黄原胶辐射接枝NVP及其对酚类物质吸附的研究

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摘要

本文以黄原胶为基材，N-乙烯基吡咯烷酮为接枝单体，利用辐射法制备了黄

原胶-N-乙烯基吡咯烷酮接枝共聚物（XG-g-NVP），研究了影响接枝共聚反应的

因素，利用红外光谱分析，热重分析，扫描电镜和 X射线衍射对接枝共聚物进行

了结构表征。利用流变仪分析了可溶性接枝共聚物的流变特性；并测定了不溶性

水凝胶的溶胀特性。通过静态吸附实验，测定了接枝共聚物吸附苯酚和多酚物质

的能力，并对其应用于茶饮料和苹果汁澄清做了初探。

研究表明吸收剂量对接枝率的影响极为显著，在黄原胶浓度及 NVP/XG 质量

比一定的情况下，接枝率随剂量的增加而增加，并逐步达到平衡；在吸收剂量和

NVP/XG 质量比一定时，接枝率在黄原胶浓度为 10 g/L 达到最大；在吸收剂量和

黄原胶浓度一定时，接枝率在质比为 10:1 达到最大值。

红外光谱研究表明接枝反应发生在 NVP 乙烯基部位，接枝共聚物保留了 NVP

的内酰胺结构。热重分析表明接枝共聚物的热稳定性得到了增强，碳化温度显著

升高。XG-g-NVP 接枝共聚物的电镜扫描图片表明，接枝后黄原胶由片状逐步变为

颗粒状，且接枝共聚物的内部为层状结构。XG-g-NVP 接枝共聚物的 X射线衍射

图谱表明接枝反应发生在黄原胶分子的侧链，且结晶度随着接枝率的增加而增加。

在低接枝率下，XG-g-NVP 共聚物保留了水溶特性，接枝共聚物的流变分析表

明接枝后黄原胶的抗高温和抗剪切的能力得到了提高。高接枝率下，XG-g-NVP

可形成水凝胶，接枝率为 623%时，其吸水能力越强，吸水速率最快，25℃下的最

大溶胀度为 62.1g/g。接枝率高于 623%时，随着接枝率的增加 XG-g-NVP 的溶胀

度逐渐下降。

XG-g-NVP 与酚类物质作用的部位发生在 NVP 的内酰胺基团。接枝共聚物吸

附苯酚的最适 PH 值为 5；吸附多酚类物质的 PH 值应控制在弱酸性环境中，PH 值

在4~6 之间。在接枝率为 623%时，XG-g-NVP 吸附酚类的量最多。苯酚和茶多酚

的浓度为 10mg/mL 时，XG-g-NVP 对其的吸附量分别为 0.76g/g 和2.85g/g。相对

于苯酚，XG-g-NVP 更容易吸附茶多酚。XG-g-NVP 对酚类的吸附符合 Freundlich

方程，吸附属于单分子层吸附，吸附过程属于物理吸附。添加少量 XG-g-NVP 即

可达到对茶汤和苹果汁澄清的目的。

关键词：黄原胶 N-乙烯基吡咯烷酮辐射接枝苯酚多酚吸附

ABSTRACT

In this paper, Xanthan gum-N-vinylpyrrolidone graft copolymer (XG-g-NVP) was

prepared by irradiation. Xanthan gum was taken as the base material and NVP was

taken as the single body. The effects of different reaction conditions on the grafting

yield were explored. The structure of the grafted copolymers was characterized by

Fourier-Transform Infrared Spectroscopy (FT-IR), Thermo gravimetric analysis (TGA),

Scanning electron microscopy (SEM) and X-Ray Diffraction (XRD). The viscosity

behavior of solution was investigated by the rheometer; and the swelling property of

XG-g-NVP copolymer was also measured. Under static conditions, grafting copolymer

property of adsorbing pHenols was studied, which could be applied in tea beverage and

apple juice's clarification.

The research showed that the absorbed dose had the significant effect on the

grafting yield. Under the certain xanthan gum concentration and NVP/XG mass ratio

situations, the grafting yield increased with absorbed dose and gradually achieved to the

balance; under the certain absorbed dose and mass ratio conditions, the grafting yield

reached maximum at the xanthan gum concentration of 10g/L; under certain irradiation

and xanthan gum concentration situations, grafting yield reached the maximum at

NVP/XG mass ratio of 10:1.

FT-IR picture showed that grafting reaction occurred in NVP vinyl part and lactam

structure was retained. Thermo gravimetric analysis showed that XG-g-NVP enhanced

thermal stability of xanthan gum and the carbonization temperature of xanthan gum

went up. SEM pHotograpHs showed that after grafting, the structure of xanthan gum

gradually became grain-like in shape from flake-like, of which the inner part was

slice-like in shape. XRD showed the crystallinity increased after grafting and the

grafting reaction may be occurred at the side chain of XG.

At low grafting yield, the XG-g-NVP copolymer's water dissolvable characteristic

was remained and viscosity behavior analysis of XG-g-NVP showed that temperature

and shear resistance of grafting copolymer was better than xanthan gum. At grafting

yield of 623%, XG-g-NVP had the best swelling property and the fastest velocity of

absorbing water, of which the swelling degree was 62.1 g/g at 25 ℃. When grafting

yield was higher than 623%, the swelling degree of XG-g-NVP was decreased as the

increase of grafting yield.

The reaction of pHenols with XG-g-NVP was taken place at the lactam group of

NVP. The most suitable pH of absorbing phenol was at pH5.0. The PH value of

adsorbing polyphenol material should be controlled in the weak acidity environment,

which pH value was at 4.0~6.0. At grafting yield of 623%, XG-g-NVP had the

maximum adsorption capacity of pHenol and tea polypHenol, which adsorption amount

were 0.76g/g and 2.85g/g respectively at the pHenols concentration of 10 mg/mL.

Compared with phenol, tea polyphenol was more easily absorbed by XG-g-NVP. The

isotherm data of absorbing phenols were fitted to Freundlich model, which means that

the adsorption was a single molecule layer adsorption and the process was a physical

adsorption. Adding a little amount of XG-g-NVP can immediately attain the purpose of

clarifying the tea soup and apple juice.

Key Word：Xanthan gum，NVP，Irradiation grafting，Phenol，

PolypHenol，Adsorption

摘要

ABSTRACT

第一章绪论.................................................................................................................1

§1.1 黄原胶的结构、性质与应用..............................................................................1

§1.1.1 黄原胶的结构 .............................................................................................. 1

§1.1.2 黄原胶的性质 .............................................................................................. 2

§1.1.3 黄原胶的应用 .............................................................................................. 2

§1.2 黄原胶接枝改性方法及研究现状......................................................................4

§1.2.1 黄原胶的化学接枝改性 .............................................................................. 4

§1.2.2 黄原胶的化学接枝改性研究现状 .............................................................. 4

§1.2.3 黄原胶的物理接枝改性 ............................................................................... 6

§1.2.4 黄原胶的物理接枝改性研究现状 .............................................................. 6

§1.3 辐射接枝简介......................................................................................................7

§1.3.1 辐射接枝基本概念 ...................................................................................... 7

§1.3.2 共辐射接枝 .................................................................................................. 8

§1.3.3 预辐射接枝 .................................................................................................. 8

§1.3.4 辐射接枝应用现状及研究成果 .................................................................. 9

§1.4 NVP 及其聚合物性能与应用...........................................................................10

§1.4.1 NVP 的结构与性质 .................................................................................... 10

§1.4.2 NVP 聚合物的性能与应用 ........................................................................ 11

§1.5 本文研究目的与研究内容...............................................................................13

第二章 XG-g-NVP 接枝共聚物的制备与表征........................................................... 14

§ 2.1 引言...................................................................................................................14

§ 2.2 材料与方法.......................................................................................................14

§ 2.2.1 实验装置与材料 ........................................................................................ 14

§ 2.2.2 实验方法与内容 ..................................................................................... 14

§ 2.2.2.1 影响接枝率的因素 ................................................................................. 14

§ 2.2.2.2 不同接枝率 XG-g-NVP 水凝胶的制备 ............................................ 15

§ 2.2.2.3 接枝共聚物结构表征 ..........................................................................15

§ 2.3 实验结果与分析 ..............................................................................................16

§ 2.3.1 影响黄原胶接枝的因素 ........................................................................... 16

§ 2.3.1.1 吸收剂量对接枝率的影响 ..................................................................16

§ 2.3.1.2 NVP/XG 质量比对接枝率的影响........................................................16

§ 2.3.1.3 XG 浓度对接枝率的影响.....................................................................17

§ 2.3.2 不同接枝率 XG-g-NVP 水凝胶的制备 ...................................................18

§ 2.3.3 接枝共聚物结构表征................................................................................................ 18

§ 2.3.3.1 接枝共聚物红外图谱扫描 .................................................................18

§ 2.3.3.2 接枝共聚物电镜扫描 .........................................................................19

§ 2.3.3.3 接枝共聚物热重分析 .........................................................................21

§ 2.3.3.4 接枝共聚物 X射线衍射分析 ............................................................ 22

§ 2.4 本章小结 ..........................................................................................................23

第三章 XG-g-NVP 接枝共聚物的物理性能 ..................................................................24

§ 3.1 引言...................................................................................................................24

§ 3.2 材料与方法.......................................................................................................24

§ 3.2.1 实验装置与材料 ........................................................................................ 24

§ 3.2.2 实验方法与内容 ..................................................................................... 24

§ 3.2.2.1 接枝共聚物表观粘度的测定 .............................................................24

§ 3.2.2.2 接枝共聚物溶胀速率曲线的测定 .....................................................25

§ 3.2.2.3 接枝共聚物溶胀度的测定 .................................................................25

§ 3.2.2.4 接枝共聚物持水能力的测定 .............................................................26

§ 3.3 实验结果与分析 ..............................................................................................26

§ 3.3.1 黄原胶-NVP 接枝共聚物流变性 .............................................................. 26

§ 3.3.1.1 接枝率对流变性的影响 .....................................................................26

§ 3.3.1.2 剪切速率对表观粘度的影响 .............................................................26

§ 3.3.1.3 温度对表观粘度的影响 .....................................................................28

§ 3.3.2 XG-g-NVP 的溶胀性能..........................................................................28

§ 3.3.2.1 接枝共聚物的溶胀速率 .....................................................................29

§ 3.3.2.2 接枝率对溶胀性能的影响 .................................................................29

§ 3.3.2.3 温度对溶胀性能的影响 .....................................................................30

§ 3.3.2.4 接枝共聚物耐盐性分析 .....................................................................30

§ 3.3.2.5 PH 值对 XG-g-NVP 溶胀性能的影响 ...................................................31

§ 3.3.3 接枝共聚物的持水能力 ........................................................................... 32

§ 3.4 本章小结 ..........................................................................................................32

第四章 XG-g-NVP 对苯酚的吸附 ..................................................................................34

§ 4.1 引言...................................................................................................................34

§ 4.2 材料与方法 ......................................................................................................34

§ 4.2.1 实验材料 ................................................................................................... 34

§ 4.2.2 仪器与设备 ............................................................................................... 34

§ 4.2.3 XG-g-NVP 对苯酚的吸附.........................................................................34

§ 4.2.3.1 苯酚标准曲线 .....................................................................................34

§ 4.2.3.2 时间对 XG-g-NVP 吸附苯酚的影响 ................................................ 34

§ 4.2.3.3 接枝率对 XG-g-NVP 吸附苯酚的影响 ............................................ 35

§ 4.2.3.4 PH 值对 XG-g-NVP 吸附苯酚的影响 ............................................... 35

§ 4.2.3.5 XG-g-NVP 吸附苯酚的红外图谱分析 .............................................. 35

§ 4.2.3.6 XG-g-NVP 吸附苯酚的热力学参数 .................................................. 35

§ 4.3 结果与分析 ....................................................................................................36

§ 4.3.1 标准曲线 ..................................................................................................36

§ 4.3.2 时间对 XG-g-NVP 吸附苯酚的影响 ..................................................... 36

§ 4.3.3 接枝率对 XG-g-NVP 吸附苯酚的影响 ................................................. 37

§ 4.3.4 PH 值对 XG-g-NVP 吸附苯酚的影响 ....................................................37

§ 4.3.5 XG-g-NVP 接枝共聚物吸附苯酚的红外分析....................................... 38

§ 4.3.6 温度对 XG-g-NVP 吸附苯酚的影响 ..................................................... 39

§ 4.3.7 吸附热力学 ..............................................................................................40

§ 4.4 本章小结 .........................................................................................................41

第五章 XG-g-NVP 接枝共聚物对多酚类物质的吸附 ..................................................43

§ 5.1 引言 ..................................................................................................................43

§ 5.2 材料与方法 ......................................................................................................43

§ 5.2.1 实验材料 ................................................................................................... 43

§ 5.2.2 仪器与设备 ............................................................................................... 44

§ 5.2.3 XG-g-NVP 对茶多酚的吸附.....................................................................44

§ 5.2.3.1 茶多酚标准曲线 .................................................................................44

§ 5.2.3.2 时间对 XG-g-NVP 吸附茶多酚吸附的影响 .................................... 44

§ 5.2.3.3 接枝率对 XG-g-NVP 吸附茶多酚的影响 ......................................... 44

§ 5.2.3.4 pH 值对 XG-g-NVP 吸附茶多酚的影响 ............................................44

§ 5.2.3.5 XG-g-NVP 吸附茶多酚的红外图谱分析 .......................................... 45

§ 5.2.3.6 XG-g-NVP 吸附茶多酚的热力学参数 .............................................. 45

§ 5.2.4 XG-g-NVP 对茶汤的澄清.........................................................................45

§ 5.2.4.1 茶汤的制备 .........................................................................................45

§ 5.2.4.2 XG-g-NVP 添加量对茶多酚含量的影响 .......................................... 45

§ 5.2.4.3 XG-g-NVP 添加量对茶汤色度的影响 .............................................. 46

§ 5.2.4.4 XG-g-NVP 添加量对茶汤浊度的变化 .............................................. 46

§ 5.2.5 XG-g-NVP 对苹果汁的澄清.....................................................................46

§5.2.5.1 苹果汁的制备 ......................................................................................46

§5.2.5.2 标准曲线 ..............................................................................................46

§ 5.2.5.3 XG-g-NVP 添加量对总酚含量的影响 .............................................. 47

§ 5.2.5.4 XG-g-NVP 添加量对绿原酸含量的影响 .......................................... 47

§ 5.2.4.5 XG-g-NVP 添加量对苹果汁色度的影响 .......................................... 47

§ 5.2.4.6 XG-g-NVP 添加量对苹果汁白利度的影响 ...................................... 47

§ 5.2.4.7 XG-g-NVP 添加量对苹果汁浊度的影响 .......................................... 47

§ 5.3 结果与分析 ......................................................................................................48

§ 5.3.1 标准曲线 ................................................................................................... 48

§5.3.2 影响 XG-g-NVP 吸附茶多酚的因素........................................................50

§5.3.2.1 时间对 XG-g-NVP 吸附茶多酚的影响 ............................................. 50

§5.3.2.2 接枝率对 XG-g-NVP 吸附茶多酚的影响 .......................................... 50

§5.3.2.3 pH 值对 XG-g-NVP 吸附苯酚的影响 .................................................51

§5.3.3 XG-g-NVP 接枝共聚物吸附茶多酚的红外分析......................................51

§5.3.4 XG-g-NVP 吸附茶多酚的等温吸附模型..................................................52

§5.3.5 吸附热力学 ................................................................................................. 53

§ 5.3.6 XG-g-NVP 对茶汤的澄清效果.................................................................55

§ 5.3.7 XG-g-NVP 对苹果汁的澄清效果.............................................................58

§ 5.4 本章小结 ..........................................................................................................62

第六章总结与展望.......................................................................................................64

§ 6.1 主要结论 ..........................................................................................................64

§ 6.2 研究展望 ..........................................................................................................65

参考文献.........................................................................................................................66

在读期间公开发表的论文和参加的科研项目.............................................................71

致谢.................................................................................................................................72

第一章绪论

§1.1 黄原胶的结构、性质与应用

§1.1.1 黄原胶的结构

黄原胶（Xanthan gum，XG）是一种天然多糖，也是一种重要的工业生物聚合

物，是碳水化合物（淀粉）经黄胞杆菌发酵而产生的胞外酸性杂多糖。20 世纪 50

年代，美国农业部伊利诺斯州皮奥里尔北部研究所(NRRL)首次发现了黄原胶， 20

世纪 60 年代开始对其进行广泛的研究[1]。

黄原胶的结构以五糖重复单元（2个葡萄糖单元，2个甘露糖单元，1个葡萄

糖醛酸单元，摩尔比为 2.8:2.0:2.0）为主链，主链类似于纤维素的结构。黄原胶结

构的独特性质在于每隔一个单元，在主链每隔一个葡萄糖残基的 O-3 位置上存在

一个三糖侧链（两个 D-甘露糖之间包含一个 D-葡萄糖醛酸）。大约一半的 D-甘露

糖终端都包含一个丙酮酸残基，丙酮酸残基通过缩酮形式与 D-甘露糖的 4位和 6

位相连；连接主链的 D-甘露糖的 O-6 处含有一个乙酰基（黄原胶的分子结构如图

1所示）。

图1-1 黄原胶的分子结构

黄原胶的平均分子量在 2×106～2×107道尔顿之间，分子量的分布取决于链与

链、几个形成聚集体的单个独立链之间的缔合作用。生产过程中发酵条件的差异

都会影响黄原胶的分子量。乙酰基和丙酮酸残基的存在使黄原胶呈现阴离子型生

物多糖[2]。三糖侧链紧密的围绕于主链结构周围，由此产生的刚性链以单螺旋、双

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摘要：

摘要本文以黄原胶为基材，N-乙烯基吡咯烷酮为接枝单体，利用辐射法制备了黄原胶-N-乙烯基吡咯烷酮接枝共聚物（XG-g-NVP），研究了影响接枝共聚反应的因素，利用红外光谱分析，热重分析，扫描电镜和X射线衍射对接枝共聚物进行了结构表征。利用流变仪分析了可溶性接枝共聚物的流变特性；并测定了不溶性水凝胶的溶胀特性。通过静态吸附实验，测定了接枝共聚物吸附苯酚和多酚物质的能力，并对其应用于茶饮料和苹果汁澄清做了初探。研究表明吸收剂量对接枝率的影响极为显著，在黄原胶浓度及NVP/XG质量比一定的情况下，接枝率随剂量的增加而增加，并逐步达到平衡；在吸收剂量和NVP/XG质量比一定时，接枝率在黄原胶浓度为10...

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