.6%, minimal SDR value of 21.2%, and significantly decreased the peak heat release rate from 179.7 kW/m2 of neat PVC to 108.3 kW/m2. The thermal behaviors of PVC composites and the morphologies of residues were characterized.

Effects of Processing Methods, DOP Amount and Filler Content on the Mechanical Properties of Recycled Polyvinyl Chloride (PVC) Composites

PVC is one of the most commercialized thermoplastic materials with industrial and household applications. Plastic possesses an important percentage in waste stream and its recycling is vital. Plasticizer usage is also essential for the PVC manufacturing and recycling. It is the purpose of this study to determine the effects of processing methods, DOP concentration and wood flour amount on the mechanical properties of recycled PVC composites. 15 and 30 phr (per-hundred-resin) DOP and 0-15-30 phr wood flour was studied. Composite materials were produced using injection and compression molding methods. Tensile, flexural, impact, hardness (shore D) and density of the composites were determined. Based on these results, DOP and filler content and process had a significant effect on mechanical properties. Utilization of DOP in the PVC matrix made material softer and flexible. Resulting materials had higher elongation at break and impact strength and smaller shore D values. In an expense to these good results, it reduced the tensile and flexural strength and modulus values. Addition of wood filler in the system, increased modulus values while reducing strength values. In the case of processing methods, injection molded samples provided overall better properties than compression molded ones. It should be noted that, in the case of injection molding, samples were better mixed due to the screw in the machine. Recycling of PVC is a vital subject and more study is needed.