Plywood vs. Rubber

Compare Plywood vs. Rubber strength, stiffness, weight and thermal properties.

RubberBulk polymer (molded or machined)

Mechanical	Plywood	Rubber
Yield strength	not given (tensile used)	not given (tensile used)
Ultimate tensile strength	modulus of rupture41.4MPa1	23MPa2
Flexural strength	static bending MOR41.4MPa1	not sourced
Elongation at break	not sourced	830%2
Young's modulus (stiffness)	7.45GPa1	not sourced
Density	not sourced	960kg/m³2
Strength to weight	not sourced	24kN·m/kg
Stiffness to weight	not sourced	not sourced
Poisson's ratio	not sourced	government0.53
Shear modulus	not sourced	not sourced
Bulk modulus	not sourced	not sourced
Speed of sound	not sourced	not sourced

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Plywood	Rubber
Thermal conductivity	0.12W/m·K4	0.151W/m·K5
Thermal expansion	base material3.1–4.5µm/m·K6	not sourced
100 mm part over a 50 °C swing	19µm growth	not sourced
Specific heat	base material1,700J/kg·K6	government1,881J/kg·K3
Heats up and cools (diffusivity)	not sourced	0.0836mm²/s
Thermal shock resistance	not sourced	not sourced
Max service temperature	not sourced	70°C2

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

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Sources6 documents: USDA Forest Products Laboratory, Weir Minerals, National Institute of Standards and Technology, Defense Technical Information Center

Plywood: Douglas-fir plywood sheathing (construction plywood per PS 1), static bending properties from USDA FPL Wood Handbook FPL-GTR-282 Ch. 12 Table 12-2 (Biblis 2000)
Rubber: Weir Minerals Linatex Premium rubber (95 % natural rubber), typical physical properties, spec sheet WMD0118/202305

1
Wood Handbook (FPL-GTR-282), Chapter 12: Mechanical Properties of Wood-Based Composite MaterialsUSDA Forest Products LaboratoryPlywood · Ultimate tensile strength: modulus of rupture (no direct tensile value)Plywood · Flexural strength: static bending MOR (Douglas-fir); range 33.72-42.61 across speciesPlywood · Young's modulus (stiffness): static bending MOE of the panel (Douglas-fir); range 6.96-8.55 across species
2
Linatex Premium Rubber Spec Sheet (WMD0118, 2023)Weir MineralsRubber · Ultimate tensile strength: typicalRubber · Elongation at break: typicalRubber · Density: typical (specific gravity)Rubber · Max service temperature: continuous use operating range
3
Compressibility of Natural Rubber at Pressures Below 500 kg/cm², J. Res. NBS 68A (1964)National Institute of Standards and Technologyarchived copyRubber · Poisson's ratio: government (NBS J. Res. 68A, 1964): computed by NBS for peroxide-cured gum NR vulcanizate, 25 °C, infinitesimal deformation (0.49 in the solver: the linear element locks as the ratio nears 0.5 (nearly incompressible).)Rubber · Specific heat: government (NBS J. Res. 68A, Table 7; values observed for unvulcanized NR by Bekkedahl and Matheson), 25 °C
4
Thermal Properties of Wood and Wood Panel Products for Use in Buildings (1988)USDA Forest Products Laboratoryarchived copyPlywood · Thermal conductivity: APA-recommended design value (Douglas-fir plywood), as reported by FPL/ORNL
5
Thermal Conductivity of Soft Vulcanized Natural Rubber: Selected Values (AD 643325)Defense Technical Information Centerarchived copyRubber · Thermal conductivity: government selected value (US Army Natick Laboratories TR 66-49-PR, 1966), soft vulcanized natural rubber, 25 °C
6
Wood Handbook (FPL-GTR-282), Chapter 4: Moisture Relations and Physical Properties of WoodUSDA Forest Products LaboratoryPlywood · Thermal expansion: base material: solid wood parallel to grain, ovendry, range across speciesPlywood · Specific heat: base material: solid wood (all species), 12% MC, 27 C

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Mechanical

Is Plywood stronger than Rubber?

Plywood is stronger: its tensile strength is 41.4 MPa against 23 MPa for Rubber (1.8x).

Thermal

Which conducts heat better, Plywood or Rubber?

Rubber conducts heat better: 0.151 W/m·K against 0.12 W/m·K for Plywood.