Preparation And Study Of Hydrophobic Paper

Adding calcium carbonate fillers in paper products can save energy and cost,improve paper properties, and increase productivities. However, precipitated calciumcarbonate (PCC) fillers cannot be used in acid and pseudo-neutral papermaking andhave negative impact on sizing. In this paper, alkenyl succinic anhydride modifiedPCC were studied, and its application performance as fillers in papermaking wasexplored. The results indicate that alkenyl succinic acid modified PCC can improvethe acid-resistant property and enhance the sizing efficiency of PCC filled paper. Theoptimal modification conditions are as follows: the mass ratio of ASA to PCC is1:60;modification temperature is60℃； agitating rate and time are5000r/min and8min,respectively. In this paper, sodium alginate modified PCC were studied, and itsapplication performance as fillers in papermaking was explored. The results indicatethat sodium alginate modified PCC can enhance the sizing efficiency and tensilestrength of PCC filled paper. The optimal modification conditions are as follows: themass ratio of sodium alginate to PCC is1:140， agitating time is5min, and theamount of aluminum salt is20ml.Emulsion is the main application form of an organic silicon anjuvants. Anamino-silicone oil was emulsified and used as a sizing agent.The result shows thatwith increasing the charge amount of amino-silicone oil, the tensile strength of sizedpaper is declined while the sizing degree is improved significantly. When the amountof amino-silicone oil is accounted to0.8%of dry pulp, the sizing degree will be up to21.5s. AKD granules separating out from the absolute ethyl alcohol through the spiltphase method and depositing on the paper surface can effectively improve thehydrophobicity of paper. The static contact angle between paper and water can reach145°, which is close to the super-hydrophobic surface (the static contact anglebetween paper and water is more than150°). The type and the dosage of precipitanthave great influence on the hydrophobicity. The static contact angle is larger only asthe volume fraction of the precipitant is4%--6%based on the volume of AKDsolution in alcohol when using deionized water and silica as precipitant. The staticcontact angle decreases rapidly when the dosage is less than4%or more than6%.In order to improve the water and acid/alkaline resistance of paper, sodiumperiodate was used to oxidize the vicinal hydroxyl groups on the paper surface into formyl groups, then cetylamine was bonded on the oxidized paper by reacting withthe formyl groups. It was found that the paper handled in this way have goodhydrophobicity and acid and alkaline resistance. The sizing degree of paper is morethan600seconds even after immersed in acid or alkali solution.The static contact angle between paper and water can reflect the hydrophobicityof paper. The larger the contact angle is, the more hydrophobic the paper is. Whenthe contact angle is about140°, paper will show a super-hydrophobic-like feature.Homemade silica sol, nano-silica, nano-titanium dioxide were used respectively toconfer paper with high surface roughness, then hydrophobic agent such as aminosilicone oil, paraffin wax, vaseline, AKD were employed respectively to decrease thesurface energy of paper. Thus papers with high surface roughness, and low surfaceenergy were prepared. The static contact angle between the paper and water canreaches140°, and the paper has a very high hydrophobicity.