Marina Galià

Plant Oils as Platform Chemicals for Polyurethane Synthesis: Current State-of-the-Art

Plant oils are already one of the most important platform chemicals for the chemical industry due to its universal availability, inherent biodegradability, and low price. Nowadays, plant oils are already a commercial source of multifunctional monomers and oligomers for polyurethane synthesis, and the design of novel biobased polyols derived from them is an active area of research. By taking advantage of the wide variety of possibilities for chemical modification of plant oils, there is a broad palette of strategies to functionalize its structure with hydroxyl groups. The purpose of this review is to comprehensively overview recent developments on the preparation of biobased polyols from plant oils, covering from the general epoxidation and ring-opening approach to novel routes based on thiol-ene click chemistry as well as to highlight the properties of polyurethanes obtained from them.

Chemically modified polymeric resin used as sorbent in a solid-phase extraction process to determine phenolic compounds in water

A chemically modified polymeric resin with an acetyl group is developed for use in a solid-phase extraction process. The breakthrough volumes and selectivity of several phenolic compounds were studied and compared with the ones obtained for several commercial sorbents such as PLRP-s, Amberchrom, Envi-Chrom P and LiChrolut EN. The study was carried out by coupling an on-line solid-phase extraction system to a modified liquid chromatograph where compounds were eluted only by the organic solvent of the mobile phase. The sorbent studied was used to establish a method for determining eleven Environmental Protection Agency priority phenolic compounds in water at low levels.

New chemically modified polymeric resin for solid-phase extraction of pesticides and phenolic compounds from water

A new chemically modified polymeric resin, with an o-carboxybenzoyl moiety, is developed to be used in the on-line solid-phase extraction (SPE) of some pesticides and phenolic compounds from aqueous samples, in order to obtain better breakthrough volumes than other commercial sorbents. The chemical introduction of this moiety improves the efficiency of SPE by providing better surface contact with aqueous samples. This synthesized sorbent enables higher volumes of sample to be concentrated for determining polar compounds. When analyzing real samples, tap and river waters, different quantities of sulphite were added to decrease the initial band due to fulvic and humic acids. The matrix peaks decreased and there were no losses in the studied compounds observed when 500 and 1000 microliters of 10% Na2SO3 solution for every 100 ml of sample were added to tap and river water, respectively.

Study of lanthanide triflates as new curing initiators for DGEBA

A new class of cationic initiators, lanthanide triflates, has been studied in the curing of diglycidyl ether of bisphenol-A (DGEBA). The kinetics of this process has been evaluated by the isoconversional method that has been proved as an excellent tool to predict the technical parameters of this process. The thermal stability of the crosslinked materials has been studied by thermogravimetric analysis (TGA) and their mechanical characteristics by dynamomechanic thermal analysis (DMTA).

Polybenzoxazines: new players in the bio-based polymer arena

Polybenzoxazines are phenol-like materials that have attracted significant attention from both academia and industry because of their unique advantages. The growth of this technology has always been linked to petro-based feedstocks. However, due to the incessant global energy crisis it is now finding a breakthrough through the preparation of their monomers from renewable resources. This mini-review focuses on the recent efforts to replace petro-based feedstocks with polybenzoxazine precursors.

Synthesis, Characterization and Polymerization of a Novel Glycidyl Phosphinate

With the aim to obtain flame-retardant epoxy resins, a new glycidyl phosphinate, 9-(9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide)-2,3-epoxypropyl (DOPO-Gly) was synthesized via a two-step synthesis. The subsequent reaction of DOPO-Gly with BF3·Et2O resulted in a polyether with a pendant bulky phosphorylated group. Likewise, the reaction with phthalic acid anhydride gave the expected dihydroxy ester. However, the reaction with tertiary or primary amines led to isomerization and no polymer was obtained.

Silicon-Containing Soybean-Oil-Based Copolymers. Synthesis and Properties

New silicon-containing soybean-oil-based copolymers were prepared from soybean oil, styrene, divinylbenzene, and p-trimethylsilylstyrene by cationic polymerization using boron trifluoride etherate as initiator. Soxhlet extraction and NMR spectroscopy indicate that the copolymers consist of a cross-linked network plasticized with varying amounts of oligomers and unreacted oil. This soluble fraction increases when the SiST content in the feed increases, according to a lower reactivity of this monomer. The thermal, dynamomechanical, and flame-retardant properties of these materials were examined. Thermosets with glass transition temperatures ranging from 50 to 62 degrees C, which are thermally stable below 350 degrees C, and with LOI values from 22.6 to 29.7 were obtained. Their properties suggest that these materials may prove to be useful alternatives for current non-renewable-based thermosets and that the flame-retardant properties of vegetable-oil-based thermosets can be improved by adding covalently bonded silicon to the polymer.

Synthesis of New Epoxy Liquid-Crystalline Monomers with Azo Groups in the Central Mesogenic Core. Crosslinking with Amines

A new class of liquid-crystalline epoxy resins containing azomethine and azo groups was synthesized and structurally characterized. The liquid crystal behavior of these compounds was characterized by differential scanning calorimetry (DSC), hot-stage polarized optical microscopy (POM) and wide-angle X-Ray diffraction (WAXS). An aliphatic spacer between the mesogenic aromatic central core and the glycidyl groups favors the formation of different types of smectic mesophases with a wide range of stability. The LC resins were cured to obtain liquid crystal thermosets (LCTs). The cure was tested using aromatic primary diamines as curing agents and nematic-like networks were obtained. When tertiary amines were used catalytically, smectic C-like networks were retained when the spacer length had four methylene units or more. The polydomain ordered materials obtained were characterized by WAXS and their thermal stability was tested by thermogravimetric analysis (TGA).

Thiol–yne reaction of alkyne-derivatized fatty acids: biobased polyols and cytocompatibility of derived polyurethanes

With the goal of obtaining renewable diols and polyols for polyurethane (PU) technology, the thiol–yne coupling reaction was applied to alkyne-derivatized fatty acids derived from naturally occurring oleic and 10-undecenoic acids. The resulting monomers were then polymerized with 4,4′-methylenebis(phenylisocyanate) to produce the corresponding PUs. The chemical structures and thermal and mechanical properties of the synthesized PUs have been evaluated by FTIR and NMR spectroscopy, DSC, TGA and tensile tests respectively. Moreover, the biocompatibilities of the synthesized PUs with human osteoblast-like cell line (MG63) have also been evaluated for tissue engineering purposes.

“Click” Synthesis of Fatty Acid Derivatives as Fast-Degrading Polyanhydride Precursors

Fast-degrading linear and branched polyanhydrides are obtained by melt-condensation of novel di- and tri-carboxylic acid monomers based on oleic and undecylenic acid synthesized using photoinitiated thiol-ene click chemistry. (1)H NMR spectroscopy, size exclusion chromatography, differential scanning calorimetry, thermogravimetric analysis, and FT-IR spectroscopy have been used to fully characterize these polymers. The hydrolytic degradation of these polymers was studied by means of weight loss, anhydride bond loss, and changes in molecular weight, showing fast degrading properties. Drug release studies from the synthesized polyanhydrides have also been conducted, using rhodamine B as a hydrophobic model drug, to evaluate the potential of these polymers in biomedical applications.