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Due to the increasing amount of polyurethane waste, chemical recycling of these materials is a topic of growing interest for many researchers. The primary purpose of polyurethane feedstock recycling is to recover the starting polyol. In this study glycerolysis using glycerine from two sources and two purity grades is proposed as a method of chemical recycling. The main effort of this paper focuses on the employment of commercial glycerine of analytical grade and waste glycerine without purification derived from the biodiesel production, as a decomposing agent for polyurethane recycling. In this study, the influence of polyurethane to glycerine mass ratio (PU/GL) and the type of decomposing agent on the chemical structure by FTIR, 1H NMR and GPC was examined. FTIR analysis of the glycerolysates showed absorption peaks similar to the virgin polyol. Those results are in compliance with GPC chromatograms, which showed for all samples, well-defined peak at ca. 13 min of retention time. The molecular weight of glycerolysates was ranging from 800 to 1300 g mol−1 depending on PU/GL mass ratio. The novel decomposition agent, namely waste glycerine derived from biodiesel production was successfully used in glycerolysis process.

In this work polyurethane elastomers were synthesised by using different mixtures of a petrochemical and glycerolysate polyols and 4,4-diphenylmethane diisocyanate (MDI). Glycerolysate polyol was produced from polyurethane foam decomposition using crude glycerine as a decomposition agent. The structure and thermal properties of obtained semi-product were similar to the polyol used in the synthesis of original foam. Glycerolysate polyol was incorporated into polyurethane formulation as soft segment (SS). Since polyol is one of the major component in polyurethane system (>70%) introducing recycled components leads to lowering of consumption of petrochemicals and valorisation of recycled products. Polyurethane elastomers containing up to 16.4 wt.% of glycerolysate polyol were synthesised, soluble in dimethylformamide (DMF) up to ca. 12 wt.%. The effect of glycerolysate polyol content on the structure and properties was analysed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and mechanical tests. Thermal properties did not worsen after using glycerolysate into polyurethane formulation. A slight increase in glass transition temperature is observed with the incorporation of glycerolysate polyol. Elastic modulus, tensile strength and hardness of polyurethane elastomers increased with recycled polyol content. Moreover they showed high elongation at break values.

Polyurethane (PU) recycling is a topic of growing interest due to the increasing amount of polyurethane waste. The main purpose of polyurethane chemical recycling is to recover the starting polyol. In this study, a method of polyurethane thermochemical recycling, glycerolysis by means of crude glycerin, is proposed. This work presents a comparative study of commercial catalysts used in order to accelerate the decomposition process, namely triethylamine (TEA), potassium acetate (KAc), 1,4-diazabicyclo[2.2.2]octane (DABCO), sodium hydroxide (NaOH), dibutyltin dilaurate (DbDl), and stannous octoate (StOc).The effect of used catalyst on the chemical structure and rheological properties was studied. The type of catalyst does not have significant influence on the chemical structure, but causes different course of reaction: split- and single-phase in applied conditions. Glycerolysates were measured by Brookfield Rheometer. It was found that repolyols can be described by the Herschel–Bulkely mathematical model in the best accuracy. The investigation showed that the rheological behavior of glycerolysates depended on the catalyst used in glycerolysis process. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

Polyurethane recycling is a topic of growing interest due to the increasing amount of polyurethanewaste. The main purpose of polyurethane feedstock recycling is to recover the starting polyol, a valuable material. In thiswork, amethod of polyurethane thermo-chemical recycling, glycerolysisbymeansof crude glycerine, is proposed. Themaineffort is focusedonthe employment of crude glycerine without purification from biodiesel production as a decomposing agent for polyurethane recycling. The influenceofpolyurethane-to-glycerinemass ratio (PU/GL)onchemical structurewas examined using Fourier transforminfrared (FTIR) and 1H NMR spectroscopies and gel permeation chromatography (GPC). Glass transition temperature (Tg) and thermal properties using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and also rheology were analysed. FTIR and 1HNMRanalyses of the glycerolysates showed peaks similar to those of virgin polyol. FromGPC chromatogramsitwas concluded thatglycerolysates are amixture of compoundswith different molecularweights, such as recoveredpolyol, urethane oligomers or carbamates. Glycerolysates indicated Tg in the range from −65 to −60 ∘C and, for high PU/GL ratio, a second Tg appeared. Thermal stability of glycerolysates increased with increasing PU/GL ratio. The molecular weight of glycerolysates ranged from 700 to 1020gmol−1 depending on PU/GL mass ratio. The semi-products were defined as non-Newtonian fluids, where viscosity depended on the shear rate. Crude glycerine, derived from biodiesel production, was successfully used in polyurethane decomposition, resulting in valuable semi-products.

Plastics have become widely used materials in everyday life due to their special properties such as durability, easy processing, lightweight nature, and low cost of production. However, because of their stable and nonbiodegradable nature, postconsumer plastics become an issue to the environment. The growing amounts of waste are generated, as plastic products are commonly used only once before disposal. The alternatives of practical techniques for solid waste management are redesign, reprocessing, and recycling. Thus, even recycling is not the most profitable technique for the treatment of plastic waste, and it should be constantly developed. The recycling of plastic waste helps to conserve natural resources due to polymeric materials being made from oil and gas. There are four main recycling methods: reuse, mechanical recycling, chemical recycling, and energy recovery. Mechanical recycling turns polymeric waste into new polymer products when energy recovery process releases the energy contained wi...

The presented study examined the morphology and mechanical properties of biocomposites obtained from kenaf natural fibre and thermoplastic polyurethane. Kenaf was modified using various methods, namely: acetylation, blocked isocyanate, maleic anhydride and permanganate treatment. Those methods and ways of carrying out of surface modifications were not studied before on kenaf/thermoplastic polyurethane composites. Different fibre loadings: 10% and 30% (by weight) were applied. The chemical treatments of fibres was confirmed by FTIR. The fibres surface and adhesion of the fibres to matrix was investigated using a scanning electron microscope (SEM). The modulus, tensile strength, elongation at break, hardness, resilience and water absorption were also determined; all results were compared with a untreated kenaf fibre composite. SEM investigations of fibres showed the differences of fibre surface after the chemical treatment. A good adhesion between the polymer matrix and fibres was observed for PU/PMn-KF 30 sample. DMA results indicated that the greatest values exhibited samples with fibre treated by acetylation and permanganate treatment. Increasing the amount of fillers in the polymer matrix leads to higher hardness values and water uptake. Tensile strength and resilience of composites decreased when a higher proportion of kenaf fibre was added. It was observed that the treated fibre composites showed improvement in tensile properties, hardness, resilience and lower water uptake for composites with 10% fibre loading.