Synthesis and characterization of chitosan-g-poly(acrylic acid)/attapulgite superabsorbent composites Junping Zhang a,b, Qin Wang a,b, Aiqin Wang a,* Carbohydrate Polymers 68 (2007) 367–374 指導教授：林鴻儒 博士 姓名：徐楓茜 日期：

Outline Introduction Materials Experimental Results and discussion Conclusions

Introduction 親水性的網狀高分子，可把水份鎖在裡面，不易流失。像 傳統的吸水性材料如海綿，棉和紙漿等。這些高吸水性材 料廣泛的應用在衛生產品，園藝，藥物釋放，煤炭脫水， 然而這些材料都容易降解，對環境有影響。 因此 Kiatkamjornwong 等人利用親水性單體乙烯基接枝在天 然高分子澱粉及 Chitosan 側鏈上的 -NH 2 及 -OH ，使其水膠 具有吸水之性質。 現今 Chitosan 廣泛的應用於生醫材料，且具有較好的生物 相容性。 因此利用高吸水性材料丙烯酸接枝 Chitosan ，不僅可以改 善生物降解的問題，且材料也具有吸水的特點。

近年來， Clay 常應用於與吸水性材料做結合，來改善其膨 潤性質與降低成本並可加強水膠之強度。 Introduction

Material Acrylic acid (AA) ammonium persulfate (APS) N,N’-methylenebisacrylamide (MBA) Chitosan (CTS) Attapulgite (APT)

Experimental - different MW 40 ml distilled water 2 g CTS 30% H 2 O 2 (0.3, 1.0, 3.7, 9.4ml) Suspension Stirred and kept at 50 ℃, 2h Filtrated Solid Solid (washed) Washed with distilled water to pH=7 Solid Dried under vacuum at 50 ℃ Average molecular weight of CTS was determined by viscometry measurement

Preparation of CTS-g-PAA/APT 1% acetic acid solution 30ml In the 250 ml four-neck flask, equipped with a mechanical stirrer, a reflux condenser, a funnel and a nitrogen line Purged with nitrogen for 30 min to remove oxygen and heated to 60 ℃ 0.10 g APS 3.55 g AA MBA and APT 10 min The water bath, kept 60 ℃, 3h Transferred 1M NaOH aqueous solution to be neutralized to pH=7, dried in oven or dewatering agents, methanol, ethanol and acetone Use filter paper wiping off excessive dewatering agents Spread on a dish to dry overnight at room temperature Use mesh milled CTS

Results and discussion Fig. 2. IR spectra of (a) APT, (b) uncrosslinked CTS-g-PAA/APT, (c) CTS, (d) CTS-g-PAA and (e) CTS-g-PAA/APT. Weight ratio of AA to CTS is 7.2; average molecular weight of CTS is 22.9*10 4 ; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol. OH C-H COOHCOO - C-H C=O -NHCO C 3 -OH C 6 -OH Si-OH COO - -NH 2 COO - C-H

Fig. 3. TGA curves of CTS-g-PAA and CTS-g-PAA/APT. Weight ratio of AA to CTS is 7.2; average molecular weight of CTS is 22.9*10 4 ; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol ℃ ℃ ℃

Fig. 4. SEM micrographs of (a) APT, (b) CTS-g-PAA and (c) CTS-g-PAA/APT superabsorbent composite. Weight ratio of AA to CTS is 7.2; average molecular weight of CTS is 22.9*10 4 ; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol.

Fig. 6. Variation of water absorbency for the CTS-g-PAA/APT superabsorbent composite with MBA content. Weight ratio of AA to CTS is 7.2; average molecular weight of CTS is 22.9*10 4 ; APT content is 10 wt%; dewatered with methanol. Fig. 5. Variation of water absorbency for the CTS-g-PAA/APT superabsorbent with average molecular weight of CTS. Weight ratio of AA to CTS is 7.2; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol.

Fig. 7. Variation of water absorbency for the CTS-g-PAA/APT superabsorbent composite with weight ratio of AA to CTS. Average molecular weight of CTS is 22.9*10 4 ; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol. Fig. 8. Variation of water absorbency for the CTS-g-PAA/APT superabsorbent composite with weight ratio of AA to CTS. Weight ratio of AA to CTS is 7.2; average molecular weight of CTS is 22.9*10 4 ; MBA content is 2.94 wt%; dewatered with methanol.

Fig. 9. Variation of water absorbency for the CTS-g-PAA/APT superabsorbent composite with dewatering agents. Weight ratio of AA to CTS is 7.2; average molecular weight of CTS is 22.9 *10 4 ; MBA content is 2.94 wt%; APT content is 30 wt%.

Conclusion CTS, AA and APT 接枝聚合後，使用 NaOH 中和，可得到新穎的超吸水複合材料。 CTS 的 -OH, -NH 2, -NHCO 和 APT 的 -OH 會與 AA 接枝聚合成水膠。 以 TGA 和 SEM 觀察其材料可看出，添加 APT 後，可以增加材料的熱穩定性及其網狀 結構的孔洞會更加緊實。 少量的 APT 可改善 CTS-g-PAA 的吸水性。