Mechanical strength citric acid

KEY WORDS citric acid, gypsum, mechanical properties, mechanism of sel retardation, microstnicture of retarded gypsum mortars, texture index, strength, creep properties... 

Recently, urea and urease inhibitor Af-(n-butyl) thiophosphoric triamide ( BTPT) were used to modify wheat straw-soy flour particleboards. Boric and citric acid, along sodium hypophosphite monohydrate, were used to modify soy carbohydrates. Particleboard bonded by urea and high concentrations of n BTPT-treated soy flour showed improved mechanical properties, whereas that bonded by boric acid-treated soy flour had better water resistance. The adhesive made from soy flour treated with 1.5M urea, 0.4 per cent n BTPT, 7 per cent CA, 4 pa- cent NaH2P02, 3 per cent boric acid, and 1.85 per cent NaOH, produced particleboard with the maximum mechanical strength and water resistance [57]. 

Modifications in order to improve starch matrix-starch nanoparticles nanocomposites were also proposed. For example, Ma et al. (2008c), proposed the fabrication and characterization of citric acid-modified starch nanoparticles/plasti-cized pea starch composites. In dynamic mechanical thermal analysis, the introduction of CA-S-NP could improve the storage modulus and the glass transition temperature of pea starch/CA-S-NP composites. The tensile yield strength and Young s modulus increased Irom 3.94 to 8.12 MPa and from 49.8 to 125.1 MPa, respectively, when the CA-S-NP contents varied fiom 0 to 4 wt%. 

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