Biobased additives as biodegradability enhancers with application in TPU-based footwear components

Among the wide variety of materials employed in the manufacture of shoes, thermoplastic polyurethanes (TPUs) are one of the most widely used. Given its widespread use, and associated waste management problems, the development of more biodegradable and evironmentally compatible solutions is needed. In this work, a polyester-based TPU used in the footwear industry for outsoles production was modified by compounding with lignin, starch and cellulose at content of 4% (w/w). The biodegradability was evaluated by using agar plate tests with the fungi Aspergillus niger ATCC16404, the Gram-negative bacteria Pseudomonas aeruginosa ATCC9027 and an association of both (consortium), and soil tests at 37 °C and 58 °C. The obtained results evidenced a positive effect of the tested biobased additives, the most favourable results being registered with lignin. These results were corroborated by the structural modifications observed by FTIR analysis. Additionally, mechanical tests prove the suitability of using the lignin modified TPUs for footwear outsoles production.

Ratios and indicators that determine return on equity

This study aims to investigate factors that may affect return on equity (ROE). The ROE is a gauge of profit generating efficiency and a strong measure of how well the management of a firm creates value for its shareholders. Firms with higher ROE typically have competitive advantages over their competitors which translates into superior returns for investors. Therefore, seems imperative to study the drivers of ROE, particularly ratios and indicators that may have considerable impact. The analysis is done on a sample of 90 largest non-financial companies which are components of NASDAQ-100 index and also on industry sector samples. The ordinary least squares method is used to find the most impactful drivers of ROE. The extended DuPont model’s components are considered as the primary factors affecting ROE. In addition, other ratios and indicators such as price to earnings, price to book and current are also incorporated. Consequently, the study uses eight ratios that are believed to have impact on ROE. According to our findings, the most relevant ratios that determine ROE are tax burden, interest burden, operating margin, asset turnover and financial leverage (extended DuPont components) regardless of industry sectors.