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1.
The study employs limiting oxygen index (LOI) measurements, cone calorimetry (CONE) and thermogravimetric analysis (TGA) to examine the catalytic effect of zinc ion content on the flame retardance and thermal degradation of alginate fibers. LOI results show that all zinc alginate fibers are intrinsically flame retardant, with LOI values of over 27.0, as compared with about 24.5 for alginic acid fiber. The heat release rate (HRR) and total heat release values of zinc alginate fibers (obtained from CONE) are significantly less than those of alginic acid fiber, and decrease with increasing zinc ion content. TGA indicates that char formation increases and maximum thermal weight-loss rate is reduced when zinc content in the fibers is increased. The residues of zinc alginate fibers keep their shapes better than those of the alginic acid fiber. Further discussion of the combustion process and flame retardant mechanism is presented.  相似文献   

2.
Nanofibrous mats of poly (?-caprolactone)/nanoclay nanocomposites were fabricated using electrospinning method. Effects of nanoclay content of the nanocomposite on final nanofiber structures were investigated and characterized by scanning electron microscope (SEM) and differential scanning calorimetry (DSC) analysis. The results showed that the presence of the nanoclay promoted the creation of fibrous structure in comparison with solely poly (?-caprolactone). Furthermore, increase in nanoclay content led to the formation of more uniform nanofiber structures and caused a decrease in the mean nanofiber diameter. DSC results showed that the addition of nanoclay reduced the crystallinity of the nanocomposite in compared with pristine PCL. Studies of the mechanical properties, wettability and degradability showed that the presence of nanoclay improved tensile modulus, tensile strength, wettability and biodegradability of the nanocomposites. To evaluate the effect of nanoclay on the cell adhesion and bioactivity of the poly (?-caprolactone)/nanoclay nanocomposites, fibroblasts cells were seeded on the mats. The results showed that the prepared nanocomposite could be a potential candidate for tissue engineering.  相似文献   

3.
The objective of this study was to investigate the influence of nanoclay incorporation procedure on the mechanical and water vapor barrier properties of starch/nanoclay composite films. Cassava starch films were prepared with (nanocomposite) and without nanoclay (control) in two steps: firstly the production of extruded pellets and secondly thermo-pressing. The nanocomposite films were prepared via two different methods: in D samples the nanoclay was dispersed in glycerol and subsequently incorporated into the starch; and in ND samples all ingredients were added in a single step before the extrusion. All the composite-films were prepared with cassava starch using 0.25 g of glycerol/g of starch and 0.03 g of nanoclay/g of starch. Control samples showed VA-type crystallinity induced by the manufacturing process and the nanocomposites presented a semicrystalline and intercalated structure. The nanoclay improved the water vapor barrier properties of the starch film and this effect was more pronounced in D samples, where the water vapor permeability (Kw) was 60% lower than that of the control samples. The Kw reduction was associated with decreases in the effective diffusion coefficient (approximately 61%) and in the coefficient of solubility (approximately 22-32%). On the other hand, the incorporation of nanoclay increased the tensile strength and the rigidity of the films and this effect was more significant when the nanoclay was dispersed in glycerol. Thus, the incorporation of nanoclay into starch-based films is a promising way to manufacture films with better mechanical and water vapor barrier properties.  相似文献   

4.
Flame-retardant cellulose fibers were prepared by dissolving cellulose in tetrabutylammonium acetate and dimethyl sulfoxide, and blending with amino silicone oil (ASO). The ASO was used as a novel fabric softener and flame retardant for cellulose fibers. Fourier-transform infrared spectroscopy showed that blending with ASO did not adversely affect the cellulose fibers. The flame retardancy of the cellulose fibers blended with ASO was determined based on the limiting oxygen index (LOI). Cellulose fibers blended with 8 wt% (add-on) ASO gave the best flame retardancy, with an LOI of 28, which was higher than that of the virgin fibers. The thermal properties of the flame-retardant cellulose fibers were investigated using differential scanning calorimetry and thermogravimetric analysis. The results showed that ASO prevented degradation of the cellulose fibers, hindered the formation of volatile species, and favored char formation. The mechanical properties of the flame-retardant cellulose fibers were better than those of virgin cellulose fibers.  相似文献   

5.
The Fe-montmorillonite (Fe-MMT) combined catalysis effects of Fe ion with barrier effects of silicate clays, was firstly synthesized by hydrothermal method, and then was modified by cetyltrimethyl ammonium bromide (CTAB). The organic-modified Fe-montmorillonite (Fe-OMT) was dispersed in the N, N-dimethyl formamide (DMF) and then compounded with polyacrylonitrile (PAN) solution which was dissolved in DMF. The composite solutions were electrospun to form PAN/Fe-OMT nanocomposite fibers. The influences of the Fe-OMT on the structure, morphology, thermal, flammability and mechanical properties of PAN nanocomposite fibers were respectively characterized by X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM), Thermogravimetric analyses (TGA), Micro Combustion Calorimeter (MCC) and Electronic Single Yarn Strength Tester. It was found from XRD curves that there was not observable diffraction peak of silicate clay, indicating that the silicate clay layers were well dispersed within the PAN nanofibers. The HRTEM image indicated that the multilayer stacks of nanoclays could be found within the nanofibers and were aligned almost along the axis of the nanofibers. The SEM images showed that the diameters of nanocomposite fibers were decreased with the loading of the Fe-OMT. The TGA analyses revealed that the onset temperature of thermal degradation and charred residue at 700°C of PAN nanocomposite fibers were notably increased compared with the pure PAN nanofibers, contributing to the improved thermal stability properties. It was also observed from MCC analyses that the decreased peak of heat release rate (PHRR) of the PAN nanocomposite fibers reduced the flammability properties. The loadings of Fe-OMT increased the tensile strength of PAN nanocomposite fibers, but the elongation at break of PAN nanocomposite fibers was lower than that of the PAN nanofibers.  相似文献   

6.
Phosphorus-nitrogen (P-N) or sulfur (S) containing compounds are well known for their effectiveness as flame retardant additives for many polymeric systems. When either phosphorus or nitrogen is combined with sulfur, the new systems prove to be successful combinations. This research aims to learn the impact of two systems, P-N and S-P-N, on the flammability and thermal properties of cotton fabrics. The process includes the synthesis of two compounds, tetraethyl piperazine-1,4-diyldiphosphonate (TEPP) and O,O,O',O'-tetramethyl piperazine-1,4-diyldiphosphonothioate (TMPT), and the evaluation of flammability, thermal degradation, and surface morphology of the treated fabrics. Both compounds exhibit similar burning behavior and show improved flame retardancy and thermal properties when used on various cotton fabrics. Some unique flame retardant properties for the two compounds are also disclosed.  相似文献   

7.
Composite fibers made of polyvinyl alcohol (PVA) and melamine-formaldehyde (MF) resins with different reaction degrees were prepared by wet spinning. The phase structures of MF/PVA spinning dopes and composite fibers were observed by using optical microscope (OM) and scanning electron microscope with energy-dispersive X-ray spetroscopy (SEM-EDS). Crystal structures of composite fibers were studied by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The loss of MF resins in the spinning process was calculated by using Kjeldahl. The mechanical properties, the flame retardant property, the water resistant property, and the thermal stability of composite fibers were also tested. Results show that with an increase in the reaction degree of MF resin, the phase separation degrees of spinning dopes and composite fibers rise up, the size of MF microphase grows larger, and the loss of MF resin diminishes; consequently, the hot water resistance and the flame retardancy of the fiber ameliorate while the tensile strength and the thermal stability perform a tendency of dropping after rising.  相似文献   

8.
The fire resistant poly(lactic acid) fibers with polysulfonyldiphenylene phenyl phosphonate flame retardant were prepared by melt spinning. The rheology property and spinnability of samples were measured by a capillary rheometer and recording the number of fiber breakage during a 30-min melt spinning. The thermal stability and combustion behaviors of fibers were investigated by Thermogravimetric Analysis, Limiting Oxygen Index and Vertical Burning tests, respectively. It was found that the flame retardation and anti-dripping performance of PLA were distinctly improved by OP. The pyrolysis behavior of fibers was tested by a Pyrolysis-Gas Chromatography-Mass Spectrometry, the structure and degree of graphitization of char residue were analyzed by Scanning Electronic Microscopy and Raman Spectroscopy. The results suggested that OP can promote the forming of char layer on the surface of PLA matrix during burning. The miscibility and spinnability of PLA was negatively affected by OP and the breaking strength of FR-PLA fibers dropped from 3.30 to 2.30 cN/dtex at the presence of 10 wt. % OP.  相似文献   

9.
Unfilled polypropylene and polyropylene/ZnO nanocomposite fibers were produced using a melt spinning apparatus; then the fibers were exposed to UV irradiation. The structure and properties of the fibers were examined using scanning electron microscopy, tensile measurements, wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR) spectroscopy, birefringence measurements and differential scanning calorimetry (DSC). Following 150 hours of exposure to UV irradiation, some transverse cracks on the surface of unfilled polypropylene fibers were observed. It was observed that both carbonyl and hydroperoxide indexes, which are the criteria for the detection of UV degradation of the fibers, were increased due to the increase in the UV irradiation exposure time and the increase in these indexes was smaller for nanocomposite fibers than those of unfilled Polypropylene fibers. It was also observed that crystallinity, crystallite size and total molecular orientation of UV irradiated nanocomposite fibers were increased in comparison with non-irradiated nanocomposite fibers. It was also found that the extent of increase in molecular orientation of the fibers was higher comparing to that for the nanocomposite fibers due to the UV irradiation exposure for the unfilled polypropylene fibers. Tensile properties of both unfilled and nanocomposite fibers were decreased after UV irradiation; this reduction correlated with the extent of the increase in molecular degradation of the fibers, as determined by measuring carbonyl and hydroperoxide indexes.  相似文献   

10.
The development of high tenacity, high modulus monofilaments from Polypropylene/Clay nanocomposite has been investigated. Pure sodium montmorillonite nanoclay was modified using hexadecyl trimethyl ammonium bromide (HTAB) via an ion exchange reaction. Pure and modified clay were characterized through X-ray diffraction, FTIR and TGA. The modified clay was melt blended with polypropylene (PP) in presence of a swelling agent. Composite filaments from PP/Clay nanocomposite were prepared at different weight percentages of nanoclay and the spinning and drawing conditions were optimized. The filaments were characterized for their mechanical, morphological and thermal properties. The composite PP filaments with modified clay showed improved tensile strength, modulus and reduced elongation at break. The composite filaments with unmodified clay did not show any improvement in tensile strength but the modulus improved. The sharp and narrow X-ray diffraction peaks of PP/nanoclay composite filaments indicate increase in crystallinity in presence of modified clay at small loadings (0.5%). The improved thermal stability was observed in filaments with modified as well as unmodified clays.  相似文献   

11.
Since natural fiber/polymer composites are increasingly used, the development of safe and environmental friendly flame retarding bio-based composites is of great importance. But this issue must maintain the mechanical performance of these composites. To study these objectives, four levels of magnesium hydroxide Mg(OH)2 of (0, 10, 20, 30 phc) and two levels of nanoclay (0, 3 phc) were considered and incorporated into HDPE/wheat straw composites. Maleic anhydride grafted polyethylene (PE-g-MA) was also used as a compatibilizer at constant content. The samples were prepared by melt compounding and injection molding processes, respectively. The some properties of samples including burning rate and mechanical properties (tensile and impact strengths) were tested based on the ASTM standard. The results showed that the burning rate of samples decreased with increasing the nanoclay and Mg(OH)2 content. The tensile and impact strengths showed a marginal reduction by adding Mg(OH)2 from 10 phc to 30 phc and the tensile modulus and impact strength revealed an increase by increasing the amount of nanoclay up to 3 phc. Generally, these results confirmed that the fire retarding and mechanical properties of HDPE/wheat straw composites could be significantly improved with an appropriate combination of the nanoclay and Mg(OH)2 in the composites.  相似文献   

12.
In this paper, viscose rayon-based knitted fabrics were utilized as the precursor to produce activated carbon fiber absorbents (ACFA). To obtain better pore characteristics and higher weight yield of ACFA, the effect of flame retardant reagent concentration was studied. Experimental results revealed that both BET surface area and micropore volume increased with increasing flame retardant reagent concentration. On the other hand, both weight yield and micropore volume ratio (Vmic/Vtot) decreased as the flame retardant reagent concentration increased. It was therefore concluded that controlling the flame retardant reagent concentration at 30% not only could obtain better absorption property of ACFA but also helped maintain its production efficiency.  相似文献   

13.
A novel flame retardant monomer DDPSi-FR containing organophosphorus and silicon was prepared using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 4-hydroxybenzaldehyde (HBA), and 3-glycidoxypropyltrimethoxysilane (GPTMS). The chemical structure of DDPSi-FR was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Subsequently, after treating the wool fabrics, the effects of the monomer on the flame retardancy, thermal stability, and mechanical properties were studied. The flame retardant and thermal properties were evaluated by conducting vertical flame tests, limiting oxygen index (LOI) determination, and thermogravimetric analysis (TGA). The results showed that improved flame retardancy and thermal stability were achieved. Notably, the flame retardancy was retained even after 15 washing cycles. The mechanical properties were evaluated using the bursting strength, and the results indicated that DDPSi-FR treatment improved the breaking strength.  相似文献   

14.
In order to comply with the safety environment requirements, this research is being carried out for reinforcing inorganic additives to improve fire retardancy of composite. In the present study, abaca fabric/vinyl ester (AF/VE) composites were prepared by vacuum assisted resin transfer (VARTM) molding process. For improving flame retardant property of the composites, three different types of halogen free inorganic fillers, i.e. nano-clay (NC), halloysite nanotubes (HNT) and ammonium polyphosphate (APP) were used. The flammability, thermal stability and mechanical properties of composites have been investigated by Horizontal burning test, Thermogravimetric analysis (TGA), tensile, and flexural test respectively. FESEM was used to observe the morphology of the fractured surface of the tensile specimens. Taguchi method was used to optimize the process and minimize the number of experiments for fillers addition. The results showed that the flame retardancy and thermal stability increased with increasing percentage of fillers, but mechanical properties slightly decreased simultaneously.  相似文献   

15.
Aluminum particles (Al) were added to polypropylene (PP) in the presence of poly ethylene glycol (PEG) and polypropylene-graft-maleic anhydride to produce composites. The composites were then melt-spun into a mono filament and tested for tensile properties, diameter evenness and morphology. Melt rheological properties of Al/PP composites were studied in linear viscoelastic response regions. It was observed that level of dispersion of aluminum particles within a polypropylene composite fiber could be improved by incorporating polyethylene glycol. The improvement of dispersion led to an improvement in the fibers mechanical properties through a reduction of the coefficient of variation of fiber diameter.  相似文献   

16.
Thermal degradation behaviors and fire retardant properties of poly(1,3,4-oxadiazole)s (POD) and poly(m-phenylene isophthalamide) (PMIA) fibers were investigated. The thermal gravimetric analysis (TGA) demonstrated that POD exhibited higher onset thermal degradation temperature (Tonset) than PMIA, exceeding nearly 80 °C. The thermal degradation kinetics, evaluated by the modified Coats-Redfern method, displayed that the apparent activation energy (Ea) of POD and PMIA fibers was similar when the conversion rate (α) ranges from 0.2 to 0.5, while with the α from 0.6 to 0.8, the Ea of POD was significantly lower than that of PMIA. The fire retardant performance of POD and PMIA fibers were evaluated by cone calorimeter under heat fluxes of 35, 50 and 75 kW/m2, during which the temperature of the fibers were monitored by a thermocouple. Surprisingly, POD fibers showed inferior fire retardant performance in comparison with PMIA, with lower time to ignition (TTI) and higher peak heat release rate (PHRR). The origin of the different fire retardant properties of both fibers was revealed by analyzing the residual chars and gaseous products during thermal pyrolysis. The morphology confirmed that stable and compact chars can be formed in PMIA. In addition, the Fourier Transform Infrared Spectroscopy (FTIR) characterization of the residual char revealed that POD can form carbonaceous chars at the heat flux of 50 kW/m2, while the heat flux of PMIA was 75 kW/m2. The pyrolysis products characterized by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) indicated that POD can be pyrolyzed completely at 600 °C, while the temperature of PMIA was 700 °C.  相似文献   

17.
Unmodified polyamide 6 commonly dyed with acid dyes, and has no flame-retarded properties. So they are flammable and can be easily stained by foods or drinks that contain acid dyes. However, the acid groups react with amino groups that existed at the end of PA6 chain while using cationic dyes. Thus, the acid dyes can be washed immediately. In this study, the flame retardant and cationic dyeable polyamide 6 (FRCD-PA6) modified with 5-sulfoisophthalic acid sodium (5-SSIPA) and melamine cyanurate (MCA) was successfully prepared by the two-step-melt polymerization method. Firstly, cationic dyeable polyamide 6 (CD-PA6) was prepared with sodium salt from 5-sulfoisphthalic acid. Secondly, melamine cyanurate, as an efficient flame retardant, was blended into the reaction. The chemical and crystalline structures of FRCDPA6 were characterized by the Fourier transform infrared spectroscopy (FT-IR) and wide angle X-ray diffraction (XRD). Their thermal properties were tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and morphology was analyzed by SEM, respectively. It had been measured to prove the dispersion of 5-SSIPA and MCA on polyamide 6 matrix. Incorporating with 5-SSIPA created more amorphous regions and rose up the dyeing rate easily, with a highest dyeing rate for about 96.79 %. The effect of varying MCA content on the composites showed more flame retardant and made better heat-resistance. Moreover, with the appropriate addition of MCA content, the limit oxygen index (LOI) reached up to 27, less smoking, no more black smoke, droplet phenomenon was slightly, and flame resistance had greatly improved. Because of the good synergy between 5-SSIPA and MCA, a kind of novel modified polyamide 6 which own both cationic dyeable and efficient flame retardant properties was born.  相似文献   

18.
Nanocomposite fibers of polyamide 6 (PA6) and hydroxyapatite (HA) were prepared and doped with silver to investigate antibacterial activities due to good potential for textile modification. Nano-sized HA could be synthesized using agarose and ethanol as thickener and washing medium, respectively. The PA6/HA nanocomposite fibers could be doped with silver by dipping the fibers having HA in aqueous AgNO3 solution containing 300 ppm of Ag ion for 1 min utilizing HA as a carrier to load silver through ion-exchange mechanism. It was found that silver was successfully doped to PA6/HA nanocomposite fibers from the EDS spectra. The nanocomposite fibers containing 3.3 wt% of HA after silver doping demonstrated such excellent antibacterial activities against K. pneumonia and E. coli that they are expected to serve as functional antibacterial materials in various application fields.  相似文献   

19.
In order to improve the thermostability and fire resistance of kenaf, kenaf was treated with halogen-free flame retardant triethyl phosphate (TEP) adopting dipping principle. Adding flame retardant kenaf (fbk) to high impact polystyrene (HIPS) resin, fbk/HIPS composites were prepared by extrusion molding and injection molding. The differences of untreated kenaf and treated kenaf on structure, thermal behavior, combustion, mechanical properties of HIPS were contrasted and analyzed. The results showed that kenaf treated with TEP had superior thermal stability at high temperature and produced significantly reinforcing effect on HIPS resin.  相似文献   

20.
Fire-retardant fiber was prepared from goatskin fiber by treating with a melamine-based flame retardant. Kissinger and Flynn-Wall-Ozawa methods were used for analyzing the thermo-gravimetric data obtained from the goatskin fiber and the fire-retardant fiber at different heating rates. Kinetic parameters were calculated from the thermo-gravimetric data at different heating rates. Activation energies obtained using the Kissinger and Flynn-Wall-Ozawa methods were 154.57 kJ/mol and 158.45 kJ/mol, respectively, for the goatskin fiber and 210.15 kJ/mol and 212.52 kJ/mol, respectively, for the fireretardant fiber. The oxygen index of the fire-retardant fiber treated with 4 wt% melamine-based flame retardant increased significantly to a value of 31.7 %. The thermal stability and the flame retardant property of the fire-retardant fiber were improved significantly.  相似文献   

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