Preparation of a New Hydrophobic Modified Starch and Its Effect on Paper Properties

Petroleum-based compounds are widely used to enhance the hydrophobicity of paper but compromise its biodegradability. The development of biocompatible natural materials for the hydrophobic treatment of paper is of great significance. This study used corn starch (St) as raw material and prepared double-modified starch (PT-St) through dual modification of polyethyleneimine (PEI) and tetradecyl succinic anhydride (TDSA). The conditions for double modification starch were optimized through single-factor and orthogonal experiments. The effects of PT-St modified starch on the mechanical properties, hydrophobicity, and barrier properties of different paper types were studied. The results showed that the tensile index of 100% waste pulp (WEP), wood pulp (hardwood pulp: softwood pulp = 7:3) (WDP), and 100% bamboo pulp (BOP) coated with PT-St increased by 44.11%, 37.41%, and 20.39%, respectively, and the contact angle was 118.42 degrees, 120.17 degrees and 122.37 degrees, respectively. The water vapor transmission rate decreased by 35.03%, 20.32% and 21.83%, respectively. This new hydrophobic-enhanced modified starch has considerable potential application potential in food packaging paper.