Polyesters of 2-Pyrone-4,6-dicarboxylic Acid (PDC) as Bio-based Plastics Exhibiting Strong Adhering Properties

Abstract

2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable metabolic intermediate of lignin, its bis(hydroxyethyl) derivative (BHPDC) and bis(hydroxyethyl) terephthalate (BHT) were polymerized to prepare the corresponding polyesters carrying the oxyethyleneoxycarbonyl(2-pyrone-4,6-diyl)carbonyl and oxyethyleneoxy-terephthaloyl units [x and y units, resp., x þ y ¼ 1] by polycondensation eliminating water and/or 1,2-ethanediol molecules. The polyesters were mostly stable up to 210 C, after that the degradation of pyrone ring commenced. These polyesters exhibited strong adhering properties against metal, glass and surfaces with increasing the x unit content to 0.4-0.6, such as about 50-60 MPa for SUS/polyester/SUS or Al/ polyester/Al samples, by the JIS K 6849:1994 testing method of tensile strength. As the fracturing plane was the midst of the polyester layer and at the interface, the polyester was tenaciously adhering to the metal surface.

Tenacious Epoxy Adhesives Prepared from Lignin-derived Stable Metabolic Intermediate

“…The strong adhesion property of DGPDC adhesive would be originated from the interaction between polar surfaces and of 2-pyrone nuclei that might produce ring-opening addition structures (Fig. 6) as discussed in our previous paper describing about adhesion properties of PDC copolyester [17]. Since both the adhesion strength between metals mediated from opened 2-pyrone ring and the tensile strength of resin consisted of DGPDC and acid anhydride (i.e.…”

“…cured adhesives) are necessary to retainment of adhesion surface, an appropriate amount of 2-pyrone ring-opening reaction should be important for the strong adhesion property. This hypothesis is supported by the result in which the excess amount of PDC in copolyester adhesive made its adhesion property to become weak [17]. Therefore, the various tendency of adhesion strength depending on the metal species should be occurred by the difference of surface condition by metals (e.g.…”

“…By using its bifunctional character as a polycondensation monomer, our group has synthesized the biomass-based copolyester from the mixture of PDC and BHT [bis (2-hydroxyethyl) terephthalate] [16,17]. During the course, the strong adhesive property of PDC polyester to polar surfaces such as metal and glass surfaces by heating at 250 was found [17]. The adhesive property was supposed to be originating to the 2-pyrone repeating units, as no adhesive property was exhibited upon the removal of PDC unit from the copolyester.…”

Click synthesis and adhesive properties of novel biomass-based polymers from lignin-derived stable metabolic intermediate

“…11,15 In addition, the first noticeable application of CuAAC in materials science was the specific adhesion of poly(triazole) derivatives to a Cu surface, which was achieved by the partial crosslinking of the polymer chains with a small amount of the leached Cu I . 25 As P1 and P2 contain both PDC and triazole moieties, they are promising materials for adhesive applications.…”

“…In the past few years, a series of PDC polyesters was synthesized by the direct dehydrated polycondensation with various diol co-monomers, and their excellent biodegradable, mechanical and adhesive properties were demonstrated. [10][11][12][13][14][15][16] However, the major problem of the PDC polyesters was their relatively low molecular weights. In order to improve the polymer properties, other efficient base-free polymerization methods were desired.…”