S. Giraud

Microencapsulation of phosphate: application to flame retarded coated cotton

Polyurethane-phosphates combination is known to form a flame retardant (FR) intumescent system. The intumescent formulation could not be permanent because of the water solubility of the phosphate. This problem could be solved by the technique of microencapsulation. Di-ammonium hydrogen phosphate (DAHP) was microencapsulated with a polyurethane (PU) shell. Polyurethane for textile coating was loaded with neat or microencapsulated DAHP. We studied the thermal degradation behaviour of DAHP microcapsules, PU loaded formulations and cotton coated by these PU formulations. Improvement of the thermal stability for PU textile coating was observed with neat and microencapsulated DAHP. The flame retarding behaviour of these coated cotton fabrics was also valued with the cone calorimeter. This new concept of phosphate encapsulated by PU shell showed a significant FR effect.

Flame Behavior of Cotton Coated with Polyurethane Containing Microencapsulated Flame Retardant Agent

Polyurethane-phosphates combination is known to form flame retardant (FR) intumescent system. But the intumescent formulation could not be permanent because of the water solubility of the phosphate. This problem could be solved by the technique of microencapsulation. Microcapsules of di-ammonium hydrogen phosphate (DAHP) with a polyurethane (PU) shell were synthesized. Chemical and physical structure of the DAHP microcapsules were characterized. Cotton fabrics were coated with polyurethane (PU) coating including neat DAHP or encapsulated DAHP. The flame retarding behavior of these coated cotton fabrics was valued with the cone calorimeter. This new concept of phosphate encapsulated by PU shell showed a significant FR effect.

PLA with Intumescent System Containing Lignin and Ammonium Polyphosphate for Flame Retardant Textile

Using bio-based polymers to replace of polymers from petrochemicals in the manufacture of textile fibers is a possible way to improve sustainable development for the textile industry. Polylactic acid (PLA) is one of the available bio-based polymers. One way to improve the fire behavior of this bio-based polymer is to add an intumescent formulation mainly composed of acid and carbon sources. In order to optimize the amount of bio-based product in the final material composition, lignin from wood waste was selected as the carbon source. Different formulations of and/or ammonium polyphosphate (AP) were prepared by melt extrusion and then hot-pressed into sheets. The thermal properties (thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC)) and fire properties (UL-94) were measured. The spinnability of the various composites was evaluated. The mechanical properties and physical aspect (microscopy) of PLA multifilaments with lignin (LK) were checked. A PLA multifilament with up to 10 wt % of intumescent formulation was processed, and the fire behavior of PLA fabrics with lignin/AP formulation was studied by cone calorimeter.

Surface behavior and bulk properties of aqueous chitosan and type-B gelatin solutions for effective emulsion formulation

The behavior of aqueous chitosan (CH), type-B gelatin (GB) and CH-GB coacervate was studied on oil-in-water emulsion formulation at various pH and concentration ratio. The coacervate was formed by phase separation at ratios CH:GB, 1:10 to 1:1 with total biopolymer concentrations of 0.55%-1.0% (w/v) at pH 4.0-5.5. Soluble complexes were formed below pH 5.0 and coacervate formation was confirmed at pH 5.0 and above by zeta potential and UV-spectroscopy measurements. The coacervate formation was found maximum at the CH-GB ratios of 1:10 and 1:5 at pH 5.5. Formulated emulsions (>10μm droplets) using 1% (w/v) chitosan and GB were found stable (+52.5mv and creaming index 86%) and unstable respectively. Emulsion stabilized by mixed CH:GB 1:5 (3%w/v) had no creaming effect. The instability was attributed to the lower surface activity (K=5.0Lg-1) of pure GB compared to CH (K=14.3Lg-1). The formulation and methods can successfully tune the stability of the emulsions.

Use of mesoporous silica as a reinforcing agent in rubber compounds

Abstract Mesoporous silica is used as filler for styrene-butadiene rubber (SBR); filler-polymer interactions are compared with those exhibited when Ultrasil silica (VN3) is used. A silane coupling agent is added to improve filler dispersion and its influence on the bound-rubber formation is also investigated. The bound-rubber content is higher for the mesoporous silica and increases further for the sample containing silane. The increase is explained by chemical interactions between filler and rubber and penetration of the rubber chains into the mesopores. This is confirmed by 13C solid-state NMR, IR spectroscopy and differential scanning calorimetry. Dynamic mechanical thermal analysis shows higher storage modulus for the rubber filled with mesoporous silica.

PROCESS OPTIMIZATION OF ECO-FRIENDLY FLAME RETARDANT FINISH FOR COTTON FABRIC: A RESPONSE SURFACE METHODOLOGY APPROACH

The n-methylol dimethyl phosphono propionamide (MDPA) flame retardant compounds are predominantly used for cotton fabric treatments with trimethylol melamine (TMM) to obtain better crosslinking and enhanced flame retardant properties. Nevertheless, such treatments are associated with a toxic issue of cancer-causing formaldehyde release. An eco-friendly finishing was used to get formaldehyde-free fixation of flame retardant to the cotton fabric. Citric acid as a crosslinking agent along with the sodium hypophosphite as a catalyst in the treatment was utilized. The process parameters of the treatment were enhanced for optimized flame retardant properties, in addition, low mechanical loss to the fabric by response surface methodology using Box–Behnken statistical design experiment methodology was achieved. The effects of concentrations on the fabric’s properties (flame retardancy and mechanical properties) were evaluated. The regression equations for the prediction of concentrations and mechanical properties of the fabric were also obtained for the eco-friendly treatment. The R-squared values of all the responses were above 0.95 for the reagents used, indicating the degree of relationship between the predicted values by the Box–Behnken design and the actual experimental results. It was also found that the concentration parameters (crosslinking reagents and catalysts) in the treatment formulation have a prime role in the overall performance of flame retardant cotton fabrics.

Chitosan-Based Sustainable Textile Technology: Process, Mechanism, Innovation, and Safety

This chapter reviews relevant findings regarding the activities and contributions of chitosan in different textile processing following the varieties of process, mechanism, and applications. Chitosan is a better candidate in both aspects of biodegradability and efficiency instead of synthetic polymers. The technical and scientific discussions behind the role of chitosan in all the processes and treatments have been explored in the chapter. Over the last few years, enormous efforts and challenges are being practiced in research and industry to design and development of eco-friendly and sustainable technologies. Therefore, the chapter emphasizes on chitosan-based formulations of fibers, fabrics, coatings, and functional textiles.

Application of Flame-Retardant Double-Layered Shell Microcapsules to Nonwoven Polyester

A microencapsulated flame retardant was used in order to produce a flame retardant nonwoven substrate. Melamine-formaldehyde polymer-shell microcapsules, containing Afflamit® PLF 280 (resorcinol bis(diphenyl phosphate)) as the core substance, were coated by an outer thermoplastic wall (polystyrene (PS) or poly(methyl methacrylate)), before being applied to a core/sheet-type bi-component PET/co-PET spunbond nonwoven substrate using impregnation. The outer wall of the microcapsules was heated to the softening temperature of the thermoplastic shell in order to be bonded onto the textile fibres. The thermal stability of the microcapsules was examined using thermogravimetric analysis. The textile samples were observed with a scanning electron microscope, and the flame retardancy performance was evaluated using the NF P92-504 standard. The results show that the composition of the outer polymeric shell affected the thermal stability of the microcapsules, since the particles with a PS shell are more stable. Furthermore, the microcapsules were more located at the nonwoven surface without affecting the thickness of the samples. Based on the results of the NF P92-504 test, the flame spread rate was relatively low for all of the tested formulations. Only the formulation with a low content of PS was classified M2 while the others were M3.

Functionalization of a bamboo knitted fabric using air plasma treatment for the improvement of microcapsules embedding

The research presented in the paper is based on the idea of optimizing the processing and use of cosmetotextiles. The production of these materials involved: Use of a textile knitted support with 3D surface geometry (in order to create a massaging effect) made of bamboo yarns (for improved comfort characteristics). Functionalization of the textile support with air plasma treatment improving the hydrophilic characteristics and increasing the surface energy available, facilitating the bonding of microcapsules. The paper highlights the improvement of microcapsules embedding by the functionalization of a textile knitted support with 3D surface geometry, made of bamboo yarns. The surface of the bamboo knitted fabric was pre-functionalized by an air atmospheric plasma treatment irradiation before applying microcapsules; the characterization and quantification of the amount of microcapsules bonded to the fibers were being carried out using a co-assisted technique: gas chromatography associated with mass spectrometry, scanning electron microscopy, electric parameters analysis (zeta potential ξ), and determination of air permeability.

Water vapor permeability of thermosensitive polyurethane films obtained from isophorone diisocyanate and polyester or polyether polyol

A series of thermosensitive films for firefighting applications were synthesized by two-step polymerization from two types of polyol and isophorone diisocyanate and by the formation of aqueous polyurethane dispersions. This study was conducted to clarify the influence of different parameters such as the type of polyol, the chain length of polyol, and the hard segment content on the chemical, thermal, mechanical and diffusion properties of the final films using ATR infrared spectroscopy, differential scanning calorimetry, thermogravimetric analyses, water vapor permeability, swelling behavior, contact angle measurement, and dynamic mechanical analyses. It was noticed that the humidity transfer was influenced by the soft segment crystallization. Indeed, it enhanced the chain mobility in bulk materials leading to an increase in water vapor permeability rather than in swelling. In contrast, low crystallization induced surface state modification resulting in higher swelling capacity.