Glass Wool Fibers Research Articles

Impact of shock waves on glass wool composition and properties

Glass wool finds its application in soundproofing materials and insulation. This paper studies the effect of high-energy shock waves on glass wool fibres using modified Reddy shock tube. Changes in composition and properties of fibres are reported through SEM analysis. With driver pressure of 6.79 bar, Mach number, maximum pressure and temperature achieved are 1.46, 4.845 atm and 482.91 K respectively. Due to diaphragm material, carbon content of 2.92% by weight is observed in shocked specimen. SEM images show curliness in fibers, increased number and uniform distribution of binder clusters and air voids resulting in enhanced strength, hardness and insulation properties of fibres.

Content of Vitamin C, Phenols and Carotenoids Extracted from Capsicum annuum with Antioxidant, Antimicrobial and Coloring Effects.

Capsicum annuum is considered a good source of various natural compounds. The current study aimed to assess the vitamin C and total phenolic and carotenoid contents in C. annuum using standard methods. Microwave and Soxhlet extraction by using water and acetone were used to extract vitamin C and phenols. Saponification extraction was used to extract carotenoids. The antioxidant activities of each extract were assessed using a DPPH assay. The Minimum Inhibitory Concentration and Minimum Bactericidal Concentration (MIC and MBC) against Escherichia coli and Staphylococcus aureus were determined using the broth microdilution method. The coloring capacity for the acetone extract was evaluated and determined using glass wool fiber at different concentrations and then used in the formulation of multivitamin hard candy. The acetone extract showed the highest phenol and vitamin C content (1.03±0.02 and 9.7±1.3 mg mL-1, respectively), antioxidant activity (67.12±3.8 mg mL-1) and MIC and MBC of 0.96 and 1.88 mg mL-1 against E. coli and 3.75 and 7.5 mg mL-1 against S. aureus. It also showed an intense orange shade on wool fiber and on the prepared multivitamin candy at concentrations of 6 and 0.5% (w/w), respectively. Saponifications of the acetone extract yield (23.49±0.13 μg g-1) of carotenoids. The prepared acetone extract of C. annuum stands as a potential pharmaceutical additive, which can be used as coloring and preservative agents in the formulation of kids multi-vitamin candy.

Effects of luffa and glass fibers in polyurethane-based ternary sandwich composites for building materials

Luffa fiber, glass wool (yellow) and glass fiber (white) were used into polyurethane (PU) to prepare sandwich composites. Effects of reinforcement in the composites were evaluated in terms of sound absorbance, water absorption and mechanical properties. In addition, the elastic and plastic nature along with the ignition property of the composites due to the reinforcement of the fibers was also revealed. The thermal properties of the composites were determined by differential scanning calorimetry and thermogravimetric analysis, whereas, the surface morphology of the samples before and after the ignition were examined by scanning electron microscopy (SEM). Result analysis revealed that the PU composites reinforced with glass fiber (white) showed the highest sound absorbance (21.3 dB) and tensile strength (0.96 MPa) compare to the others. The thermal stability was enhanced by 10 °C due to the reinforcement of the glass and luffa fiber. The glass transition temperature was increased significantly (58 °C) by the addition of glass fiber. The sound absorption coefficient changed from 0.21 to 0.27 due to the incorporation of the glass fiber. A large number of different-sized pores created in the composites as observed from the SEM analysis.

Hot-box measurements to investigate the internal convection of highly insulated loose-fill insulation roof structures

The purpose of this study was to investigate how internal convection in loose-fill insulations affects the insulation properties of highly insulated roof structures. This study consists of laboratory measurements of roof structures insulated by two different blown-in insulations. The measurements are repeated with two temperature differences and air velocities for 300 mm and 600 mm thick insulation layers both with and without trusses, making a total of 24 case studies. The measurements were conducted with equipment using the calibrated hot-box method. The results of the tests show that internal convection can reduce insulation capacity significantly, especially with low-density loose-fill insulations, such as blown-in glass wool. A critical evaluation should be performed as to whether international standards and national building regulations take internal convection into account adequately. According to this study, 5 should be used as a critical modified Rayleigh number for horizontal roof structures with an open upper surface when used insulation material is loose-fill glass wool or wood fibre insulation as in this study.

GWF-NH2 enhanced OSN membrane with trifluoromethyl groups in polyamide layer for rapid methanol recycling

Textile dyeing industry (TDI) produced huge amount of methanol effluent. An organic solvent nanofiltration (OSN) membrane owns ultra-high methanol permeance was developed in this study with a highly reactive and chemically stable symmetrical dianiline structure into its active layer. The so-called “BHTTM” molecule owns double trifluoromethyl (CF3) which offers polarity and negative charge while the matrix was doped with positively charged processed glass wool fiber (GWF-NH2) to form a specific active layer/area. FT-IR and EDX results demonstrated the successful introduction of BHTTM and their specific morphology were captured by FE-SEM. The membrane offered molecular weight cut-off value of 441.9 in water but smaller in organic solvents. It displayed outstanding OSN performance in which the methanol permeance reached 117.2 ± 9.8 L m−2 h−1 MPa−1 with 99.5 ± 0.1% rejection of Chlorazol black and methanol effluent with Rose bengal was also totally decolorized (99.5 ± 0.2%).

Effect of the thermal insulators on the thermal and energetic performance of the envelope of a house located in Marrakesh

Thermal insulation has become essential, firstly to ensure the thermal comfort of the occupants and secondly to save energy and that’s why we find more and more varieties of insulators (organic, inorganic and synthetic) in the Moroccan market, depending on the need when to make the right choice. This paper presents the theoretical part of a thermal and an energetic study of the envelop of a house located in the city of Marrakesh (Morocco), by using four types of insulators, that are mostly used in Moroccan markets, for different thicknesses to determine the most suitable insulator for Marrakech climate and its optimal thickness. The insulators studied are: Expanded Polystyrene, glass wool, rock wool and wood fiber. The numerical simulations were realized using the software of thermal dynamic simulation TRNSYS. The results show that for a thickness of 8 cm of the wood fiber insulator saves about 7% for heating and 14% for cooling loads. For temperatures, in January temperatures are higher by 0.26 °C, and in July are lower by 0.49 °C.

THERMAL BEHAVIOR OF TRADITIONAL LIGHTWEIGHT GYPSUM WITH CONSTRUCTION AND DEMOLITION WASTE MATERIALS

The Waste to Resources (W2R) project is designing several new materials using waste generated in building rehabilitation works in order to improve energy efficiency. A catalogue of different building construction materials using CDW is developed focused on gypsum and cement conglomerates. This paper shows part of the results obtained in this project related to the thermal behavior of some of the analyzed gypsum compounds containing: expanded polystyrene (EPS), extruded polystyrene (XPS), glass waste and a mixture of glass wool fiber and glass-powder. In addition, a reference sample was prepared for comparing the results. All samples were tested with a thermal conductivity analyzer (Model C-Therm Tci™) obtaining the following thermal properties: thermal effusivity, thermal conductivity, thermal diffusivity and heat capacity. Results of reference samples were compared with those obtained by other authors in previous researches where other techniques of measurement were used. In addition, a visual exploration was carried out with a Dino-Lite ™ digital microscope. Key words: Thermal conductivity, Gypsum, Construction and demolition waste, Recycled material

Capillary condensation mechanism for gas transport in fiber reinforced poly (ether-b-amide) membranes

One of the most important shortcomings of the polymeric membranes in comparison with inorganic membranes is the trade-off between permeability and selectivity. Gas permeability in inorganic membranes follows different mechanisms including capillary condensation mechanism. The aim of present study was improving the polymeric membranes performance by introducing capillary condensation mechanism for the gas transport similar to that observed in the inorganic membranes. Capillary condensation of gases needs a continuous diffusion pathway, therefore in the present study short glass wool fibers (with a micro size in diameter and millimeter size in length) were chosen as a proper alternative instead of nanoparticles. Short glass wool fibers present proper dispersion in the Pebax matrix as a result of its good compatibility with polymer segments. Gas permeability behavior in such composite membranes was assisted using pure CO2, CH4 and N2 gases. Obtained results demonstrated that gas permeability behavior in the short fiber reinforced composite membranes is depends on the fiber content. At lower content of the fiber, such reinforcement causes simultaneous increment in gas permeabilities in a way that 62.37%, 32.12% and 50.71% increase in permeability was observed for CO2, CH4, and N2 respectively. But at higher content due to formation of more continuous interface, capillary condensation was appeared for more condensable gas (CO2) which results in 17.65% reduction in its permeability. Based on the results the using of short fiber instead of nanoparticles in polymeric membranes can be more beneficial in performance and economic point of view.

Tribological performance evaluation of epoxy modified phenolic FC reinforced with chemically modified Prosopis juliflora bark fiber

Tribological performance of the Prosopis juliflora (PJ) bark fiber and its chemical treatments in the epoxy modified Phenolic composite has been evaluated in this study. The alkaline and silane treated PJ fibers were characterized by a scanning electron microscope and energy-dispersive x-ray spectroscopy and found that the surface properties were improved. The tribological performance of epoxy modified Phenolic friction composites developed with 5 and 10 wt% of alkaline and silane treated PJ fiber was investigated and compared with commercial fibers namely Glass and Rock Wool fiber. Extension evaluation method was applied to rank the friction composites based on tribological parameters such as hot, normal and performance coefficient of friction, fade rate, recovery rate and wear rate. The experiments and performance evaluation shows that the 5 wt% silane treated PJ fiber reinforced friction composite exhibited the overall quality as a weighted average of the dependent degree of extension evaluation.

N-acetylcysteine prevents cytotoxic effects induced by man-made mineral fibers in a human bronchial epithelial cell line

Man-made mineral fibres (MMMFs) such as glass wool (GW), rock wool (RW) and refractory ceramic fibres (RCFs) are widely used as substitutes of asbestos. The present study aimed to investigate the cytotoxic effects on human bronchial epithelial cells (BEAS-2B) exposed to GW1, RW1 and RCF2, considering their properties similar to that of asbestos. We assessed cell viability; cell morphological changes; apoptotic rate; DNA damage; reactive oxygen species (ROS) generation; activities of caspase-3, caspase-8 and caspase-9; and expression levels of FasL, phosphorylated p38, and total p38 MAPK proteins. N-acetyl-l-cysteine (NAC) was used as an ROS scavenger. We observed that MMMFs, especially RCF2, evidently changed cellular morphology, promoted DNA damage, and induced apoptosis. In addition, the cytotoxicities of MMMFs were dependent on ROS generation, and NAC could decrease their toxicity. Furthermore, our results showed that apoptosis induced by MMMFs was mediated by the mitochondrial apoptotic pathway and Fas death receptor pathway. Moreover, the p38 MAPK signalling pathway was also involved in the cytotoxicities of MMMFs. NAC exerts a protective effect against apoptosis and DNA damage induced by GW1, RW1 and RCF2. This study provides important implications for understanding the potential toxic effects of GW1, RW1 and RCF2 exposure; it also indicates that NAC may prevent respiratory diseases induced by exposure to MMMFs.

Performance evaluation of glass and rock wool fibers to improve thermal stability and mechanical strength of monolithic phenol-formaldehyde based carbon aerogels

Rock and glass wool fiber reinforced phenol-formaldehyde monolithic composite aerogels (PF/RWF and PF/GWF, respectively) were prepared using solvent saturated sol–gel and impregnation of fibers by initial PF sol. The composite wet gels were dried by using ambient-pressure drying technique. After it, synthesized polymeric aerogels were transformed to rock and glass wool fiber reinforced monolithic carbon composite aerogels (C/RWF and C/GWF) through carbonization at 850 °C. The effect of fiber concentration on the physical and morphological properties of both types of composite aerogels was evaluated. The SEM analysis was also conducted to understand the microstructural changes during the carbonization step. Compressive stress-strain behavior of polymeric and carbon composite aerogels changed drastically by addition of fibers. The Young's modulus of polymeric and carbon composite aerogels increased by increasing of fibers concentration in the aerogel structure and showed a yield stress. The compressive strength of carbon composite aerogels was decreased with respect to the formation of voids and cracks around the fibers through the pyrolysis step. The degradation kinetic parameters of polymeric composite aerogels were evaluated using characteristic kinetic temperature-characteristic kinetic temperature range model (CKT-CKTR). The results showed the higher performance of rock wool fibers to thermal stability enhancement of PF aerogels. By 2.5 wt% wool fibers content, the maximum oxidation rate temperature increased from 594 °C for carbon aerogel to about 620 and 643 °C for C/RWF and C/GWF composite aerogels, respectively. The effect of rock wool fibers on the improvement of thermal oxidation resistance of samples was stronger than glass wool fibers.

Determination of the fibre orientation distribution of a mineral wool network and prediction of its transverse stiffness using X-ray tomography

A method to determine the orientation and diameter distributions of mineral wool fibre networks using X-ray tomography and image analysis is presented. The method is applied to two different types of mineral wool: glass wool and stone wool. The orientation information is obtained from the computation of the structure tensor, and the diameter is estimated by applying a greyscale granulometry. The results of the image analysis indicate the two types of fibres are distributed in a 2D planar arrangement with the glass wool fibres showing a higher degree of planarity than the stone wool fibres. The orientation information is included in an analytical model based on a Euler–Bernoulli beam approximation. The model enables prediction of the transverse stiffness. It is indicated that the glass wool transverse stiffness is lower than the stone wool transverse stiffness. Comparison with experimental results confirms the assumption that the underlying deformation mechanism of mineral wool is the bending of fibre segments between bonds.

Re-Use of Glass Wool Fiber as New Composite Polyester System

Re-Use of Glass Wool Fiber as New Composite Polyester System

Impact of fiberizing method on physical properties of glass wool fibers

The physical properties of the glass fibers and their woven and non-woven products are affected by many factors, such as glass composition, thermal history, melting conditions, and fiberizing method. In this work, we have investigated the impact of fiberizing method on dynamic properties and relaxation behavior of the glass wool fibers, and inferred its effect on the mechanical properties of the filtration mats consisting of glass wool fibers. We have fabricated the glass wool fibers using the rotary (R) and flame (F) attenuation processes, which are denominated as R- and F- fibers, respectively. Both fibers have the same chemical composition and hence similar structural features, surface quality, glass transition temperature (Tg), and sub-Tg enthalpy relaxation behaviors. However, two fibers show striking differences in the surface hydroxyl (OH) content, fictive temperature (Tf) and cooling rate (qc). F-fibers have weakly hydrogen-bonded surface hydroxy (OH) groups, while R-fibers have free OH groups and strongly hydrogen-bonded OH groups. F-fibers have higher Tf and qc than R-fibers. We argue that the higher tensile strength of the F-fiber mat (compared to the R-fiber mat) could be attributed to both the weaker hydrogen-bonded surface OH groups, and the higher Tf and qc values that may increase the tensile strength of fiber itself. This work gives guidance for designing the fiber mat products with high tensile strength.

Short fiber/polyurethane composite membrane for gas separation

In this research, short fiber/polymer composite membranes is introduced for gas separation. Our attempt is to increase the membranes performance by using wide interface between fiber and polymer. Short glass wool fiber (SGWF) was used as a polar micro size reinforcement and was mechanically dispersed in polyurethane matrix. Scanning electron microscope (SEM) images showed that fibers have a good dispersion and adhesion to polymer matrix. In order to survey the phase separation and crystallization behavior of polyurethane segments, differential scanning calorimetery (DSC) and dynamic mechanical thermal analysis (DMTA) were used. The results indicated that polar surface of glass wool is a suitable site for attraction of hard segments. Thermal transition of soft segments were assisted using DMTA. Obtained results were showed that the presence of glass wool fiber remarkably reduced the soft segments glass transition temperature (Tg). Gas permeation properties of membranes were assisted using pure CO2, CH4 and N2 gases. Presence of SGWF caused a simultaneous increase in permeability and ideal selectivity (permselectivity) in a way that composite membranes showed high performance. Thus, using of fiber instead of nanoparticles in polymeric membranes can be more beneficial in view of economic and performance for industrial applications.

PRELIMINARY STUDY ON THE SOUND ABSORPTION BEHAVIOR OF SPENT TEA LEAVES FILLED WITH NATURAL RUBBER LATEX BINDER

Nowadays, sound control has been regarded as one of the important requirements for human comfort. For an instance, control of room acoustic enables the room to achieve a good auditive environment for effective speech deliverance and presentations. Synthetic fibers such as glass wool fiber are commonly used for sound absorption. Over the years, it was discovered that synthetic fibers are expensive and possess potential hazard to environment and human health. Therefore, growing attention has been turned to natural fibers as an alternative to synthetic fibers. This paper demonstrates the feasibility of spent tea leaf (STL) fiber as an eco-friendly sound absorbing material. STL fiber is a by-product which was extracted from tea plant. It is unique with fresh aroma and rich in phenolic extractive content. Three different grades of STL fiber were studied and the acoustic property was analyzed in terms of sound absorption coefficient (SAC). Results showed that all the samples obtained maximum SAC above 0.70 at frequency range of 1993-3861 Hz. Furthermore, it was found that finest STL fiber grade exhibits better acoustic performance among others with a maximum SAC of 0.88 at 1993 Hz. Besides, the effect of latex binder on the acoustic property of STL fiber was also analyzed. Results suggest that the types of latex binder did not influence the acoustic performance of STL fiber. The overall results indicate that STL fiber can be a promising environment-friendly sound absorbing material.

Pseudomonas aeruginosa cells attached to a surface display a typical proteome early as 20 minutes of incubation.

Biofilms are present in all environments and often result in negative effects due to properties of the biofilm lifestyle and especially antibiotics resistance. Biofilms are associated with chronic infections. Controlling bacterial attachment, the first step of biofilm formation, is crucial for fighting against biofilm and subsequently preventing the persistence of infection. Thus deciphering the underlying molecular mechanisms involved in attachment could allow discovering molecular targets from it would be possible to develop inhibitors against bacterial colonization and potentiate antibiotherapy. To identify the key components and pathways that aid the opportunistic pathogen Pseudomonas aeruginosa in attachment we performed for the first time a proteomic analysis as early as after 20 minutes of incubation using glass wool fibers as a surface. We compared the protein contents of the attached and unattached bacteria. Using mass spectrometry, 3043 proteins were identified. Our results showed that, as of 20 minutes of incubation, using stringent quantification criteria 616 proteins presented a modification of their abundance in the attached cells compared to their unattached counterparts. The attached cells presented an overall reduced gene expression and characteristics of slow-growing cells. The over-accumulation of outer membrane proteins, periplasmic folding proteins and O-antigen chain length regulators was also observed, indicating a profound modification of the cell envelope. Consistently the sigma factor AlgU required for cell envelope homeostasis was highly over-accumulated in attached cells. In addition our data suggested a role of alarmone (p)ppGpp and polyphosphate during the early attachment phase. Furthermore, almost 150 proteins of unknown function were differentially accumulated in the attached cells. Our proteomic analysis revealed the existence of distinctive biological features in attached cells as early as 20 minutes of incubation. Analysis of some mutants demonstrated the interest of this proteomic approach in identifying genes involved in the early phase of adhesion to a surface.

Effects of Glass Wool Fibre on the Strength Properties of Hollow Sandcrete Block

Effects of Glass Wool Fibre on the Strength Properties of Hollow Sandcrete Block

Roundup

Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2016, 94 (11), p 16March 14, 2016Cite this:C&EN 94, 11, 16AbstractNippon Shokubai and LG Chem have settled a patent infringement lawsuit that Shokubai filed in South Korea in 2014 related to making superabsorbent polymers. Shokubai, the world’s top producer of superabsorbents, filed a similar suit against Sumitomo Seika Chemicals in Japan last month. Covestro, formerly Bayer MaterialScience, has inked an agreement with Japan’s Nanodax to develop composites made from polycarbonate and glass wool. The small-diameter glass wool fibers, Covestro says, are more flexible than the glass fibers conventionally used to reinforce thermoplastics. Dorf Ketal Chemicals has acquired FlowChem Technologies, a U.S. provider of specialty chemicals used in oil drilling. The Indian firm says the purchase will help it access the U.S. market and enhance its offerings to drillers operating off the coast of Brazil. NexWafe, a spin-off of the Fraunhofer Institute for Solar Energy Systems, has raised $6.6 million in a first round of funding from private equity firmView: PDF | Full Text HTML

Moisture induced changes in the building physics parameters of insulation materials

In recent years measurements and calculations of the thermal properties of building physics parameters of materials have become very important for thermal sizing and designing buildings. Moisture is an essential factor to consider when designing and applying building materials. This article investigates the influence of moisture in building physical properties of insulating materials. Thermal insulating of buildings is sorely needed regarding energy as well as saving money. This article presents calculations for the changes in the most important building physics parameters of insulation materials influenced by water after measuring their thermal conductivity, moisture content, and density. Furthermore, this article will also present the positive or negative effects of water. Three different types of polystyrene (expanded, graphite doped expanded, extruded), mineral and glass wool fibers, as well as gypsum boards were tested. The non-equilibrium sorption behavior of the expanded polystyrene materials was achieved in a type Climacell 111 climatic chamber after drying them in a type Venticell 111 desiccating apparatus. The relative humidity varied from 25% to 90% at 293 K for 240 min. The thermal conductivity of each sample was determined by using a Holometrix 2000 heat flow meter after drying the samples to changeless weight in the above mentioned desiccating apparatus.