Composites of Open-Cell Viscoelastic Foams with Blackcurrant Pomace

Taking into account the circular economy guidelines and results of life cycle analyses of various materials, it was proposed to use a blackcurrant pomace filler in the production process of viscoelastic polyurethane (PUR) foams intended for application as mattresses, pillows, or elements for orthopedics. Open-cell viscoelastic PUR foams containing 10–60 per hundred polyols (php) blackcurrant pomace were prepared. It was found that after introducing the filler to the PUR foam formulation, the speed of the first stage of the foaming process significantly decreases, the maximum temperature achieved during the synthesis drops (by 30 °C for the foam containing 40 php of filler compared to unfilled foam), and the maximum pressure achieved during the synthesis of foam containing 20 php is reduced by approximately 57% compared to the foam without filler. The growth time of the foams increases with increasing the amount of introduced filler; for the foam containing 60 php, the time is extended even by about 24%. The effect of the filler on the physical, morphological, mechanical, and functional performances of PUR foam composites has been analyzed. The use of 60 php as the filler reduced the hardness of the foams by approximately 30% and increased their comfort factor from 3 to 5.

Viscoelastic epoxy foams by an aqueous emulsion foaming process

The research proposed an aqueous emulsion foaming process to produce a viscoelastic epoxy foam having a density of 0.33–0.36 g/cm3 from the polyamide–epoxy adduct, which uses a reverse ratio of epoxy and polyamide hardener. The process is simple, economical and uses no surfactant, thanks to the emulsifying ability of polyamide hardener. Firstly, the mixture of excess polyamide, epoxy and sodium bicarbonate was emulsified with distilled water using high-speed stirring to form dispersed epoxy droplets in water. Secondly, a solution of ammonium chloride was added, which reacted with sodium bicarbonate to produce carbon dioxide and ammonia gases dispersed in the epoxy emulsion. The expanding gases induced flocculation and partial coalescence of the epoxy droplets; sequentially water molecules were entrapped within them. Finally, a curing process was carried out to stabilise the foam morphology and structure. Two types of pore morphologies were observed: a large foam-pore generated from blowing-agent gases and a cell-wall pore formed from the vapourisation of entrapped water (as the void template). Porosity and pore morphologies depended on blowing-agent content, and the viscoelasticity was affected by the epoxy/polyamide ratio. The obtained viscoelastic foams showed a large number of interconnected cells and exhibited high compression set values.

Structure–property performance of natural palm olein polyol in the viscoelastic polyurethane foam

Structure–property behavior of the palm olein-based natural oil polyol (E-135 NOP) was investigated in viscoelastic “memory” foams. In a model viscoelastic foam formulation, the E-135 NOP with pendant hydroxyls was used as a drop-in replacement for the well-defined model polyether polyol with terminal hydroxyls, Poly-G® 76-120. Both polyols have comparable equivalent weight and concentrations of primary and secondary hydroxyls. The data showed that replacing Poly-G® 76-120 polyether polyol with the E-135 NOP did not significantly impact the foaming reactivity. Increasing the E-135 NOP concentration in the VE foams increased the average foam cell size while maintaining the open cell structure. Aging properties of the VE foams were mostly unaffected by the replacement of the Poly-G® 76-120 with the E-135 NOP. Furthermore, addition of E-135 had no impact on foam density; however, it increased the support factor of the viscoelastic foams. Differential scanning calorimetry, dynamic mechanical analyzer, and Fourier transform infrared spectroscopy analyses indicate less defined morphological separation of hard and soft segments in the viscoelastic foams with higher concentration of E-135 NOP. Overall, the results demonstrated the feasibility that natural oil polyols can be used in viscoelastic polyurethane foams to replace a significant portion of the polyether polyols with comparable equivalent weights and concentrations of primary and secondary hydroxyls. In future, the feasibility study of E-135 NOP as a drop-in replacement of combination polyether polyols in viscoelastic foams formulation will be conducted. Furthermore, the effect of palm olein-based natural oil polyol in high resilience foam will be evaluated.