Surface Modification Of Precipitated Calcium Carbonate(PCC) By Plant Gum Crosslinking And Its Application As Papermaking Filler

The application of papermaking fillers can improve the performance of paper,reduce the production cost and increase the drainage of furnish.The production of highly filled paper has become one of the important trends.However,the traditional filling method will lead to the negative effect on paper strength properties,so its application is limited.In this paper,organic crosslinking agents(i.e.,organic boron and organic titanium)and inorganic crosslinking agents(i.e.,boric acid and borax)were used,and several plant gums with diffirent structures(i.e.,guar gum,sesbania gum,konjac gum,tara gum,fenugreek gum and locust bean gum)were cross-linked and coated onto the surface of precipitated calcium carbonate(PCC)to prepare new modified precipitated calcium carbonate(MPCC).The resultant MPCC particles were characterized by FT-IR,XRD,XPS and SEM to reveal the modification mechanism.The MPCC particles were used as papermaking fillers,the effect of MPCC on the physical properties of handsheet and filler retention were investaged,and the optimum preparation conditions of MPCC(plant glue dosage,crosslinking agent dosage,crosslinking temperature and crosslinking reaction time)were obtained and the application performance of MPCC in the production of highly filled paper and low grammage paper was disgussed.The main conclusions are as follows:(1)Using organic titanium as crosslinking agent,guar gum,sesbania gum,konjac gum,tara gum,fenugreek gum and locust bean gum were cross-linked and coated onto the surface of precipitated calcium carbonate(PCC),respectively,and new modified precipitated calcium carbonate particles(marked as MPCC1-1,MPCC1-2,MPCC1-3,MPCC1-4,MPCC1-5 and MPCC1-6)were prepared and characterized.The optimum process conditions were obtained,and guar gum-modified PCC had the best filler effect,and MPCCi was suitable for the production of highly filled paper.(2)Using organic borox as crosslinking agent,guar gum,sesbania gum and konjac gum were cross-linked and coated onto the surface of precipitated calcium carbonate(PCC),respectively,and new modified precipitated calcium carbonate particles(marked as MPCC2-1,MPCC2-2 and MPCC2-3)were prepared and characterized.The optimim modification conditions were obtained.It was found that MPCC2 was suitable for the production of highly filled paper although its application performance was lower than that of MPCC1.(3)Using borax as inorganic crosslinking agent,guar gum,sesbania gum,konjac gum and locust bean gum were cross-linked and coated onto the surface of precipitated calcium carbonate(PCC),respectively,and new modified precipitated calcium carbonate particles(marked as MPCC3-1,MPCC3-2,MPCC3.3 and MPCC3-4)were prepared and characterized.The optimim modification conditions were obtained.It was found that was suitable for the production of highly filled paper,and the application performance of MPCC3 was lower than that of MPCC1,but was better than that of MPCC2.(4)Using boric acid as inorganic crosslinking agent,guar gum was cross-linked and coated onto the surface of precipitated calcium carbonate(PCC),and modified precipitated calcium carbonate(MPCC4)was prapared and characterized.The optimim modification conditions of MPCC4 were obtained.It was found that MPCC4 was suitable for the production of highly filled paper,and the application performance of MPCC4 was equivalent to that of MPCC3.(5)It was found through comparing the performance of the MPCC prapered with different plant gums and different crosslinking agents that the performance of the MPCC not only was related to the vicinal cis hydroxyl groups of plant gum surface,but also was affected by the steric hindrance and activity of non-ortho cis hydroxyl groups.The reaction ability of boron ion crosslinking agent was directly related to the activity of ortho cis hydroxyl groups of plant gum.The application performance of organic crosslinking agents was better than that of inorganic crosslinking agents,and the application performance of organic titanium was better than that of organic boron crosslinking agent.(6)MPCC was suitable for the preparation of highly filled paper.In the same plant gum and different crosslinking agents modified PCC,the application performance of organic titanium crosslinking agent was the best.In different plant gums and inorganic crosslinking agents modified PCC,the application performance of fenugreek gum was better.In different plant gums and organic crosslinking agents modified PCC,the application performance of sesbania gum and guar gum was better.MPCC was suitable for preparing low grammage paper.Guar gum showed better application effect when using organic titanium crosslinker.The plant gum modified PCC(MPCC)was well retained on the wire section,hence filler retention was improved.Also,the bonding ability between pulp fibers and MPCC was all enchanced and the mechanical properties of handsheet were increased.This study extended the application range of PCC in papermaking,provided a new idea for PCC modification and application,improved the theories about the utilization of MPCC in wet end.Hence,this study was possessed of important application value and research significance.