聚丙烯酸钠/改性纳米纤维素晶体复合高吸水性树脂的制备及溶胀行为毕业论文

 2021-04-27 10:04

摘 要

聚丙烯酸钠高吸水性树脂是一类被广泛研究和应用的合成高吸水性树脂,但其存在耐盐性差、吸水速率慢、吸水后强度低等缺点,必须通过改性才能满足各种应用的需要。对高吸水性树脂进行纳米复合是目前的一种重要改性方法。纳米纤维素晶体(NCC)具有强度高、比重小、易于表面改性、与水溶性聚合物基体相容性好等优点,非常适合用于对高吸水性树脂的纳米复合改性。因此,本文开展了用改性纳米纤维素晶体对聚丙烯酸钠高吸水性树脂进行纳米复合改性的研究工作。

先用硫酸水解微晶纤维素制得纳米纤维素晶体(NCC),再用铈(Ⅳ)盐引发丙烯酰胺(AM)在NCC表面接枝聚合,接枝产物NCC-g-PAM可稳定地分散在丙烯酸钠/丙烯酸混合单体水溶液中;然后以N,N-亚甲基双丙烯酰胺作交联剂,通过光聚合制得PAANa/NCC-g-PAM复合高吸水性树脂。用红外光谱、X射线衍射分析、元素分析和粒径分析对NCC-g-PAM进行了表征,通过红外光谱、扫描电镜、溶胀实验和保水实验考察了NCC-g-PAM的添加对高吸水性树脂结构、形貌、吸水性能和保水性能的影响,结果表明:NCC-g-PAM中NCC 的晶态结构未改变,PAM的含量为59.54%。PAANa/NCC-g-PAM复合高吸水性树脂具有丰富的网孔结构,NCC-g-PAM中的PAM链与PAANa基体间形成了氢键。与PAANa高吸水性树脂相比,PAANa/NCC-g-PAM复合高吸水性树脂的吸水倍率和吸水速率均增加,吸水倍率最高可达3000 g/g,是PAANa的3.2倍,吸生理盐水倍率最高可达139 g/g,是PAANa的2.5倍。在恒定温度(60或80℃)下,PAANa高吸水性树脂比PAANa/NCC-g-PAM复合高吸水性树脂具有更高的保水率。

关键词:聚丙烯酸钠;纳米纤维素晶体;复合高吸水性树脂;吸水性能;保水性能

Preparation and Swelling Behavior of Sodium Polyacrylate/Modified Nanocrysatlline Cellulose Superabsorbent Composites

ABSTRACT

Sodium polyacrylate is a kind of synthetic superabsorbent resin, which is widely studied and applied. However, because of the poor salinity tolerance, slow water absorption rate and low strength after water absorption, it must be modified to meet the needs of various applications. Nanocomposite of superabsorbent resin is a significant modification method at present. Nanocrysatlline cellulose(NCC) has the advantages of high strength, small specific gravity, easy modification in the surface and good compatibility with water-soluble polymer matrix. It is very suitable for the nano composite modification of superabsorbent resin. Therefore, this test researches nano composite modification of sodium polyacrylate superabsorbent by the modified NCC.

NCC was obtained by the hydrolysis of sulphuric acid,acrylamide(AM) was grafted onto the surface of NCC by initiating of cerium(Ⅳ) salt to give NCC-g-PAM, which can disperse stablely in the solution of mixed sodium acrylate(AANa)/acrylic acid(AA) monomers. NCC-g-PAM was further in situ photopolymerized with AANa/AA monomers to obtain PAANa/NCC-g-PAM superabsorbent composites with N,N’-methylenebisacrylamide as crosslinker. NCC-g-PAM was characterized by IR, particle size analysis, XRD and elemental analysis. The structure, morphology ,water absorption and water retention of PAANa/NCC-g-PAM superabsorbent composites were investigated by IR, SEM,water retention test and swelling test. The results show that the crysatlline structure of NCC in NCC-g-PAM remained, and that the PAM content in NCC-g-PAM is 59.54%. The PAANa/NCC-g-PAM superabsorbent composites have rich mesh structure,and hydrogen bonds are formed between the PAM segment in NCC-g-PAM and the PAANa matrix. Water absorption capacity and water absorption rate of the PAANa/NCC-g-PAM superabsorbent composites are higher than the PAANa superabsorbent. The highest water absorption capacity of PAANa/NCC-g-PAM is 3000g/g, which is 3.2 times of PAANa. The highest normal saline absorption capacity of PAANa/NCC-g-PAM is 139g/g, which is 2.5 times of PAANa. At the constant temperature (60 or 80 ℃), PAANa/NCC-g-PAM superabsorbent composite has higher water retention than the original PAANa superabsorbent .

Keywords: sodium polyacrylate; nanocrysatlline cellulose; superabsorbent composites; water absorption; water retention

目录

1文献综述 - 1 -

1.1高吸水性树脂 - 1 -

1.1.1高吸水性树脂的定义 - 1 -

1.1.2高吸水性树脂的分类 - 1 -

1.1.3高吸水性树脂的应用 - 1 -

1.2聚丙烯酸类高吸水性树脂 - 1 -

1.2.1 聚丙烯酸类高吸水性树脂简介 - 1 -

1.2.2聚丙烯酸类高吸水性树脂的改性 - 2 -

1.3纳米纤维素晶体 - 3 -

1.3.1纳米纤维素晶体简介 - 3 -

1.3.2纳米纤维素晶体在复合高吸水性树脂中的应用 - 4 -

1.4. 本课题研究目的及意义 -5 -

2 实验部分 -6 -

2.1 试剂与仪器 - 6 -

2.1.1试剂 - 6 -

2.1.2仪器 - 6 -

2.2 样品的制备 - 6 -

2.2.1 NCC-g-PAM的制备 -6-

2.2.2 PAANa/NCC-g-PAM复合高吸水性树脂的光聚合制备 - 6 -

2.3 样品的表征 - 7 -

2.3.1 NCC和NCC-g-PAM的表征 - 7 -

2.3.2 PAANa/NCC-g-PAM复合高吸水性树脂的结构及性能表征 - 7 -

3结果与讨论 -9 -

3.1 NCC-g-PAM的制备与表征 - 9 -

3.2 PAANa/NCC-g-PAM复合高吸水性树脂的结构分析 - 11 -

3.3 PAANa/NCC-g-PAM复合高吸水性树脂的吸(盐)水性能分析 - 13 -

3.3.1交联剂MBA用量的选择 - 13 -

3.3.2 NCC-g-PAM添加量对吸水倍率的影响 - 14 -

3.3.3 NCC-g-PAM添加量对吸水速率的影响 - 15 -

3.4 PAANa/NCC-g-PAM复合高吸水性树脂的保水性能分析 - 16 -

4结 论 - 18 -

致 谢 - 19 -

参考文献 - 20 -

1文献综述

1.1高吸水性树脂

1.1.1高吸水性树脂的定义

高吸水性树脂(Super Absorbent Polymer,简称SAP)是具有高吸水性能和较高保水性能的这一类高分子聚合物的的统称,它出现于上世纪60年代,是一种具有三维网络结构的功能高分子材料。由于它本身含有强亲水性基团,可以通过水合作用等吸收自身重量数百倍至上千倍的水,它的吸水速度快,吸水倍率高,吸水后呈凝胶状且能反复吸水、脱水,还具有安全无毒的特点[1-4]

1.1.2高吸水性树脂的分类

高吸水性树脂种类繁多,可以根据不同的分类方法进行分类[5]:

(1) 按照原料来源分:淀粉系高吸水性树脂、纤维素系高吸水性树脂、合成聚合物系高吸水性树脂、共混物及复合物系高吸水性树脂。

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