Properties Of Polyurethane Coatings Research Articles

Preparation and properties of UV-curable rosin-based polyurethane coatings

Ultraviolet (UV)-curable coatings were prepared using rosin-based polyurethane as an oligomer with different active diluents and cross-linking monomers. The effects of the levels of different components on the properties of the polyurethane coatings were investigated, and the effects of the mass ratios of active diluents, cross-linking monomers, adhesion-promoting monomers and photoinitiators and curing times on the polyurethane coatings are discussed. The results showed that when hydroxypropyl acrylate was used as an end-capping agent, 40% methyl methacrylate as a reactive diluent, 10% dimethylolpropane tetracrylate as a cross-linking monomer, 7% hydroxyethyl diacrylate phosphate as an adhesion promoter, 4% 1173 as a photoinitiator and a curing time of 120 s, the UV-curable resin exhibited the best coating properties: a pendulum hardness of 0.63, a 60° gloss of 153.9, grade 2 adhesion, an impact strength of 500 J/m2 and water resistance exceeding 30 days.

The effect of lignin-based polyols on the properties of polyurethane coatings

The aim of this research was to replace petroleum-based polyols with polyols made from lignin and nano-lignin in the production of polyurethane coatings. Lignin and nano-lignin were first reacted with either diethylenetriamine or ethylenediamine. Subsequently, they were modified with propylene carbonate. The lignin- and nano-lignin-derived polyols replaced the conventional acrylic polyol in the production of polyurethane coatings. The results of Fourier transform infrared analysis showed that urethane, isothiocyanate and strong C–N bonds were formed in nano-lignin-based polyurethanes. Moreover, the surface adhesion test of the lignin-based polyurethane coating showed that with increasing lignin content, the adhesion strength of the coating decreased. Mixing lignin nanoparticles into the polyurethane substrate caused the adhesion strength to rise from 1.67 to 4.52 MPa. An increase in the amino nano-lignin content of oil-based polyol of up to 7% improved the curing of the coating and increased the scratch resistance to more than 5 kg. The results showed that lignin from a mechanical pulping process has a direct effect on reducing the smoothness and the glossiness of polyurethane coatings.

Tailoring the Properties of Polyurethane Coatings with Epoxidized Bio-Polyol Spin-Coated onto Glass and P-Type Si(100) Substrates

High-performance plastics or engineering polymers have been actively studied for various microelectronic applications as the demand for faster processing speeds increases. Taking advantage of its high Young’s modulus ideal for inter-layer dielectric applications, polyurethane (PU), a class of linearly-segmented polymer primarily made by reacting isocyanate and polyol, were deposited on borosilicate glass and p-type Si (100) substrates via spin coating method utilizing epoxidized soybean oil as a bio-polyol replacement. Optical micrographs showed that 100% ESBO-based PU coatings exhibited homogeneous and superior quality coatings in contrast to 50% ESBO-and 100% petroleum-based PU coatings as confirmed by scanning electron micrographs and EDX analysis. Based on the surface profilometry data, we found out that PU coatings with film thickness ranging from 6 μm to 28.5 μm can be achieved. FTIR-ATR analysis revealed that maintaining the stoichiometric ratio between O–H and N–C–O vibrational modes closer to unity is a vital factor to produce a high-quality PU coating regardless of the choice of substrate. The average bandgap energy of 4.35 ± 0.03 eV was estimated from the UV-vis reflectance spectra, and the electrical resistance of 107–1010 orders of magnitude was measured using a two-probe method which are typical for dielectric materials. Preliminary insights about the dielectric response of the fabricated PU coatings were investigated using electrochemical impedance spectroscopy and a low κ-value of 2.749 was calculated from the Nyquist plot of the 7.9-μm thick 100% ESBO-based PU coating deposited at 6000 rpm for 45 seconds. These promising results proved that PU coatings from bio-polyols can be tailored to achieve desired coating properties that are amenable for next-generation microelectronic packaging and curable photoresists.

Polyurethane as smart biocoatings: Effects of hard segments on phase structures and properties

Development of smart polyurethane (PU) coatings for enhancing the biocompatibility of the metal scaffold has attracted great interest in the past few years, and the investigation of the relationship between phase structure and smart properties is necessary. Herein, two series of PU biocoatings with different hard segment structures and soft segment length were prepared, and the soft segments consist of the polycaprolactone diols (PCL) with different molecular weights, and the hard segments were made of 1, 4-butanediol (BDO) and hexamethylene diisocyanate (HDI) with linear structure, or BDO and isophorone diisocyanate (IPDI) with alicyclic structure, respectively. To understand the phase structures, the chemical structure, surface micromorphology, and segmental incompatibility of the PU films were characterized, which reveals that IPDI-based PU possesses a phase compatible structure with a single-phase transition above 0 °C. Besides, the IPDI-based PU shows the thermal-responsive deformation at the temperature of 45 °C, slightly higher than the human body temperature. In contrast, the HDI-based PU possesses the excellent shape memory property caused by the microphase separation structure, because of the crystallization of soft and hard segments from the melt. Further, based on the characteristics of phase structure, the potential application of the IPDI-based PU and HDI-based PU is explored, offering a useful approach to effectively design the structures and properties of PU coatings.

Incorporation of Modified Nano Montmorillonite (MMT) in Polyurethane Coatings Based on Acrylic Copolymer and Trimer of Isophorone Diisocyanate

This work presents the synthesis of acrylic copolymer and trimer of isophorone diisocyanate (IPDI) for preparation of polyurethane (PU) coatings. Further we have studied the effect of silane modified nano montmorillonite (MMT) on the properties of PU coatings. Nano MMT was modified by vinyltriethoxysilane (TEVS) coupling agent and incorporated in PU coatings made from acrylic copolymers and trimer of IPDI. Acrylic copolymer was synthesized in the laboratory using butyl acrylate (BA), methyl methacrylate (MMA), styrene and hydroxyl ethyl acrylate (HEA) monomers. Coating properties of prepared PU coatings studied are gloss, impact resistance, flexibility, cross hatch adhesion and physicochemical properties include chemical resistance. The experimental results revealed that polyurethane coatings based on MMT based acrylic polyol and IPDI trimer showed good gloss and excellent adhesion. Thermal stability of these PU samples was found upto 229 °C. Physicochemical properties reflected that these PU have excellent chemical and solvent resistance.

Synthesis and properties of polyurethane coatings: the effect of different types of soft segments and their ratios

Polyurethane (PU) coatings were prepared using siloxane polyol [poly(dimethyl siloxane), PDMS], polyether polyol [poly(propylene oxide glycol), PPG], and polyester polyol [poly(tetramethylene adipate glycol), PTAd]. The PTAd/PPG ratio was altered, whereas the PDMS content was fixed during PU synthesis. The structural elucidation of the synthesized PU was performed by Fourier transform infrared (FT-IR), 1H NMR, 13C NMR, and 29Si NMR spectroscopic techniques. The PU-film surface was characterized by X-ray Photoelectron Spectrometer and atomic force microscopy techniques and it was found that the surface smoothness depended on the PPG/PTAd ratio. The PU melting temperature, crystallinity, mechanical properties (tensile strength and Young’s modulus), and adhesive strength were also depended on the PPG/PTAd ratio. The adhesive strength to poly(vinyl chloride) of the coating with the proper polyol ratio (PTAd 12.50 mol% and PPG 16.67 mol%) was almost unaffected after immersion (three months) in artificial salt.

Influence of cycloaliphatic compounds on the properties of polyurethane coatings

A series of polyester polyol resin was synthesized by using 1,4-cyclohexanedimethanol (1,4-CHDM) and three different diacids: 1,3-cyclohexanedicarboxylic acid (1,3-CHDA), isophthalic acid (IPA) and adipic acid (AA). The solubility and viscosity of the polyester polyols were determined by using methyl ethyl ketone (MEK). All the polyester polyols were crosslinked with hexamethylene diisocyanate (HDI) isocyanurate to form polyurethane coating films. These films were evaluated for their mechanical and chemical resistance properties. Studies on the film characteristics revealed that the polyurethane films based on cycloaliphatic diacid generally showed comparatively better performance properties than the polyurethane film based on aromatic and linear aliphatic diacids in general.

Properties of polyurethane coatings containing additives of phenolic compounds

AbstractThe properties of polyurethane containing five kinds of model phenolic additives were investigated. The IR spectra of polyurethane containing phenolic additives indicated that the phenolic additives reacted with isocyanate groups in a polyisocyanate compound. For an index of anticorrosion, the tensile adhesion strength was measured for polyurethane coatings with phenolic additives on steel plates treated with the salt‐water spraying test for 3000 h. It was found that there was a relationship between the tensile adhesion strength of polyurethane and the density. We considered the reason to be that the increase in density (i.e., a reduction in free volume) should provide a route to reduce salt‐water access to an adhesive bond. The increase in density was explained by the term antiplasticizers, which means that the phenolic additives reduce the free volume that is available for molecular motion in the stiff chain of polyurethane. In the polyurethanes with every phenolic additive, the elongation was increased, the moduli were decreased, the storage modulus was decreased, and the coefficient of thermal expansion was increased. These phenomena are the characteristics of plasticizers. Thus, the phenolic additives have both the character of antiplasticizers and plasticizers, but the polyurethane with phenolic additives had more characteristics of plasticizers than those of antiplasticizers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2099–2106, 2006

Optical-guiding properties of polyurethane coatings based on polyester polyol

Optical-guiding properties of polyurethane coatings based on polyester polyol

Preparation and Properties of Polyurethane Coatings

Preparation and Properties of Polyurethane Coatings