PET bottle
A clear bottle moulded from PET — the signature work of the Ethylene × p-Xylene household.
Ancestors: Ethylene · p-xyleneSOUL/ALLOY Science · Organic Materials
Petrochemical Family Tree
From crude oil through the naphtha cracker, five midstream sisters are born — and the resins and rubbers they raise. One canvas, the whole lineage.
19nodes20links8everyday items
SUPPLY CHAIN · 19 NODES
Petrochemical Family Tree — single-canvas supply chain
From upstream crude oil and naphtha, through the five midstream monomer sisters (ethylene, propylene, butadiene, benzene, p-xylene), to six downstream resins, five synthetic rubbers and one independent natural rubber — 19 nodes connected. Solid lines: single-parent lineages. Dashed lines: convergent lineages with two parents.
Solid: single-parent lineageDashed: convergent lineage (two monomers join)
UPSTREAM
Upstream — crude oil and the naphtha-cracker flame
Naphtha (C5–C12) is distilled from crude oil and fed into a steam cracker at 800–870°C. In just 0.2–0.4 seconds of pyrolysis, the matriarchs of the family rise from the flame.
Crude oil and naphtha now have their own personas — meet them via the links below.MIDSTREAM · 5 MONOMERS
Midstream — five monomer sisters
Five monomers born from the cracker. Each has its own double bond or aromatic ring, and each becomes the mother of countless plastics, rubbers, and fibres.
C₂H₄
Ethylene
Bright matriarch of a big family. The world's largest monomer at 200 Mt/year and source of all four commodity plastics.
“PE, PVC, PET — all my children”View persona ↗C₃H₆
Propylene
The methodical second sister. Mother of PP, contributing genes to EPDM and IIR.
“Order is what lets me be useful”View persona ↗C₄H₆
Butadiene
The springy younger brother. The bounce in SBR, BR, and NBR all comes from him.
“Bouncing — that's my job”View persona ↗C₆H₆
Benzene
Classical aromatic prince. Ancestor of PS via styrene and of NBR via acrylonitrile.
“Kekulé's dreamed serpent — that's me”View persona ↗p-C₈H₁₀
p-Xylene
Artisan of symmetry. Co-parent of PET via PTA — the source of bottles and polyester fibre.
“I just live straight”View persona ↗
DOWNSTREAM · 12 MATERIALS
Downstream — the lineage of resins and rubbers
Six commodity resins, five synthetic rubbers, and one independent natural rubber. Almost every material around you is a descendant of one of these branches.
Commodity resins 6
Synthetic rubbers 5
Natural rubber (independent) 1
REVERSE LOOKUP
Reverse lookup — your everyday objects
PET bottles, shopping bags, tyres, containers… Pick something near you and walk the tree backwards to its molecular ancestors.
Shopping bag · cling film
Soft, stretchy LDPE and crisp, tough HDPE — twin children of Ethylene.
Ancestors: EthyleneCar tyre
SBR and BR carry friction and bounce, NR absorbs shocks. A trio collaboration of the rubber siblings.
Ancestors: Butadiene · BenzenePlastic containers and caps
Microwave-safe PP, thin and strong HDPE — your kitchen shelf is a duet of two houses.
Ancestors: Ethylene · PropylenePolyester clothing
PET spun into fibre — sportswear to fleece, this is where p-Xylene's family shines.
Ancestors: Ethylene · p-xyleneCD/DVD case · foam
Hard, transparent PS is an artistic crystal of Benzene × Ethylene; foamed, it insulates buildings.
Ancestors: Ethylene · BenzenePVC pipe · window frame
Ethylene's youngest paired with chlorine — the unsung hero of construction and plumbing.
Ancestors: EthyleneNitrile gloves · oil hose
NBR from butadiene × acrylonitrile — oil-resistant star of medical and industrial fields.
Ancestors: Butadiene · BenzeneSOURCES · REFERENCES
Sources & references
Data on this page draws on government statistics, industry associations, IEA reports, and scientific databases.