Benjamin Woldt

Synthesis and Application of Carbonated Fatty Acid Esters from Carbon Dioxide Including a Life Cycle Analysis

Carbon dioxide can be used in various ways as a cheap C1 source. However, the utilization of CO2 requires energy or energy-rich reagents, which leads to further emissions, and therefore, diminishes the CO2-saving potential. Therefore, life cycle assessment (LCA) is required for each process that uses CO2 to provide valid data for CO2 savings. Carbon dioxide can be incorporated into epoxidized fatty acid esters to provide the corresponding carbonates. A robust catalytic process was developed based on simple halide salts in combination with a phase-transfer catalyst. The CO2-saving potential was determined by comparing the carbonates as a plasticizer with an established phthalate-based plasticizer. Although CO2 savings of up to 80 % were achieved, most of the savings arose from indirect effects and not from CO2 utilization. Furthermore, other categories have been analyzed in the LCA. The use of biobased material has a variety of impacts on categories such as eutrophication and marine toxicity. Therefore, the benefits of biobased materials have to be evaluated carefully for each case. Finally, interesting properties as plasticizers were obtained with the carbonates. The volatility and water extraction could be improved relative to the epoxidized system.

Sulfur-containing fatty acid-based plasticizers via thiol–ene addition and oxidation: synthesis and evaluation in PVC formulations

A new family of sulfur-containing plasticizers derived from fatty acids has been developed. The synthetic approach is based on the thiol–ene addition of alkyl thiols to the double bond of technical oleic acid, followed by oxidation of the sulfide group to either sulfoxide or sulfone groups. It has been found that both sulfide and sulfoxide derivatives are not suitable as plasticizers due to their unpleasant odor and limited thermal stabilities. However, the sulfone derivatives are odorless, thermally stable, and show plasticizing properties similar to those of established PVC plasticizers such as cyclohexane-1,2-dicarboxylic acid diisononyl ester (ELATUR® CH) and diisononyl phthalate (VESTINOL® 9). A wide range of application tests is reported to support this conclusion. Furthermore, a mixture of fatty acids obtained from commercial rapeseed oil has been used as a cheap and readily available alternative source of oleic acid to obtain such plasticizers.

Nondestructive Quantification of Local Plasticizer Concentration in PVC by 1H NMR Relaxometry

The properties of plasticized poly(vinyl chloride) (PVC) , one of the most important polymers today, are strongly dictated by the concentration of plasticizer. Yet, it has been impossible to quantify this concentration at different positions inside a PVC product without its destruction because of a lack of suitable analytical methods. Thus, this paper introduces a simple, fast, and efficient way to determine truly nondestructively the concentration of plasticizer in PVC by single-sided nuclear magnetic resonance (NMR). With the help of correlation curves between the concentration of plasticizer inside nonaged PVC samples and the corresponding volume-averaged NMR parameters, single-sided NMR allows the quantification of the local concentration of plasticizer in aged PVC plates at different depths by spatially resolved relaxation measurements. The presented approach represents a fundamental step toward in situ characterization of plasticized PVC.