Reuse potential of functionalized thermoplastic waste as reinforcement for thermoset polymers: Mechanical properties and erosion resistance

Two types of polymer waste materials, poly(ethylene terephthalate) (PET) and polycarbonate based Colombian Resin (CR-39), were used for the designing of fully recycled composite materials. Waste PET was employed for the synthesis of thermoset unsaturated polyester resin (UPR), while CR-39 was used as reinforcement in the UPR matrix. Prior to mixing, CR-39 particles were subjected to oxidation and chemical activation using acids/base and ethanol amine, respectively. The effect of the modifier type and variable loading of the activated CR-39 particles on mechanical and dynamic-mechanical properties of the corresponding composites was investigated. The greatest improvement in the tensile and flexural strength of UPR resin was achieved with the composite containing 0.5 wt% of amine activated filler particles, 96.0% and 62.2%, respectively. The Arrhenius equation was used to calculate the activation energy for glass transition from dynamic mechanical properties measured at various frequencies. The activation energy of the main transition for UPR resin and composites were calculated to be 173 and 350 kJ center dot mol(-1) indicating that reinforcement results in an increase in the energy barrier to macromolecules viscoelastic relaxation. In addition, erosion resistance was studied during exposure of samples to cavitation tests. According to the obtained results, these materials can be applied in construction and mining industry

Tailoring the properties of waterborne polyurethanes by incorporating different content of poly(dimethylsiloxane)

A series of novel waterborne polyurethanes (WBPUs) was synthesized using alpha,omega-dihydroxypropyl poly(dimethylsiloxane) (PDMS), isophorone diisocyanate (IPDI), 2,2-bis-(hydroxymethyl) propionic acid (DMPA) and triethylamine (TEA). Different DMPA/PDMS molar ratio (from 0.2 to 0.7) and fixed -NCO/-OH molar ratio of 1.7, has been applied for the synthesis of six different WBPU films, without utilization of chain extension step during the synthesis. The structure of the prepared WBPUs was examined and confirmed by FTIR and NMR spectroscopy. The particle size of the prepared WBPU dispersions and molecular weight of WBPU films decrease with increasing DMPA content. In order to investigate the effect of the DMPA/PDMS ratio on thermal, mechanical and morphological properties, as well as the water resistance of the prepared WBPUs, diverse experimental techniques, such as thermogravimetric analysis, dynamic mechanical analysis, tensile tests, X-ray diffraction analysis (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and water contact angle measurements have been carried out. This research has shown that the incorporation of PDMS in WBPUs led to the appearance of microphase separation and provided surface hydrophobicity, good thermal and mechanical properties, which allow application of these WBPUs as coatings for various purposes