Preparation Of Waterproof And Oil-Proof Agent Based On Hemicelluloseand Its Effect On Paper

The use of petroleum-based plastic packaging materials brings about serious problems,including resource consumption and environmental pollution.Paper based materials are good substitutes for plastic products because of their biodegradability,abundant resources and recyclability.However,paper has poor water resistance and oil resistance,which limits its wide application in the field of packaging.The use of oil and water repellent is an effective strategy to improve the barrier property of paper.In this paper,hemicellulose,a by-product produced in the production process of dissolved pulp,was used as raw material to prepare bio-based waterproof and oil-proof agent and explore its influence on the waterproof and oil-proof properties of paper.(1)In order to improve the oil barrier property of paper,hemicellulose,a by-product produced in the production process of dissolved pulp,was applied to the surface of paper to prepare paper with good barrier property and mechanical strength.SEM and ATR-FTIR results showed that the polymer chains on the paper surface formed dense polymer films through hydrogen bond interaction after coating with starch and hemicellulose.When the coating amount is 6.9±0.2 g/m~2,the paper air permeability and water vapor transmittance are reduced by 93.8%and 39.7%respectively.After coated paper oil grade from 0 to 7,in line with the requirements of oil proof paper.Compared with base paper,the hydrophobicity and mechanical strength of paper are also improved.(2)In order to further improve its hydrophobicity,hemicellulose was modified by carboxymethylation and AKD.The modified product ACMHC can be self-emulsified into oil-in-water emulsion due to the electrostatic repulsion of negatively charged groups and the spatial repulsion of macromolecular groups.The ACMHC emulsion has good stability under different ionic strength(0-1 M),temperature(4-95℃),pH value(4.5-7.5)and long-term storage.In addition,the prepared ACMHC emulsion was coated on the surface of the paper to improve the barrier property of the paper.When the coating amount is 6.11g/m~2,the oil resistance grade of the paper increases from 0 to 5,and the water contact Angle increases from 36.28° to 108.53°.(3)Compound ACMHC emulsion,starch and citric acid to prepare compound waterproof and oil-proof agent.In order to explore the influence of compound waterproof and oil-proof agent on the barrier property of paper,ACMHC concentration,citric acid concentration and starch concentration on the barrier property of paper were studied respectively.Orthogonal test was used to further optimize the formulation of waterproof and oil-proof agent,and the optimal process parameters were determined as follows:ACMCH 7.5%,citric acid 20%,starch 2%.Under these conditions,the oil-proof grade of the oil-proof paper obtained is 6.The initial contact angle is 111.70±1.762°.The penetration time was 107±2.387 s.Then,based on the optimized oil and water repellent agent,the oil and water repellent properties and mechanical properties of oil and water repellent paper prepared by five different processes were explored.The results show that the method of coating the surface with waterproof and oil-proof agent has the best result,and its oil-proof grade reaches 7.The air permeability of paper decreased by 90.25%.The tensile strength and elongation at break increased by 57.71%and 68.35%compared with base paper.Waterproof performance has also been greatly improved.