【摘要】：本文以二醋酸纖維素(CA)為成膜聚合物,N-甲基-2-吡咯烷酮(NMP)和脂類(lèi)物質(zhì)LA為混合稀釋劑,聚乙二醇(PEG400)為成孔添加劑,采用復(fù)合熱致相分離法(Complex Thermally Induced Phase Separation,c-TIPS)制備了CA平板膜和CA中空纖維膜。研究凝固浴溫度和混合稀釋劑質(zhì)量比對(duì)CA平板膜結(jié)構(gòu)與性能的影響,同時(shí)探究了紡絲工藝如紡絲溫度、繞絲速度、氣隙長(zhǎng)度等對(duì)CA中空纖維膜結(jié)構(gòu)與性能的影響。通過(guò)熱處理、表面交聯(lián)等后處理手段構(gòu)建CA膜的脫鹽層,探究熱處理溫度、交聯(lián)溫度、交聯(lián)時(shí)間、醛類(lèi)物質(zhì)B溶液的質(zhì)量分?jǐn)?shù)等對(duì)CA膜結(jié)構(gòu)與性能的影響。用掃描電子顯微鏡觀察了CA膜橫截面和表面形態(tài),用電子萬(wàn)能試驗(yàn)機(jī)測(cè)試膜的拉伸強(qiáng)度,并用自制的水通量測(cè)試裝置測(cè)定了CA膜的水通量和脫鹽率,得到了本研究范圍內(nèi)最佳的鑄膜液配方、紡絲工藝和表面交聯(lián)工藝。研究結(jié)果表明,隨著凝固浴溫度提高,CA平板膜出現(xiàn)越來(lái)越多的指狀孔結(jié)構(gòu),凝固浴溫度降低到10℃,可以有效的減少指狀孔結(jié)構(gòu)。調(diào)節(jié)混合稀釋劑的質(zhì)量比,能夠控制CA平板膜的孔結(jié)構(gòu),當(dāng)NMP/LA的質(zhì)量比為8:2時(shí),制備出皮層較薄、支撐層為雙連續(xù)網(wǎng)狀孔,膜孔孔徑大小呈梯度分布的CA平板膜;進(jìn)一步優(yōu)化混合稀釋劑的質(zhì)量比,NMP/LA的質(zhì)量比為8.2:1.8時(shí),CA平板膜的形貌結(jié)構(gòu)更加完善,CA平板膜的水通量和脫鹽率分別為28.27 L/(m2·h)、15.43%,拉伸強(qiáng)度是4.05 MPa。在紡絲工藝中,提高紡絲溫度制備的CA中空纖維膜脫鹽率有一定的升高趨勢(shì),而水通量急劇下降,噴絲頭溫度為130℃時(shí),CA中空纖維膜橫截面形貌結(jié)構(gòu)變差,體系的紡絲穩(wěn)定性差;氣隙長(zhǎng)度的增加,CA中空纖維膜指狀孔變少,形貌結(jié)構(gòu)越來(lái)越完善,膜絲的水通量降低而脫鹽率升高;而提高繞絲速度,對(duì)CA中空纖維膜的脫鹽率影響較小,有助于水通量和拉伸強(qiáng)度的提高;在噴絲頭溫度100℃、氣隙長(zhǎng)度為10 cm,繞絲速度100 m/min的工藝條件下,CA中空纖維膜的水通量為15.06 L/(m2·h),脫鹽率為62.34%。為進(jìn)一步提高CA膜的滲透和脫鹽性能,構(gòu)建CA膜更加致密的脫鹽層,采用縮醛化表面交聯(lián)反應(yīng),在交聯(lián)溫度95℃、醛類(lèi)物質(zhì)B溶液質(zhì)量分?jǐn)?shù)12%、交聯(lián)時(shí)間40min的交聯(lián)工藝條件下,CA平板膜的脫鹽率為95.68%,水通量為9.85 L/(m2·h),而CA中空纖維膜的脫鹽率為83.26%,水通量為6.09 L/(m2·h),CA中空纖維膜的脫鹽性能了較大的提升。
[Abstract]:In this paper, cellulose diacetate (CA) was used as film forming polymer, N-methyl-2-pyrrolidone (NMP) and lipids (LA) were used as mixed diluents and polyethylene glycol (PEG400) as pore forming additive. The composite thermal phase separation (Complex Thermally Induced Phase Separation,) method was used. CA flat membrane and CA hollow fiber membrane were prepared by c-TIPS. The effects of coagulation bath temperature and mass ratio of mixed diluents on the structure and properties of CA flat membrane were studied. The effects of spinning process such as spinning temperature, spinning speed and air gap length on the structure and properties of CA hollow fiber membrane were investigated. The desalination layer of CA membrane was constructed by heat treatment and surface crosslinking. The effects of heat treatment temperature, crosslinking time and mass fraction of aldehyde B solution on the structure and properties of CA membrane were investigated. The cross section and surface morphology of CA membrane were observed by scanning electron microscope (SEM), the tensile strength of the membrane was measured by electronic universal testing machine, and the water flux and desalination rate of CA membrane were measured by a self-made water flux test device. The optimum casting solution formulation, spinning process and surface crosslinking technology were obtained. The results show that with the increase of coagulation bath temperature, more and more finger pore structures appear in CA flat film, and the decrease of coagulation bath temperature to 10 鈩，

本文編號(hào)：2296033