Preparing Cationic Cellulose Derivative In Aqueous Solution Of NaOH/Urea And Its Performance As Filler Modifier

Filler addition,which can reduce cost,saving raw materials and improve paper properties.However,the combination between the fillers and various fibers was poor because of the natural differences of the fillers and various fibers,which caused negative effects on paper strength and sizing properties.Filler modification is a recommended procedure to improve the content of fillers in papers,promote the performance of papers and thereby promote the comprehensive quality of paper in desirable applications.In order to improve the combination between the fillers and fibers,it is of significant value to modifiy the fillers by cellulose derivatives due to the fact that there is of great compatibility and affinity between the fibers and cellulose.In this work 3-Chloro-2-hydroxypropyltrimethyl ammonium chloride(CHPTAC)and 2,3-epoxypropyltrimethylammonium chloride(EMPTAC)were used as the modifier to prepare the water soluble cellulose based cationic polymer Cellulose-CHPTAC and Cellulose-EMPTAC in NaOH/urea aqueous solution,under homogeneous conditions,respectively.The structure of Cellulose-CHPTAC and Cellulose-EMPTAC were characterized respectively using the Fourier transform infrared spectroscopy(FT IR),X-ray diffraction(XRD),nuclear magnetic resonance(1H NMR,13 C NMR and 2D-HSQC),and thermal gravimetric analysis(TGA).The results showed that DS of the Cellulose-CHPTAC and Cellulose-EMPTAC was affected by the reaction time,reaction temperature,molar ratio of CHPTAC/anhydroglucose unit(AGU),and the concentration of the cellulose.A maximal DS 0.52 was obtained under the optimal conditions: reaction temperature of 70°C,reaction time of 10 h,molar ratio of CHPTAC/AGU=9:1,and concentration of the cellulose was 3wt%.In order to make cross-linked between the cellulose based cationic polymer Cellulose-CHPTAC molecules and coated on the surface of the filler calcium carbonate,epichlorohydrin(ECH)was used as the crosslinker,and the effects of reaction time,the dosage of the Cellulose-CHPTAC and ECH,etc.were also studied.It was shown that a better improved effects can be obtained after the GCC was modified with the Cellulose-CHPTAC under the conditions: positive charge density(PCD)of the Cellulose-CHPTAC was 1.69 mmol/g,the content of cationic cellulose was 15% compared with the dosage of GCC,the molar ratio of ECH: Cellulose-CHPTAC was 6:1,modified time was 4 h,and the modified temperature was 45°C.After modified,there was some quaternary ammonium positive charge groups and hydroxyl were stayed on the surface of fillers,and the surface of fillers was rough and size of the fillers was increased to a certain extent.The modified fillers(M-GCC)was used to papermaking for studying the effect of M-GCC on the strength of papers and filler retention rate in desirable applications,and the effects of application conditions on the filling effect were also explored.The results showed that the modified calcium carbonate fillers can effectively compensate the reduction of the physical strength of the papers due to the addition of the inorganic fillers through the improvement of combation between the fibers and Cellulose-CHPTAC,while the filler retention rate was also increased to a large extent with the introduce of the quaternary ammonium positive charge groups.Furthermore,the temperature of the slurry system will have a certain effect on the filling effect of the modified calcium carbonate fillers,while the conditions of filling time and sheared force have a poor effect on paper strength and filler retention rate,and the fillers modified by Cellulose-CHPTAC could meet the high speed paper machine system.