Functional Mechanism of Polymers for Papermaking : Fundamental Research Using Fluorescently Labeled Polymers.

通过向聚丙烯酰胺（PAM）水溶液中加入氯化胆碱，利用霍夫曼反应合成了含有伯胺和季胺的阳离子聚丙烯酰胺（C-PAM）。在20 ° C下60分钟后，反应完成90%。通过控制NaOH、NaOCl和氯化胆碱的相对浓度，可使C-PAM的阴离子化度达到70%以上，并可在较大范围内改变伯胺和季胺的比例。丹磺酰化C-PAM（DC-PAM）在水中的最佳激发波长为333 nm，相应的发射波长为540 nm。（B）CD恒定（1.4 meq/g），MW变化（2 × 10 *4，4 × 10 *5和8 × 10 *6）。 ...更多信息 rse聚苯乙烯胶乳（PSL）在纤维素纤维上的吸附速率与分子量和粒径无关，但由于纤维素纤维的多孔性，分子量和粒径对吸附速率有显著影响。然而，在纤维的情况下，也迅速实现了相当程度的吸附。吸附的聚合物的电荷的基板的电荷的比例进行了讨论的基础上获得的吸附等温线。荧光标记对C-PAM在PSL和纤维素纤维上的吸附性能影响不大，可能是因为C-PAM的取代度较低。对于具有最高MW的C-PAM，在PSL或纤维上没有检测到显著的交换。当使用具有最高CD的C-PAM时，在PSL和纤维两者上发生轻微交换。在PSL上，交换水平仅受置换开始前的时间（预吸附时间）的轻微影响，2小时后，解吸没有进一步减少。另一方面，在纤维上，交换的水平受到预吸收时间的显著影响，交换的程度甚至在3周后仍在继续。不同分子量的DC-PAM，在预吸附1 h时，从纤维到PSL的交换速率为中等>高>低。有趣的是，注意到具有最高MW的DC-PAM相当容易转移，考虑到对于这样的高MW的交换反应在上述PSL或纤维上不发生。聚合物的CD对聚合物转移的影响不大。当聚合物转移时，聚合物链发生断裂。转移分数近似地收敛于纤维电荷与PSL电荷的比值。少

Cationic polyacrylamides (C-PAM) which contain both primary and quaternary amines were prepared according to the Hofmann reaction by adding choline chloride to a solution of PAM in water. The reaction was 90 % complete after 60 min at 20ﾟC. The degree of aniNation was over 70 % and the proportion of primary and quaternary amines could be altered widely by controlling the relative concentrations of NaOH, NaOCl and choline chloride.C-PAM was dansylated (fluorescently labeled) in a homogeneous system using aqueous dimethylformamide as solvent. The optimum excitation wavelength for dansylated C-PAM (DC-PAM) in water was 333 nm and the corresponding emission wavelength 540 nm.Series of C-PAMs in which (a) the molecular weight (MW) was constant (4x10*5) and the charge densities (CD) varied (0.65, 1.4 and 2.5 meq/g) and (b) the CD was constant (1.4 meq/g) and MWs varied (2x10*4, 4x10*5 and 8x10*6) were prepared with and without a fluorescent label.The adsorption of these C-PAMs onto monodispe … More rse polystyrene latex (PSL) was very rapid regardless of MW and CD, but the adsorption rate onto cellulose fibers were significantly influenced by MW and CD due to the porous nature of fibers. A considerable degree of adsorption was, however, also rapidlyachieved in the case of fibers. The ratio of the charge of the adsorbed polymer to the charge of the substrate is discussed on the basis of the adsorption isotherms obtained. The fluorescent labeling had little effect on the adsorptivity of C-PAM on either PSL or fibers, probably because of the low degree of substitution.The exchange reaction of C-PAMs on PSL and cellulose fibers have been studied using with the same MW and CD except that the pre-adsorbed polymers were fluorescently labeled. For C-PAM with the highest MW no significant exchange could be detected on PSL or on fibers. When C-PAM with the highest CD was used a slight exchange occurred on both PSL and fibers. On PSL the level of exchange was influenced only slightly by the time before displacement started (pre-adsorption time), and after 2 hr there was no further reduction in deabsorption. On fibers, on the other hand, the levels of exchange were affected significantly by the pre-absorption time, and the degree in exchange continued even after 3 weeks. The rates and levels of exchange were also influenced by the MW and CD.For DC-PAM with different MWs, the rate of transfer from fibers to PSL 1 hr pre-adsorption time was in the following order, medium > high > low. It is interesting to note that DC-PAM with highest MW is transfered fairly easily considering that an exchange reaction for such a high MW does not take ple on PSL or on fibers described above. The effects of the CD of the polymer on polymer transfer were not great. When polymers transferred the cleavage of polymer chain occurred. The transferred fraction converged approximately to the ratio of charges of fibers and PSL. Less