PA12 vs PA11 properties overlap across most datasheet lines, which is exactly why the two long-chain polyamides get treated as interchangeable until a flexibility, bio-content or cost review surfaces the difference. PA11 is polymerised from castor oil and carries the renewable-feedstock story; PA12 comes from petrochemical laurolactam and is the volume workhorse. This guide walks through the thermal, mechanical and processing deltas, and lists what an RFQ should pin down.
Feedstock and sustainability position
The first fork is origin. pa11 bio based nylon starts with castor beans — ricinoleic acid converted to amino-undecanoic acid — in a route that is not food-crop based and that published comparisons score roughly thirty percent lower in per-kilogram CO2 against petrochemical PA12. PA12 synthesis starts from butadiene and yields laurolactam. Neither route changes the shape of the mechanical data, but both change documentation: a bio-content claim needs a feedstock chain statement and a recognised certificate scheme, and large brands increasingly ask for one.
Thermal and physical comparison
| Property | PA11 | PA12 |
|---|---|---|
| Melting point | 185-190 °C | 175-180 °C |
| Density | 1.03-1.04 g/cm³ | 1.01-1.02 g/cm³ |
| Moisture absorption at equilibrium | ~0.3-0.5% | ~0.2-0.3% |
| Glass transition | ~42 °C | ~48-60 °C |
| Flexural modulus | ~335 MPa, flexible | ~1200 MPa, stiff |
PA11 holds the thermal edge — roughly ten degrees of melt advantage and a lower glass transition that suits cold-weather and low-temperature flexing. PA12 is marginally lighter and marginally less hygroscopic at equilibrium. Neither grade approaches the water sensitivity of PA6 or PA66, so both stabilise after moulding without the long conditioning cycles that short-chain nylons need.
Stiffness, toughness and dimensional stability
The mechanical split is stiffness against toughness. A castor oil based polyamide such as PA11 gives elongation back: in laser-sintered form, published figures show about 54 MPa tensile strength and 31% elongation at break against roughly 45 MPa and 18% for PA12, whose flexural modulus runs three to four times higher. For moulded parts the direction is the same: PA11 wins snap-fits, hinges and repeated-flex duty, PA12 wins load-bearing geometry and tighter dimensional control. The same shortlist usually carries shorter-chain options, so our nylon PA6 versus PA66 guide and POM versus PA66 wear comparison cover those neighbours.
Processing long-chain nylons
Both grades dry at 80-90 °C for four to six hours to below 0.1% moisture — a gentler schedule than PA66 demands, as resin drying guides explain in detail. Melt temperature runs 210-250 °C for PA11 and 200-240 °C for PA12, with mould temperatures of 40-80 °C unreinforced and 80-120 °C glass-filled. Flow-direction shrinkage sits near 1.0-1.5%, similar to short-chain nylons, and an anneal at 150-165 °C improves crystallinity and dimensional stability for precision parts. Longer cyclic moisture swings cost the long-chain grades less dimensional drift than they cost PA66, which is why fastener clips and printed assemblies hold tolerance better.
Applications and market position
PA12 dominates automotive fuel and brake lines — multilayer constructions with barrier layers hold permeation below regulatory limits and resist zinc chloride road salt — and powder-bed 3D printing, where it is the reference material. PA11 covers pneumatic tubing, flexible insulation, agricultural parts that flex daily and consumer products that monetise the renewable feedstock. Long chain polyamide capacity is small next to PA6/PA66 volumes, but new Chinese PA12 capacity is steadily widening the merchant market and narrowing the historic supply concentration.
PA12 vs PA11 properties: what to confirm in an RFQ
- Feedstock documentation: a castor-oil chain statement when bio-content matters.
- Grade datasheet: melting point, moisture and modulus for the specific grade, not the family.
- Drying schedule: recommended dryer temperature and residence time per lot.
- Application validation: flex-life, permeation or immersion testing against the service liquid.
Compound suppliers across both grades are listed in the supplier directory, and the full resin library sits in the plastic materials hub.
