The hydrophilic polypropylene/poly(ethylene-co-vinyl alcohol) hollow fiber membrane with bimodal microporous structure prepared by melt-spinning and stretching

•The hydrophilic PMEVOH-HFMs with bimodal microporous structure are prepared by MS-S.•The role of EVOH in controlling structure of PMEVOH-HFMs is elucidated.•The rejection and antifouling models of PMEVOH-HFM are established. Green and sustainable preparation of high-performance polymeric hollow fiber membranes will be more competitive in the context of advocating green manufacturing. Herein, hydrophilic polypropylene (PP)/poly(ethylene-co-vinyl alcohol) (EVOH) hollow fiber membranes (PMEVOH-HFMs) with PP grafted maleic anhydride (PP-g-MAH) as compatibilizer were prepared by melt-spinning and stretching. Due to the bimodal microporous structure of PMEVOH-HFMs, compared with PPHFM, the porosity (>80%) and pure water flux (>300% L/(m2·h)) of PMEVOH-HFMs were significantly improved, and PMEVOH-HFMs exhibted good rejection performance (>99.5%). The regulation of bimodal microporous structure was correlated with crystallization behavior of PMEVOH blends. EVOH played an important role in heterogeneous nucleation for PP phase, which could increase nucleation density of PP phase and reduce the PP spherulite size. The pore sizes of small micropores in bimodal microporous structure of PMEVOH-HFMs were lower than PPHFM, and was similar to the variation tendency of lamellae in PMEVOH hollow fibers. The pore sizes of large micropores in bimodal microporous structure was increased due to the deterioration of system compatibility. Moreover, the rejection model and antifouling model of PMEVOH-HFMs were also established in order to better understand the characteristics of bimodal microporous structure. This work provided a new idea for green and controllable fabrication of high-performance polymeric hollow fiber membranes.