Nanostructured copolymer latexes for enhanced wax inhibition and rheological control in waxy crude oils

Abstract

This work simultaneously addresses two challenges: the intricate synthesis of stable, nano-scale polymer latexes and the complex chemical treatment of waxy crude oils. While microemulsion polymerization is a powerful tool, achieving stable latexes requires synergistic process control, and ensuring crude oil flowability typically necessitates a cocktail of additives. Herein, we introduce a unified “synthesis-for-function” strategy, where a series of exceptionally stable, dual-function copolymer nano-latexes were synthesized via a meticulously controlled semi-batch microemulsion polymerization. The key innovation lies in engineering the copolymer architecture and surfactant system to deliver dual functionality. The structural integrity and molecular weights (Mw) of the target copolymers—poly(THSPM-co-DSM), poly(THFA-co-DSM), and poly(VAc-co-DSM)—were rigorously confirmed by spectroscopic (FTIR, ¹H/¹³C NMR) and chromatographic (GPC) analysis. Furthermore, SEM analysis verified the formation of uniform nano-latexes in the 18–44 nm range. Two of the three nano-latexes acted as particularly potent dual-function additives, exhibiting clear structure-performance relationships. The silanol-functionalized copolymer proved superior, achieving a remarkable wax inhibition (WI) of 95–96%, a ΔPPT of 21–24 °C, and superior rheological modification; it delivered a 61.4–65.1% reduction in dynamic viscosity and substantial reductions in both ideal (73.3–77.9%) and thixotropic (53.8–66.1%) yield stress at the untreated-PPT. The tetrahydrofurfuryl analogue also demonstrated strong efficacy, providing a 89–92% WI and a ΔPPT of 15–18 °C. This aqueous-based platform offers a robust, economically viable, and eco-friendly alternative to conventional, solvent-based additives, providing a streamlined solution for major flow assurance challenges.