Synthesis of Polyols for the preparation of biodegradable polyurethanes

Natural oils such as rapeseed oil do not contain the necessary chemical functionality (hydroxyl groups) required for the synthesis of the target biodegradable Polyurethane. The main aim of this work was to find an appropriate dihydroxylation reaction route to convert natural oils containing double bonds into polyols that can be used to produce biodegradable polyurethanes. We were particularly aiming for a low-cost process which could also be scaled up. Initial experiments were performed on model substrates containing double bonds (hexene and decatriene) to allow complete characterization of the compounds and consequently gain a more thorough understanding of the chemistry taking place. Several methods were investigated to find a suitable process to dihydroxylate alkenes and also to convert the unsaturated oils into polyols suitable for the preparation of polyurethanes. The permanganate and water system was suitable for the model compounds, but requiring a stoichiometriс amount of catalyst was a disadvantage for scale-up. The results of hydroxylation reaction of alkenes using hydrogen peroxide and formic acid were not encouraging. The results of hydroxylation reactions using phosphoric acid and hydrogen peroxide were quite encouraging. The reactions using natural oils were quite successful producing polyols with the hydroxide numbers of 187 and 164 for soyabean and rapeseed samples respectively. The method using organic peroxide, meta-сhlого perbenzoic acid (m-СРВА) was also encouraging. The (^1)Ή NMR analysis of the reaction of m-CPBA with the decatriene model compound revealed that m-CPBA selectively hydroxylates the internal double bonds. However, when natural oils, water and m-CPBA powder were mixed and stirred the reaction mixtures became dough like and were therefore difficult to manipulate

Sustainable engineered designs and manufacturing of waste derived graphenes reinforced polypropylene composite for automotive interior parts

The automotive sector is actively pursuing a lightweighting strategy as a means to urgently decrease greenhouse gas emissions, which are a significant driver of climate change. The development of lightweight composite structures has been identified as crucial for enhancing part performance while mitigating negative environmental impacts and adopting energy-efficient manufacturing methods. This comprehensive study aimed to decrease the main reinforcement content of talc in commercial compounds while integrating graphene derived from waste polypropylene (PP) grown on talc and graphene nanoplatelet obtained from waste tires by upcycling processes into the PP compound. The entire value chain of interior automotive part production, from compound development and scaling up with a high-shear mixer, to injection molding of the part and performance tests, was investigated with a focus on sustainability considerations. The successful integration of 4 wt % micron talc, together with 1 wt % graphene nanoparticles and 1 wt % hybrid additive into the blended HomoPP/CopoPP matrix resulted in a 10% weight reduction compared to the conventional part. Moreover, significant improvements in flexural and tensile strength were observed, with enhancements of 52 and 38%, respectively. The uniform dispersion of additives and improved interfacial adhesion between the PP matrix and additives facilitated efficient stress transfer, contributing to enhanced mechanical properties. Furthermore, a systematic life cycle assessment study demonstrated the positive impact of waste PP incorporation on CO2 reduction, achieving a remarkable 95% reduction compared to virgin PP. The developed compound also demonstrated favorable processability and flow properties, supporting its potential for mass production. Overall, this study presents a sustainable and effective approach for lightweight automotive interior part production using a synergistically designed PP compound meeting the requirements of the automotive industry