ForMatter/Materials/smart/Phase-Change Material (Paraffin Wax)
mat_smart_phase_change_paraffin

Phase-Change Material (Paraffin Wax)

alkane phase-change material, latent-heat storage · PCM, paraffin PCM, thermal-storage wax
highlast updated 2026-04-27
metallic 0.00
hue shift +0°

Wax that melts at a chosen temperature — and stores a large amount of heat as latent heat of fusion at that temperature, holding any system in contact at the wax's melting point until the wax has fully melted. The reason ski jackets stay warm in cold weather without overheating in moderate weather, the medium that keeps a temperature-sensitive medical shipment at 4 °C overnight, and the heat-spreader inside many CPU coolers. The pure-paraffin grades in the 18–30 °C range are the most common.

n-alkanes C18 to C32, individually or as eutectic blends. Latent heat of fusion 200–250 J/g across the relevant melting-point range. Melting points (specific alkane): octadecane 28 °C, eicosane 37 °C, docosane 44 °C — eutectic blends produce intermediate melting points. Density 0.78–0.85 g/cm³ liquid, 0.86–0.90 g/cm³ solid. Almost universally microencapsulated for product use to prevent leakage during melt phase.

thermal

  • latent_heat_j_g_typical220
  • melting_point_c_octadecane28
source: Microtek MPCM technical bulletin; Rubitherm RT-series datasheets

Sustainability

  • embodied carbon kg co2e per kg0.9
  • sourceEditorial estimate from ICE / Granta CES EduPack class databases — industry mean, with cradle-to-gate boundary unless otherwise noted. Embodied carbon for any specific product depends on supplier mix, recycled content, and energy grid; verify against a primary source before using these numbers in a sustainability claim.
  • recyclabilitymoderate — bulk paraffin recyclable as petroleum stream
  • biodegradableFalse
visual
white waxy solid below melting point, clear-pale-yellow liquid above
tactile
characteristic paraffin feel; microencapsulated form is fine powder

PBR starter values

Principled BSDF defaults derived from the sphere matte finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material.

# finish:      matte
albedo        #e8e4dc
metallic      0.00
roughness     0.75
ior           1.45
transmission  0.00
clearcoat     0.00
sheen         0.00
anisotropic   0.00
copy as JSON 
{
  "albedo": "#e8e4dc",
  "metallic": 0.0,
  "roughness": 0.75,
  "ior": 1.45,
  "transmission": 0.0,
  "clearcoat": 0.0,
  "sheen": 0.0,
  "anisotropic": 0.0
}
Blender 4.x Python 
# Blender 4.x — Principled BSDF
# Phase-Change Material (Paraffin Wax) · finish: matte
import bpy
mat = bpy.data.materials.new(name="mat_smart_phase_change_paraffin")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value         = (0.807, 0.7758, 0.7157, 1.0)
bsdf.inputs["Metallic"].default_value           = 0.000
bsdf.inputs["Roughness"].default_value          = 0.750
bsdf.inputs["IOR"].default_value                = 1.450
bsdf.inputs["Transmission Weight"].default_value = 0.000
bsdf.inputs["Coat Weight"].default_value        = 0.000
bsdf.inputs["Sheen Weight"].default_value       = 0.000
bsdf.inputs["Anisotropic"].default_value        = 0.000
KeyShot Python (lux) 
# KeyShot 11+ — lux Python API, Generic material
# Phase-Change Material (Paraffin Wax) · finish: matte
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_smart_phase_change_paraffin", materialType="Generic")
mat.setProperty("diffuse",      (232, 228, 220))   # 8-bit sRGB
mat.setProperty("metallic",     0.000)
mat.setProperty("roughness",    0.750)
mat.setProperty("indexOfRefraction", 1.450)
mat.setProperty("transparency", 0.000)
mat.setProperty("coatingWeight", 0.000)
Substance pbrMetalRough 
{
  "_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
  "_about": "Phase-Change Material (Paraffin Wax) \u00b7 finish: matte",
  "baseColor": {
    "r": 0.807,
    "g": 0.7758,
    "b": 0.7157
  },
  "metallic": 0.0,
  "roughness": 0.75,
  "ior": 1.45,
  "opacity": 1.0,
  "anisotropyLevel": 0.0,
  "_notes": "Channels listed are the standard Substance pbrMetalRough output. Drop into a Uniform Color node per channel, or as the constant input on a layered stack."
}
glTF 2.0 Metallic-Roughness 
{
  "asset": {
    "version": "2.0",
    "generator": "ForMatter"
  },
  "materials": [
    {
      "name": "mat_smart_phase_change_paraffin",
      "pbrMetallicRoughness": {
        "baseColorFactor": [
          0.807,
          0.7758,
          0.7157,
          1.0
        ],
        "metallicFactor": 0.0,
        "roughnessFactor": 0.75
      },
      "extensions": {
        "KHR_materials_ior": {
          "ior": 1.45
        }
      }
    }
  ]
}
USD Preview Surface 
# USD Preview Surface — UsdShade.MaterialLook prim attributes
# Phase-Change Material (Paraffin Wax) · finish: matte
def Material "mat_smart_phase_change_paraffin" {
    token outputs:surface.connect = </mat_smart_phase_change_paraffin/PreviewSurface.outputs:surface>

    def Shader "PreviewSurface" {
        uniform token info:id = "UsdPreviewSurface"
        color3f inputs:diffuseColor = (0.807, 0.7758, 0.7157)
        float   inputs:metallic     = 0.000
        float   inputs:roughness    = 0.750
        float   inputs:ior          = 1.450
        float   inputs:opacity      = 1.000
        float   inputs:clearcoat    = 0.000
        token   outputs:surface
    }
}
↓ download glTF material

Citations