邢明飞,徐萍,董丽丽,等. 废弃碳纤维预浸料DMF溶解回收及产物性能[J].河南理工大学学报(自然科学版)，doi: 10.16186/j.cnki.1673-9787.2026050006.

XING M F, XU P, DONG L L, et al．DMF solubilization and recovery of waste carbon fiber prepregs and properties of the products [J]. Journal of Henan Polytechnic University( Natural Science) ， doi: 10.16186/j.cnki.1673-9787.2026050006.

废弃碳纤维预浸料DMF溶解回收及产物性能(网络首发)

邢明飞，徐萍，董丽丽，赵丽

河南理工大学 资源环境学院,河南 焦作 454003

摘要: 目的 为解决废弃碳纤维环氧树脂预浸料经长期常温存放后，因溶剂挥发、组分持续交联引发树脂老化，造成再成型性能劣化、热压复材力学性能大幅下降的问题，采用N,N-二甲基甲酰胺（DMF）溶解法，实现预浸料中半固化环氧树脂与碳纤维的高效分离及再生利用。 方法系统考察6种常用有机溶剂的溶解特性后揭示N,N-二甲基甲酰胺（DMF）的溶解机理，并对溶剂和回收产物的循环利用性能进行全面评价。使用傅里叶变换红外光谱仪（FTIR）分析溶剂和树脂分子间的相互作用机制；扫描电子显微镜（SEM）观察回收碳纤维的微观形貌及表面树脂残留情况。加入减压旋转蒸发建立溶剂闭环回收系统，用万能试验机和碳纤维强度拉伸仪对回收树脂、单丝碳纤维以及用热压工艺重新制备的再生碳纤维增强树脂基复合材料（CFRP）板材进行力学性能测试。结果 常温放置1~4个月的废弃预浸料所制CFRP板抗弯强度和拉伸强度分别降至原始板材的19.44 %~76.15 %和44.28 %~75.04 %，而预浸料中碳纤维单丝力学性能基本不变，维持原始值的94.70 %~98.90 %。在搅拌速率40 r/min、液固比5:2 mL/g、常温溶解25 min的最优条件下，DMF对半固化环氧树脂的溶解率达98.15 %。FTIR分析可知，DMF其分子中甲酰基和N-羰基和树脂羟基及醚键形成多重氢键产生物理作用使树脂溶胀分离，不破坏树脂化学结构。经DMF处理后，回收碳纤维单丝拉伸强度和模量分别保持在原始纤维的98.2%和99.96%。DMF在90 ℃，0.1 Mpa，10 min条件下旋蒸DMF首次对数值的溶解率为97.13 %，循环使用5次后对树脂溶解率仍达90%以上。8 cm回收碳纤维丝束和新鲜树脂热压制备的再生CFRP板，拉伸强度为227.56 MPa、抗弯强度为887.31 Mpa，回收碳纤维与回收树脂制备的再生CFRP板拉伸强度为204.32 MPa、抗弯强度为815.35 MPa。结论 DMF 溶解法可高效实现废弃半固化碳纤维预浸料中树脂与碳纤维的分离再生，回收纤维、树脂结构及力学性能损伤小，溶剂可闭环循环利用；再生复合材料力学保持率优异，工艺可行、经济性好，具备良好的工程推广与资源化应用前景。

关键词: 废弃碳纤维预浸料；半固化环氧树脂；碳纤维回收；DMF溶解；再生CFRP板

doi: 10.16186/j.cnki.1673-9787.2026050006.

基金项目: 国家自然科学基金资助项目 (52370135）；河南省科技攻关项目（242102320079）

收稿日期：2026-05-07

修回日期：2026-08-06

网络首发日期：2026-08-15

DMF solubilization and recovery of waste carbon fiber prepregs and properties of the products (Online)

XING Mingfei, XU Ping, DONG Lili, ZHAO Li

School of Resources and Environment,Henan Polytechnic University,Jiaozuo 454003,Henan, China

Abstract: Objectives To address the problem that waste carbon fiber/epoxy prepreg, after long-term storage at ambient temperature, undergoes resin aging caused by solvent evaporation and progressive crosslinking of components, leading to deteriorated re-moldability and a significant decline in the mechanical properties of hot-pressed composites, this study employs a dissolution method using N,N-dimethylformamide (DMF) to achieve efficient separation and recycling of the semi-cured epoxy resin and carbon fiber from the prepreg. ,Methods  After the dissolution characteristics of six common organic solvents were systematically investigated, the dissolution mechanism of N,N-dimethylformamide (DMF) was revealed, and the recycling performance of the solvent and recovered products was comprehensively evaluated. Fourier transform infrared spectroscopy (FTIR) was used to analyze the interaction mechanism between solvent and resin molecules, and scanning electron microscopy (SEM) was used to observe the micromorphology of the recovered carbon fibers and residual resin on their surfaces. A closed-loop solvent recovery system was established by incorporating vacuum rotary evaporation. The mechanical properties of the recovered resin, single carbon fibers, and recycled carbon fiber reinforced polymer (CFRP) plates re-prepared by hot pressing were tested using a universal testing machine and a carbon fiber tensile strength tester. Results For CFRP plates fabricated from waste prepreg stored at ambient temperature for 1–4 months, the flexural strength and tensile strength decreased to 19.44%–76.15% and 44.28%–75.04% of those of the original plates, respectively, while the mechanical properties of the carbon fiber monofilaments in the prepreg remained largely unchanged, retaining 94.70%–98.90% of the original values. Under the optimal conditions of a stirring speed of 40 r/min, a liquid-to-solid ratio of 5:2 mL/g, and dissolution at room temperature for 25 min, the dissolution rate of the semi-cured epoxy resin by DMF reached 98.15%. FTIR analysis revealed that the formyl and N-carbonyl groups in DMF molecules form multiple hydrogen bonds with the hydroxyl and ether bonds of the resin, causing the resin to swell and separate through physical interactions without disrupting its chemical structure. After DMF treatment, the tensile strength and modulus of the recovered carbon fiber monofilaments were retained at 98.2% and 99.96% of those of the original fibers, respectively. When DMF was recovered by rotary evaporation at 90 °C and 0.1 MPa for 10 min, the dissolution rate of the resin using the first recovered DMF was 97.13%, and after five reuse cycles the resin dissolution rate still exceeded 90%. A recycled CFRP plate prepared by hot pressing 8 cm recovered carbon fiber tows with fresh resin exhibited a tensile strength of 227.56 MPa and a flexural strength of 887.31 MPa, whereas a recycled CFRP plate prepared from recovered carbon fiber and recovered resin showed a tensile strength of 204.32 MPa and a flexural strength of 815.35 MPa. Conclusions  It can be concluded that the DMF dissolution method can efficiently realize the separation and recycling of resin and carbon fiber from waste semicured carbon fiber prepreg. The recovered fibers and resin suffer minimal damage in structure and mechanical properties, and the solvent can be recycled in a closed loop. The recycled composites demonstrate excellent mechanical property retention, and the process is both feasible and economical, exhibiting a promising prospect for engineering dissemination and resource-oriented application.

Keywords: waste discarded carbon fiber prepreg; semi-cured epoxy resin; carbon fiber recycling;DMF dissolution; recycled CFRP plate