Filtern
Dokumenttyp
- Zeitschriftenartikel (4)
- Vortrag (3)
- Beitrag zu einem Tagungsband (1)
- Dissertation (1)
- Posterpräsentation (1)
Schlagworte
- Polymer (5)
- Fire retardant (4)
- Plasma (4)
- Plasma polymerization (4)
- Flame retardancy (3)
- Polyethylene (3)
- Polystyrene (3)
- Curing (2)
- Dip-coating (2)
- Melamine resin (2)
- Methylated poly(melamine-co-formaldehyde) (2)
- Adhesion (1)
- Allyl alcohol (1)
- Analytik (1)
- Dip coating (1)
- Flame retardants (1)
- Hexamethyldisiloxane plasma polymer (1)
- Melamine precursors (1)
- Plasmatechnologie (1)
- Polypropylene (1)
- Thick melamine layers (1)
Eingeladener Vortrag
- nein (3)
Melamine and melamine resins are widely used as fire retardants for polymer materials used in pharmaceutical, plastic, textile, rubber, and construction industry. Melamine-based flame retardants act by blowing off intumescent layers, char formation, and emission of quenching ammonia gas and diluent molecular nitrogen. Special advantages are: low cost, low smoke density and toxicity, low corrosive activity, safe handling, and environmental friendliness. Methylated poly(melamine-co-formaldehyde) (mPMF) was used as thick (≥40 µm) fire-retardant coating for plasma pretreated polymers. A combined low-pressure plasma pretreatment consisting of oxygen plasma exposure followed by deposition of thin poly(allylamine) (ppAAm) and poly(allyl alcohol) (ppAAl) plasma polymers as adhesion promoters have improved the adhesion of thick mPMF coatings strongly. Chemical structure and composition of deposited polymer films were characterized by infrared-attenuated total reflectance and X-ray photoelectron spectroscopy (XPS). After peeling, the peeled layer surfaces were also investigated for identification of the locus of failure and their topography using optical microscopy and XPS. Often the adhesion promotion was so efficient that the peeling of coating was not possible. Thermal properties of plasma polymers and dip-coating films were analyzed by thermogravimetric analysis. Significant improvement of fire-retardant properties of coated polymers was confirmed by flame tests.
Melamine and melamine resins are widely used as fire-retardants for polymer building materials. Cured melamine systems are used in heat-sensitive items, such as furniture and window frames and sills. In this work, differently cured methylated poly(melamine-co-formaldehyde) (cmPMF) resins were used as fire-retardant coverage for poly(styrene) (PS) and poly(ethylene) (PE) building materials. Such polymer layers should have several tenths of micrometers thickness to produce sufficient fire retardancy. These thick layers were produced by dip-coating. To promote sufficient adhesion of such thick coating to the polyolefin substrates, also in the case of high temperatures occurring at fire exposure, the polymer substrates were firstly coated with a few hundred nanometer thick adhesion-promoting plasma polymer layer. Such thin plasma polymer layers were deposited by low-pressure plasma polymerization of allyl alcohol (ppAAl). It was assumed that the hydroxyl groups of ppAAl interact with the melamine resin; therefore, ppAAl was well suited as adhesion promoter for thick melamine resin coatings. Chemical structure and composition of polymer films were investigated using infrared-attenuated total reflectance and X-ray photoelectron spectroscopy (XPS). Peel strengths of coatings were measured. After peeling, the peeled polymer surfaces were also investigated using optical microscopy and XPS the layers for identification of the locus of peel front propagation. Thermal properties were analyzed using TGA (thermo-gravimetric analyses). Finally, the fire-retardant properties of such thick coated polymers were evaluated by exposure to flames.
First goal of this work was to produce thick fire-resistant coatings, which are able to withdraw the direct contact to flames. Preliminary tests had shown that thicknesses more than 10 μm are needed to measure effects on flammability. Here, 40 μm thick layers are prepared. The adhesion of such thick layers mainly depends on the use of surface treatment of polyolefin substrates. Plasma exposure and deposition of plasma polymer layers are easiest and most efficient methods to promote the adhesion of thick layers used for the fire protection of materials. Indeed, plasma processing doesn’t modify the intrinsic properties of materials such as the mechanical properties, easily processed, and can be applied over a wide range of materials even though for metals.
To achieve very high adhesion of such thick coatings to the polymer substrates it has to be considered that the chemical nature of coating and polymers is different, strong different thermal expansion coefficients exist and therefore adhesion was most oftenabsent.
Melamine resins were used as 50-µm-thick fire retardant coatings for polypropylene (PP). Preceding deposition, low-pressure plasma polymer films of allyl alcohol were coated onto PP to improve the adhesion between PP and melamine resin coatings. The efficiency of such fire retardant coatings was confirmed by flame tests. The plasma-deposited polymer and the dip-coated melamine resin films were characterized by Fourier transform infrared-attenuated total reflectance spectroscopy and X-ray photoelectron spectroscopy (XPS). The adhesion of coatings was measured using a 90° peel test with a doubled-faced adhesive tape. To detect the locus of failure, the peeled layer surfaces were inspected using optical microscopy and XPS. Thermal properties of PP thick melamine resin-coated films were analyzed by thermogravimetric analysis.
Thick coating of polyolefins
(2014)
Mixtures of hexamethyldisiloxane (HMDSO) and oxygen have been used for deposition of SiO2-like layers by plasma polymerization under low-pressure conditions onto polyethylene and polystyrene used as basecoat. Water glass was cast onto these 0.5 µm plasma thick siloxane-like layers with a thickness of 5 to 40 µm. The adhesion of these bilayer systems and their flame resistance were tested.
The effect of different plasma parameters such as monomer/gas ratio, pressure and power input into the discharge on the deposition rate and the composition of the formed layers was studied. Characterization and chemical composition of the formed films were performed using infrared, X-ray photoelectron and solid state nuclear magnetic resonance spectroscopy.
Peel strengths of composites were measured and the locus of peel front propagation was detected. Thermal properties of composites were analyzed by thermo-gravimetric analysis. Finally, the fire-retardant properties of thick coated polymers were determined by exposure to flames and the behavior of coatings on the polymers during flaming was observed visually.
Mixtures of hexamethyldisiloxane (HMDSO) and oxygen have been used for deposition of SiO2-like layers by plasma polymerization under low-pressure conditions onto polyethylene and polystyrene used as basecoat. Water glass was cast onto these 0.5 pm plasma thick siloxane-like layers with a thickness of 5 to 40 mu m. The adhesion of these bilayer systems and their flame resistance were tested. The effect of different plasma parameters such as monomer/gas ratio, pressure and power input into the discharge on the deposition rate and the composition of the formed layers was studied. Characterization and chemical composition of the formed films were performed using infrared, X-ray photoelectron and solid state nuclear magnetic resonance spectroscopy. Peel strengths of composites were measured and the locus of peel front propagation was detected. Thermal properties of composites were analyzed by thermo-gravimetric analysis. Finally, the fire-retardant properties of thick coated polymers were determined by exposure to flames and the behavior of coatings on the polymers during flaming was observed visually.