Novel thermosetting resins for SMC applications from linseed oil: Synthesis, characterization, and properties

Synthesis of Lactic Acid-Based Thermosetting Resins and Their Ageing and Biodegradability

The present work is focused on the synthesis of bio-based thermoset polymers and their thermo–oxidative ageing and biodegradability. Toward this aim, bio-based thermoset resins with different chemical architectures were synthesized from lactic acid by direct condensation with ethylene glycol, glycerol and pentaerythritol. The resulting branched molecules with chain lengths (n) of three were then end-functionalized with methacrylic anhydride. The chemical structures of the synthesized lactic acid derivatives were confirmed by proton nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared spectroscopy (FT–IR) before curing. To evaluate the effects of structure on their properties, the samples were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the tensile testing. The samples went through thermo-oxidative ageing and biodegradation; and their effects were investigated. FT-IR and ¹H-NMR results showed that three different bio-based resins were synthesized using polycondensation and end-functionalization. Lactic acid derivatives showed great potential to be used as matrixes in polymer composites. The glass transition temperature of the cured resins ranged between 44 and 52 °C. Pentaerythritol/lactic acid cured resin had the highest tensile modulus and it was the most thermally stable among all three resins. Degradative processes during ageing of the samples lead to the changes in chemical structures and the variations in Young’s modulus. Microscopic images showed the macro-scale surface degradation on a soil burial test.

Bio-Based Hybrid Polymers from Vinyl Ester Resin and Modified Palm Oil: Synthesis and Characterization

A series of bio-based hybrid thermosets composed of maleinated acrylated epoxidized palm oil (MAEPO) and vinyl ester resin (VE) were produced using free radical-induced crosslinking. The amount of petroleum-based resin which was replaced by bio-resin (MAEPO) was varied from 5 to 20 wt%. The structure of the polymer systems was investigated by scanning electron microscopy and dynamic mechanical analysis. The mechanical properties of the VE/MAEPO resins were studied using tensile, flexural and impact tests. The result obtained from structural analysis revealed that for the polymer hybrids with up to 20 wt% bio-resin content, there is good compatibility between MAEPO and VE as no phase separation was observed for these systems. The prepared eco-friendly bio-based thermosetting resins exhibit remarkable improvement in toughness parameters, such as ductility and impact strength, thereby showing potential for use in composites and nanocomposites applications.

Microbial degradation of linseed oil-based elastomer and subsequent accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer

The microbial synthesis of environment-friendly poly(3-hydroxybutyrate--co-3-hydroxyvalerate), PHBV, has been performed by using an alkaliphilic microorganism, Alkaliphilus oremlandii OhILAs strain (GenBank Accession number NR_043674.1), at pH 8 and at a temperature of 30-32 °C through the biodegradation of linseed oil-based elastomer. The yield of the copolymer on dry cell weight basis is 90 %. The elastomers used for the biodegradation have been synthesized by cationic polymerization technique. The yield of the PHBV copolymer also varies with the variation of linseed oil content (30-60 %) in the elastomer. Spectroscopic characterization ((1)H NMR and FTIR) of the accumulated product through biodegradation of linseed oil-based elastomers indicates that the accumulated product is a PHBV copolymer consisting of 13.85 mol% of 3-hydroxyvalerate unit. The differential scanning calorimetry (DSC) results indicate a decrease in the melting (T m) and glass transition temperature (T g) of PHBV copolymer with an increase in the content of linseed oil in the elastomer, which is used for the biodegradation. The gel permeation chromatography (GPC) results indicate that the weight average molecular weight (M w) of PHBV copolymer decreases with an increasing concentration of linseed oil in the elastomer. The surface morphology of the elastomer before and after biodegradation is observed under scanning electron microscope (SEM) and atomic force microscope (AFM); these results indicate about porous morphology of the biodegraded elastomer.

Engineered elastomeric bio-nanocomposites from linseed oil/organoclay tailored for vibration damping

This study deals with the preparation and characterization of elastomeric nanocomposites from renewable resources for vibration damping applications.