HiSiaddi Resolves Unstable Polymerization Reactions for Polymer Manufacturers

As an innovative foreign trade service provider driven by both technology commercialization and cross-border trading, HiSiaddi has built a proprietary "1+2+3+4=1" service framework and supplies sulfolane sourced directly from multiple well-known original manufacturers. Boasting in-house R&D capabilities and close technical cooperation with production plants, HiSiaddi accurately captures market demands to resolve customized product requirements and deliver optimized formulation solutions for sulfolane clients time and again.

Technical Dilemmas: Unstable Polymerization & High-Temperature Yellow Discoloration

In April 2025, a South Korean specialty polymer manufacturer producing polysulfone (PSU) and polyethersulfone (PES) resins for food-grade filtration membranes and medical devices encountered severe technical issues after purchasing Chinese sulfolane:

1. Unstable      polymerization reactions: Fluctuating sulfolane purity (99.2%–99.5%) and      excessive water content (≥200 ppm) led to broad molecular weight      distribution (PDI ≥1.8) of PSU polymers, volatile viscosity, low tensile      strength and brittle resin, with a production pass rate of only 78%.

2. Thermal      degradation & yellowing at high temperatures: Under polymerization      temperatures of 210–220°C, insufficient thermal stability of sulfolane and      trace impurities catalyzed degradation, resulting in yellow resin with a      yellowness index ≥15, which failed to meet transparency requirements for      food-contact products.

3. Low      solvent recovery efficiency: Poor separation between sulfolane and salt      by-products limited recovered purity to 97%. Accumulated impurities from      repeated recycling further degraded product quality and pushed up      production costs.

The client’s technical team spent one month troubleshooting without resolution, facing delayed order fulfillment and the risk of losing high-end customers, prompting an urgent request for HiSiaddi technical support.

HiSiaddi Solution: Precision Index Control & Process Parameter Optimization

HiSiaddi collaborated with domestic petrochemical research institutes and sulfolane producers, sending senior chemical engineers to conduct on-site diagnostics in South Korea. Root causes and targeted solutions are outlined below:

1. Precise      raw material index control (formulation compatibility)

A dedicated polymerization-grade sulfolane standard was established: purity ≥99.8%, water ≤80 ppm, free acid ≤5 ppm, total impurities ≤0.1%, and metal ions strictly limited to ≤10 ppb to prevent catalytic degradation.

The mass ratio of sulfolane to monomers in PSU polymerization was adjusted to 6:4 to reduce system viscosity and improve reaction uniformity. Nitrogen purging for 30 minutes prior to polymerization eliminated trace oxygen and suppressed oxidative degradation under high heat.

1. Polymerization      process parameter optimization (production compatibility)

Temperature profiles were recalibrated to maintain a constant 210°C polymerization temperature (±2°C) to avoid overheating-induced degradation. Holding time was extended to 1.5 hours to guarantee complete reactions and narrow molecular weight distribution (PDI ≤1.3).

0.05% phosphite antioxidant was compounded with sulfolane to capture degradation free radicals, lowering the resin yellowness index to ≤5 to satisfy food-grade transparency standards.

1. Solvent      recovery system retrofitting (cost reduction & efficiency improvement)

A modified recovery process combining vacuum distillation (0.09 MPa vacuum, 120°C) and activated carbon adsorption boosted recovered sulfolane purity to 99.5%, enabling direct cyclic reuse and cutting solvent loss from 8% to 2%.

On-site training covered three trial production batches, optimizing feeding sequences, stirring speed, nitrogen flow and distillation parameters. Client technicians were trained to identify abnormalities including yellowing, viscosity fluctuations and low recovery purity, as well as routine quality control protocols.

Long-Term Supplier Partnership Established with South Korean Client

Post-optimization PSU resin achieved PDI ≤1.3, tensile strength ≥75 MPa and yellowness index ≤5, with a production pass rate rising to 98%, fully complying with food-contact and medical device specifications. Improved sulfolane recovery and reduced solvent losses cut production costs by USD 120 per ton of resin.

Between May and December 2025, the client purchased 28 tons of polymerization-grade sulfolane from HiSiaddi. HiSiaddi provides quarterly technical follow-ups, batch quality tracking and joint development of new formulations, evolving from a raw material supplier to a core technical partner and advancing domestic substitution of high-end polysulfone resins.