Latex Foam Research Articles

Employeess Turnover at Latex Foam Company Limited in Ghana

Employeess Turnover at Latex Foam Company Limited in Ghana

Imparting antimicrobial properties to natural rubber latex foam via green synthesized silver nanoparticles

AbstractThe green synthesis of silver nanoparticles (AgNPs) in centrifuged natural rubber latex (NRL) by in situ reduction of silver nitrate by NRL is described. The synthesis of AgNP within NRL was successfully carried out without the addition of any reducing agent or stabilizers. The modified AgNP incorporated with centrifuged NRL (GAgNP_NRL) was used to make NRL foam (NRLF) by the Dunlop production method. An ultraviolet–visible (UV‐Vis) spectrophotometer analysis, Zeta potential analysis data and transmission electron micrograph analysis proved that the modified centrifuged NRL consisted of stable nanometer‐sized silver particles. A scanning electron microscopic (SEM)/energy‐dispersive X‐ray spectroscopy (EDX) analysis and UV‐Vis analysis of a latex film made out of the modified GAgNP_NRL compound showed nano‐sized silver particles inside the rubber matrix. The final product of the NRLF (GAgNP_NRLF) made out of the GAgNP_NRL compound was tested for antimicrobial properties against gram‐negative Escherichia coli, gram‐positive Staphylococcus aureus and Staphylococcus epidermidis. The resultant GAgNP_NRLF strongly inhibited the bacteria. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40155.

Natural Rubber Latex Foam Loading with Metronidazole

Normally, natural rubber latex foam (NRLF) has been produced from natural rubber latex with centrifugation and addition of foaming agent such as ammonium olaete. In this study, the different porosities of NRLFs were loaded with metronidazole (MET), the antibiotic and powerful antiprotozoal agent. NRLFs topography, water uptake and erosion properties were studied. Release of MET from NRLFs was performed in phosphate buffer pH 7.4 at 37°C and the cumulative amount of MET liberation was determined by UV-Vis spectrophotometer. NRLFs exhibited the apparent porous structure with highly water uptake and no erosion. Burst release of MET from NRLFs was noticed for all NRLFs. Therefore, the MET-loaded NRLFs were properly suitable for fast release and their dramatically porous topography was applicable for high loading capacity of selected active compounds.

Enhancement of the antibacterial activity of natural rubber latex foam by the incorporation of zinc oxide nanoparticles

ABSTRACTThe synthesis and characterization of ZnO‐nanoparticle‐incorporated natural rubber latex foam (NRLF) are described in this article. ZnO nanoparticles were added as the primary gelling agent by the replacement of the microsized ZnO particles, whereas the control sample of the NRLF was made without the addition of any ZnO particles. ZnO nanopowder was evaluated by X‐ray diffraction (XRD), whereas the aqueous dispersion of nano‐ZnO was evaluated by transmission electron microscopy (TEM) micrograph analysis. The modified NRLF materials were evaluated by scanning electron microscopy (SEM)–energy‐dispersive X‐ray (EDX) analysis and XRD analysis. The antibacterial activities of the modified NRLF samples were evaluated quantitatively and qualitatively by antibacterial susceptibility tests against Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli bacteria. We found that the XRD peaks matched perfectly with reference code 98‐002‐6593, which was the hexagonal phase. The particle sizes given by TEM image analysis were less than 60 nm. Most of the XRD peaks obtained for the modified NRLF matched with that of the ZnO nanopowder; this proved the presence of nano‐ZnO in the modified NRLF. Further, it was proven by SEM and EDX analysis. The NRLF modified by nanosized ZnO inhibited the growth of the so‐called bacteria in a very strong manner. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39601.

Novel Method of Incorporating Silver Nanoparticles into Natural Rubber Latex Foam

Silver nanoparticles (SNP) incorporated potassium oleate (KOL) soap by in situ reduction of silver nitrate by trisodium citrate (TSC) was described. Novel incorporation method of SNP into the natural rubber latex foam (NRLF) was successfully carried out by mixing 4 parts per hundred rubber (pphr) of SNP incorporated KOL soap in to the natural rubber latex (NRL) compound. UV-Visible spectrophotometer analysis, particle size analysis data and transmission electron micrograph analysis proved the modified KOL soap consisted of stable mono-dispersed nanometer size silver particles. SEM/EDX analysis of a latex film made out with modified NRL compound by SNP incorporated KOL soap shows nanosized silver particles inside it. Modified KOL and final product of modified NRLF by SNP incorporated KOL soap tested for antimicrobial properties against Escherichia coli (E. coli). The resultant KOL itself can inhibit Gram negative E. coli bacterium in a very strong manner. Inhibition of the same strain of E. coli bacterium by modified NRLF showed positive result.

Effect of Rice Husk Powder on Compression Behavior and Thermal Stability of Natural Rubber Latex Foam

Rice husk constitutes the largest by-product of the rice milling industry. Numerous research studies have been conducted on the utilization of rice husk powder (RHP), but research on incorporating RHP into natural rubber latex foam (NRLF) is lacking. The purpose of this study was to use RHP as a filler for NRLF. A compression test was performed on RHP-filled NRLFs, and they were compared with the control NRLF. The compression set increased, while the recovery percentage decreased, as RHP loading increased. The stress versus strain curve showed increasing stress with increasing RHP loading. The increase in thermal stability and decreased (Qf/Qg) value of RHP-filled NRLFs indicated good interaction between RHP and NRLF. RHP incorporation can contribute to NRLF industries with environmentally friendly products such as mattresses and cushioning materials by lowering costs.

Biological synthesis of copper nanoparticles using Magnolia kobus leaf extract and their antibacterial activity

AbstractBakgroundBiological methods for metal nanoparticle synthesis using plant extracts have been suggested as possible ecofriendly alternatives to chemical and physical methods. In the present study, copper nanoparticles were biologically synthesized using Magnolia kobus leaf extract as reducing agent and their antibacterial activity was evaluated against Escherichia coli.ResultsOn treatment of aqueous solution of CuSO4·5H2O with Magnolia kobus leaf extract, stable copper nanoparticles were formed. UV–vis spectroscopy was used to monitor the quantitative formation of copper nanoparticles. The synthesized nanoparticles were characterized with inductively coupled plasma spectrometry (ICP), energy dispersive X‐ray spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), and high‐resolution transmission electron microscopy (HR‐TEM). Electron microscopy analysis of copper nanoparticles indicated that they ranged in average size from 37 to 110 nm. Antibacterial tests were carried out by counting viable E. coli cells after 24 h growth in shake flasks containing latex foams coated with copper nanoparticles. As a result, foams coated with biologically synthesized copper nanoparticles showed higher antibacterial activity compared with foams untreated and foams treated with chemically synthesized copper nanoparticles using sodium borohydride and Tween 20. The antibacterial activities were inversely proportional to the average nanoparticle sizes.ConclusionThe present results show that stable copper nanoparticles can be ecofriendly synthesized using Magnolia kobus leaf extract, offering an inexpensive alternative to antibacterial silver nanoparticles. © 2013 Society of Chemical Industry

Preparation and Characterization of Rice Husk Powder Incorporated Natural Rubber Latex Foam

Rice husk powder (RHP) is an abundant agricultural by product that is produced in bulk quantity as part of rice milling. This research is carried out to incorporate RHP with natural rubber latex (NRL) compound. Different loading of RHP is added to NRL compound and is foamed to make natural rubber latex foam (NRLF) using a well known technique called the Dunlop method. The tensile properties of modified NRLF is studied and compared with the controlled NRLF which has zero RHP loading. The morphology and micro structural characterization has been performed by Tabletop microscopy (TM1000). The tensile strength decreases at 2.5 pphr but increases again as the filler loading increases. Elongation at break decreases whereas modulus at 100% elongation (M 100) and hardness increases as the filler loading increases.

Aqueous Dispersion of Rice Husk Powder as a Compatible Filler for Natural Rubber Latex Foam

Rice husk powder (RHP) which is a fibrous agricultural waste is widely used as potential filler, novel adsorbent or coating for dry polymers. However, the compatibility of RHP with natural rubber latex (NRL) is yet to be studied. The main goal of this reported work was to create a method to incorporate RHP with NRL and achieve a compatible dispersion. However the amorphous silica content (acidic nature) in RHP makes it difficult to directly incorporate RHP to NRL compound. In this research, RHP was modified by adding ammonia, distilled water and dispersing agents to make an aqueous compatible alkaline dispersion for NRL. Also the particle size of RHP is reduced up to - 300micron to make it more compatible with the NRL. The compatibility of modified RHP is analyzed by sedimentation with time, particle size analyzer, pH and morphology study. The test results supports that modified RHP is more compatible with the NRL compound to obtain a stable foam in NRLF preparation.

Tensile and Morphological Properties of Rice Husk Powder Filled Natural Rubber Latex Foam

Rice husk powder (RHP) is an agricultural by-product, and this research is carried out to incorporate RHP with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) using the Dunlop method. The tensile properties of modified NRLF is studied and compared with the controlled NRLF (zero RHP loading). The morphology and micro structural characterization has been performed by tabletop microscopy (TM1000). The tensile strength decreases at 2.5 pphr but increases again with increasing filler loading. Elongation at break decreases, whereas modulus at 100% elongation (M 100) and hardness increases with increasing filler loading.

Antibacterial latex foams coated with biologically synthesized silver nanoparticles using Magnolia kobus leaf extract

Silver nanoparticles are used in many industries due to their disinfection and antibacterial properties. Biological methods of nanoparticle synthesis have been suggested as possible ecofriendly alternatives to chemical and physical methods. In this study, biologically synthesized silver nanoparticles using Magnolia kobus leaf extract were coated on the surface of latex foam products using dip coating (exposure to nanoparticle solution) or ultrasonic treatment. SEM image of the treated foam showed that silver nanoparticles were uniformly coated on the surface of latex foam. Antibacterial properties were tested by counting viable Escherichia coli cells after 24 h growth in shake flask cultures containing latex foams coated with silver nanoparticles. Foams coated with silver nanoparticles showed higher antibacterial activities compared with foams untreated. Smaller silver nanoparticles synthesized at higher temperature showed higher antibacterial activity due to the larger specific surface area and higher content of silver nanoparticles. The growth of E. coli decreased with increasing the concentration of silver nanoparticles. Ultrasonic treatment showed higher adsorption and lower desorption of silver nanoparticles to and from the foams compared with dip coating, resulting in higher antibacterial activity.

Preparation and characterization of baked nitrile latex foam reinforced with biomasses

Nitrile latex foam was prepared by baking method using a chemical blowing agent along with the addition of fungal starch, calcium carbonate and aspen fiber. The influences of these components on the mechanical properties of latex foams were studied. Different additives showed different enforcement behaviors. Results showed that aspen fiber had the best reinforcement behaviors on the mechanical properties of latex foam. The thermal degradation as well as its foam morphology was investigated. Fourier transform infrared spectroscopy and thermal gravimetric analysis clearly identified that the latex foam was a composite of the mixture of foam components with nitrile latex film. The result of scanning electron microscopy exhibited that both starch particles and calcium carbonate particles were richly distributed around wood fiber.

Evaluation of Pads and Geometrical Shapes for Constructing Evaporative Cooling System

Investigations were carried out into local materials as cooling pads, and shapes for constructing evaporative coolers. Materials investigated include jute, latex foam, charcoal and wood shavings. Shapes of cooling systems considered were of hexagonal and square cross-sections. Some physical properties of pad materials that could affect the effectiveness of the evaporative coolers were also determined. Results of “No – load” tests carried out on the coolers indicated that the effectiveness of the cooling pads was in the following decreasing order of magnitude - Jute, latex foam, charcoal and wood shavings. The hexagonal shape cooler was found to be more efficient than the square shape. The average cooling or saturation efficiency for hexagonal cooler was 93.5% (jute), 91.4% (latex foam), 91.3% (charcoal) and 91.9% (wood shavings). The maximum temperatures observed were 6.4 (jute pad), 4.9 (latex foam pad), 5.2 (charcoal pad) and 3.6 degree Celsius. The results of this study will assist researchers in their selection of pad materials in the study of evaporative cooling systems.

Synthesis and Characterization of Nano-Silver Incorporated Natural Rubber Latex Foam

Synthesis and characterization of silver nanoparticles (SNP) incorporated natural rubber latex foam (NRLF) is described. SNP synthesized by reducing of Silver Nitrate (AgNO3) with Tri-Sodium Citrate (TSC) were adsorbed in-situ on to the NRLF matrix. Antimicrobial activities were tested by qualitatively and quantitatively against Gram positive Staphylococcus aureus and Gram negative Escherichia coli. It was found that the resultant NRLF samples inhibit the growth of so called two main groups of bacteria in very strong manner. The SEM and EDX analysis provided evidence of adsorbed silver particles on the foam rubber matrix are in nanometer size.

Synthesis and characterization of nano silver based natural rubber latex foam for imparting antibacterial and anti-fungal properties

Synthesis and characterization of nanosilver based antimicrobial natural rubber latex foam (NRLF) is described. Silver nanoparticles were synthesized by reducing silver nitrate by tri-sodium citrate in an aqueous medium. UV–Vis spectrophotometer analysis, particle size analysis and transmission electron image analysis proved that the resultant silver nanocolloid was an aqueous dispersion consisting of stable nanometer size silver particles. Antibacterial activities were tested against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli (E. coli) bacteria, whereas antifungal activities were tested against Aspergilles niger (A. niger). It was found that the resultant NRLF samples inhibit the growth of the these bacteria and fungus in a very strong manner.

Study on Resilience of Mattress Foam and Body Pressure Distribution Characteristic of Mattress

The resilience of mattress foam has influenced on body pressure distribution characteristic of mattress and human comfort. This paper dealt with resilience of foam and body pressure distribution through resilience test instrument for mattress foam and body pressure distribution system. The results showed that the resilience of latex foam was better and the body pressure distribution of mattress with latex foam layer was better. This study results have important reference value to the flexibility of mattress and comfort design.

A randomized, comparative trial: does pillow type alter cervico-thoracic spinal posture when side lying?

BackgroundMany patients ask for advice about choosing a pillow. This research was undertaken to determine if pillow type alters cervico-thoracic spine position when resting in the side-lying position.AimTo investigate the effect of different pillow shape and content on the slope of cervico-thoracic spine segments when side lying.Materials and methodsThe study was a randomized blinded comparative trial set in a laboratory that replicated a bedroom. The subjects were side sleepers aged over 18 years. Exclusion criteria were history of surgery to the cervico-thoracic spine, an injury or accident to the cervico-thoracic spine in the preceding year, or currently receiving treatment for neck symptoms. Each participant rested in a standardized side-lying position for 10 minutes on each of the trial pillows: regular shaped polyester, foam, feather, and latex pillows, and a contour shaped foam pillow. Reflective markers were placed on external occipital protuberance (EOP), C2, C4, C7, and T3, and digital images were recorded of subjects at 0 and 10 minutes on each pillow. Images were digitized using each reflective marker and the slope of each spinal segment calculated. Univariate analysis of variance models were used to investigate slope differences between pillows at 0 and 10 minutes. Significance was established at P < 0.01 to take account of chance effects from repeated measures and multiple comparisons.ResultsAt 0 and 10 minutes, the EOP-C2, C2-C4, and C4-C7 segmental slopes were significantly different across all pillows. Significant differences were identified when comparing the feather pillow with the latex, regular and contour foam pillows, and when comparing the polyester and foam contour pillows. The regular and contour foam pillows produced similar slopes at all spinal segments.ConclusionCervico-thoracic spinal segment slope alters significantly when people change from a foam, latex, or polyester pillow to a feather pillow and vice versa. The shape of a foam pillow (contour versus regular shape) does not significantly alter cervico-thoracic spinal segment slope.

SYMPTEK Homemade Foam Models for Client Education and Emergency Obstetric Care Skills Training in Low-resource Settings

Clinical training for health care workers using anatomical models and simulation has become an established norm. A major requirement for this approach is the availability of lifelike training models or simulators for skills practice. Manufactured sophisticated human models such as the resuscitation neonatal dolls, the Zoë gynaecologic simulator, and other pelvic models are very expensive, and are beyond the budgets of many training programs or activities in low-resource countries. Clinical training programs in many low-resource countries suffer greatly because of this cost limitation. Yet it is also in these same poor countries that the need for skilled human resources in reproductive health is greatest.The SYMPTEK homemade models were developed in response to the need for cheaper, more readily available humanistic models for training in emergency obstetric skills and also for client education. With minimal training, a variety of cheap SYMPTEK models can easily be made, by both trainees and facilitators, from high-density latex foam material commonly used for furnishings. The models are reusable, durable, portable, and easily maintained. The uses, advantages, disadvantages, and development of the SYMPTEK foam models are described in this article.

高分子微粒子を利用する多孔質炭素材料の新規創出法

A series of colloidally stable near-monodisperse polyacrylonitrile (PAN) latex particles with a submicrometer diameter were synthesized by either dispersion or emulsion polymerization and examined for their performance in the preparation of highly stable latex foams. Poly(N-vinylpyrrolidone) was used as a colloidal stabilizer, which adsorbed at PAN particle surface. The PAN particles were extensively characterized using scanning electron microscopy, fourier transform infrared spectroscopy, and dynamic light scattering method. Submicrometer-sized PAN latex particles were invariably adsorbed at air-water interface and stabilized foams generated by simple hand-shaking or using a foam column, with no additives (e.g., surfactant, salt, or cosolvent) being required to induce latex destabilization. The foams stabilized with the PAN particles could keep their 3 dimensional porous structures even after drying. Scanning electron microscopy studies indicate near close-packed PAN particles within the dried foam, which suggests high colloid stability for the PAN particles prior to their adsorption at the air-water interface. Annealing the particulate foams up to 1000℃ under nitrogen atmosphere led to black-colored materials. Thermogravimetry and fourier transform infrared spectroscopy studies and scanning electron microscopy observation confirmed that porous carbon materials were successfully synthesized from the PAN latex-stabilized particulate foam. This particulate foam-based method should be advantageous because only particles, water and air are required, and production on an industrial scale is much more likely compared to a template-based synthetic route. Potential applications for these porous carbon materials include catalyst supports and novel electronic and optical devices.

Preparation of stable foams using sterically stabilized pH-responsive latexes synthesized by emulsion polymerization

Three near-monodisperse poly(2-vinylpyridine) (P2VP) latexes of 380 nm, 640 nm and 820 nm diameter were prepared in turn by emulsion copolymerization of 2-vinylpyridine and divinylbenzene using a monomethoxy-capped poly(ethylene glycol) monomethacrylate (PEGMA) macromonomer as a reactive steric stabilizer. Each of these latexes proved to be effective particulate stabilizers for the production of long-lived foams by either hand-shaking or using foam columns. Scanning electron microscopy studies confirmed that the dried foams contained well-defined latex bilayers in each case, suggesting that the original air bubbles were stabilized with latex monolayers. Dried foams prepared using the smallest latex exhibited interesting optical effects when viewed in reflectance mode. This is most likely due to light diffraction by the latex bilayers, since the mean latex diameter of 380 nm is approximately half that of visible light. These PEGMA–P2VP particles undergo a latex-to-microgel transition at low pH. Such swelling causes catastrophic instability within the wet foams, presumably due to microgel desorption from the air–water interface. Thus these latex foams exhibit pH-responsive behavior.