Note: This calculation illustrates the treat-rate efficiency advantage of poly-succinimide. In practice, dispersancy performance is not perfectly linear with N% alone (adsorption mechanism quality also matters), but the quantitative N-delivery efficiency is a reliable starting point for formulation screening. The poly-succinimide's multi-point chelate adsorption mechanism provides additional dispersancy quality beyond the N% quantity advantage.

For extreme-duty HDEO applications - EGR rates exceeding 25%, soot concentrations reaching 5–6 wt% by mid-drain, ultra-long drain intervals of 80,000–100,000 km - the dispersant capacity ceiling of mono- and bis-succinimide is approached or exceeded. Poly-succinimide provides the maximum soot-holding capacity needed for these applications, particularly when used as a blend-in booster (1–3 wt% poly-succinimide) added to a standard mono/bis dispersant package to extend the formulation's dispersancy capacity ceiling without exceeding the SAE viscosity grade target.

In SAE 0W-16 and 0W-20 PCMO formulations for modern turbocharged GDI engines (API SP, ILSAC GF-6A/B), the tight kinematic viscosity window (5.6–7.1 cSt for 0W-16; 6.9–9.3 cSt for 0W-20 @100°C) severely limits dispersant treat rates. Poly-succinimide's superior N-delivery efficiency per unit of viscosity contribution makes it the preferred dispersant for these formulations - achieving the required ASTM Sequence VH sludge and VIH deposit ratings at 2–3 wt% treat rather than 6–8 wt% of mono-PIBSI, consuming far less of the viscosity budget. This preserves the viscosity window for low-viscosity Group III/IV base oil selection that is essential for fuel efficiency performance (ASTM Sequence VIII fuel economy rating).

Aviation turbine oils based on polyol ester or diester base oils operate under extreme thermal conditions (bearing temperatures 200–250°C, sump temperatures 150–180°C) that demand a dispersant with superior thermal stability and high flash point. PIB Poly-Succinimide's FP ≥190°C and high-MW polymer architecture provide better thermal durability than lower-MW Mono/Bis dispersants in these conditions. At 1–3 wt% treat in the ester base oil formulation, poly-succinimide prevents varnish formation and maintains filter cleanliness over the 2,000–4,000 hour turbine service interval between overhauls - a critical function for maintaining fuel system and hydraulic system cleanliness in commercial and military aviation.

In industrial gear oils with 3–5 year service intervals (DIN 51517 CLP, AGMA 9005), compressor oils with 4,000–8,000 hour change intervals, and marine trunk piston engine oils (BN 25–40) operating on VLSFO at high soot loading, poly-succinimide at 1–4 wt% provides the long-service deposit control performance that mono- and bis-succinimide cannot sustain over such extended intervals. The multi-point adsorption mechanism's superior resistance to competitive displacement ensures that dispersancy capacity is maintained throughout the long service interval - preventing the progressive varnish accumulation that is the primary cause of industrial gearbox, compressor valve, and marine engine component failures between planned maintenance intervals.

Q: Is PIB Poly-Succinimide always the best choice if I want maximum dispersancy?

Not necessarily - "best" depends on what constraints dominate your formulation. Poly-succinimide is the best choice when: (a) N content per unit viscosity contribution is the binding constraint (low-viscosity SAE grades, tight finished oil viscosity window); (b) soot concentration will exceed 4 wt% (high-EGR HDEO, extreme long-drain); (c) very long service intervals are required (industrial gear, aviation); (d) multi-point adsorption strength is needed (severe thermal stress, high competitive displacement risk). However, poly-succinimide is NOT the best choice when: (a) cost minimisation is the primary driver (poly-succinimide is more expensive per kg than mono/bis); (b) Sequence VH sludge rating is the dominant performance test (mono-PIBSI's free terminal –NH₂ is marginally better for this test); (c) standard PCMO with modest dispersancy requirements where mono or bis at standard treat rate is fully adequate. In practice, the most common usage of poly-succinimide is as a 1–3 wt% performance-boosting addition to a standard mono/bis package for applications that exceed the standard package's dispersancy limits.

Q: How do I handle PIB Poly-Succinimide in the blending plant given its high viscosity (200–1000 cSt)?

PIB Poly-Succinimide requires more careful handling than Mono/Bis grades: (1) Pre-heat drums or IBC tanks to 50–70°C using steam coil heating or a drum oven before attempting to pump - do not exceed 90°C to avoid potential N-group degradation; steam heating at ≤80°C is preferred; (2) Use gear pumps or progressive cavity pumps rated for high-viscosity polymers - centrifugal pumps are not suitable; (3) All transfer lines should be trace-heated (50–60°C) to prevent viscosity increase during transfer; (4) For blending, add the poly-succinimide early in the blending sequence when base oil is already at blending temperature (50–60°C) and use high-shear mixing - the high-N compound blends well once the viscosity is managed; (5) Measure and verify viscosity contribution on a blend test before scale-up, using ASTM D341 blending index method. Storage: in cold climates (<10°C), maintain drum/IBC temperatures above 15°C to prevent congealing of the high-MW polymer fraction.

Q: Does the 5–20% diluent oil content in PIB Poly-Succinimide affect formulation calculations?

Yes - the diluent oil content must be accounted for in three ways: (1) N% on as-received basis: the N% on the COA is measured on the full product including diluent - the active dispersant N% on a diluent-free basis is N% × (100/(100 – diluent%)). For a product with N% = 4.0% and diluent = 20%, the active-basis N% ≈ 5.0%. Sinolook reports N% on the as-received basis, which is the correct number to use for treat-rate calculations in finished oil formulations; (2) Base oil contribution: the diluent oil (typically Group I/II) contributes to the base oil blend viscosity and may affect Group III/IV base stock compatibility if the finished oil is a premium PAO or ester synthetic; specify diluent type when ordering if this matters for your formulation; (3) Viscosity calculation: include the full as-received product viscosity (200–1000 cSt) in the ASTM D341 blending calculation - the diluent is already included in the measured product viscosity. Do not attempt to adjust for diluent separately.

Ashless Dispersants: PIBSI ✅ · Bis-Succinimide ✅ · Poly-Succinimide ✅ · Borated PIBSI (next) · Borated Bis-Succinimide · Boron-Phosphated Bis-Succinimide · Low Viscosity Dispersant