Synthesis and characterization of chitosan-g-poly(acrylic acid)/attapulgite

superabsorbent compositesJunping 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： 98.08.14

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 -NH2 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% H2O2(0.3, 1.0, 3.7, 9.4ml)

Suspension

Stirred and kept at 50 , 2h℃

Filtrated

SolidSolid (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 40-80 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*104; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol.

OHC-H

COOH COO- C-H

C=O

-NHCO

C3-OH

C6-OH

Si-OHCOO-

-NH2

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*104; MBA content is 2.94 wt%; APT content is 10 wt%; dewatered with methanol.

381.7℃578.4℃

604.3℃

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*104; 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*104; 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*104; 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*104; 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 *104; 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, -NH2, -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。