Adhesion promotion of thick fire-retardant melamine polymer dip-coatings at polyolefin surfaces by using plasma polymers

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.     

Plasma deposition of adhesion-promoting polymer layers onto polypropylene for subsequent covering with thick fire retardant coatings

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.     

Adhesion promotion of thick polyphosphate-poly(allylamine) films onto polyolefin substrates by plasma polymers

The adhesion of thick poly(allylamine)-polyphosphate layers (1 μm) deposited by the wet-chemical layer-by-layer (LbL) technique onto polyethylene or polystyrene (each 100 μm) was very low. To promote the adhesion of these LbL deposited layers, the polyolefin substrates were oxidized at the surface by short exposure to the oxygen plasma (2 or 5 s) and subsequently coated with an interlayer of plasma-deposited poly(allylamine) or poly(allyl alcohol) (100 nm). The plasma polymer interlayers have improved strongly the adhesion between polyolefin substrates and polyphosphate coatings. Such phosphate coatings are interesting for life sciences (nucleotide formation) but also for fire retardancy in combination with N-rich compounds such as melamine. The intention was to prefer chemical hydrogen bonds for adhesion promoting because of their high binding energy. Therefore the introduced oxygen-containing groups at the polyolefin surface could interact with the OH or NH₂ groups of the adhesion-promoting plasma polymer interlayer. These groups were also able to interact strongly with the poly(allylamine)-polyphosphate topcoating. The coated polyolefins were investigated using Fourier transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), X-ray photoelectron spectroscopy, thermogravimetric analyses and atomic force spectroscopy, and 90° peel test.     

Plasma etching and plasma polymerization coating of carbon fibers. Part 2. Characterization of plasma polymer coated carbon fibers

Unsized AS-4 carbon fibers were subjected to RF plasma etching and/or plasma polymerization coating in order to enhance their adhesion to vinyl ester resin. Ar, N₂ and O₂ were utilized for plasma etching, and acetylene, butadiene and acrylonitrile were used for plasma polymerization coating. Etching and coating conditions were optimized in terms of plasma power, treatment time, and gas (or monomer) pressure by measuring the interfacial adhesion strength. Interfacial adhesion was evaluated using micro-droplet specimens prepared with vinyl ester resin and plasma etched and/or plasma polymer coated carbon fibers. Surface modified fibers were characterized by SEM, XPS, FT-IR, α-Step, dynamic contact angle analyzer (DCA) and tensile strength measurements. Interfacial adhesion between plasma etched and/or plasma polymer coated carbon fibers and vinyl ester resin was reported previously (Part 1), and characterization results are discussed is this paper (Part 2). Gas plasma etching resulted in preferential etching of the fiber surface along the draw direction and decreased the tensile strength, while plasma polymer coatings altered neither the surface topography of fibers nor the tensile strength. Water contact angle decreased with plasma etching, as well as with acrylonitrile and acetylene plasma polymer coatings, but did not change with butadiene plasma polymer coating. FT-IR and XPS analyses revealed the presence of functional groups in plasma polymer coatings.     

Coating of carbon fibers with adhesion-promoting thin poly(acrylic acid) and poly(hydroxyethylmethacrylate) layers using electrospray ionization

Thin coatings of poly(acrylic acid) (PAA) and poly(hydroxyethylmethacrylate) (PHEMA) were deposited onto carbon fibers by means of the electrospray ionization (ESI) technique in ambient air. These high-molecular weight polymer layers were used as adhesion promoters in carbon fiber–epoxy resin composites. Within the ESI process, the carbon fibers were completely enwrapped with polymer in the upper 10 plies of a carbon fiber roving. As identified with scanning electron microscopy also shadowed fibers in a bundle as well as backsides of fiber rovings were pinhole-free coated with polymers (‘electrophoretic effect’). Under the conditions used, the layers have a granular structure. Residual solvent was absent in the deposit. PAA and PHEMA films did not show any changes in composition and structure in comparison with the original polymers as analyzed by X-ray photo-electron spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Single-fiber pullout tests of coated fibers embedded in epoxy resin showed significantly increased interfacial shear strength. It is assumed that chemical bonds between carbon fiber poly(acrylic acid) and epoxy resin contribute significantly to the improved interactions.     

溴碳树脂在防火涂料中的应用与发展

综述了近年来从基体树脂入手,在防火涂料的研究与应用中的成果,详细介绍了溴碳树脂在钢结构建筑防火涂料、饰面型防火涂料、防火防腐地坪涂料及水性环保型防火涂料中的应用情况,并结合我国的实际情况对溴碳树脂的应用前景进行了展望。     

膨胀型防火涂料防火体系的研究

以聚磷酸铵(APP)/三聚氰胺(MEL)/双季戊四醇(DPER)为防火体系,自交联硅丙乳液为基质树脂的膨胀型防火涂料为研究对象,研究双季戊四醇对防火涂料耐水性和炭化层结构的影响,并采用正交试验对防火体系的配比进行优化.     

Effect of solubility and miscibility on the adhesion behavior of polymer‐coated carbon fibers with vinyl ester resins

Interfacial shear strength (IFSS) of carbon fibers with vinyl ester resin was investigated as a function of the structure of the polymer coating on carbon fibers via microdroplet tests. For coating carbon fibers, high‐performance polymers such as poly(arylene ether phosphine oxide) (PEPO), Udel® P‐1700, and Ultem® 1000, water‐soluble poly(hydroxy ether ethanol amine) (PHEA), water‐dispersed carboxy‐modified poly(hydroxy ether) (C‐PHE), and water‐insoluble poly(hydroxy ether) (PHE) were utilized. Adhesion of polymers to carbon fibers was also evaluated and the failure surface of the fibers was analyzed by SEM to understand the adhesion mechanism. Diffusion between polymers and vinyl ester resins was investigated and the solubility parameters of the polymers were calculated, with the results being correlated to the IFSS. A highly enhanced IFSS was obtained with PEPO coating, while marginally improved IFSS resulted from PHE, Udel®, and C‐PHE coatings. However, PHEA and Ultem® coatings showed no improvement. Such results were attributed to the extent of solubility and/or miscibility of polymer coatings in vinyl ester resin, with better solubility and miscibility leading to a higher IFSS. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1042–1053, 2001     

Improved adhesion of aluminum layers deposited on plasma and thermally treated poly(paraphenylene-vinylene) films substrates

Searching for better adhesion properties of metallic thin films to polymer substrates, we have studied the influence of the plasma and thermal treatments of poly(paraphenylene-vinylene) thin films on their adhesion to aluminum layers. The adhesion was found to be substantially increased when the polymer surface was treated with oxygen by RF sputtering, or when it was kept at high temperature prior to the metal deposition. An attempt has been made to explain the adhesion improvement in terms of surface analysis (XPS) and scanning electron microscopy (SEM) results of the treated surfaces. Both the metal-oxygen-carbon complex formation at the interface and the roughness induced by the oxygen treatment were found to be the reasons for the improved adhesion properties.     

水性基料在超薄型钢结构防火防腐涂层体系构建中的应用

探讨了市面上不同树脂水分散体作为超薄型钢结构防火防腐涂料基料的可能性,通过长时间浸泡涂层考察各水性树脂的耐水性、涂层致密性以及填料溶失程度,结果表明:水性基料不适用于含有水溶性填料的单涂层体系。通过热重分析对比发泡填料体系和各树脂的热降解行为,选择热降解温程较为相似的乙酸乙烯酯共聚物和环氧共聚物作为优化涂层防火功能的主要基料。通过垂直燃烧实验测试被涂覆试样的背板温度,优化了防火涂层的颜基比;并通过调整基料复配比例,使得涂层在灼烧后可以得到膨胀厚实且粘附稳定、致密均匀的发泡层。以此为基础,构建了防腐—防火—封闭的多层防火防腐体系,该体系具有良好的耐腐蚀性及耐火性,尤其是长期浸泡后的可持续耐火性与溶剂型同类产品相当。     

Plasma etching and plasma polymerization coating of carbon fibers. Part 1. Interfacial adhesion study

Unsized AS-4 carbon fibers were etched by RF plasma and then coated via plasma polymerization in order to enhance their adhesion to vinyl ester resin. Gases utilized for plasma etching were Ar, N₂ and O₂, while monomers used in plasma polymerization coating were acetylene, butadiene and acrylonitrile. Plasma etchings were carried out as a function of plasma power (30–70 W), treatment time (1–10 min) and gas pressure (20–40 mtorr). Plasma polymerizations were performed by varying the treatment time (15–60 s), plasma power (10–30 W) and gas pressure (20-40 mtorr). The conditions for plasma etching and plasma polymerization were optimized by measuring interfacial adhesion with vinyl ester resin via micro-droplet tests. Plasma etched and plasma polymer coated carbon fibers were characterized by SEM, XPS, FT-IR and α-Step, dynamic contact angle analyzer (DCA) and tensile strength measurements. In Part 1, interfacial adhesion of plasma etched and plasma polymer coated carbon fibers to vinyl ester resin is reported, while characterization results including tensile strength of carbon fibers are reported in Part 2. Among the treatment conditions, a combination of Ar plasma etching and acetylene plasma polymer coating provided greatly improved interfacial shear strength (IFSS) of 69 MPa, compared to 43 MPa obtained from as-received carbon fiber. Based on the SEM analysis of failure surfaces and load-displacement curves, the failure was found to occur at the interface between plasma polymer coating and vinyl ester resin.     

Influence of PEPA-containing polyether structure on fire protection of transparent fire-resistant coatings

Three kinds of novel PEPA-containing polyether flame retardants were synthesized by 1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo [2.2.2] octane (PEPA), phosphorus oxychloride (POCl₃), and polyether with different structures (PEG, PPG, and PTMG). Their structures were confirmed by ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR). The solubility test showed that PEPA modified by polyethylene glycol (PEG) and polypropylene glycol (PPG) had better water solubility than that modified by poly(tetrahydrofuran) (PTMG). The decomposition process of PEPA-containing polyether flame retardants (PCPE) was studied by thermogravimetric analysis (TG) and derivative thermogravimetry. A possible mechanism was proposed to analyze the influence of polyether structure on the thermal degradation process of PCPEs. Afterward, the PEPA-containing polyether flame retardants were mixed with melamine formaldehyde resin to prepare the transparent fire-resistant coatings. The influences of polyether structure on the properties of the coatings were investigated in detail by fire protection test, TG, FTIR, X-ray photoelectron spectroscopy (XPS), and scanning electron microscope. It was found that the fire protection of the coating and foam structure of char layer were significantly improved when the number of carbon atoms in a unit of polyether chain was less. TG results showed that the chain unit of polyether with less carbon atom number could increase the residue weights of the coatings. FTIR and XPS result illustrated that the char layers were mainly composed of aromatic rings and phosphorus oxide, and the antioxidation and char-forming ability of coatings were enhanced effectively with the decrease in the number of carbon atoms in a unit of polyether chain.     

低温快干氨基塑料涂料的研制

采用低羟基丙烯酸树脂和混醚化三聚氰胺甲醛树脂在酸催化下 ,低温交联固化形成高光、附着力强、耐候性优良的单组分塑料涂料。讨论了树脂配比、助剂用量、烘干温度等对涂膜性能的影响。     

聚丙烯基材表面树脂附着的研究进展

表面能低、惰性及低极性是聚丙烯难以被附着的重要原因。选择附着树脂对聚丙烯表面改性有助于涂料润湿和附着成膜。附着树脂主要包括聚烯烃类、有机硼引发类、端叠氮基芳香聚合物等。聚烯烃类附着树脂一种是聚丙烯的氯化物或马来酸酐接枝物,以及它们的再功能化扩链产品,另一种是其他聚烯烃的接枝物。有机硼和端叠氮基芳香聚合物是原位化学接枝的附着树脂新类型,拓展了聚烯烃类的适用温度和适用环境。     

High density hydrophilic and hydrophobic brush coatings using a polymeric primer layer

Polymer brush coatings, consisting of polymer chains covalently attached to a surface and being less than a hundred nanometer thick, allow the creation of functional surfaces without altering the inherent bulk properties or appearance of a product. Surface properties depend on the type and length of the polymer used, as well as on the grafting density of the polymer brush. By making use of a polymeric primer layer that is covalently linked to the substrate and creates a uniform and highly functionalized surface, polymer brush coatings with high grafting densities can be created. In this paper we report the preparation of hydrophilic as well as hydrophobic brush coatings on different substrates through the use of a poly(acrylic acid) primer layer. In addition, hydrophilic poly(ethylene glycol) brush coatings thus produced were shown to decrease adhesion of marine bacteria.     

Effects of expandable graphite on char morphology and pyrolysis of epoxy based intumescent fire-retardant coating

The current study was designed to investigate the effects of expandable graphite (EG) on fire protection properties of intumescent fire-retardant coating for steel structures. Several formulations of intumescent coating were prepared and tested according to ISO 834 for char expansion. The chars were found without cracks and bonded with the steel substrate. The results showed that the coating slowly degraded during the test and char remained in contact with vertically tested coated substrate. The coated substrates were also tested for weather resistance using humid and ultraviolet environment. The char was characterized by using FESEM, XRD, FTIR, TGA, and XPS analysis. FESEM examined char morphology of the coatings after furnace fire test. XRD and FTIR showed the presence of graphite, borophosphate; boron oxide and sassolite in the char. TGA and DTGA results disclosed that EG improved the residual mass of coating. XPS analysis showed the percentages of carbon and oxygen are 48.50 and 43.45 in char of formulation with 12.8% EG. The results of weathering test coatings showed decreased in char expansion because of a humidity and UV light. The formulation with 9.8% EG showed the maximum char expansion and high residual mass among the formulations investigated in this study. The weathering tested coated samples showed their capability of fire protection.     

仿瓷阻燃脲醛涂料的研制

以改性的脲醛权脂为基料，磷酸和淀粉为阻燃剂制成膨胀型透明防火涂料，本文介绍了该涂料的配方和生产方法，讨论了改性的脲醛树脂结构，防火剂的组成及作用机理，列举了涂料的防火性能和理化性能的测试结果。     

Effect of Surface Energetics of Substrates on Adhesion Characteristics of Poly (p-xylylenes)

In investigating the effect of the surface energetics of substrate materials on the adhesion characteristics of poly(p-xylylene) and poly(chloro-p-xylylene) by the “Scotch Tape” method, it was found that if the substrates had not been preconditioned (treated with argon or a methane plasma), the adhesion was poor. The characteristics of water resistant adhesion that were observed when coated substrates were boiled in 0.9% sodium chloride solution were found to vary from excellent (when the polymer did not peel from the substrate after three cycles of 8 hours of boiling and 16 hours at room temperature) to poor (when the polymer peeled off almost immediately). It was noticed that water resistant adhesion depends on the hydrophobicity of the substrate material (the greater the hydrophobicity, the greater the adhesion) and is not related to the dry adhesive strength of poly(p-xylylene). The oxygen glow discharge treatment of the substrates decreased both the dry and wet adhesive strength of the polymer. The effect of the argon glow discharge treatment depended on the surface energetics of the substrate, and the methane glow discharge treatment increased both the dry and wet adhesive strength of the polymer. These preconditioning processes are discussed in terms of the sputtering of the material from the wall of the reactor in contact with the plasma and the deposition of the plasma polymer of the sputtered material on the substrate surface.     

制罐用白可丁的研制

使用聚酯树脂和甲醚化氨基树脂配合制备制罐用白可丁，讨论了不同聚酯树脂、氨基树脂及催化剂的选择，及其对漆膜性能的影响。     

Effect of Surface Energetics of Substrates on Adhesion Characteristics of Poly (p-xylylenes)

In investigating the effect of the surface energetics of substrate materials on the adhesion characteristics of poly(p-xylylene) and poly(chloro-p-xylylene) by the “Scotch Tape” method, it was found that if the substrates had not been preconditioned (treated with argon or a methane plasma), the adhesion was poor. The characteristics of water resistant adhesion that were observed when coated substrates were boiled in 0.9% sodium chloride solution were found to vary from excellent (when the polymer did not peel from the substrate after three cycles of 8 hours of boiling and 16 hours at room temperature) to poor (when the polymer peeled off almost immediately). It was noticed that water resistant adhesion depends on the hydrophobicity of the substrate material (the greater the hydrophobicity, the greater the adhesion) and is not related to the dry adhesive strength of poly(p-xylylene). The oxygen glow discharge treatment of the substrates decreased both the dry and wet adhesive strength of the polymer. The effect of the argon glow discharge treatment depended on the surface energetics of the substrate, and the methane glow discharge treatment increased both the dry and wet adhesive strength of the polymer. These preconditioning processes are discussed in terms of the sputtering of the material from the wall of the reactor in contact with the plasma and the deposition of the plasma polymer of the sputtered material on the substrate surface.