Polyvinyl Chloride Foam Research Articles

Mechanical performances of polyvinyl chloride (PVC) foam sandwich composites with glass cloth face-sheet

The mechanical performances of polyvinyl chloride (PVC) foam sandwich panels with different types of cores prepared by vacuum-assisted resin infusion process (VARI) were investigated. The flatwise, edge-wise compression, flexural and impact properties of three types of PVC sandwich panels of the prepared panels were performed. The results show that the mechanical performances of the foam sandwich composites can be enhanced due to the presence of polymer pins, and the impact properties appear slightly different at different stages. Due to the existence of pins, the energy absorption and impact properties of the sandwich panels are slightly reduced during the impact rebound phase, while the impact properties of the three sandwich panels do not change much during the impact penetrated phase. The contact surface and the cross-section through the damaged area were observed to analyze the failure modes of sandwich composites.

Influence of specimen profile size and thickness on the dynamic compressive behavior of rigid PVC foams

Split Hopkinson Pressure Bar (SHPB) apparatuses were extensively utilized in the dynamic testing of polymeric foams in previous studies; however, there are many technical limitations on the specimen size when utilizing SHPBs. Consequently, most research on the influence of specimen size on the mechanical response was limited to the quasi-static loading regime. The specimen size effect was reported to be negligible in the quasi-static regime. This observation was traditionally extrapolated to the dynamic regime; however, the hypothesis has not been thoroughly verified by experimental testing. The present study represents the most thorough investigation (to date) on the influence of specimen shape, cross-sectional area and thickness on the dynamic mechanical response of Polyvinyl Chloride (PVC) foams. A drop tower testing machine equipped with a massive 45.45 kg dropping entity and a novel sacrificial energy dissipation system was employed for the dynamic testing. The findings from this work revealed a significant sensitivity to the specimen profile on the dynamic mechanical response of PVC foams in contrast to the negligible effects in the quasi-static regime. Investigating the effect of specimen thickness on the mechanical response further demonstrated that the engineering strain rate is not a suitable index for reporting PVC foams’ rate sensitivity. Instead, the impact velocity is more appropriate since specimens with different thicknesses exhibited a similar compressive stress/strain response when tested at the same impact velocities while experiencing different engineering strain rates. The influence of specimen shape (rectangular versus cylindrical) was negligible in both the quasi-static and dynamic regimes.

Mechanical responses of CFRP/PVC foam sandwich plate impacted by hailstone

Mechanical responses of sandwich plate with carbon fiber reinforced polymer (CFRP) laminate as face-sheets and polyvinyl chloride (PVC) foam as core, which is promising in the lightweight design of high-speed maglev trains, was studied for the case of hailstone impact. Nine 500 × 500 mm sandwich plate specimens of three face-sheet thicknesses 1, 2 and 3 mm and a constant core thickness 30 mm were fabricated and tested under the impact of ice spheres of 50 mm in diameter propelled by the first-stage light gas gun. Three impact speeds, i.e. 30, 60 and 90 m/s, of the ice spheres and three incident angles, i.e. 0°, 30° and 45°, were investigated. For all cases, no macro failures were observed, but invisible damages, i.e. delamination in the upper face-sheets and indentation of the foam core, were found by high resolution ultrasonic testing. The experimental results were then used to calibrate the corresponding numerical model, based on which a thorough parametric analysis was performed to show the full dynamical responses of CFRP/PVC foam sandwich panels under hailstone impact. It is found that the foam cushion could effectively protect the rear face-sheet and increasing the ratio of span to thickness of the panel could reduce the damage degree due to the change of failure mode from local to global.

Mechanical performance of sandwich materials with reduced environmental impact for marine structures

Glass fibre reinforced composite facings on PVC (poly(vinyl chloride)) foam cores are widely used sandwich materials in boat structures, but life cycle analysis suggests that alternative materials may be preferable for the environment. However, in order to design with these alternative materials their mechanical behaviour must be characterized and understood. This paper describes an experimental campaign to evaluate the performance of alternative sandwich materials with reduced environmental impact, under loading conditions relevant to boat design. Flax and bamboo composite faced PET (poly(ethylene terephthalate)) foam sandwich materials are compared to the current PVC foam sandwich on a constant weight basis. A series of quasi-static tests is described first and analysed. Then hard and soft impact tests are described, which allow a comparison to be made between existing and alternative sandwich options. The results indicate that the alternative materials show lower flexural stiffness. Damage initiation levels are also lower, but the impact energy levels they can support are promising, and facing improvements could raise these further.

Evaluation of foam-based composite materials for automotive industry

Composite materials influenced engineering materials study, which led to new composite materials. Composites allowed this. Aerospace, car manufacturing, shipbuilding, and civil work use sandwich composites. Composites are also used in civil building. These composites can be used to make light, small, quiet, and temperature-controlled products. Sandwich composites combine reinforcement and matrix to create rigid, light composites. This creates sandwich-like products. This makes sandwich hybrid materials possible. Each shape is made from a distinct foam material. Foam materials vary in size, form, and density. This study created a composite material with foam and fibre parts that can be arranged in various ways. Many ways to assemble this stuff. Polyurethane foam, PVC foam, and a matrix with fibre support make a hybrid sandwich composite material. Hybrid sandwich composites have many elements. Polyurethane foam, PVC foam, epoxy resin, and carbon are needed to form a hybrid sandwich composite. These elements built it. Polyurethane, PVC, and mixed sandwich composites are made by hand-laying up. Each orientation of polyurethane, polyvinyl chloride (PVC), and hybrid material has unique characteristics. All composite foams are aligned at 0 degrees, 45 degrees, and 90 degrees.

Fabrication and characterization of light weight PVC foam based E-glass reinforced polyester sandwich composites

The chemical, mechanical, thermal, and microstructural properties of Poly Vinyl Chloride (PVC) foam based E-glass reinforced polyester sandwich composites are evaluated as compared with single layer E-glass both side of PVC foam polyester composite (C1) and double layer E-galss both side of PVC foam polyester composite (C2). Fourier transform infrared (FTIR) spectroscopy was used to analyze the chemical composition of composites. The mechanical properties of fabricated composites were studied in terms of impact, flexural, and tensile strength. Thermogravimetric analysis and Dynamic mechanical analysis tests were done for examine thermal properties. Carbonyl group –C=O of the ester group, unsaturation sites of –(CH2)n–, CH, and CH3 stretching were identified in chemical analysis. The tensile strength and tensile modulus for C2 was found higher 37% and 152% more respectively as compared to C1 composite however C1 composite showed better flexural properties as compared to C2. C2 composite has a 31% higher impact strength than composite C1. Both C1 and C2 composite showed approximately equal thermal stability whereas C2 composite showed better damping properties. SEM micrograph of fractured surface divulges the fiber pullout, matrix cracking, and honeycomb structure. Fabricated light weight sandwich composites can be used for marine application.

Free vibration analysis of curved asymmetric sandwich structures

This study deals with free vibration analysis of asymmetric sandwich structures that have different curvature angles. Polyvinyl chloride (PVC) foam, carbon fiber, and glass fiber were used as the core and surface sheets of the sandwich structures, respectively. The finite element method is used for the study. Commercially available software ANSYS apdl is employed to investigate the vibration study of curved asymmetric sandwich structures. Firstly, the accuracy of the finite element method is determined by making a comparison with the literature. Following that, the first six natural frequencies of sandwich structures were obtained for various sandwich configurations to examine the effects of asymmetry and curvature angle on the sandwich structures' characteristics. To achieve that two different configurations of sandwich structures are modeled. Each configuration has 5 different sandwich structures whose curvature angles are 0,15,30,45 and 60 degrees. All of the sandwich structures were modeled and solved using ANSYS apdl. Results show the impact of asymmetry and curvature angles on sandwich structure free vibration behavior. Also, it was obtained that free vibration analysis of curved sandwich structure can be performed by the proposed method accurately, which is hard to obtain by the analytical method and expensive by the experimental method. Using this method one can investigate different scenarios in a short time. Also, one can use this method before production to see if it is good for application.

Buckling behavior of fiber reinforced Innegra sandwich beams incorporating carbon nanofiber

This study examined the effect of carbon nanofiber (CNF) on the buckling behavior of sandwich beams under axial compressive load. Three different configurations of sandwich beams consisting of composite skins with different arrangement of layers and polyvinyl chloride (PVC) foam core were considered. Each composite skin is made of four layers reinforced with different materials consisting of Innegra, carbon and Innegra/carbon (hybrid) and epoxy resin modified by CNF. Because of the difference in the thickness of the samples, the specific critical load parameter (the ratio of the critical buckling load to the thickness of the structure) was used to compare the buckling behavior of sandwich beams. The experimental test results indicated that carbon fiber as a stiffening interface in hybrid samples improved the specific critical load compared to Innegra samples. Also, the addition of 0.3 wt%-CNF increases the specific critical load, while the further increase of CNF led to the decrease of the specific critical loads, which is the main cause of weak interfacial stress between CNF and epoxy resin. In addition, the effect of different percentages of CNF and types of fibers on the increase in toughness and damage mechanisms were investigated.

Ice impact response and energy dissipation characteristics of PVC foam core sandwich plates: Experimental and numerical study

In this paper, the dynamic responses and energy dissipation characteristics of polyvinyl chloride (PVC) foam core sandwich plates under ice impact are investigated. The ice impact tests of PVC foam core sandwich plates were conducted by employing the horizontal impact experimental apparatus. The finite element simulations were conducted to analyze the dynamic response of PVC foam core sandwich plates based on soil and concrete material model for ice impactor. It was demonstrated that numerical results were in good agreement with experimental results. The deformation modes of the top facesheets were coupling of local indentation with global bending deformation, while the deformation modes of bottom facesheets were overall bending deformation. The permanent deformation of face sheets show that the impact resistance of sandwich plate is better than that of equivalent weight hull plate (EWHP). In addition, based on the actual navigation environment of ship, the effect of impact angle and ice floe shape on dynamic response and energy dissipation are analyzed.

Experimental Study of the Mechanical Behavior of Polyvinyl Chloride Foam under Shear Stress

Experimental Study of the Mechanical Behavior of Polyvinyl Chloride Foam under Shear Stress

The compressive mechanical properties of honeycomb plates and beetle elytron plates with different foam densities and height-to-thickness ratios

To investigate a new type of bionic energy-saving sandwich plate—the beetle elytron plate (BEP), the compressive mechanical properties of short basalt fiber reinforced epoxy resin composite BEPs and honeycomb plates with different polyvinyl chloride foam densities and height-to-thickness ratios were investigated. The mechanism of the coupling effect of the core structure, foam density and height-to-thickness ratio was revealed by observing the failure mode of the outer and inner ring honeycomb walls. This study can provide useful instruction for designing lightweight sandwich structures and accelerate the application of BEPs in engineering.

Prediction of bulk mechanical properties of PVC foam based on microscopic model:Part I-Microstructure characterization and generation algorithm

The mechanical properties of porous materials greatly depend on their microstructures, so the generation of realistic microstructures is the premise for a sound numerical simulation and analytical prediction. This paper presented the microstructure generation of three kinds of transversely isotropic closed-cell polyvinyl chloride (PVC) foams with different densities based on the geometric characteristics obtained from the X-ray computed tomography (CT) technology. Advancing front method was used to densely pack a set of spheres whose volume distribution is proportion to the cell volume distribution and the microstructure was formed by Laguerre tessellation. Then the geometric characteristics of the numerical models were compared with those from the CT. The good consistence proves that the proposed method is accurate and efficient to produce the representative microstructure of the PVC foams. Finally, a method was proposed to optimize the microstructure of small size numerical specimens, by which the small specimens could give similar geometric characteristics to those of the large specimens.

The effect of calcium carbonate content and particle size on the mechanical and morphological properties of a PVC foamed layer used for coated textiles

Due to recent developments in composite formulations and coating technology, polyvinyl chloride (PVC)-coated textiles are becoming increasingly popular in the textile industry. The most critical properties of PVC-coated textiles are their mechanical characteristics and morphological properties because they control their cost well. This study focuses on the impact of filler diameter and content on the mechanical properties of the PVC foam layer used for coated textiles stuffed with calcium carbonate (CaCO3). The mechanical properties of the PVC foamed layer (breaking load, tearing strength and elongation at break) were studied. The applied contents were found to significantly influence the mechanical properties of the PVC foamed layer. The addition of CaCO3 fillers improved their mechanical properties. The results also showed that mechanical properties were enhanced using calcium carbonate with different particle sizes; the smallest particle size gave the highest mechanical resistance. The morphology of the different samples showed that the employment of calcium carbonate increases foam formation. A higher CaCO3 content can deteriorate the PVC foam layer structure. Using a small filler particle diameter decreased pore sizes and ameliorated the regularity in pore size distribution.

Prediction of bulk mechanical properties of PVC foam based on microscopic model：Part II-Material characterization and analytical formulae

The bulk mechanical properties of a foam are strongly related with the modulus of elasticity and yield strength of the base material and the geometric features of the foam microstructure. This paper proposed a method to predict the bulk mechanical properties of transversely isotropic closed-cell polyvinyl chloride (PVC) foams based on the numerical analysis of microscopic models. Firstly, the elastic modulus of the base material was determined through nanoindentation and the macro compressive stress-strain curves in three orthogonal directions were measured for the Divinycell H100 foam. Then, the influence of variation of the scaling factor, which transformed an isotropic microstructure to a transversely isotropic one, on the mechanical properties were investigated numerically. It is found that the ratio of the two moduli of elasticity in the rise direction and in the transverse direction linearly depends on the scaling factor, so does the ratio of the yield strengths. Next, the relations of the bulk mechanical properties of the transversely isotropic foam in the two directions with the relative density were formulated. Finally, this method was validated by being successfully applied to foams of the same base material but different densities.

Polivinil klorür (PVC)’ün geri dönüştürülmesi: PVC köpük üretimi ve Karakterizasyonu

Plastikler hayatımızın birçok alanında yıllardır kullanılmakta olup kullanım ömrü sonunda önemli miktarda atık oluşturmaktadır. Doğada uzun yıllar bozunmadan kalan ve çevreye zarar veren bu malzemelerin geri dönüştürülüp tekrar kullanıma kazandırılması önem taşımaktadır. Termoplastik köpük malzemeler düşük yoğunluk, yüksek spesifik mukavemet, yüksek enerji absorblama özellikleri ve üstün yalıtım özelliklerinden dolayı ısı yalıtımı, otomotiv koltukları, ambalaj malzemeleri ve enerji absorblayıcı (soğurucu) malzemeler olarak yaygın bir şekilde kullanılmaktadır. Bu çalışmada, en çok kullanılan plastiklerden biri olan ve önemli miktarda atık oluşturan polivinil klorür (PVC)’ün geri dönüşüm yoluyla termoplastik köpük malzemelerin üretiminde kullanımı amaçlanmıştır. Bu amaçla kapı ve pencere profil atıklarından elde edilen atık PVC kullanılarak termoplastik köpük malzemeler üretilmiştir. PVC köpük malzemelerin bazı fiziksel, mekanik ve morfolojik özellikleri üzerine kimyasal köpük oluşturucu miktarının etkisi incelenmiştir. Üretilen PVC köpük malzemelerde kimyasal köpük oluşturucu malzeme miktarının artması ile PVC köpüklerin yoğunluk değerlerinde %40’lara kadar bir azalma sağlanmıştır. PVC köpüklerin spesifik darbe direnci değerleri kimyasal köpük oluşturucu miktarı ile doğrusal bir şekilde artış göstermiştir. Köpüklerin hücre yapısı incelendiğinde ise kimyasal köpük oluşturucu miktarının artması ile hücre birleşmelerinin meydana geldiği ve daha büyük hücrelerin oluştuğu gözlemlenmiştir.

Experimental Study of the Dynamic and Static Compression Mechanical Properties of Closed-Cell PVC Foams.

Closed-cell polyvinyl chloride foam (PVC) possesses many advantages, including its light weight, moisture protection, high specific strength, high specific stiffness, and low thermal conductivity, and is widely used as the core material in composite sandwich structures. It is increasingly used in fields with light weight requirements, such as shipbuilding and aerospace. Some of these structures can be affected by the action of dynamic loads during their lifespan, such as accidental or hostile blast loads as well as wind-loaded debris shocks. Examining the material properties of PVC foams under dynamic load is essential to predict the performance of foam sandwich designs. In this study, the compressive responses of a group of PVC foams with different densities were investigated under a broad range of quasi-static conditions and high strain rates using a universal testing machine and a lengthened Split Hopkinson press bar (SHPB) fabricated from titanium alloy. The results show that the mechanical properties of foam materials are related to their density and are strain rate-sensitive. The compressive strength and plateau stress of the foams were augmented with increased foam density. In the quasi-static strain rate range, the compressive strength of PVC foams at 10−1 s−1 was 27% higher than that at 10−4 s−1. With a strain rate of 1700 s−1, the strength was 107% higher than the quasi-static value at 10−4 s−1.

Research on the feasibility of polyethylene terephthalate foam used in wind turbine blades

AbstractThe sandwich foam materials of wind turbine blades are mainly polyvinyl chloride (PVC) and styrene–acrylonitrile (SAN) foams due to their good mechanical properties. However, PVC foam is unrecyclable and not resistant to high‐temperature conditions, while SAN foam is more expensive than PVC foam. Polyethylene terephthalate (PET) has irreplaceable advantages than both PVC and SAN foams because of its better mechanical performance, fantastic heat‐resistant, low cost, and environmental friendliness (100% recyclability). In this article, the mechanical properties, thermal stability, resin uptake, and cellular morphology of PET T92, PVC H60, and SAN T400 foams were discussed. The results showed that the mechanical properties of T92 were equivalent to the existing H60 and T400, and even exceed their properties. It was found that the thermal stability of T92 was better than H60 and T400 under the same high temperature. Moreover, the pore of T92 was more uniform and regular than H60 and T400. Furthermore, the overall cost of T92 was lower than H60 and T400. The findings suggest that PET foam with a density of 100 kg/m3 can completely replace PVC 60 kg/m3 and SAN 71 kg/m3 foams from the perspective of mechanical performance, cost, thermal stability, and environmental protection.

Thermomechanical evaluation of expanded ethylene‐propylene diene monomers rubber mixed with recycled polyvinyl chloride foams

The hazardous practice of landfilling at the end of life (EoL) of large amounts of rigid crosslinked interpenetrated network polyvinyl chloride (PVC) foams urgently requires development of effective recycling methods. In this work, PVC foam waste obtained from an industrial process was mixed with ethylene-propylene diene monomers (EPDM) rubber. The waste PVC foam naturally contained water (up to 35%) which was exploited for the expansion of EPDM rubber. For this, various amounts of recycled polyvinyl chloride (PVC) (20%, 30%, 40% by weight) were melt compounded with ethylene-propylene diene monomer rubber (EPDM) at 60 °C for 15 min. The obtained rubber mixtures were vulcanized at 160 °C for 20 min under varied compression time to create square sheets of expanded EPDM/PVC blends. The insertion of the humid PVC foam promoted the foaming of EPDM rubber up to a total porosity of 40% meanwhile geometrical density was decreased by 33% by the expansion of the rubber. Tensile tests revealed that, despite the presence of rigid PVC foams, the expanded EPDM/PVC blends manifested appreciable elongation at break values (up to 700%). Both compression set and shore A values of rubber increased with the addition of the rigid PVC foam. Moreover, all expanded blends showed low thermal conductivity values with a minimum of 0.07 W/m K.

An experimental study on the flexural behaviour of symmetric and asymmetric marine composite sandwich beams

This paper presents a rigorous study on the flexural behaviour of symmetric and asymmetric marine sandwich beams consisting of polyvinyl chloride (PVC) foam core and glass fibre composite face-sheets. The sandwich beams have a shear-span-to depth ratio (a/d) ranging from 2 to 7.5 and loaded under three- and four-point static bending configurations. The effect of mid-plane asymmetry, stacking sequence, fabric weight, and core type on the failure mode, bending rigidity and strength of the sandwich composites were investigated. Two-way analysis of variance (ANOVA) analysis indicated that the effect of the a/d ratio and the loading type had a similar effect on failure load. The a/d ratio had a greater influence on the initial bending stiffness than the loading type for the asymmetric beams.

Effect of fillers on compression loading performance of modified re-entrant honeycomb auxetic sandwich structures

The auxetic sandwich panels for structures have been designed to provide impact protection. The aim of this work is to modify an auxetic (re-entrant) honeycomb cell to reduce the stress concentrations within the cell structure, and further enhancement of this design. The auxetic structure was filled to achieve a greater energy absorbance and enhance safety applications. Analytical and elastic three-dimensional finite element approaches were used to investigate the structural strength performance. The basic model (i.e. modified re-entrant strut cell design) consisted of the honeycomb auxetic polypropylene (PP) structure sandwiched between two steel plates (known as safety panels) which were placed under static compression loading. The cell geometry and size were then modified to reduce the stress concentration zones. The structure cells were filled with silly putty and polyvinyl chloride (PVC) foam. The effect of the filling the cells on the stress concentration and energy absorbance were analysed using elastic stress and deformation analysis methods. During the stress path analysis, it was found that an increase in Young’s modulus of the filling was directly proportional to a decrease in internal stresses. It was concluded that while filling the basic model with soft materials reduced the stress concentration, but it led to a reduction in the energy absorbance capability. Further on, the lower stress produced by the enhanced could be useful to prevent significant penetration of the protective panel. Compared to similar structures of steel, auxetic foam panels have the advantage of having only a fraction of the weight and being corrosion resistant at the same time as keeping impact strength. Graphical abstract [Formula: see text]