Abstract: As a natural cellulose fiber, pineapple fiber features eco‑friendliness, biodegradability and excellent mechanical potential, which makes it an important sustainable raw material for textile industry. Non‑cellulosic gums such as pectin, hemicellulose and lignin are tightly adhered inside and on fiber surface, resulting in stiff fiber bundles, rough hand‑feel and poor cohesion, which cannot satisfy spinning requirements. Therefore, degumming is essential to remove these gums and obtain fiber bundles with appropriate length and strength, which is the primary procedure for textile application of pineapple fibers. At present, industrial degumming mainly adopts strong‑alkali boiling chemical process. Although it can remove gums effectively, it has disadvantages including high energy consumption and long treatment time. Moreover, it may degrade cellulose molecular chains and cause fiber damage and strength loss. To solve the above problems, an NHPI‑assisted Na₂CO₃/H₂O₂ synergistic catalytic oxidation degumming system was established in this paper. Sodium carbonate provides mild alkaline environment to dissolve partial gums and activate H₂O₂ to produce hydroxyl radicals (·OH). The key innovation is introducing small‑molecule organic catalyst NHPI. Under alkaline conditions, NHPI is oxidized by H₂O₂ to generate highly reactive N‑oxyl radicals (PINO) and oxoammonium cations (PINO⁺). These active species selectively oxidize non‑cellulosic components and degrade them into water‑soluble small molecules for removal. They preferentially act on C6 primary hydroxyl groups of cellulose, with little damage to β‑1,4‑glycosidic bonds of cellulose backbone. Therefore, efficient degumming is realized while protecting cellulose skeleton. Taking residual gum content and breaking strength as core evaluation indexes, single‑factor experiments were carried out to investigate the effects of process parameters, and Box‑Behnken response surface methodology was used for process optimization. The optimal conditions are as follows: Na₂CO₃ 9 g/L, H₂O₂ 7.8 g/L, NHPI 0.8 g/L, temperature 90 ℃, time 120 min. Under the optimal conditions, residual gum content is 6.86%, breaking strength reaches 4.05 cN/dtex, and the error compared with predicted values is below 2.7%. Compared with single alkali degumming, breaking strength increases by 10.1% and whiteness increases by 26.3%. SEM shows smooth fiber surface without cracks. XRD verifies well‑preserved cellulose crystalline structure with crystallinity of 58.5%. This synergistic catalytic oxidation system achieves a good balance between degumming efficiency and fiber protection, showing broad application prospect for pineapple fiber degumming.

Key words: pineapple fiber, N?hydroxyphthalimide (NHPI), collaborative degumming, response surface methodology, residual gum content, breaking strength

摘要： 为实现菠萝纤维高效、低损伤脱胶,提出一种基于 N-羟基邻苯二甲酰亚胺(N-Hydroxyphthalimide,NHPI)辅助 Na2CO3/ H2O2 的协同脱胶方法。 以残胶率和断裂强度为考察指标,通过单因素实验与响应面法对 Na2CO3 质量浓度、H2O2 质量浓度、NHPI 质量浓度、煮练温度和时间等关键工艺参数进行优化,并采用SEM 与 XRD 进行测试分析。 结果表明:最佳的脱胶工艺为 9 g / L Na2CO3 、7. 8 g / L H2O2 、0. 8 g / L NHPI、温度90 ℃ 、时间 120 min。 在此条件下,纤维残胶率为 6. 86%,与单一碱法相近;断裂强度为 4. 05 cN/ dtex,较单一 碱法提升 10. 1%。 该工艺在有效脱胶的同时,纤维素结晶结构可较完整保留。 研究结果可为菠萝纤维“高效-低损伤”协同脱胶提供有益的参考。

关键词: 菠萝纤维, N-羟基邻苯二甲酰亚胺(NHPI), 协同脱胶, 响应面, 残胶率, 断裂强度