Synthesis and characterization of methacrylated star‐shaped poly(lactic acid) employing core molecules with different hydroxyl groups

Abstract

A set of novel bio-based star-shaped thermoset resins was synthesized via ring-opening polymerization of lactide and employing different multi-hydroxyl core molecules, including ethylene glycol, glycerol, and erythritol. The branches were endfunctionalized with methacrylic anhydride. The effect of the core molecule on the melt viscosity, the curing behavior of the thermosets and also, the thermomechanical properties of the cured resins were investigated. Resins were characterized by Fourier-transform infrared spectroscopy, 13 C-NMR, and 1 H-NMR to confirm the chemical structure. Rheological analysis and differential scanning calorimetry analysis were performed to obtain the melt viscosity and the curing behavior of the studied star-shaped resins. Thermomechanical properties of the cured resins were also measured by dynamic mechanical analysis. The erythritol-based resin had superior thermomechanical properties compared to the other resins and also, lower melt viscosity compared to the glycerol-based resin. These are of desired characteristics for a resin, intended to be used as a matrix for the structural composites. Thermomechanical properties of the cured resins were also compared to a commercial unsaturated polyester resin and the experimental results indicated that erythritol-based resin with 82% bio-based content has superior thermomechanical properties, compared to the commercial polyester resin. Results of this study indicated that although core molecule with higher number of hydroxyl groups results in resins with better thermomechanical properties, number of hydroxyl groups is not the only governing factor for average molecular weight and melt viscosity of the uncured S-LA resins.

Glycerol‐lactic acid star‐shaped oligomers as efficient biobased surface modifiers for improving superabsorbent polymer hydrogels

“…Star‐shaped bioresins are a class of evolved branched polymers with a hyperbranched core molecule and linear arms, which are currently tailored to add a special functionality to the resin . These polymers contain a hydrophilic core along with hydrophobic arms .…”

“…These polymers contain a hydrophilic core along with hydrophobic arms . So far, star‐shaped lactic acid (LA)‐based resins were synthesized employing hydrophilic cores, including glycerol, xylitol, ethylene glycol, and erythritol for different applications. Glycerol, which is a byproduct of biodiesel transesterification processes, is an attractive inexpensive renewable material, which is considered as an important biobased platform for the production of chemicals including epicholorohydrin, acrylic acid, as well as 1,3 butandiol .…”

“…The star‐shaped resins from LA and glycerol backbone (star‐shaped resins) were synthesized by a similar procedure with the previously reported method . In this study, in an attempt to alleviate the gel blockage of the hydrogels, surface crosslinking strategy, using star‐shaped modifiers, has been employed.…”

Synthesis of Polyoxygenated Heterocycles by Diastereoselective Functionalization of a Bio-Based Chiral Aldehyde Exploiting the Passerini Reaction

“…A bio-based building block readily available from lignocellulosic biomass is erythritol 1 , which is produced from glycerol [ 13 ] or from waste cooking oil [ 14 ] by means of osmophilic yeasts, such as Yarrowia lipolytica . This molecule is used as artificial sweetener [ 15 ], but it has found many applications in polymer chemistry, such as biodegradable polyurethanes [ 16 , 17 ] or polyesters [ 18 ], or in the synthesis of plant derived phthalates [ 19 ]. Erythritol, a meso compound, can be efficiently desymmetrized by means of Amano PS lipase [ 5 ] to give chiral monoesters, such as 2 .…”

Biobased waterborne, tough hyperbranched polyester thermosets as environmentally benign polymeric materials

“…reported the synthesis of a star‐shaped polyester thermoset by condensation reaction of glycerol and itaconic acid, but they used methanesulfonic acid as catalyst and toluene as solvent. A biobased star‐shaped polyester thermoset was also synthesized by Esmaeili et al . via ring‐opening polymerization of lactide and employing different multihydroxyl core molecules such as glycerol, ethylene glycol, and erythritol, but they used high temperature and tin(II)‐2‐ethylhexanoate as catalysts.…”