聚乙烯基吡咯烷酮催化水解反应研究
张世杰1,2 刘述梅2 赵建青 2 章明秋1 1.中山大学化学与化学工程学院,广州,510275 2.华南理工大学材料科学与工程学院,广州,
510640
尼龙6纤维(锦纶)具有耐磨、染色性好、比重轻、弹性好等许多优异的性能。
但与棉麻等天然纤维相比,吸湿性较低,穿着舒适性较差,限制了其在服装工业中的应用[1]。
为解决这个问题,人们对共聚、纤维后处理等改性方法[2,3]进行P V P 水解率(%)
反应 温 度(℃)
Fig.1 Relationship between PVP hydrolysis Fig.2 Influence of reaction time on PVP
conversion and reaction temperature hydrolysis conversion and pH value (NaOH / PVP (mol ratio)=1.25,reaction time 3h) (NaOH / PVP (mol ratio)=1.25,30℃)
从图1中看出在纳米金属催化剂存在下,随着水解反应温度的提高,原料PVP的水解转化率逐渐增大,当温度超过30℃后逐渐趋于恒定。
从图2中看出NaOH溶液加入后,随着反应时间的延长,PVP逐渐发生开环水解反应,水解率不断提高。
同时溶液碱性降低,当反应进行150min后,水解反应逐渐达到平衡状态,此时PVP水解率最高,溶液pH值最小。
以上现象符合化学反应一般规律。
Fig.4 Localization of C atoms Fig.5 13C-NMR spectra of PVP and PVP hydrolysis product in PVP molecule
从图5中看出,纯PVP分子中原有C原子对应的核磁共振峰(定位顺序如图4所示)在PVP水解产物中仍然存在,峰位无明显变化(只有C2原子对应峰向高位移动了0.6ppm),部分峰强度发生了改变,说明PVP发生了部分水解,水解产物中仍然存在PVP对应链节。
经对比发现PVP水解产物谱中δc=190.2、42.7、38.7、22.8 ppm处新出现了四个共振峰。
通过对PVP分子中各C原子在水解反应发生前后化学环境改变情况的分析,可以推断出δc=190.2 ppm处的峰对应
水解产物的分子链长度和分布没有发生明显改变,纳米金属颗粒能够对PVP水解反应产生明显的催化作用,在水解过程中PVP没有明显的降解和交联。
由于PVP水解产物每个链节中含有两个亲水基团比PVP多一个,而高分子的吸湿性能与其分子结构中所含极性亲水基团的数量成正比关系,所以PVP水解物的吸湿性明显强于PVP(经在25℃、相对湿度RH65%条件下测定:PVP的平衡吸湿率为34%,MPVP为63%)。
参考文献
1. 白桂捷.合成纤维,1989,18(1):49~56
2. US,3 654 370
3. US,341 773
4. DD,146 309
5. 张世杰等. 塑料工业,2003,31(1):33~35
Study on catalytical hydrolysis reaction of Polyvinylpyrrolidone Shijie Zhang1,2 Shumei Liu2 Jianqing Zhao2 Mingqiu Zhang1
1. School of Chemistry and Chemical Engineering ,Zhongshan University,
Guangzhou, 510275,China
2. College of Materials Science and Engineering, South China University of
Technology, Guangzhou, 510640,China
Polyamide 6 (nylon 6) fiber is widely used in the production of clothing with many merits of ductility, abradability, chromaticity, low specific density and elasticity. Due to the worse hygroscopicity and moisture penetrability, user feel bad in the use of underwear and bed linens which is produced by polyamide 6 fiber. With the merits of wide adjustable range in technology, low operational cost, blend modification has been used in fiber modification field. It represents the development tendency of polyamide 6 fiber hygroscopicity improvement.
In order to improve the hygroscopicity of PA6 blend furthermore, the hydrolysis reaction of PVP was done. In this paper metal nanoparticle was used as catalyst to make PVP hydrolyze in mild condition without the crosslinking structure yield. PVP hydrolysis product (MPVP) was obtained by using metal nanoparticle as catalyst at the room temperature, the atmosphere pressure and the basic condition. Keywords: Polyvinylpyrrolidone Catalysis Hydrolysis。