The effect of phosphorus content on the thermal and the burning properties of cotton fabric coated with an ultrathin film of a phosphorus-containing polymer

The effect of phosphorus content on thermal degradation and burning behavior of poly(acryloyloxyethyl diethyl phosphate) or PADEP-coated cotton was studied. The results showed that PADEP-coated cotton prepared by admicellar polymerization using hexadecyltrimethylammonium bromide (HTAB) as a surfactant has higher amounts of phosphorus than that prepared using dodecyltrimethylammonium bromide (DTAB). Higher phosphorus content led to lower decomposition temperatures and greater amounts of char formation after thermal degradation. The effectiveness of the amount of phosphorus on the burning behavior of the treated cotton was investigated by an ASTM flammabilty test. In the case of PADEP-coated cotton prepared with DTAB, the flame spread slowly and extinguished with char formation on the fabric. For untreated cotton however, the flame spread quickly and burned the fabric entirely without char formation. Cotton coated with PADEP using HTAB exhibited self-extinguishing behavior after removing the ignition source. Decrease in decomposition temperature, increase in char formation and the burning behavior of PADEP-coated cotton are all consistent with phosphorus content on the treated fabric.     

Design and fabrication of thin polymer coating on cotton fabric surface to impart hydrophobicity: An admicellar polymerization approach

The fluorinated poly(trifluoroethylmethacrylate) thin polymers were successfully prepared through free radical initiating admicellar polymerization approach using fluorosurfactant and 2,2,2-trifluoroethylmethacrylate (TFEM, monomer) system, which was initiated with potassium persulfate (KPS) initiator. The structure of the resultant polymer and morphology of the modified cotton fabric surfaces were confirmed by SEM and EDX analysis. The surface wettability of the modified cotton fabric was characterized by a water drop stay time and contact angle (CA) measurement. The coated cotton fabric exhibited excellent hydrophobicity with a water contact angle of 137.79°.     

Admicellar polymerization of styrene on cotton

Thin-film coating on cotton by the admicellar polymerization process was investigated. In this work, styrene was used as the monomer to coat styrene on cotton. The effects of surfactant, styrene, initiator, and electrolyte concentrations on the polymerization process were determined. The polystyrene film formed was characterized by SEM, FTIR, and GPC. The increase in the hydrophobicity of the treated cotton surface was determined by the drop test. Results show that polystyrene thin film was successfully formed on cotton, resulting in cotton that can resist wetting by a water droplet for longer than 30 min.     

Polypyrrole-coated natural rubber latex by admicellar polymerization

Admicellar polymerization has been used for the preparation of an electrically conductive polypyrrole coating on latex particles. An anionic surfactant, sodium dodecyl sulfate (SDS), was adsorbed onto natural rubber (NR) latex particles to form the surfactant bilayers after adjusting the pH below the point of zero charge of the latex surface. Adsorption of SDS and pyrrole adsolubilization were determined as a function of pyrrole and sodium chloride concentrations. Pyrrole caused a decrease in SDS adsorption at equilibrium. Sodium chloride increased the surfactant adsorption and the pyrrole adsolubilization. Thermogravimetric results showed the presence of polypyrrole. The conductivity of the polypyrrole-coated NR latex film prepared by admicellar polymerization without salt was the lowest; however, with salt addition, the conductivity of the film improved significantly. The oxidative polymerization technique resulted in a relatively higher conductivity than oxidative admicellar polymerization.     

Rubber products prepared from silica modified by radiation-induced admicellar polymerization

Unmodified silica, silica modified with Si69, silica modified by thermal admicellar polymerization and silica modified by radiation-induced admicellar polymerization were applied as rubber reinforcement. Mechanical properties of these different rubber formulae were subsequently tested. The results revealed that the mechanical properties of rubber reinforced with silica modified by admicellar polymerization were superior to those reinforced with unmodified silica or silica modified with Si69. As for the silica modified by admicellar polymerization, cetyltrimethyl ammonium bromide (CTAB) proved to be the most effective surfactant, compared to dodecyltrimethyl ammonium bromide (DTAB) and tetradecyltrimethyl ammonium bromide (TTAB).     

Synthesis of nanometer-scale polymeric structures on surfaces from template assisted admicellar polymerization: a comparative study with protein adsorption

A novel method for the formation of nanometer-scale polymer structures via template assisted admicellar polymerization (TAAP) is described. Admicellar polymerization uses a surfactant layer adsorbed on a surface to localize monomer to the surface prior to polymerization of the monomer. Nanostructures are formed by restricting adsorption to the uncovered sites of an already-templated surface, in this case to the interstitial sites between adsorbed latex spheres. Unlike most other process that form polymer nanostructures, polymer dimensions can be significantly smaller than the interstitial size because of sphere-surfactant interactions. Protein adsorption in the interstitial sites of colloidal arrays was also studied for three different proteins, and the results were compared with those obtained via admicellar polymerization.     

X-ray photoelectron spectroscopic studies of hydrophilic surfaces modified via admicellar polymerization

Admicellar polymerization with styrene monomer was used to coat the surface of two porous solids: titanium dioxide and alumina. X-ray photoelectron spectroscopy (XPS) measurements clearly indicate that after admicellar polymerization, organic material and surfactant are present on the surface of the solids. Water washes, performed immediately after admicellar polymerization, were successful in removing approximately 30% of the organic material, presumably mostly surfactant. The water wash was followed by Soxhlet extraction with toluene, with no measurable removal of organic material according to ignition loss measurements of the solid, gel permeation chromatography of the extracting solvent and also UV/VIS spectroscopy of the extracting solvent. However, there was a 5-15% drop in organic material after Soxhlet extraction according to XPS measurements. This difference is attributed to the difference in sampling; XPS samples only the exterior surface area while these bulk measurements sample both the interior and exterior surface area. This study details the ability of different washing steps to remove materials from the porous substrates used in this study.     

Factors affecting the synthesis of polymeric nanostructures from template assisted admicellar polymerization

Template assisted admicellar polymerization (TAAP) utilizes a surfactant layer adsorbed on a surface to localize a monomer to the surface prior to polymerization of the monomer. Nanostructures are formed by restricting adsorption to the uncovered sites of an already-templated surface, in this case, to the interstitial sites between adsorbed latex spheres. This work studies the factors affecting the synthesis of polymeric nanostructures from TAAP for three different monomers, aniline, pyrrole, and methyl methacrylate, and three different surfaces, highly ordered pyrolytic graphite (HOPG), gold, and SiO2. Among the parameters discussed are the effects of monomer and surfactant concentration, surfactant chain length, polymerization time and temperature, and solution ionic strength. Control of the aforementioned parameters allows some control over the nanostructure morphology. Polymer nanopillars, nanorings, honeycombs, and "honeytubes" have been synthesized. Important conclusions regarding the conditions favoring admicellar polymerization relative to polymerization in solution are drawn from the experimental results as well. Sample characterization includes scanning electron microscopy (SEM), Raman spectroscopy, and alternating current (ac) impedance measurements.     

Radiation induced graft polymerization of a fluorinated acrylate onto fabric

A fluoride acrylate monomer, 1H,1H,2H,2H-nonafluorohexyl-1-acrylate (denoted as F4), was grafted onto cotton fabric through a simultaneous irradiation induced graft polymerization technique. The grafted cotton fabric (denoted as cotton–F4) is superhydrophobic (SCF) when the degree of grafting (DG) exceeded 10%. The morphology of the cotton fabric was unchanged. In addition, the mechanical properties of the cotton fabric and SCF samples were also studied. The results showed that the decrease in mechanical properties was less than 20%, indicating that the SCF retained good mechanical strength.     

表面化学接枝改性阻燃棉织物的制备与性能

采用高碘酸钠对棉织物表面进行选择性氧化生成醛基,选取乙二胺与醛基反应,通过膦氢化加成反应将阻燃剂亚磷酸二甲酯接枝到棉织物表面,最后通过三羟甲基三聚氰胺对棉织物表面进行接枝改性,制备了含三羟甲基三聚氰胺/乙二胺/亚磷酸二甲酯阻燃棉织物.通过傅里叶红外光谱（FTIR）对改性后棉织物的结构进行了表征,通过极限氧指数（LOI）测试研究了其阻燃性能,通过锥形量热测试研究了其燃烧行为,通过在40℃皂水中洗涤10次考察了其耐水性能,通过扫描电子显微镜测试了其表面及燃烧后炭层的形貌.研究结果表明,经表面改性后,棉织物的LOI值由（19.5±1.0）%提高到了（43.1±1.0）%,经耐水洗测试后,LOI值仅下降至（42.6±1.0）%,保持了非常好的阻燃性能,表明通过表面接枝方法制备的三羟甲基三聚氰胺/乙二胺/亚磷酸二甲酯阻燃棉织物具有非常好的耐水洗性能.表面阻燃改性提高了棉织物在燃烧过程中的成炭性能,形成的连续膨胀的炭层较好地保护了内部织物,抑制了织物的降解和燃烧,从而提高了棉织物的阻燃性能.     

Layer-by-layer assembled thin films based on fully biobased polysaccharides: chitosan and phosphorylated cellulose for flame-retardant cotton fabric

Polyelectrolytes multilayer (PEM) films based on fully biobased polysaccharides, chitosan and phosphorylated cellulose (PCL) were deposited on the surface of cotton fabric by the layer-by-layer assembly method. Altering the concentration of PCL could modify the final loading on the surface of cotton fabrics. A higher PCL concentration (2 wt%) could result in more loading. Attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis directly showed that chitosan and PCL were successfully deposited onto the surface of cotton fabric. In the vertical flame test, the cotton fabric with 20 bilayers at the higher PCL concentration (2 wt%) could extinguish the flame. Microcombustion calorimetry results showed that all coated cotton fabrics reduced the peak heat release rate (HRR) and total heat release (THR) relative to the pure one, especially for (CH0.5/PCL2)₂₀, which showed the greatest reduction in peak HRR and THR. Thermogravimetric analysis results showed that the char residue at temperatures ranging from 400 to 700 °C was enhanced compared to that in the pure cotton fabric, especially in the case of higher PCL concentration (2 wt%). The work first provided a PEM film based on fully biobased polysaccharide, chitosan and PCL on cotton fabric to enhance its flame retardancy and thermal stability via the layer-by-layer assembly method.     

Effect of urea additive on the thermal decomposition of greige cotton nonwoven fabric treated with diammonium phosphate

This study showed that greige cotton nonwoven fabric can effectively be flame retardant by applying the phosphorus of diammonium phosphate (DAP) as low as 0.8 wt% with the addition of urea. At such a low content of phosphorus, the char length and limiting oxygen index (LOI) were continuously decreased and increased, respectively, as the concentration of urea increased. The effect of urea additive on the thermal decomposition of flame retardant greige cotton nonwoven fabric was investigated by thermogravimetry, ATR-FTIR, XRD, ¹H → ¹³C CP/MAS NMR, and SEM. The results indicated that, upon heating, urea not only facilitated the phosphorylation reaction of DAP but also introduced carbamate groups into cellulose to decrease the degree of crystallinity prior to the decomposition of the crystalline cellulose. Compared with DAP treatment alone, the addition of urea accelerated the decomposition of glycosyl units, which resulted in a slight increase of weight loss and decrease of char yield. The char morphology observed after LOI tests indicates that urea released nonflammable gases, which blew the carboneous char layer to protect the underlying substrate.     

Hydrophobic thin fluoropolymer coating on cotton surfaces

We report a simple novel procedure to prepare hydrophobic cotton textiles by admicellar polymerization. By in situ introducing fluoropolymer on cotton fibers to generate a dual-size surface roughness, followed by hydrophobization with a little amount of fluoromonomer Octafluoropentamethyl methacrylate (OFPM) with short time, normally hydrophilic cotton has been easily turned into hydrophobic. Hydrophobic cotton textile exhibits a static water contact angle of 124° for a 10?µl droplet. When an octa fluoroalkyl chain is introduced to the cotton surface, the originally smooth surface changed immediately to rough surface which is the key factor for hydrophobicity like lotus leaves.     

Novel method for ultraviolet protection and flame retardancy of cotton fabrics by low-temperature plasma

A novel approach, namely the nitrogen plasma technique, to confer flame-retardant and ultraviolet (UV)-protective properties on cotton fabric is described. Treated cotton fabrics showed very good UV-blocking property. According to the standard, the treated cotton fabric can be claimed to be a “UV-protective” product. The fire-retardant character of the treated fabrics was investigated by char yield, thermogravimetric analysis, and limiting oxygen index measurements. Also, the effect of aging on the mentioned properties was studied. The ultraviolet protection factor and flame-retardant properties of atmospheric pressure plasma-treated cotton were also measured and compared with nitrogen plasma treatment.     

Comparison of the properties of the polyimides,polyamides and polyureas derived from 1-[(dialkoxyphosphinyl)-methyl]-2,4- and -2,6-diaminobenzenes and m-phenylenediamine

The physical and thermal properties of various phosphorus-containing polyimides, polyamides and polyureas based on 1-[(dialkoxyphosphinyl)methyl]-2,4- and -2,6-diaminobenzenes as well as of the corresponding common polymers derived from m-phenylenediamine were compared and correlated with their chemical structure. Differential scanning calorimetry (DSC) measurements showed that the introduction of the (dialkoxyphosphinyl) methyl groups in the polymers converted their endothermic pyrolysis under anaerobic conditions to exothermic or reduced the heat adsorbed during their pyrolysis. Thermogravimetric analysis (TGA) showed that the thermal stability of the polymers and the char yield formed during their pyrolysis were in the order polyureas < polyamides < polyimides. All phosphorylated polymers showed a lower degree of polymerization, a lower polymer decomposition temperature and formed higher char residue on pyrolysis than the corresponding common polymers.     

Synthesis and characterization of a novel phosphorus–nitrogen‐containing flame retardant and its application for textile

The economic and environmentally friendly flame‐retardant compound, tetramethyl (6‐chloro‐1,3,5‐triazine‐2,4‐diyl)bis(oxy)bis(methylene) diphosphonate ( CN‐1 ), was synthesized by a simple two‐step procedure from dimethyl phosphate, and its chemical structure was characterized by ¹H, ¹³C, and ³¹P nuclear magnetic resonance and gas chromatography mass spectroscopy. Using the traditional pad–dry–cure method, we obtained several different add‐ons (wt%) by treating cotton twill fabric with flame retardant ( CN‐1 ). Thermogravimetric analysis, in an air and nitrogen atmosphere, of the modified cotton showed that decomposition occurred ~230°C with 16% residue weight char yield at 600°C, indicating high thermal stability for all treated levels. Limiting oxygen index (LOI) and the vertical flammability test were employed to determine the effectiveness of the flame‐retardant treatments on the fabrics. LOI values increased from ~18 vol% oxygen in nitrogen for untreated fabric to maximum of 34 vol% for the highest treatment level. Fabrics with higher levels of flame retardant also easily passed the vertical flammability test. Furthermore, Fourier transform infrared and scanning electron microscopy were utilized to characterize the chemical structure as well as the surface morphology of the flame‐retardant treated twill fabrics, including char area and the edge between unburned fabric and char area. Copyright © 2011 John Wiley & Sons, Ltd.     

Surface characterization of cotton coated by a thin film of polystyrene with and without a cross-linking agent

Thin polystyrene film coated on cotton was successfully formed by admicellar polymerization. Divinylbenzene (DVB) was used as a cross-linking agent to form networked polystyrene to improve film coverage. A wettability test and XPS analysis were used to characterize the coated surface. The optimum amount of DVB was around 1%. At this amount, the film coverage was most complete, as judged by the reduction of the O1s signal in XPS analysis.     

Polypyrrole thin films formed by admicellar polymerization support the osteogenic differentiation of mesenchymal stem cells

The objective of this study was to evaluate the attachment, proliferation, and differentiation of rat mesenchymal stem cells (MSC) toward the osteoblastic phenotype seeded on polypyrrole (PPy) thin films made by admicellar polymerization. Three different concentrations of pyrrole (Py) monomer (20, 35, and 50 x 10(-3) M) were used with the PPy films deposited on tissue culture polystyrene dishes (TCP). Regular TCP dishes and PPy polymerized on TCP by chemical polymerization without surfactant using 5 x 10(-3) M Py, were used as controls. Rat MSC were seeded on these surfaces and cultured for up to 20 d in osteogenic media. Surface topography was characterized by atomic force microscopy, X-ray photoelectron spectroscopy, and static contact angle. Cell attachment, proliferation, alkaline phosphatase (ALP) activity, and calcium content were measured to evaluate the ability of MSC to adhere and differentiate on PPy-coated TCP. Increased monomer concentrations resulted in PPy films of increased thickness and surface roughness. PPy films generated by different monomer concentrations induced drastically different cellular events. A wide spectrum of cell attachment characteristics (from excellent cell attachment to the complete inability to adhere) were obtained by varying the monomer concentration from 20 m to 50 x 10(-3) M. In particular the 20 x 10(-3) M PPy thin films demonstrated superior induction of MSC osteogenicity, which was comparable to standard TCP dishes, unlike PPy films of similar thickness prepared by chemical polymerization without surfactant. Adhesion of mesenchymal stem cells on tissue culture plates (TCP) coated with polypyrrole thin films made by admicellar polymerization.     

A simple method for determining the total amount of physically and chemically bound water of different cements

A novel environmentally friendly flame-retardant compound, diethyl 3-(triethoxysilanepropyl) phosphoramidate (DTP) was synthesized via a simple one-step procedure with good yield and characterized by FT-IR and ¹H-NMR, ³¹P-NMR and ²⁹Si-NMR. The synthesized compound was coated onto cotton fabrics with different levels of add-ons (5–17 mass%) using the traditional pad-dry-cure method. SEM and XPS were conducted to characterize the surfaces of the coated cotton fabrics. The XPS results showed that DTP was attached to cotton through covalent bond. Cone calorimeter test showed that the cotton fabric treated with DTP became less flammable due to the lower HRR, THR and CO₂/CO ratio. The modified cotton fabrics exhibited efficient flame retardancy, which was evidenced by limiting oxygen index (LOI) and vertical flammability test. Cotton fabrics treated with DTP in 5–17 mass% add-ons had high LOI values of 23–32%. Thermogravimetric analysis results show that the usage of DTP promotes degradation of the cotton fabrics and catalyzes its char formation.     

Formation of polymeric films on cellulosic surfaces by admicellar polymerization

Cellulose fibers suspended in an aqueous medium were placed in contactwith increasing amounts of either a cationic or an anionic surfactant. Only theformer was adsorbed, forming admicellar morphologies. The addition of alkenylmonomers to these systems and their subsequent polymerization resulted in theformation of polymer both in the aqueous medium and around the fibers. Thelatter 'coating', which was rather irregular in coverage, produceda strong increase in the hydrophobic character of the cellulosic surface.