Structure property relationship in polyurethanes coatings

structure property relationship in polyurethanes coatings

To evaluate the structure–property relationship, polyurethane acrylate coating dispersions were synthesized with aromatic and aliphatic hard. The chemical structure and properties of polyurethane are a logical relationship between the glass transition temperature of the coating and. Structure-property relationships of polyurethane anionomer acrylates Polyurethane (PU) ionomer acrylates and non-ionomer acrylates were synthesized from poly(propylene glycol) (PPG), isophorone J. Coated Fabrics, 8 (), p.

Most of them are high solids and solventless PU coatings [ 4 ]. PU are family of engineering thermoplastic elastomers. Different kinds of polyurethane based coatings have been developed and used in different industries due to their superior properties, such as flexibility at low temperature, high abrasion resistance, high impact and tensile strength, high transparency, excellent gloss, color retention, corrosion protection properties, and good weathering resistance [ 56 ].

However, polyurethane has some disadvantages, that is, low thermal resistance, low adhesion, and low mechanical and anticorrosive properties [ 7 ].

In recent years, researchers have tried to conquest these disadvantages through different ways. Addition of pigments to the coatings has been introduced as an effective way to obtain polyurethane based coatings with enhanced mechanical and anticorrosion properties [ 89 ]. In this regard, the use of fillers in polymer matrix allows for further improving of mechanical behavior. The resulted composites have properties different than the properties of the bulk polymer matrix itself [ 10 — 12 ].

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The chemical structure and properties of polyurethane are influenced by using the metal complex systems based on transition metal for their synthesis, where metal complexes have the ability to order the chains, as well as have an effect on the chemical properties, and can improve the mechanical and anticorrosion properties of the coatings of polyurethanes [ 14 ]. They understood that the procedure of composite preparation is so important which can affect the filler dispersibility in the resin.

It was shown that there is a logical relationship between the glass transition temperature of the coating and the amount of resin chemically bonded to the filler surface.

International Journal of Polymer Science

Fillers could increase the of the coating when the resin segment chemically linked to the surface of particles. Depending on the surface nature of the filler, they could migrate to the surface of the coating or remain in the bulk [ 1516 ]. Metallophthalocyanines are interesting classes of organic fillers; they have been used as a new brand of materials to reach this target, due to their high specific surface area and thermal and chemical stability [ 17 ].

The contribution of our group to this field of research has been quite remarkable and described in detail in [ 1819 ]. As reported in literature, a considerable academic research efforts have described some metallophthalocyanine derivatives modified coatings for improving the mechanical and anticorrosion properties of the coatings.

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In addition, copper phthalocyanine was used as a filler in a PU matrix to enhance its dielectric properties [ 21 ]. The results indicated that the incorporation of Fe-OCAP significantly improved the tensile strength, elongation at break, and thermal deformation property of PU matrix [ 22 ].

Therefore, the improvements of the mechanical properties of polyurethane as mentioned above are essential for its industrial, technical requirements for several applications and help to create high performance PU coatings [ 23 ]. Materials and Methods 2. The octahydroxycopper II phthalocyanine 3 was synthesized as reported in our previous work [ 24 ]. Analytical grade dimethylformamide DMF was dried with CaH2, distilled in vacuo, and stored under dry nitrogen.

The other reagents, such as organic solvents and bases, were analytical grade. Apparatus Microwave oven utilized for heating was used: The mixture was stirred for 2 days at room temperature, then methanol was added slowly, and dark green suspensions were formed.

The suspended solution was centrifuged. Preparation of octahydroxycopper II phthalocyanine 3. The mixture was then ultrasonically stirred for approximately 2 h to obtain a homogeneous solution. Afterwards, the mixture was casted on either glass or cement substrates at different wet thicknesses. The schematic of possible dispersions of CuPc in PU skeleton. The molds were left at room temperature for 6 hours.

After evaporation of the solvent. The resulting polymer composite specimens were then easily removed from the bone-shaped molds. They were stored under vacuum at room temperature until needed for testing. Spectra were analyzed using Opus 6.

The parameters used for the determination of each spectrum were the following: Elementary analyses were performed on a Carlo Erba Elemental Analyzer The abrasion resistance test of the films was measured using a Taber Abrasion Tester Model The pull-off test of the films was measured using an Elcometer adhesion tester.

Polyurethane

The test is done by securing loading fixtures dollies perpendicular to the surface of a coating with an adhesive. This type of machine has two crossheads; one is adjusted for the length of the specimen and the other is driven to apply tension to the test specimen.

Dynamic mechanical analyses were performed with a TA Q dynamic mechanical analyzer. The size of samples was about The parameters such as storage modulus,and displacement as a function of temperature which corresponded to the irreversible deformation of the samples were obtained.

Results and Discussion 3. Characterization of Octahydroxycopper II phthalocyanine [ OH 8CuPc] 3 The first main task for this work was the synthetic route to novel peripherally octasubstituted copper II phthalocyanine 3, Scheme 1.

structure property relationship in polyurethanes coatings

It was synthesized as reported in our previous work [ 24 ]. The new copper phthalocyanine 3 was purified. It was characterized by spectral data IR, UV-Visible spectroscopy, mass spectral data, and elemental analysis. The characterization data of the new compound were consistent with the assigned formula. The result of elemental analysis also confirmed the structure of complex 3.

Health and safety[ edit ] Fully reacted polyurethane polymer is chemically inert. It is not regulated by OSHA for carcinogenicity. Top, untreated polyurethane foam burns vigorously.

structure property relationship in polyurethanes coatings

Bottom, with fire-retardant treatment. Polyurethane polymer is a combustible solid and can be ignited if exposed to an open flame. Green Science Policy Institute states: Consumers who wish to reduce household exposure to flame retardants can look for a TB tag on furniture, and verify with retailers that products do not contain flame retardants.

Isocyanates are known skin and respiratory sensitizers. Additionally, amines, glycols, and phosphate present in spray polyurethane foams present risks. Manufacturing[ edit ] The methods of manufacturing polyurethane finished goods range from small, hand pour piece-part operations to large, high-volume bunstock and boardstock production lines.

Regardless of the end-product, the manufacturing principle is the same: Dispensing equipment[ edit ] Although the capital outlay can be high, it is desirable to use a meter-mix or dispense unit for even low-volume production operations that require a steady output of finished parts. Dispense equipment consists of material holding day tanks, metering pumps, a mix head, and a control unit. Often, a conditioning or heater-chiller unit is added to control material temperature in order to improve mix efficiency, cure rate, and to reduce process variability.

Choice of dispense equipment components depends on shot size, throughput, material characteristics such as viscosity and filler content, and process control. Material day tanks may be single to hundreds of gallons in size, and may be supplied directly from drums, IBCs intermediate bulk containerssuch as totesor bulk storage tanks.

They may incorporate level sensors, conditioning jackets, and mixers. Pumps can be sized to meter in single grams per second up to hundreds of pounds per minute. They can be rotary, gear, or piston pumps, or can be specially hardened lance pumps to meter liquids containing highly abrasive fillers such as chopped or hammer milled glass fibres and wollastonite.

A high pressure polyurethane dispense unit, showing control panel, high pressure pump, integral day tanks, and hydraulic drive unit.

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A high pressure mix head, showing simple controls. A high pressure mix head, showing material supply and hydraulic actuator lines. Mix heads can be simple static mix tubes, rotary element mixers, low-pressure dynamic mixers, or high-pressure hydraulically actuated direct impingement mixers.

Add-ons to dispense equipment include nucleation or gas injection units, and third or fourth stream capability for adding pigments or metering in supplemental additive packages. A low pressure mix head with calibration chamber installed, showing material supply and air actuator lines.

Low pressure mix head components, including mix chambers, conical mixers, and mounting plates. Tooling[ edit ] Distinct from pour-in-place, bun and boardstock, and coating applications, the production of piece parts requires tooling to contain and form the reacting liquid.

The choice of mold-making material is dependent on the expected number of uses to end-of-life EOLmolding pressure, flexibility, and heat transfer characteristics. It is typically used for molding rigid foam parts, where the ability to stretch and peel the mold around undercuts is needed. The heat transfer characteristic of RTV silicone tooling is poor. High-performance, flexible polyurethane elastomers are also used in this way.