SYUCT Publishes High-Level Academic Paper in International Top Journal Advanced Materials as First Author Institution

Reactive high-fluorine-content oligomers refer to α,ω-low-molecular-weight fluoropolymers with a molecular weight of 1,000–30,000, a fluorine content exceeding 60%, and active functional groups. These materials can serve as precursors for functional fluoropolymers, high-end sealing materials, and high-performance fluorinated coatings, demonstrating broad application prospects. Currently, such materials can be synthesized through forward methods like iodine telomerization of fluoroolefins and functional group-initiated radical polymerization. However, achieving precise control over molecular chain sequence structures remains a challenge. In contrast to forward synthesis, the oxidative degradation (reverse) route leverages the chemical reactivity of vinylidene fluoride (VDF) units in fluoropolymers, offering a unique strategy for the sequence-controlled synthesis of reactive high-fluorine-content oligomers.

Meanwhile, addressing the global challenge of waste fluororubber—difficult to recycle or biodegrade, and currently disposed of via inefficient methods like landfilling and incineration, leading to soil, water, and air pollution with potential risks to human health—Professor Donghan Li’s research group, in collaboration with Professor Dawei Zhao, has proposed an innovative “reverse molecular reconstruction” strategy. This approach upgrades waste fluororubber into a high-performance advanced reactive high-fluorine-content oligomer by exploiting the chemical reactivity of VDF units in waste fluororubber.

Figure 1: Graphical abstract of “Molecular Reconstruction for the High-Performance Recycled Fluororubbers.”

The related findings have been published in the prestigious journal Advanced Materials under the title “Molecular Reconstruction for the High-Performance Recycled Fluororubbers.” The first author is Professor Donghan Li from the School of Materials Science and Engineering, with co-first author Shurui Ning (a master’s student), and co-corresponding author Professor Dawei Zhao from the Key Laboratory of Specialty Resource Chemistry and Materials, Ministry of Education.

Figure 2: Reaction pathway and degradation mechanism for upcycling waste fluororubber into high-performance advanced reactive high-fluorine-content oligomers.

As illustrated in Figure 2, this study successfully upcycled waste fluororubber into a high-performance advanced reactive high-fluorine-content oligomer with tunable properties by establishing three efficient reaction systems. First, controlled oxidative degradation of waste fluororubber yielded α,ω-carboxyl-terminated low-molecular-weight fluoropolymers (CTLF). To address residual double bonds in CTLF chains, a fluorination addition system was developed, synthesizing saturated α,ω-carboxyl-terminated low-molecular-weight fluoropolymers (SCTLF) with higher fluorine content and superior thermal stability, achieving full-chain reinforcement. Subsequently, a decarboxylation-amination system converted carboxyl groups into highly reactive amino groups, producing chemically activatable α,ω-amino-terminated low-molecular-weight fluoropolymers (ATLF-Boc). By constructing an epoxy resin curing system for ATLF, efficient molding was achieved. The cured products not only exhibited performance comparable to FKM or FFKM but also, for the first time, enabled tunable surface hydrophilicity/hydrophobicity in high-fluorine-content polymer materials.

Figure 3: (a) Tunable hydrophilic-hydrophobic GTE and E51 curing systems. (b) FT-IR spectra of GTE-cured ATLF. (c) FT-IR spectra of E51-cured ATLF. (d) Comparison of contact angles and fluorine content between cured ATLF and other materials.

As shown in Figure 3, compared to other fluoropolymers, ATLF’s high fluorine content, thermal stability, and highly reactive end groups endowed its cured products with superior surface properties and adjustable hydrophilicity/hydrophobicity (43°–114°), a tensile strength of 13.3 MPa, excellent thermal stability (T_d＞350℃), and chemical resistance.

In summary, the advanced reactive high-fluorine-content oligomers developed in this study exhibit significant potential in high-end sealing materials, high-performance coatings, and other fields. Particularly in high-tech industries such as aerospace, petrochemicals, and electronics, ATLF offers innovative solutions. Crucially, this work not only achieves high-value recycling of waste fluororubber but also pioneers a novel reverse synthesis strategy for functional fluoropolymers.