Study On The Application Of Sodium Carboxymethyl Cellulose In Water Soluble Paper

In recent years,the demands for environment and sustainable development are put forward more often,and the lignocellulosic fiber material,as a kind of abuntant plant resource,has received wide attention in many fields because of its unique characteristics,such as low density,low cost,recyclablility and biodegradablility.As one kind of natural cellulose derivative,carboxymethyl cellulose sodium(CMC)overcomes its shortcomings of being insoluble in water and can be used as a raw material for producing water-soluble paper.However,at present,the research on the properties of CMC and the dissolution mechanism of water-soluble paper was very limited,which is extremely important for the production of water-soluble paper and improvement of its properties.Firstly,the adsorption kinetics including the first-order model and second-order model were used to analysis the water adsorption process of the handsheets based on fibrous CMC,and the dynamic contact angle and swelling ration were also determined to values the wettability of the handsheets.Experimental results revealed that the water adsorption process was controlled by the physical adsorption,which was confirmed by the pseudo-first-order model with a high correlation coefficient(R2>0.95).Meanwhile,with the increase of the degree of substitute(DS),the water absorption rate and the amount of water absorbed increased,as well as the wettability and the water absorption ability.Secondly,the process of dissolving the CMC handsheets was monitored in real time using the focused beam reflectometer(FBRM).The behavioral changes of the fibrous CMC handsheets in the process of the deconstruction and dissolving were analyzed,and their deconstruction model was established,which furthers the understanding of the CMC behavior during the dissolution of the handsheets.The results showed that with the increase of CMC DS,the dissolving rate of CMC handsheets continuously increased and the whole process could be divided into three stages.The dissolving time of the handsheets decreased from 37s to 17s when the DS of CMC increased from 0.50 to 0.80,which was caused by the increasing molecular polarity of CMC with the increasing CMC DS.Thus the dissolving ability of CMC handsheets was promoted.Finally,for the CMC chains,the cellulase will cleave only between two adjacent unsubstituted residues among the CMC chain,the enzymatic method was use to characterized the distribution of the substitution of CMC including two parameters:the average length of the substituted chain(LSn)and the average length of the unsubstituted chain(LGn).The results revealed that the CMCs obtained Lsn from 9.6 to 49.5.Its contribution was to quantify the distribution of substituents on the CMC molecular chain,which deepens the cognition of the distribution of CMC substituents on the molecular chain.At the same time,the relationship between the dissolution capacity of CMC handsheets and the distribution of their substituents was analyzed based on the dissolving model of CMC handsheets,which showed that with the increase of the Lsn of the CMC,the water penetration and spreading ability in the CMC handsheets were significantly improved.