Photo-cured Materials from Vegetable Oils

Abstract

Photo-polymerization technology, which exhibits high efficiency and low energy consumption has been widely studied and applied in many areas such as coatings, adhesives, printing inks and so on. This technology is based on high-performance photo-initiators e.g. high quantum yield for radical formation, high reactivity and compatibility toward the monomer, low odor and toxicity, low mobility and good stability. However, the monomers that are used to form photo-cured materials are mainly derived from petroleum products. The petroleum in the Earth will last for fewer than 100 years, hence, in the past few decades, much attention has been paid to feedstocks for polymers based on renewable resources. One of the most stable and renewable resources is vegetable oils. Vegetable oils have already been utilized extensively in coatings, inks, lubricants, resins, agrochemicals and plasticizers. Because of the presences of CC bonds in vegetable oils, they can be easily functionalized with reactive groups such as epoxy, hydroxyl, carboxyl and acrylate. These functionalized vegetable oils have been used to prepare polyurethane, elastomers, plastics and pressure-sensitive adhesives. In contrast to feedstocks extracted from petroleum, vegetable oil feedstocks are non-toxic and friendly to the environment. Therefore, in view of the attractive advantages of both photo-curing technologies and vegetable oils, it is worth the energy and money required to research and develop photo-cured materials based on vegetable oils.

Soybean oil-based UV-curable coatings strengthened by crosslink agent derived from itaconic acid together with 2-hydroxyethyl methacrylate phosphate

“…[4,5] Especially, its derivatives epoxidized soybean oil (ESO) and acrylated epoxidized soybean oil (AESO) have been widely applied in the UV curable coatings. [6,7] However, due to the flexible long aliphatic chain of soybean oil, as much as 50% or more petroleum-based rigid compounds, such as styrene [8,9], acrylate acid [10] and divinylbenzene [11,12], are necessary to make its mechanical or thermal properties acceptable for end use. Recently, with the rapid progress on bio-based materials, the exploration of bio-based compounds to strengthen the polymers derived from soybean oil so as to ensure a higher bio-based content has been frequently reported [5,[13][14][15][16][17].…”

Development of completely bio‐based epoxy networks derived from epoxidized linseed and castor oil cured with citric acid

“…Its high degree of unsaturation (6.6 double bonds per triglyceride) receives greater importance as a biorenewable raw material to form prepolymers or even polymers. Consequently, there has been a growing interest by researchers from academia as well as industry for adhesive, coating, and composite applications to use epoxidized LO (ELO), acrylated ELO, and epoxidized methyl esters of LO . Similarly, castor oil (CO) is a natural polyol consisting of unsaturated fatty acid, hydroxyl functionalities, usually ricinoleic acid (12‐hydroxy‐9‐ cis ‐octadecenoic acid), which almost covers 90% of the fatty acid content .…”

Preparation of the flexible soybean oil‐based material via [2 + 2] cycloaddition photo‐polymerization

“…[10][11][12] Additionally, it usually reacts with acrylic monomers (such as acrylic acid) to synthesize free-radical-type UV-curable prepolymers, which has been widely used in UV curing coatings. 13,14 However, acrylic acid is fossil derived and has strong volatility. 15,16 The acrylic acid volatility during synthesis process and curing process will do great harm to human health, which is a particularly severe problem in coating industry.…”

“…Epoxy soybean oil (ESO) is a kind of promising renewable raw material for the synthesis of sustainable polymers due to the existence of epoxy groups with high reactivity 10–12 . Additionally, it usually reacts with acrylic monomers (such as acrylic acid) to synthesize free‐radical‐type UV‐curable prepolymers, which has been widely used in UV curing coatings 13,14 . However, acrylic acid is fossil derived and has strong volatility 15,16 .…”