光引发点击化学接枝聚合制备多壁碳纳米管接枝聚(N-异丙基丙烯酰胺)及对聚偏氟乙烯超滤膜性能的影响

Preparation of MWCNTs-g-PNIPAM by Photo-Initiated Click Chemical Graft Polymerization and Its Effect on Performance of PVDF Ultrafiltration Membrane

以紫外光引发的巯基-炔基绿色点击化学反应接枝聚合制备多壁碳纳米管接枝聚(N-异丙基丙烯酰胺)(MWCNTs-g-PNIPAM),通过改变接枝时间得到了不同接枝率的MWCNTs-g-PNIPAM,并通过非溶剂致相分离法(NIPS)制备了聚偏氟乙烯(PVDF)/MWCNTs-g-PNIPAM复合超滤膜。通过差示扫描量热分析和红外光谱、水接触角和水通量、场发射电子显微镜和机械拉伸试验研究了MWCNTs对PVDF超滤膜的结晶度和β相结晶含量、亲水性能、表面和断面形貌、拉伸强度和断裂伸长率的影响。结果表明,无金属催化剂的光引发点击化学在接枝时间为3 h时,PNIPAM的最大接枝率为9.76%,改善了碳纳米管与PVDF的界面结合力,使碳纳米管能够满足亲水性的同时还能在PVDF基体中良好分散。其中,β相结晶含量由纯PVDF膜的68.64%提升至95.32%,结晶度由46.30%提升至57.95%,拉伸强度与断裂伸长率分别由5.37 MPa和53.2%提升至7.85 MPa和54.32%,水接触角由95°降至69.75°,水通量由3.18 LMH提升至21.68 LMH。

Multi-walled carbon nanotubes grafted poly(N-isopropylacrylamide)(MWCNTs-g-PNIPAM)was prepared by mercapto-alkynyl green click chemical reaction graft polymerization initiated by ultraviolet light.Then,polyvinylidene fluoride(PVDF)/MWCNTs-g-PNIPAM composite ultrafiltration membranes incorporating MWCNTs-g-PNIPAM with different PNIPAM grafting degrees were prepared by non-solvent-induced phase separation(NIPS)method.The effects of MWCNTs on the crystallinity and crystallization content ofβphase,hydrophilicity,surface and section morphology,tensile strength and elongation at break of ultrafiltration membranes were studied by differential scanning calorimetryand total reflection infrared spectroscopy,water contact angle and water flux,field emission electron microscopy and mechanical tensile tests.The results show that when the graft time is 3 h by photocatalytic photocatalysis,the maximum graft rate of PNIPAM is 9.76%,which improves the interfacial bonding force between the carbon nanotubes and PVDF,so that the carbon nanotubes can meet the hydrophilicity while being well dispersed in the PVDF matrix.Among them,theβ-phase crystal content is increased from 68.64%of pure PVDF film to 95.32%,the crystallinity is increased from 46.30%to 57.95%,the tensile strength and elongation at break are increased from 5.37 MPa and 53.2%to 7.85 MPa and 54.32%,respectively,the water contact angle is decreased from 95°to 69.75°and the water flux is increased from 3.18 LMH to 21.68 LMH.