Improvement of Bending Motion by Catalyst Addition of Pd-Al<SUB>2</SUB>O<SUB>3</SUB> Powder for an Uni-Morph Soft Device Constructed of Polymer Sheets with and without Powder Dispersion of Hydrogen Storage Alloy

Abstract

In order to generate the soft bending motion driven by pressure change in hydrogen gas, a soft device was made up and tested. In former research, a unimorph structure was proposed, in which a silicone rubber with LaNi 5 alloy powder distributed was piled up on a pure silicone rubber sheet. Using this structure we succeeded a bending motion of the soft device by applying hydrogen gas pressure. However the mechanical response was slow. To improve the active motion, a catalyst of Pd-Al 2 O 3 powder was mixed into the hydrogen storage alloy powder in the rubber. By simple addition of catalyst powder before dispersion into the rubber, we obtained drastically modified responses and displacement in the movement of the device. The catalyst probably accelerated dissociation of hydrogen molecule on the surface of hydrogen storage material particle.

An Improved H₂-Gas Pressure Operated LaNi₅ Powder-Dispersed Polyurethane/Titanium 2-Layer Actuator with Reversible Giant and Rapid Expansion by Hydrogenation

“…[6][7][8] An addition of Pd-Al 2 O 3 catalyst to the LaNi 5 powder prior to dispersion in polymer has enhanced the responsiveness as well as motion strain. 9) Stiffness has been improved in 2-layer actuators (PU:LaNi 5 /PU) 10) where both layers are 500 μm thick polyurethane (PU): the driving PU layer dispersed with (35 vol%) LaNi 5 -Pd-Al 2 O 3 mixture prepared by solution cast method. The PU:LaNi 5 /PU 10) actuators take advantage of both high elasticity as well as high limit value of elastic strain of PU where geometry and mixed ratio [PU]-[LaNi 5 -Pd-Al 2 O 3 ] are easily controlled.…”

Reversible Bending Motion of Unimorph Composites Driven by Combining LaNi<SUB>5</SUB> Alloy Powders Dispersed Polyurethane and Thin Supporting Copper Sheet under Partial Hydrogen Gas Pressure

“…max of PU+LaNi 5 / Cu Figure 5 shows cyclic changes in bending strain of reversible motion (") of unimorph PU+LaNi 5 /Cu sheet after exposure to hydrogen under 0.2 MPa and to vacuum against reaction time (t/ks), together with unimorph sheets of PU+LaNi 5 /PU, 14) SR+LaNi 5 /SR 10) and ABS+LaNi 5 / ABS. 14) The maximum strain (1520 ppm) of the unimorph PU+LaNi 5 /Cu sheet is lower than that (2300 ppm) by PU+LaNi 5 /PU 14) at vertical direction.…”

“…14) silicon rubber (SR+LaNi 5 /SR) 10) and ABS polymer (ABS+LaNi 5 /ABS), 14) and supporting sheets of pure polyurethane, silicon rubber and ABS polymer. (" e/p ) of stress-strain curves of unimorph (PU+LaNi 5 /Cu) sheet, which is constructed with driving composites of 35 vol%LaNi 5 powders dispersed polyurethane (solid line) and supporting copper film of copper (10 mm thickness) against hydrogenation reaction time (t), together with the reversible motions of unimorph sheets constructed with driving composites of 35 vol%LaNi 5 powders dispersed polyurethane (PU+LaNi 5 / PU), 14) silicon rubber (SR+LaNi 5 /SR) 10) and ABS polymer (ABS+LaNi 5 /ABS), 14) and supporting sheets of pure polyurethane, silicon rubber and ABS polymer.…”

“…Since the residual strain is zero, this bending motion is reversible, that is, elastic deformation. , and supporting sheets of pure polyurethane, 14) silicon rubber 10) and ABS polymer. 14) tion exhibits the reversible straight lines for each unimorph composites sheets (see Fig.…”

“…As the strong improvement has been required, it has been also reported that the addition of catalyst of Pd-Al 2 O 3 powders to the hydrogen storage alloy powders before dispersing improves the motion strain, as well as its responsiveness. 10) Thus, silicone rubber unimorph (SR+LaNi 5 /SR) sheet, which is constructed with the driving silicone rubber composites and pure silicone rubber supporting sheet, has been successfully developed. Besides, the silicone rubber with good formability at room temperature exhibits the high limit strain of elasticity, whereas it is too soft.…”