Synthesis and characterization of hyperbranched alkyd resins based on tall oil fatty acids

doi:10.1016/j.porgcoat.2010.04.018

Progress in Organic Coatings

Volume 69, Issue 3, November 2010, Pages 235-240

https://doi.org/10.1016/j.porgcoat.2010.04.018 Get rights and content

Abstract

Hyperbranched alkyd resins (HBRA) were synthesized from fourth generation hydroxylated hyperbranched polyester (HBP1–4) and tall oil fatty acids (TOFA) using acid catalysis. Different molar ratio of HBP1–4 and TOFA were used. Iodine values increased with the TOFA content. TOFA characteristic –HC double bond CH– bonds were detected in the infrared and nuclear magnetic resonance spectrum. Average molar mass number (Mn) and weight average molar mass (Mw) of the HBRA resins were determined by gel permeation chromatography (GPC). The values increased with the TOFA content. The viscosity of the HBRA resins was between 0.015 and 0.17 Pa s for 0.11 s⁻¹ shear rate. The dynamic light scattering (DLS) analysis revealed that the hydrodynamic dimensions of the HBRA resins are polydisperse. The HBRA resins exhibited excellent adhesion, flexibility, drying time, gloss and chemical resistance.

Introduction

Dendritic polymers are interesting materials due to their chemical and physical properties. They can be used in various applications such as coating, drug delivery, thermosets and crosslinking agents [1], [2].

The dendrimers and hyperbranched polymers belong to the group of polymer known as polymer dendritic. The dendrimers have perfectly branched structures while hyperbranched polymers (HBPs) have imperfect branched structure [3]. The synthesis of dendrimers is going step-by-step. The process involves many protection, deprotection and purification steps. All these steps make large-scale production difficult. HBPs can also be prepared by one-step synthesis, however, this simplified procedure yields less perfect structures with very broad molar mass distributions [3], [4].

The hyperbranched polymers in solution and molten state have lower viscosities compare to those of linear polymers with the same molar mass. This type of polymers have a high functionality and their reactive groups are located in the periphery, which facilities the reaction with others materials. The diameters and end groups increase with the molar mass [5].

Hydroxylated hyperbranched polyester have been synthesized by bulk polymerization from 2,2-bis(hydroxymethyl)propanoic acid with trimethylolpropane [6], pentaerythritol [7] and ethoxylated pentaerythritol [8]. The properties of hydroxylated hyperbranched polyester have been widely studied [6], [7], [8]. In Fig. 1 is presented a schematic representation of hydroxylated hyperbranched polyester.

Vegetable oils traditionally have been used as raw materials for preparation organic coatings. Alkyds or linseed oil derived coatings have mostly been air-dried systems [9]. Alkyd resin coatings have good wetting, mechanical properties and durability. One of the factors affecting coating properties is the type of fatty acid or oil used in the alkyd production [10]. The number of double allylic groups in the unsaturated fatty chain has a big influence on drying time. The H-abstraction from a monoallylic group is slower than from a double allylic site [11].

The hyperbranched alkyd resins are hydroxylated hyperbranched polyester modified with fatty acids [12]. Highly branched chains have several advantages compared to the conventional alkyd resins with the same molecular weight, such as, a lower viscosity, higher gloss, better chemical resistance and less chemical drying time [13].

Hyperbranched alkyd resins were synthesized with high content of solid and their properties were compared with a conventional alkyd resin. The hyperbranched alkyd resins showed higher elasticity, lower viscosity and drying times [12]. Fig. 2 shows a schematic representation of a HBRA resin.

Bat et al. studied the synthesis of HBRA resins based in a hydroxylated hyperbranched polyester obtained from dipentaerythritol and 2,2-bis(hydroxymethyl)propanoic acid and posterior modification with castor oil fatty acids, linseed oil fatty acids and benzoic acids. They found that the hardness of the resins increased with fatty acids and linseed oil fatty acids contents but the hardness did not change with benzoic acid content [14].

Another advantage of this type of resins is that can be synthesized by direct esterification. Since, the fatty acids are not forming triglycerides, this means that they are in free state, then the process no longer requires the transesterification step, shortening the preparation time.

In this work fourth hyperbranched alkyd resins (HBRA), with different ratio of HBP1–4 hydroxylated hyperbranched polyester and TOFA were synthesized by esterification reaction between acid groups of TOFA and OH groups of HBP1–4. The structural, physical and mechanical properties of hyperbranched alkyd resins (HBRA) were studied.

Section snippets

Materials

The HBP1–4 hydroxylated hyperbranched polyester was synthesized in our group and the details were reported in an earlier publication [7]. TOFA is a mixture of oleic acid (29.0%), linoleic acid (57.0%), rosin acids (2.0%), linolenic acid (7.0%), saturated fatty acids (3.0%) and unsaponifiables (2.0%). TOFA was supplied from Arizona Chemical. Xylene, tetrahydrofurane, sodium hydroxide, p-toluenesulfonic acid (PTAS), sodium chloride and hydrochloric acid, were purchased from Sigma–Aldrich and they

Iodine and refractive index values of the HBRA resins

The color of all HBRA resins was light yellow; this implies that they can be used in the production of white coatings, Ikhuoria et al. [15] and Dutta et al. [16] had reported brown color for conventional alkyd resins.

Table 2 presents iodine and refractive index values of the HBRA resins. The iodine value measures the C double bond C unsaturation degree of the HBRA resin and it increases with TOFA content. It can be seen clearly that refractive index increases with TOFA content since the molecular weight of

Conclusions

The esterification reaction between HBP1–4 and TOFA was evidenced by infrared and magnetic nuclear resonance. The modification of the HBP1–4, the refractive index, Mn and Mw increase with the TOFA content. All resins presented low viscosity, this makes easier and encourage producing hyperbranched alkyd resins with high solid content. The rheological behavior of the HBRA resins was Newtonian and they showed high stability in the time, also they presented good adhesion, flexibility, short drying

Acknowledgements

We thank to el Programa Estrategia para Sostenibilidad de los Grupos A1 y A convocatoria año 2009 Universidad de Antioquia for the financial support.

References (24)

D. Thomasson et al.
React. Funct. Polym.
(2006)
D.A. Tomalia
Prog. Polym. Sci.
(2005)
M. Seiler
Fluid Phase Equilib.
(2006)
J. Samuelsson et al.
Prog. Org. Coat.
(2004)
Z.O. Oyman et al.
Prog. Org. Coat.
(2005)
K. Manczyk et al.
Prog. Org. Coat.
(2002)
J. Lindeboom
Prog. Org. Coat.
(1998)
N. Dutta et al.
Prog. Org. Coat.
(2004)
T.T. Hsieh et al.
Polymer
(2001)
T.T. Hsieh et al.
Polymer
(2001)

S. Haseebuddin et al.

Prog. Org. Coat.

(2009)

J. Dullius et al.

Prog. Org. Coat.

(2006)

Cited by (54)

A review on the production and application of tall oil with a focus on sustainable fuels
2024, Renewable and Sustainable Energy Reviews
The world's rapid energy demand through overpopulation and industrial development, coupled with environmental trends to reduce fossil fuel reliance, has created a global need for renewable and sustainable fuel sources. As researchers, governments, and industries look towards non-edible oils as a source for biofuels, the pulping industry by-product, tall oil, has promise as a feedstock. This review provides an overview of tall oil production from woody biomass, tall oil purification, and treatment of refined tall oil for biochemistry, bioenergy, and miscellaneous applications. Further, this review investigates the recent trends and barriers toward tall oil-derived biofuels. Tall oil and its components currently contribute to the circular bioeconomy through several applications, primarily being biochemicals. Recent commercialization of stand-alone tall oil biorefineries has demonstrated that biodiesel is the main pathway for tall oil-derived fuels, however, experimental gasoline and jet fuel pathways have shown promise in meeting fuel standards. Limited studies have co-processed tall oil biocrude with petroleum intermediates, facing challenges to stay within fuel specifications. Showing technical feasibility as a fuel source, tall oil's by-product nature has an economic and legislature-supported advantage over other biofuel sources, being closer to competing with fossil fuels. Yet tall oil's inflexible global supply as well as demand from biochemical industries may cause future supply chain challenges. The lack of political commitment and scaling uncertainty pose further barriers for tall oil-derived fuels that must be overcome to contribute to biofuel demand in future years.
Hybrid alkyds, the glowing route to reach cutting-edge properties?
2021, Progress in Organic Coatings
This review highlights both the various polymers grafted to alkyd resins reported in the literature and the different routes to synthesize these alkyd hybrids. Alkyd resins were discovered in the mid-1920s. Then, they quickly found a prominent place among coatings and paint binders thanks to their numerous advantages such as good heat resistance, excellent gloss, and low cost. Nevertheless, in the 50 s, the emergence of new synthetic polymers with better properties (chemical resistance, mechanical and thermal properties) such as epoxy, acrylic or polyurethane, weakened the position of the alkyd resins among coating industry. Nowadays, due to global issues such as health and environmental concerns, research focuses on biobased polymers. Since, alkyd resins are mainly biobased, they have gained increasing attention in the last decade. Nevertheless, the issue of using volatile organic compounds (VOC) and the urge of replacing them, have led to the development of new synthetic routes. Moreover, in order to enhance alkyd properties and bridge the gap with new materials, other polymers such as epoxy, acrylates, polyurethanes or siloxanes were used to form alkyd hybrids. Hence, the different strategies to perform alkyd hybrids are detailed and discussed in this review. Furthermore, composites made with alkyd hybrid matrix are presented. Finally, the perspectives about the future developments of alkyd hybrids and the most promising hybrids are discussed.
Synthesis and characterization of ricinoleic acid based hyperbranched alkyds for coating application
2020, Progress in Organic Coatings
Hyperbranched alkyds based on ditrimethylolpropane, dimethylolpropionic acid, and ricinoleic acid were synthesized. The synthesized resins were characterized by the determination of hydroxyl and acid numbers, viscosity, average molecular masses, and molecular masses distribution. Compared with conventional alkyd resins of similar molar masses, the synthesized hyperbranched alkyds have significantly lower viscosity values at a given temperature. Therefore, a significantly smaller amount of organic solvents is required for their dissolution and can be used as precursors to obtain eco-friendly coatings. The obtained hyperbranched alkyd resins were cured by two commercial melamine resins (mass ratio 70:30). The curing of the resin mixtures was examined by FTIR spectroscopy, rheometry, and by the determination of gel content. The curing of the resin mixtures proceeds via the reactions between hydroxyl and carboxyl groups of hyperbranched alkyds with isobutoxymethyl and methoxymethyl groups in melamine resins. Hyperbranched alkyd/melamine resin mixtures were cured at 150 °C for 60 min. Thermal properties, dynamic mechanical behavior, physico-mechanical characteristics, and chemical resistance of cured films were determined. The crosslinking densities of films obtained from mixtures using hexamethoxymethyl melamine resin are significantly higher than those based on mixtures using isobutylated melamine resin. The thermal degradation of cured films is a complex process, and their thermal stability increases slightly with the increase of hyperbranched alkyds generation. It is assumed that mixtures of synthesized hyperbranched alkyds with melamine resins would be suitable for obtaining the coatings with good chemical resistance and physical-mechanical properties.
Robust alkyd/exfoliated graphene oxide nanocomposite as a surface coating
2019, Progress in Organic Coatings
Design of advanced nanostructured coatings with ecofriendly character and highly branched structure has been given a particular attention. In this work, we developed a novel robust alkyd/exfoliated graphene oxide (GO) nanosheets composite coating via solution casting. Alkyd matrix with hyperbranched moiety was developed via polyesterification of sunflower oil and polyester. Hyperbranched polyester was facilely synthesized via A₂ and B₃ technique. Exfoliated GO with 0.5–2 nm sheet thickness was successfully prepared using a modified Hummer’s technique. Alkyd/GO composite paint was dried using auto-oxidative drying. Designing alkyd/exfoliated GO sheets with superior physico-mechanical properties exhibit high levels of durability and corrosion resistance for coating application. The influences of dispersing various GO nanosheet percentages in the synthesized alkyd were studied. Water contact angle measurements were used to assess the surface properties, while the salt spray test in 5% NaCl was performed to investigate the corrosion protection characteristics. The robustness of nanocoatings were investigated mechanically using impact, bending, crosshatch and abrasion experiments and thermally using the thermal gravimetric analysis. Well dispersed exfoliated GO nanofillers up to 0.5 wt. % achieved compatibility and superiority in reinforcing the mechanical and anti-corrosive properties of alkyd nanocoatings. The modeled coatings possess numerous advantages, such as simple preparation, cost-savings, ecofriendly construction, robustness, and durability.
Ceramic hyperbranched alkyd/γ-Al<inf>2</inf>O<inf>3</inf> nanorods composite as a surface coating
2018, Progress in Organic Coatings
Citation Excerpt :
Excellent colour retention, durability, weathering resistance, low viscosity and high anticorrosive resistance are among other advantages of hyperbranched alkyd resins [7]. They possess higher strength and drying properties as compared to high solid alkyds [8]. Alkyds are polyester based materials obtained by polyesterification with unsaturated fatty acids of drying oils [9].
The work reports engineering an eco-friendly series of ceramic hyperbranched alkyd/γ-Al₂O₃ nanorods composite coatings via solution casting method and auto-oxidation curing mechanism. Sunflower oil based hyperbranched alkyd resin was successfully prepared by using polyesterification method. Controlled synthesis of single crystal γ-Al₂O₃ nanorods with 20 nm average diameter exposed by {400} crystal plane was carried out via hydrothermal and decomposition methods The effects of dispersing different concentrations of one-dimensional ceramic γ-Al₂O₃ nanorod filler in the alkyd matrix were studied. The tailored alkyd/single crystal γ-Al₂O₃ nanocomposites were applied for mechanical and anticorrosive coatings. Coatings' surface and anticorrosive properties were investigated via water contact angle, scanning electron microscopy and salt spray test. Studying the mechanical properties, stability against chemicals and thermal behavior of the ceramic alkyd nanocomposites were also considered. Results approved that the highest improvement was achieved with nanofiller insertion up to 0.5% γ-Al₂O₃ nanorods in the alkyd composites.
Synthesis and characterization of liquid molecular brush binder for coating applications
2018, European Polymer Journal
This report documents the facile synthesis of molecular brushes, via a grafting onto approach, with potential application as coating binders. Firstly, alternating copolymers of n-butyl vinyl ether (n-BVE) and maleic anhydride (MAh), i.e. n-BVEMAh, were synthesized via conventional radical polymerization. The anhydride reactive handle was subsequently utilised to access molecular brushes, via a grafting onto method, by imidizing the MAh repeat units with amine end-functional poly(ethylene glycol) oligomers, with 12 repeating units (PEG₁₂-NH₂). The product n-BVEMI-PEG₁₂ brushes were viscous liquids at room temperature, hence we termed them liquid molecular brushes (LMBs). The LMBs displayed Newtonian flow behaviour at shear rates below 1000 s⁻¹. We evaluated the applicability of this molecular brush system as coating binder, by grafting varying fractions of linoleamide (Lin) side chains, which has oxidative crosslinking ability, along with the PEG₁₂ onto n-BVEMAh, to access n-BVEMI-PEG₁₂/Lin. The n-BVEMI-PEG₁₂/Lin binders underwent oxidative crosslinking at 50 °C in the presence of a drier. The challenges associated with the current binder system are highlighted.

View all citing articles on Scopus

View full text

Synthesis and characterization of hyperbranched alkyd resins based on tall oil fatty acids

Abstract

Introduction

Section snippets

Materials

Iodine and refractive index values of the HBRA resins

Conclusions

Acknowledgements

React. Funct. Polym.

Prog. Polym. Sci.

Fluid Phase Equilib.

Prog. Org. Coat.

Prog. Org. Coat.

Prog. Org. Coat.

Prog. Org. Coat.

Prog. Org. Coat.

Polymer

Polymer

Prog. Org. Coat.

Prog. Org. Coat.