Thermal and mechanical performance of rigid polyurethane foam added with commercial nanoparticles

Abstract

This study investigates the effects of commercial nanoparticles on thermal and mechanical performance of rigid polyurethane foams. Two different types of nanoparticles are considered as fillers, spherical titania and rod-shaped halloysite clay nanotubes. The aim of this study was to produce rigid polyurethane foams modified with titania nanocrystals and nanohalloysite in order to obtain polyurethanes with improved properties. The laboratory scale-up will be suitable for the production in many branches of industry, such as construction and automotive production. In particular, these foams, added with commercial nanoparticles, characterized by better thermal and mechanical properties, are mainly used in construction for thermal insulation of buildings. The fillers were dispersed in the components, bringing rates up to 10%. In these investigations, the improvement of the thermal properties occurs by adding nanoparticles in the range 4-8% of titania and halloysite. The mechanical properties instead have been observed an improvement starting from 6% of nanoparticles addition. All data are in agreement with scanning electron microscope observations that shown a decrease in the average cell size and an increase in the cell density by adding nanoparticles in foams.

Effects of hydrotalcite on rigid polyurethane foam composites containing a fire retarding agent: compressive stress, combustion resistance, sound absorption, and electromagnetic shielding effectiveness

“…Solid elements that are added to a mixture, such as nanoparticles, tend to decrease the value of DG and thus improve the nucleation. 22,23 and the dense stage. 22 The compressive stress rst increases and then decreases when the hydrotalcite increases.…”

“…22,23 and the dense stage. 22 The compressive stress rst increases and then decreases when the hydrotalcite increases. The minimum and maximum compressive strength of 325.11 kpa and 479.95 kpa occur when the hydrotalcite is 0 wt% and 5 wt%, and the latter of which is 47.63% higher.…”

Mechanical properties, thermal stability, sound absorption, and flame retardancy of rigid PU foam composites containing a fire‐retarding agent: Effect of magnesium hydroxide and aluminum hydroxide

“…Figure 2A,C shows the compressive stress-strain curves of rigid foam composites based on the content of fillers, which contain three phases, including the elastic phase, the platform stage, and the dense stage. 23 As shown in Figure 2B,D, the compressive strength of the rigid PU foam increases almost gradually with the additive content increasing. For rigid PU foams containing Al (OH) 3 and Mg (OH) 2 , the maximum compressive strength of 546.44 and 468.08 Kpa occurs when the content is 20 wt%, and compressive strength increases by 51.18% and 29.50% compared with 0 wt% content.…”

“…The EMI SE of samples is measured at frequencies between 600 MHz Any solid element introduced into the mixture, such as nanoparticles, tends to decrease the value of Gibbs free energy and thus promote the nucleation. 23,24 Small-sized additives act as nucleation agents that accelerate the cell nucleation because they only require small amount of energy to create bubbles. In addition, Mg (OH) 2 has a lower molecular mass than Al (OH) 3 .…”

Blast furnace slag or fly ash filled rigid polyurethane composite foams: A comprehensive investigation

“…Most of them are focused on the addition of fillers or nanofillers. Some authors incorporated nanosilica, hollow glass microspheres, or milled carbon fibers into PU foams in order to improve their mechanical properties . Other authors investigated the effects of expandable graphite to enhance the thermal insulation property of PU foams .…”