High Density Poly Research Articles

Effect of UV exposure on bimodal HDPE floats for floating solar application

Keeping in view the conservation of natural resources, the power generation from the solar photovoltaic system is increasing day by day to meet the demand of energy worldwide. There are constraints of availability of space for ground mounted solar PV system for large installations. In some countries water bodies are being utilized to install solar PV system to reduce land use. Few floating systems using plastics have been developed to install a solar panel on it. After extensive literature studies on properties of polyolefins, High-density poly ethylene (HDPE) is found to be better material for this purpose.In order to measure its sustainability, annotation of mechanical properties using bimodal poly ethylene under accelerated weathering condition has been carried out in different intervals till 1152h, to perceive the lifespan of HDPE material. The change in its mechanical properties like tensile strength, elongation at break, maximum load bearing capacity, impact resistance and hardness were evaluated. It was observed that the tensile strength was reduced from 23.22MPa to 14.64MPa after accelerated UV exposure. It was observed that after 1000h of exposure to accelerated weathering the material still has the tendency to hold a constant load of 637.81N without rupture, compared to non-weathered sample (955.16N). The elongation at break was reduced but elongation of 6.24% was maintained after 1152h of accelerated exposure, which depicts the elasticity of the material, is still maintained. The impact resistance did not show a significant change during this period, the value varies in the range of 13.54–10.06kJ/m2. However, the hardness was increased from 61 to 66 (Shore D) due to deterioration of low molecular weight polymer present in bimodal PE. It is concluded that the mechanical properties of Biomodal HDPE material after accelerated UV exposure does not have much effect and is safe to bear the load of solar panels and other accessories mounted over it. Further studies can be done using UV stabilized biomodal HDPE.

Effects of Packaging and Storage on Keeping Quality of Bleached lac

A study on the effect of different packaging materials and storage conditions was carried out on keeping quality of freshly prepared bleached lac packaged in five different types of packaging materials: Low Density Poly Ethylene (LDPE ), High Density Poly Ethylene (HDPE), Poly Propylene (PP), Metalized Polypropylene film (METPP) and five layer craft Paper Bag (PG). The samples were stored in both ambient and refrigerated conditions (14-160C) and quality parameters were evaluated at quarterly interval after 3, 6, 9 and 12 months of storage followed by comparison with samples stored in open condition. For storage under ambient condition in room, the flow value (fluidity), life (heat polymerization time) and acid value (AV) of the packaging material was highest for metalized film bag i.e.10mm, 5 min. and 70.69 respectively and impurity content was least (2%) after 3 months of storage due to high amount of moisture (4.12% db) retained in the sample. These parameters were lower in other packaging materials due to lower moisture content (1.38-2.40% db) with the lowest value (1.01% db) in open storage condition. For storage under the refrigerated condition, these parameters were higher compared to ambient storage for all packaging material. Flow value, life and acid value of samples in the metalized bag were highest; 35mm, 10 min. and 74.36 after 3 months of storage. However, these parameters were lower in others packaging materials due lower moisture content (1.50-2.61% db) with lowest value (1.23% db) in open storage condition. The flow and life of samples packaged in metalized film bag were highest i.e. 25mm and 5 minutes respectively after six months of storage as compared to when packaged in others. During the study it was observed that keeping quality of bleached lac samples was better in metalized film bag (82.5µ) compared to other packaging materials for both ambient and refrigerated storage condition.

Flexural Behaviour of Biaxial Slabs Voided with Spherical HDPP Void Formers

Present study involves the experimental analysis of spherically voided biaxial slabs. The intention was to eliminate the unused concrete in massive slab constructions. Three voided slab specimens (2900 mm × 2900 mm × 100 mm) were cast. The voids were created by introducing spherical-shaped high-density poly propylene void formers in between the compression and tension layers of the slab. The parameter varied was the spacing of the void formers, which were kept as 20, 30 and 50 mm. The corresponding reduction in volume of concrete for the above-mentioned spacing was 22.7, 18.4 and 12.21%, respectively. The slabs were subjected to area loading instead of regular five-point loading. Analytical calculation for the ultimate load carrying capacity was carried out similar to biaxial solid slab. Comparison of load deflection behaviour showed that void spacing between 20 and 30 mm may be provided to satisfy both strength and serviceability criteria. The percentage reduction in volume of concrete was found to be directly proportional to percentage reduction in cost of construction.

Structural changes in HDPE produced by in-line plasma-pretreated reactive extrusion

Structure of high density poly ethylene (HDPE) was changed after Plasma-induced graft polymerization of methyl methacrylate (MMA) monomer onto HDPE. Continuous polymerization of monomer wetted HDPE pellets was carried out sequentially via in-line plasma pretreatment followed by reactive extrusion. It was influenced by plasma pretreatment times between 15 s and 120 s on degree of grafting and molecular structure of the extrudate. Maximum degree of grafting was limited to 6% after 30 s plasma pretreatment. The addition of dicumyl peroxide (DCP) increased the degree of grafting to 10% after 15 s of plasma treatment. Gel formation to levels in the range 3–5% was detected, increasing with plasma pretreatment time. The formation of long chain branched (LCB) architecture, of the extruded PMMA-g-HDPE, was confirmed by rheological test in oscillatory shear, which results in increases in low frequency storage and loss moduli and melt viscosity than that of neat HDPE, especially after DCP addition. Finally, formation of a fully crosslinked structure was observed after annealing at 210 °C for 1 h as evidenced by a change in rheological properties at lowest frequencies to solid-like behaviour. Such extensive crosslinking could be useful in producing high strength adhesive joints between HDPE and other materials.

Chickpea flour supplemented high protein composite formulation for flatbreads: Effect of packaging materials and storage temperature on the ready mix

Abstract Shelf life studies are gaining impetus due to the consumer’s attentiveness towards excellence of the packaged products. The present study was carried out to develop a composite premix formulation for chickpea supplemented flatbread and to estimate the suitability of packaging material and storage temperature on its quality. Whole wheat flour was supplemented with chickpea flour from 10 to 50%; fenugreek powder and onion flakes at 0–20%; salt, ginger powder, green chilli powder and red chilli powder at 0–2%, mango powder at 0–5%; glycerol mono stearate (GMS) and sodium steaoryl-2-lactylate (SSL) at 0–0.50% and fat at 0–4%. Two formulations (I and II) were prepared after selecting the appropriate levels of ingredients by sensory evaluation using trial and error method. Formulations were packed in zip pouch, aluminum laminate and high density poly ethylene at room and refrigeration temperatures. Changes in the total composition, water activity, free fatty acid, overall acceptability and texture of flatbreads were assessed for four months. Storage period had most significant effect followed by storage temperature and packaging material on quality attributes of formulations. All the samples were in acceptable condition where aluminum laminate and refrigerated temperature were the best combination for storage of formulation I and II.

Graphene oxide-based boronate polymer brushes via surface initiated atom transfer radical polymerization for the selective enrichment of glycoproteins.

Biomedical sciences, and in particular biomarker research, demand efficient glycoprotein enrichment platforms. In this work, a facile and efficient method was developed to synthesize boronic acid polymer brushes immobilized on magnetic graphene oxide via surface initiated atom transfer radical polymerization (SI-ATRP) for the selective enrichment of glycoproteins from complex biological samples. The magnetic graphene oxide (GO@Fe3O4) nanocomposites were prepared by a solvothermal reaction, providing an ultrahigh surface area and allowing fast separation. Through the self-assembly procedure, the pyrene-based initiators (GO@Br) of SI-ATRP were easily functionalized on the GO sheet via noncovalent π-π interaction between pyrene and GO. Finally, the well-defined and high density poly(4-vinylphenylboronic acid) brushes (GO@PVPBA) via SI-ATRP were successfully fabricated. The morphology and structure of GO@Fe3O4, GO@Br, and GO@PVPBA nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform-infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The selective recognition capability of GO@PVPBA nanocomposites was demonstrated by the selective enrichment of glycoproteins from a complex system consisting of standard proteins ovalbumin (OVA), transferrin (Trf), bovine serum albumin (BSA), and lysozyme (Lyz). Furthermore, the GO@PVPBA nanocomposite also exhibited a high binding capacity up to 514.8 and 445.9 mg g-1 for OVA and Trf, respectively, and was applied to capture directly glycoproteins from the egg white samples.

Effect of the MWCNTs selective localization on the dielectric properties for PVDF/PS/HDPE ternary blends with in situ formed core–shell structure

This work demonstrated the selective localization of multiwall carbon nanotubes (MWCNTs) in poly(vinylidene fluoride) (PVDF)/poly(styrene) (PS)/high-density poly(ethylene) (HDPE) blends to be an effective method to reduce the dielectric loss.

Shape stabilised phase change materials based on a high melt viscosity HDPE and paraffin waxes

Shape stabilised phase change materials (SSPCMs) based on a high density poly(ethylene)(hv-HDPE) with high (H-PW, Tm=56–58°C) and low (L-PW, Tm=18–23°C) melting point paraffin waxes were readily prepared using twin-screw extrusion. The thermo-physical properties of these materials were assessed using a combination of techniques and their suitability for latent heat thermal energy storage (LHTES) assessed. The melt processing temperature (160°C) of the HDPE used was well below the onset of thermal decomposition of H-PW (220°C), but above that for L-PW (130°C), although the decomposition process extended over a range of 120°C and the residence time of L-PW in the extruder was <30s. The SSPCMs prepared had latent heats up to 89J/g and the enthalpy values for H-PW in the respective blends decreased with increasing H-PW loading, as a consequence of co-crystallisation of H-PW and hv-HDPE. Static and dynamic mechanical analysis confirmed both waxes have a plasticisation effect on this HDPE. Irrespective of the mode of deformation (tension, flexural, compression) modulus and stress decreased with increased wax loading in the blend, but the H-PW blends were mechanically superior to those with L-PW.

Comparative Studies of PCM Based TES System Using Different PCMs

The purpose of thermal energy storage systems (TES) is to store the heat energy supplied to it for a considerable time period and give the energy back when ever need arise. On many of occasions, part of the heat energy of various systems is unutilized. If this excess heat energy be stored in such systems as TESS, utilization of energy improves. If the use of such systems is widespread, fuel is conserved and national economy is saved.Different materials can be used in TESS to store heat energy and in the present work two such materials, which are popular phase change materials (PCM) namely (a) Paraffin (b) Stearic acid are used and subsequently the performance of the TESS is studied. The PCMs are used in the form of spherical capsules made up of high density poly ethylene (HDPE) of diameter 58 mm. Charging time and amount of heat energy recovered are studied for the two PCMs mentioned above and compared. Though paraffin as PCM gives little better heat energy recovery, performance of both the materials are almost the same. Hence as the cost of stearic acid is less when compared to paraffin on economical grounds and on ease of availability basis stearic acid has advantages over paraffin.

Experimental comparison between internally and externally cooled air-solution contactors

Air-conditioning demand, especially in hot and humid climates, causes most of the energy consumption in buildings. In these applications, the latent load often constitutes a significant part of the total load. Conventional air-conditioning systems deal with the required dehumidification by cooling the moist air below its dew point and reheat it later to increase its temperature to comfortable supply conditions. By using solid/liquid desiccant systems, which absorb humidity from the air, it becomes unnecessary to reach the dew point to dehumidify, thereby reducing energy consumption. In liquid desiccant systems, dehumidification occurs in the absorber, where the humidity of the air is absorbed by direct contact with a desiccant. Most of the previous liquid desiccant system studies have used adiabatic absorbers, where the solution must be cooled externally before being delivered into the air-solution contactor. However, based on experience with closed-cycle absorption systems, internally cooled absorbers are expected to yield better performance considering that a cool solution temperature throughout the absorber will maintain a constant and low vapor pressure. This article presents an experimental study of two different internally cooled air-solution contactors using falling-film tubular heat exchangers: The tubes in one are made of titanium and in the other of high-density poly ethylene. The experiments have been conducted in a liquid desiccant system under summer conditions in the Mediterranean city of Haifa, Israel. A performance comparison is also carried out with an externally cooled air-solution contactor, using results obtained from previous studies.

Effect of seed coating material and storage containers on Germination and seedling Vigour of soybean (Glycine max L.)

A laboratory experiment was conducted to evaluate the effect of different seed coating materials and storage containers on germination, seedling vigour and suitability of packaging material for soybean seed. Seed of soybean varietyPS1024 was used for coating purpose with 6 coating treatments viz., T0 (control), T1 (Polymer coating i.e. Polykote @ 3 ml kg-1 of seed diluted with 5 ml of water), T2 (Flowable Thiram i.e. Royal flow 40 SC @ 2.4 ml kg-1 of seed), T3 (T1 + T2), T4 (Vitavax 200 i.e.thiram 37.5 % and carboxyl 37.5% @ 2 g kg-1 of seed and T5(T1+ T4). The coated seeds were stored in two kinds of containers i.e. jute canvas bag, high density poly ethylene (HDPE) non- laminated bag and bimonthly observation on germination and seedling vigour were recorded. After 8th month of storage, germination and vigour index in polythene bag stored seeds were significantly higher than the seed stored in cloth bag. Among seed coating treatments, maximum %germination was recorded in polymer coating @ 3 ml kg-1 followed by vitavax 200 @ 2 g kg-1of seed treatment (T5) which was significantly higher than rest of the coated treatment including untreated control seeds (T0 ). Similarly, maximum seed vigour index was observed in T5 and minimum vigor index was recorded with T0 (untreated control). DOI: http://dx.doi.org/10.3329/sja.v12i2.21913 SAARC J. Agri., 12(2): 16-24 (2014)

Storage stability and quality assessment of grain based instant mixes

The present investigation was carried out to develop low cost instant mixes and assess their shelf life. Four blends were optimized using response surface methodology for grain mixes. The four blends viz., rice: chickpea: groundnut; rice: mungbean: groundnut; wheat: chickpea: groundnut and wheat: mungbean: groundnut were extruded and mixed with skimmed milk powder and powdered sugar to develop instant mixes. Instant mixes were stored in high density poly ethylene for six months under ambient conditions. Moisture, the water activity, colour, free fatty acid content and sensory parameters were used to evaluate the shelf life of the products. The products were acceptable for a period of six months. The instant mixes were compared with the commercially available products and it was found that mixes were comparable to the commercial products in terms of nutrition and had considerably less cost. Hence, low cost nutritious instant mixes can be processed to combat protein energy malnutrition with high storage stability.

Photodynamic antimicrobial polymers for infection control.

Hospital-acquired infections pose both a major risk to patient wellbeing and an economic burden on global healthcare systems, with the problem compounded by the emergence of multidrug resistant and biocide tolerant bacterial pathogens. Many inanimate surfaces can act as a reservoir for infection, and adequate disinfection is difficult to achieve and requires direct intervention. In this study we demonstrate the preparation and performance of materials with inherent photodynamic, surface-active, persistent antimicrobial properties through the incorporation of photosensitizers into high density poly(ethylene) (HDPE) using hot-melt extrusion, which require no external intervention except a source of visible light. Our aim is to prevent bacterial adherence to these surfaces and eliminate them as reservoirs of nosocomial pathogens, thus presenting a valuable advance in infection control. A two-layer system with one layer comprising photosensitizer-incorporated HDPE, and one layer comprising HDPE alone is also described to demonstrate the versatility of our approach. The photosensitizer-incorporated materials are capable of reducing the adherence of viable bacteria by up to 3.62 Log colony forming units (CFU) per square centimeter of material surface for methicillin resistant Staphylococcus aureus (MRSA), and by up to 1.51 Log CFU/cm2 for Escherichia coli. Potential applications for the technology are in antimicrobial coatings for, or materials comprising objects, such as tubing, collection bags, handrails, finger-plates on hospital doors, or medical equipment found in the healthcare setting.

Flow instability of semicrystalline polymer melt during micro-injection molding

This work investigates the flow instability of thermoplastic polymer melt that occurs on the flow front when it enters micro-cavities. On the flow front, it was observed that small balls are formed and coalesce with each other, creating many micro-weld lines. The experimental results in this work showed occurrence of this phenomenon for polypropylene and polyamide but not for high density poly(ethylene), poly(methylmethacrylate) or acrylonitrile butadiene styrene. It was found that onset of this instability is related to the spherulite size. The effects of temperature and geometry have been scrutinized. As a conclusion, the ratio of spherulite size and channel width has been proposed as a dimensionless number related to this instability.

Heat transfer on grooved high density poly ethylene tube for surface water source heat pump

High density polyethylene (HDPE) tube has been successfully utilized in surface water source heat pump (SWSHP) system as a surface water heat exchanger (SWHE). Since the heat transfer coefficient (U value) of the HDPE tube directly affects performance and energy efficiency of SWSHP, this research aims to increase U value of HDPE tube by grooving external surface of conventional 32A HDPE tube to reducing cross sectional volume. The final shape of grooved HDPE tube is similar to that of fin. In order to verify the performance of grooved HDPE tube, the U values of grooved and smooth tube were compared experimentally. According to the results, U value of grooved tube showed approximately 21.5% increase with natural convection and 23.5% with forced convection system than U values obtained from smooth tube. The reason for such increase in U value was found to be the reduction in cross sectional volume of the HDPE tube.

The effect of confined crystallization on high-density poly(ethylene) lamellar morphology

High-density polyethylene (HDPE) was co-extruded against high glassy transition temperature (Tg) polycarbonate (PC) to fabricate multilayer films. Melt and recrystallization experiments were conducted on these extruded films to study the effects of isothermal recrystallization temperature and layer thickness on HDPE lamellae orientation. WAXS and AFM were used to demonstrate lamellar morphology of HDPE layers. We report that HDPE lamellae show twisted morphology in 30 nm thin layers after confined crystallization at a high temperature (128 °C). It may be the first time that anyone has created such twisted lamellar morphology with HDPE in such a thin layer. Similar twisted morphology of HDPE was also observed when HDPE was coextruded with another high Tg glassy polymer, polysulfone (PSF). Interestingly, the twisted HDPE lamellar morphology associated with an increased crystallinity improves both the oxygen and water vapor barrier properties of the multilayer films.

Effect of Blend Ratio on Phase Morphology and Mechanical Properties of High Density Polyethylene and Poly (Butylene Succinate) Blend

In this work, the effect of HDPE and PBS blend ratio on mechanical properties and phase morphology of the blend was investigated. HDPE/PBS blends were prepared at HDPE content of 20, 30, and 40 wt.% via melt mixing process and then molded using an injection machine. HDPE/PBS blend was an immiscible blend with a type of dispersed in matrix morphology and coalescence phase morphology depending on HDPE content. The blend morphology of 20 wt.% HDPE/PBS blend was a type of spherical domain dispersed in the PBS matrix. As increase HDPE content, the dispersed HDPE particles became larger and the shape turned into worm-like and elongated structure. In addition, at 40 wt.% HDPE, coalescence phase morphology was obtained. It was found that the PBS blends containing 30-40 wt.% HDPE did not show yield point; they exhibited brittle failure behavior. For tensile properties, yield strength and stress at break of HDPE/PBS blend gradually decreased with increasing HDPE content. However, addition of HDPE into PBS matrix resulted in an increase of Youngs modulus of the PBS blend. Impact strength of the blends was much lower than that of neat PBS but the impact strength of the blend insignificant changed with 30-40 wt.% HDPE comparing to that with 20 wt.% HDPE.

Poly(2-(dimethylamino)ethyl methacrylate) brushes fabricated by surface-mediated RAFT polymerization and their response to pH

In this study, well-defined, high density poly(2-(dimethylamino)ethyl methacrylate) [poly(DMAEMA)] brushes were fabricated by the combination of the self-assembly of a monolayer of RAFT agent and surface-mediated RAFT polymerization. The whole fabrication process of the poly(DMAEMA) was followed by water contact angles, grazing angle-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Kinetic studies revealed a linear increase in poly(DMAEMA) film thickness with polymerization time, indicating that the chain growth from the surface was a controlled process. Characterization of the poly(DMAEMA) brushes, such as molecular weight and thickness determination, were measured by gel permeation chromatography, and ellipsometry, and the grafting density was estimated. The pH response of the poly(DMAEMA) brushes was further investigated and the results verified the “brush-like” to “mushroom-like” transition of the poly(DMAEMA) chains due to the reversible protonation/deprotonation upon changing the solution pH.

ADR KSHARSUTRA KIT: A BREAKTHROUGH IN THE STANDARDIZATION OF KSHARSUTRA

‘Ksharsutra’ can be defined as an Ayurvedic medicated thread coated with herbal alkaline drugs. ‘Ksharasutra therapy ’ has been described as a treatment of choice for the treatment of fistula - in - ano due to low recurrence rate. However, Ksharsutra procedure is not yet globally accepted basically due to lack of standardization and poor acceptability by modern surgeons due to lack of training and fear of complications . Sta ndardization of ‘Ksharsutra’ requires standardization in preparation process and quality standards including its packaging, storage, labeling and developing scientific parameters for maintaining its uniform coating, pH, microbial check etc. To overcome all these limitations, ‘ADR - Ksharsutra Kit’ which is a disposable , non traumatic ‘K sharsutra Carrier cum Application device’ made up of High Density Poly Ethelene was invented by me . The Ksharsutra prepared as per ICMR guidelines after UV treatment , is embed ded in the instrument and is kept in airtight silver foil sachet and sealed. The m ethod of ‘ADR - Ksharsutra’ a pplication is simple and time conserving. The tip of the ‘ADR - Ksharsutra Carrier cum Application device’ is introduced in the external opening and allowed to follow the track up to the internal opening situated in the anal canal. Once the tip comes out through the internal opening, cap is removed and the Ksharsutra is held and then instrument is withdrawn from outside opening. By doing this, the embe dded Ksharsutra is automatically placed in the fistula track whose two ends are tied together. ‘ADR - Ksharsutra’ has truly made the entire procedure very smooth . No probe is required in the procedure and Ksharsutra kept in the instrument remains sterile as well. Hence, this ‘Ksharsutra carrier cum application device’ will be helpful in Globalization of Ksharsutra technique for fistula ablation .

Computational Fluid Dynamics Modeling of High Density Poly Ethylene Catalytic Cracking Reactor

The reactor of High Density Poly Ethylene –HDPE – conversion into liquid fuel was studied and modeled. The calculation software: CFD FLUENT was applied for this study. The software is a powerful tool in simulating chemical reactions. The simulation of HDPE catalytic cracking reactor was implemented by using this software and inserting both kinetic and thermodynamic conditions of the reaction in Isothermal state. To validate the simulation, the software output graphs including product compositions were put under comparisons with GC gas chromatography graphs. On the other hand, the non-catalytic reaction was modeled and the results were compared to catalytic cracking outputs. On the basis of the received data by simulation, the product content in catalytic cracking had higher values than thermal cracking reaction.