Unplasticized Poly Research Articles

Sustainable Biopolymer Composites From Perlite, Plasticized and Unplasticized Poly(Lactic Acid)

In recent years, ecological pollution has reached critical levels and that has been experienced as climate change by all living organisms. Slowing down the negative effects of climate change depends on changing our consumption behavior. Based on that, people tend to prefer more environmentally friendly, sustainable raw materials, products and processes. Since polymers are one of the most widely used raw materials in the world, any improvement regarding their recycling or biodegradation process can significantly reduce the damage to nature. Considering this fact, manufacturers are taking initiatives to develop such products in line with the demand from consumers. As known, Poly(lactic acid) (PLA), one of the most consumed biodegradable polymers in the market, however there are various problems especially in film production due to its rigid structure. Plasticization is the easiest route to minimize this disadvantage. The aim of this study is to produce and characterize PLA composites with increased flexibility by using sustainable natural materials. In this context, glycerol-plasticized PLA and unplasticized PLA composites were prepared using perlite, a natural additive, and their morphological, thermal, and mechanical properties were investigated.

Fundamental Investigation of Various Factors Affecting the Occurrence of Solvent Cracking for Unplasticized Poly Vinyl Chloride Pipes in Building Equipment

We investigated the occurrence of solvent cracking in unplasticized polyvinyl chloride pipes using test materials prepared by conventional methods. We confirmed that voids were formed on the inner surface of the pipe at a holding time of 2 weeks under conditions of room temperature (298 K), 1.0 g of applied adhesive, and 4 N/m U-band tightening torque. The voids formed linearly in the circumferential direction at regions in contact with the U-band and linearly in the axial direction at regions not in contact. Environmental agents of tetrahydrofuran (THF), 2-butane, and cyclohexanone were detected during analysis of void regions on the inner surface of the pipe and residual gas in the pipe. The results suggest that the stress generated by tightening of the U-band and the environmental agents affected void generation. Furthermore, stress analysis simulation of the U-band contact region show the presence of tensile stress at regions in contact with the U-band and compressive stress at regions not in contact. The difference in these stresses and the regularity of the molecular arrangement during manufacturing of the pipe likely influences the direction of void generation, which can progress into cracks.

Evaluation of different specimen geometries and testing configurations for the assessment of the degree of gelation of unplasticized poly(vinyl chloride) pipes using the essential work of fracture approach

An unplasticized (U-PVC) pipe sample (ABNT NBR 5647-2, nominal diameter DN 100, outside diameter 110 mm) is studied using essential work of fracture (EWF). This pipe sample is also tested for the quality of processing (degree of gelation) via differential scanning calorimetry (DSC) and tensile strength. The comparative evaluation of different specimen configurations – flat (SENB) and curved (CTPB) specimens in three-point bending, using different support spans, and C-shaped (SNRB) and full rings in tension (SNRT), shows significant differences in their suitability for EWF testing. While SENB- and CTPB-type specimens, independently of the support span ratio S/W adopted, confirm previous findings that both specimen configurations are very suitable for EWF testing of pipe samples, SNRB- and SNRT-type specimens, by their turn, do not show suitability for the purposes of this study, at least using the testing configurations here adopted. When comparing results from this study with previous publications from the authors, it is shown that EWF seems to be an interesting alternative approach for gelation assessment, since it is evident from the comparative results that there is some high degree of correlation between EWF parameters and the DSC degree of gelation.

Can aged microplastics be transport vectors for organic micropollutants? – Sorption and phytotoxicity tests

Microplastics have been investigated over the last decade as potential transport vectors for other pollutants. However, the specific role of plastic aging, in which plastics change their characteristics over time when exposed to environmental agents, has been overlooked. Therefore, sorption experiments were herein conducted using virgin and aged (by ozone treatment or rooftop weathering) microplastic particles of LDPE – low-density polyethylene, PET – poly(ethylene terephthalate), or uPVC – unplasticized poly(vinyl chloride). The organic micropollutants (OMPs) selected as sorbates comprise a diversified group of priority substances and contaminants of emerging concern, including pharmaceutical substances (florfenicol, trimethoprim, diclofenac, tramadol, citalopram, venlafaxine) and pesticides (alachlor, clofibric acid, diuron, pentachlorophenol), analyzed at trace concentrations (each ≤100 μg L−1). Sorption kinetics and equilibrium isotherms were obtained, as well as the confirmation that the aging degree of microplastics plays a major role in their sorption capacities. The results show an increased sorption of several OMPs on aged microplastics when compared to pristine samples, i.e. the sorption capacity increasing from one or two sorbed substances (maximum 3 μg g−1 per sorbate) up to nine after aging (maximum 10 μg g−1 per sorbate). The extent of sorption depends on the OMP, polymer and the effectiveness of the aging treatment. The modifications (e.g. in the chemical structure) between virgin and aged microplastics were linked to the increased sorption capacity of certain OMPs, allowing to better understand the different affinities observed. Additionally, phytotoxicity tests were performed to evaluate the mobility of the OMPs sorbed on the microplastics and the potential effects (on germination and early growth) of the combo on two species of plants (Lepidium sativum and Sinapis alba). These tests suggest low or no phytotoxicity effect under the conditions tested but indicate a need for further research on the behavior of microplastics on soil-plant systems.

Study of Concrete Filled Unplasticized Poly-Vinyl Chloride Tubes as Columns under Axial Loading

This article aims to examine the behavior of Unplasticized Poly- Vinyl-Chloride (UPVC) bounded reinforced columns with polypropylene fibers under axial compression. To develop this model, a no samples of concrete filled UPVC pipe (CFUT) with different geometric properties were tested. To obtain the specimens different class pipes with three different diameters were used to investigate the sensitivity of these columns to various parameters. The effect of each variable on the ultimate strength, ductility and confinement efficiency of the samples was investigated. All specimens were compressed by applying load only to the concrete core to obtain the load-displacement variations and the corresponding deformation mode. A finite element model was developed using the proposed stress-strain variation of confined concrete with UPVC tubes to simulate axial compression of CFUT specimens. According to the results obtained, the effect of the change in diameter-thickness ratio failure stress of concrete limited by (D/t) is obtained and discussed with empirical relationship. Polypropylene fibers were found to slightly increase column strength up to a certain volume fraction, after which the strength generally experienced a decrease.

Effect of Waterjet Machining Parameters on the Cut Quality of PP and PVC-U Materials Coated with Polyurethane and Acrylate Coatings.

The article focuses on the machining of polymeric materials polypropylene (PP) and un-plasticized poly vinyl chloride (PVC-U) after surface treatment with polyurethane and acrylate coatings using waterjet technology. Two types of waterjet technologies, abrasive waterjet (AWJ) and waterjet without abrasive (WJ), were used. The kerf width and its taper angle, at the inlet and outlet of the waterjet from the workpiece, were evaluated. Significant differences between AWJ and WJ technology were found. WJ technology proved to be less effective due to the creation of a nonuniform cutting gap and significant burrs. AWJ technology was shown to be more efficient, i.e., more uniform cuts were achieved compared to WJ technology, especially at a cutting head traverse speed of 50 mm·min−1. The most uniform kerf width or taper angle was achieved for PP + MOBIHEL (0.09°). The materials (PP and PVC-U) with the POLURAN coating had higher values of the taper angle of the cutting gap than the material with the MOBIHEL coating at all cutting head traverse speeds. The SEM results showed that the inappropriate cutting head traverse speed and the associated WJ technology resulted in significant destruction of the material to be cut on the underside of the cut. Delamination of the POLURAN and MOBIHEL coatings from the base material PP and PVC-U was not demonstrated by SEM analysis over the range of cutting head traverse speeds, i.e., 50 to 1000 mm·min−1.

Fundamental Investigation of Various Factors Affecting the Occurrence of Solvent Cracking for Unplasticized Poly Vinyl Chloride Pipes in Building Equipment

Fundamental Investigation of Various Factors Affecting the Occurrence of Solvent Cracking for Unplasticized Poly Vinyl Chloride Pipes in Building Equipment

Application of fracture mechanics for the characterization of poly(vinyl chloride) pipes. II. Evaluation of a ring‐type specimen for fracture mechanics testing

AbstractAn unplasticized poly(vinyl chloride) (U‐PVC) pipe sample used in infrastructure applications in Brazil (nominal diameter DN 100, outside diameter 110 mm) was evaluated according to different fracture mechanics methodologies, including essential work of fracture (EWF) and other fracture toughness parameters such as the stress intensity factor and plane strain energy release rate . This pipe sample was also tested for the quality of processing (degree of gelation) via differential scanning calorimetry (DSC) and tensile strength. The comparative evaluation of different specimen configurations—curved specimens in three‐point bending (CTPB) and full rings in tension (SNRT), in thicknesses varying from 5 to 30 mm, showed initial evidence of the suitability of ring‐type specimens for the evaluation of EWF and . Results also indicate that the full ring geometry, at least in the present experimental setup, presents some drawbacks probably due to the storage of large amounts of elastic energy throughout the test. This fact leads to relevant deviations in both load–displacement behavior and results for strain energy release rate (), and the results found here will guide future research using full and split rings in different loading modes and improved experimental setups. It was also confirmed that the value of , determined by a modified Charpy test, is independent of the type of specimen tested, as long as the test mode and specimen width are the same. Both the experimental value of and the estimated value for the plane strain stress intensity factor () showed excellent agreement with values reported for other U‐PVC compositions.

Assessing the Suitability of Unplasticized Poly(Vinyl Chloride) for Museum Showcase Construction

ABSTRACT Rigid, unplasticized poly(vinyl chloride) (PVC-U) sheet products were evaluated comprehensively for the first time with regard to their use in museum showcase construction. The compositions of numerous name brand products (Sintra, Forex, Komatex, Komacel, Celtec, Ex-cel FF, PALIGHT, and ePVC) have been determined using pyrolysis-gas chromatography-mass spectrometry, while their volatile emissions were assessed using modified Oddy tests as well as direct thermal desorption chromatography at elevated temperatures. Despite frequently passing the aggressive conditions of the Oddy test, most premium quality brands were found to release 2-ethylhexyl thioglycolate (2-EHTG), a sulfur-bearing byproduct of a heat stabilizing additive. Importantly, only the economy versions of PVC-U analyzed in this study (Komacel and ePVC) did not contain the sulfur compound. This volatile thioglycolate was shown here using molecular spectroscopies to deposit on and react with copper and silver surfaces. Similarly, lead white pigmented watercolor was blackened by the thioglycolate. Based on these results, alternative materials are recommended for display cases that will contain sulfide-sensitive materials like metals.

Confinement of Recycled Aggregate Concrete (M-20) Using U-PVC Pipe

There is a issue of rusting and brittle failure in building structures so there is a need of more durable structure for better performance. The durability of the structure is affected by the choice of the construction material only .But here our main focus is not only to increase the durability but we are also aiming towards increasing the strength of the structure which can be achieved by the confinement of the column. Studies shows that by confining the column, its strength can be increased significantly. From durability point of view, we have carried out the complete replacement of the natural coarse aggregate with the recycled aggregate in order to know its properties and suitability as a replacement material and to promote the idea of sustainable development. In the present paper, an experimental study is presented regarding the load carrying capacity of the unplasticized poly vinyl chloride (U-PVC) confined columns subjected to axial compressive load. The cylinders that are used for this study are M20 grade concrete cylinders which are made using the recycled coarse aggregates. The cylinders are confined using the U-PVC pipes of 2.5mm & 3.5mm thickness and epoxy resin was used to increase the bond strength between the concrete cylinders & the U-PVC pipes. The cylinders that are used in this study are of length 300mm & diameter 150mm. The concrete used in study are designed as per the latest versions of Indian Standard Code of Practice and are prepared after running various trial mixes. A total of 9 specimens were casted for this study out of which 6 specimens were confined using U-PVC pipes while the other 3 specimens were unconfined. The specimens were subjected to gradual compressive load in universal testing machine (UTM) upto the failure and the results were recorded. The results indicated significant increase in the load carrying capacity of the confined columns as compared to the unconfined columns.

A novel methodology for predicting the high rate mechanical response of polymers from low rate data: application to (plasticised) poly(vinyl chloride)

Plasticised and unplasticised poly(vinyl chloride) (PVC) are used as engineering materials in many applications where they may be subjected to impact loading leading to high strain rate deformation at a variety of temperatures. It is therefore necessary to study the mechanical responses of these and similar materials over a range of loading conditions, especially as they exhibit strong rate and temperature dependence, and could include a low temperature brittle transition. In this paper, a model of the mechanical response of a PVC with 20 wt% plasticiser and one with no plasticiser is applied over a wide range of strain rates and strains and shown to have excellent agreement with experiments conducted in a previous study. As it is challenging to obtain high rate data on rubbery materials using conventional apparatus, such as the split-Hopkinson pressure bar (SHPB), an alternative approach is presented based on a novel modelling framework, which uses the time–temperature superposition principle and is fully calibrated using quasi-static experiments at different temperatures.

Un-Plasticized Polyvinyl Chloride and its Growth on Nepalese Market

The paper presents an overview of some marketing strategies that are strongly influencing on the Nepalese un-plasticized poly vinyl chloride door and windows market. The result of the study reveals that product quality improvement is one of the important products related marketing strategies in the doors and windows market of Nepal and addition of new features. The study also reveals that advertisements and exhibitions/meets are two important promotional strategies influencing the consumers in their purchase. This study followed a judgmental sampling technique. The study shows that there is enough evidence to indicate that the brand preference is dependent on market segment in un-plasticized poly vinyl chloride windows in Kathmandu Valley market. Upon the analysis of the product delivery report of the past five years the market seems to be growing at an average rate of 25% annually. Un-plasticized poly vinyl chloride has comparative advantage over wood and aluminum profiles on technical, physical as well as overall performance comparison hence proving to be a better material for doors and windows.

Degradation of unplasticised poly vinyl chloride based engineering products upon exposure to ultra violet radiation

Poly vinyl chloride (PVC) is considered as a widely used polymer for various applications. It is durable, inexpensive and resistant to heat, water and chemicals. Additives such as lubricants, heat stabilizers, plasticizers, impact modifiers, fillers and ultra violet (UV) stabilizers enhance its durability and make it suitable for a range of applications. PVC is used for automobile and other sectors in products ranging from piping and siding, blood bags and tubing, to wire and cable insulation applications. Poly vinyl chloride exhibits high sensitivity to UV rays and it is a life time deciding factor specially in outdoor applications. This study was conducted to analyse the degradation behavior of PVC under the UV environment. Commercially available 32mm PNT7 unplasticised poly vinyl chloride (uPVC) pipes were selected for this research. Initially, tensile strength, elongation, hardness and water absorption properties were analysed. Ultra violet ray exposure test was performed for PVC samples to evaluate the photo-degradation behavior at selected UV exposure time periods. Tensile strength, elongation, hardness, water absorption properties and visual inspection tests were performed after the UV exposure test. Scanning electron microscopic images and differential thermal analysis were also used to analyze the degradation behavior. It was indicated a slight reduction of tensile strength, percentage elongation and hardness of samples with increase of UV exposure time. Scanning electron microscopic images of products showed degraded features after UV exposure test. This study revealed that uPVC based products are resistant to photodegradation by UV rays.

Electron Hopping between Fe 3 d States in Ethynylferrocene‐doped Poly(Methyl Methacrylate)‐poly(Decyl Methacrylate) Copolymer Membranes

AbstractSynchrotron radiation‐valence band spectroscopy (SR‐VBS) has been utilized in a study of redox molecule valence states implicated in the electron hopping mechanism of ethynylferrocene in unplasticized poly(methyl methacrylate)‐poly(decyl methacrylate) [PMMA‐PDMA] membranes. In this communication, it is revealed that, at high concentrations of ethynylferrocene, there are observable Fe 3d valence states that are likely linked to electron hopping between ferrocene moieties of neighbouring redox molecules. Furthermore, electrochemically induced stratification of ethynylferrocene in an oxidized PMMA‐PDMA membrane produces a gradient of Fe 3d states toward the buried interface at the glassy carbon/PMMA‐PDMA membrane enabling electron hopping and electrochemical reactivity of dissolved ethynylferrocene across this buried film.

Effect of Unplasticized Poly Vinyl Chloride (UPVC) Molecular Weight and Graft-Acrylonitrile-Butadiene-Styrene (g-ABS) Content on Compatibility and Izod Impact Strength of UPVC/g-ABS Blends

ABSTRACTIn this study three grades of rigid poly vinyl chloride (PVC) having different molar masses were melt blended with graft-acrylonitrile-butadiene-styrene (g-ABS) in different compositions. The effect of PVC molecular weight and g-ABS composition on the compatibility and Izod impact strength of the blends were investigated. Differential scanning calorimetry (DSC) results showed a single glass transition temperature (Tg) for all the blends, representative of miscibility between the PVC phase and the styrene-acrylonitrile copolymer (SAN) phase of g-ABS which, in turn, led to compatibility of the PVC/g-ABS blends. It was observed that in all the PVC grades the blends Izod impact strength increased with increasing g-ABS content. Also, at a given composition of g-ABS, by increasing the molecular weight of the PVC phase the impact strength of the blends increased. The morphology of the fracture surfaces from the impact tests were analyzed using scanning electron microscopy (SEM) micrographs and the results showed that with increasing g-ABS content in the blend, cloudy regions increased and eventually begin to overlap each other, and the deformed material on the fracture surfaces increased. This was attributed to the blend compatibility causing greater energy dissipation in the fracture process.

Frame Effects on Outdoor–Indoor Transmission Class of Fixed and Open Glass Windows

The effect of a frame around glass fixed windows on outdoor-indoor transmission class (OITC) was studied here. Three frame materials were selected, i.e., timber, Aluminum and unplasticized Poly Vinyl Chloride (uPVC). The use of real open window (to differentiate it from partially open double layered window) for natural ventilation was also studied. The top hung style was selected due to common usage and the possibility of noise blockage by the shutter. Laboratory test complies with ASTM E-90 was employed. The study showed that weight and density, which play significant roles in sound insulation quality of a material was not borne out for the window frame. Here, timber as the heaviest material gave lowest OITC and transmission loss (TL) contour. This was due to the absence of sealant and rubber strips which are unusual for timber caused by large thermal expansion coefficient. Top hung openings of 5° and 10° showed similar transmission loss contours, but the OITC of the 5° open window was slightly higher than the 10°.

Effects of Sulfate, Chloride, and Bicarbonate on Iron Stability in a PVC-U Drinking Pipe.

In order to describe iron stability in plastic pipes and to ensure the drinking water security, the influence factors and rules for iron adsorption and release were studied, dependent on the Unplasticized poly (vinyl chloride) (PVC-U) drinking pipes employed in this research. In this paper, sulfate, chloride, and bicarbonate, as well as synthesized models, were chosen to investigate the iron stability on the inner wall of PVC-U drinking pipes. The existence of the three kinds of anions could significantly affect the process of iron adsorption, and a positive association was found between the level of anion concentration and the adsorption rate. However, the scaling formed on the inner surface of the pipes would be released into the water under certain conditions. The Larson Index (LI), used for a synthetic consideration of anion effects on iron stability, was selected to investigate the iron release under multi-factor conditions. Moreover, a well fitted linear model was established to gain a better understanding of iron release under multi-factor conditions. The simulation results demonstrated that the linear model was better fitted than the LI model for the prediction of iron release.

Electrochemical Mechanism of Ferrocene-Based Redox Molecules in Thin Film Membrane Electrodes

Cyclic voltammetry (CV) in chloride-based aqueous electrolytes of ferrocene molecule doped thin membranes (∼200nm in thickness) on glassy carbon (GC) substrate electrodes, both plasticized poly(vinyl chloride) (PVC) and unplasticized poly(methyl methacrylate)/poly(decyl methacrylate) (PMMA-PDMA) membranes, has shown that the electrochemical oxidation behavior is irreversible due most likely to degradation of ferrocene at the buried interface (GC|membrane). Furthermore, CV of the ferrocene molecules at GC electrodes in organic solvents employing chloride-based and chloride-free organic electrolytes has demonstrated that the chloride anion is inextricably linked to this irreversible ferrocene oxidation electrochemistry. Accordingly, we have explored the electrochemical oxidation mechanism of ferrocene-based redox molecules in thin film plasticized and unplasticized polymeric membrane electrodes by coupling synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and near edge X-ray absorption fine structure (NEXAFS) with argon ion sputtering to depth profile the electrochemically oxidized thin membrane systems. With the PVC depth profiling studies, it was not possible to precisely study the influence of chloride on the ferrocene reactivity due to the high atomic ratio of chloride in the PVC membrane; however, the depth profiling results obtained with a chlorine-free polymer (PMMA-PDMA) provided irrefutable evidence for the formation of a chloride-based iron product at the GC|PMMA-PDMA interface. Finally, we have identified conditions that prevent the irreversible conversion of ferrocene by utilizing a high loading of redox active reagent and/or an ionic liquid (IL) membrane plasticizer with high ionicity that suppresses the mass transfer of chloride.

Fabrication of superhydrophobic unplasticized poly(vinyl chloride)/nanosilica sheets using Taguchi design methodology

This study introduces a relatively simple technique to manufacture superhydrophobic coatings on polymeric surfaces. Plastics such as unplasticized polyvinyl chloride (UPVC) do not have strong hydrophobic nature that is characterized by their low contact angles. Both techniques of increasing surface roughness and lowering surface energy are required to change their hydrophilicity to superhydrophobicity. In the present study, a coating of a low surface energy thermoplastic polyurethane (TPU) was spin coated by chemically treated nano silica to reduce the surface energy of UPVC. Nano silica particles were embedded on the surface using a hot-press. Taguchi design was used to optimize multiple processing parameters. Samples spin-coated with 10 g/L nano silica suspension in ethanol at the rate of 400 rpm for 5 s and then hot-pressed at 155° C under 2 atm for 4 minutes had ~157° contact angle and ~6° sliding angle that are characteristic of superhydrophobic surfaces. AFM and SEM imaging showed that these superhydrophobic surfaces were highly rough with nanoscale features. Peel test and SEM analysis showed that silica nanoparticles embedded in the TPU coating were more stable than particles immobilized on UPVC sheet without TPU coating, proving that a layer of more flexible coating can improve the longevity of superhydrophobic surfaces manufactured using this facile method.

STUDY THE EFFECT OF THE ENVIRONMENTAL PARAMETERS ON THE PERFORMANCE OF A PROTOTYPE FOR ASPHALT SOLAR COLLECTOR USING AIR AS A WORKING FLUID

Diminution of fossil fuel inspires researches to look for renewable energy sources. Heat island and road accidents resulted from tires explosion due to excessive asphalt heat (reach to 70 oC) were another problems. These problems oriented researchers to use asphalt as a heat collector. They found by using asphalt as a heat collector it will gain energy, reduce heat island and reduce road accidents as well. Recently researchers started to use some applications of asphalt solar collector (ASC). Majority of these applications used to heat and cool water. In this research, the first ASC prototype was built outside the laboratory and using atmospheric air as a working fluid. The environmental parameters such as ambient temperature, variation of solar day time, asphalt surface temperature is considered. This prototype consisted of buried pipes under asphalt layers with two opening ends. One end is connected to atmospheric air duct and the other ends connected to Unplasticized Poly Vinyl Chloride (UPVC) chimney. It has been found compatibility with the laboratory study in the strong effect of the chimney height on the air flow velocity through the ASC. Also it can be concluded that the ASC prototype performance for producing energy depends on prototype components in terms of chimney height, asphalt temperature and the environmental / atmospheric conditions in terms of ambient air temperature, and ambient wind speed. Key words: Asphalt collector, solar energy, energy harvesting, and air velocity.